It really depends on your idea of a "positive" thing. I don't know much of science, so I will let someone educated in science discuss Nazi technology in that area. I am, however, versed in Aircraft and Armaments from Nazi Germany, and as such I'll mention a few things the Germans brought about which had profound effect on the cold war, and arguably still today.

1. Jet Propulsion. One of Germany's pioneering achievement, was ushering in the beginnings of the Jet Age. Germany had the first ever aircraft to fly under turbojet power, namely the Heinkel He 178, and also Germany had put forward the first operation Jet fighter with the Messerschmitt Me262 'Schwalbe' (Swallow) (Note, this link shows a little reaction from B-17 crews.. quote "What was that!? What the hell was that!? it went by like we were standing still!") . I'd put these far ahead of what the allies had at the time, namely the USAAF's P-80 Shooting Star, and the only allied jet that saw WW2 service, albeit limited, the RAF's Gloster Meteor.

The Me262 was equipped with Junkers Jumo 004 jet engines, which was ahead of it's time really. Due to the stages of the war, the engines generally had 10-25 hours of service time & frequently burned holes through as the steel wasn't high enough quality. Skilled pilots who knew more about the jet itself could perhaps squeeze a bit more life out of their plane, but the Luftwaffe's habit of keeping aces on the front generally lead to most of their able pilots dead before they could get into jets. Another interesting fact of the Me262 is that it (debated by historians) is the first plane to feature a 'Swept Wing' of around 18.5°, which again was quickly decided to be the correct wing platform.

I can show you this visually from both Soviet & USAF designs -

Soviet -

MiG 9 (1946) > MiG 15 (1947)

USAF -

F-84 'Thunderjet' (1946) > F-86 'Sabre' (1947)

Another mention would be the Arado 234, another German 'worlds first', but this time a jet bomber. Again, it suffered from the same problems that plagued the 262 due to incessant interfering from Hitler, and the same problems from the powerplants as it shared the Jumo 004 engines. Despite being too late in the war, the design team went on after being captured by the soviets, producing a prototype improved Arado 234 model in '47, and also assisting to produce the first Soviet jet bomber - the Ilyushin Il-28 'Beagle'.

These failures and problems that arose from German Jet Production were fixed by the allies post-Operation Paperclip. Frank Whittle already invented the jet engine, but Germany was the first to actually produce an engine, designed by Dr. Hans von Ohain. As such, Germany had to fight technical problems, which considerably helped the Allies in later war designs, as most of the serious issues had been at least investigated and solutions provided, or actually fixed.

1. Rocket Propulsion. Germany developed the first ICBM (Inter-Continental Ballistic Missile) with the Vergeltungswaffe 2, or V-2 Rocket. Designed by famous rocket scientist, Wernher von Braun, and also part of the 'Vengeance' series, they had Devastating effect when they found their target. They were hideously costly ($3,000,000,000 for all ~1945 dollars, the Manhattan project only cost $1,900,000,000 and produced nuclear weapons!) and often missed due to British misinformation, but the technology itself was exceptional. Unlike it's predecessor the V-1, the V-2 had no sound before the impact, it flew faster than the speed of sound. This meant it was ridiculously hard to defend against - you only heard it after the impact. I feel the technology wasn't supported by other advances however - Yes, Germany got a missile into orbit, yes, they were ridiculously powerful, but guidance systems were very, very poor in comparison in 1945, and if the missile cannot hit, it's useless. Also - fuel. It took 30 tonnes of distilled potatoes turned to alcohol fuel to launch a V2, which towards 1944, Germany was struggling to eat, so this was another blow. Back on topic, the V2 was a very, very advanced ballistic package, but other technology held it back. The team of the V2 and other ballistic systems got sent to the USA post-WW2 via Operation Paperclip.. and guess where they ended up? I'll give you a hint.

Another interesting rocketry project, is the Me 163 'Komet' - to date, the only fighter aircraft to be wholly powered by rocketry. It was basically an interceptor - quick launch, rapid climb, take out enemy fighter/bombers then quickly land to rearm. Here's a link to it's takeoff. Whilst the Komet doesn't have much carry-on into allied weaponry, it's still a very interesting branch of technology to come out of Nazi Germany.

1. Anti-Ship, Air-to-Air, And Surface-to-Air Missiles.. Yup. I said it. Germany had produced all of these things first. Firstly - the Anti-ship Missile. Germany had 2 Anti-ship missiles produced - the Henschel Hs 293 and the 'Fritz-X' missile systems ready for around ~1943. The Hs 293 was a radio-controlled glide bomb powered by the same powerplant as the Me163 Komet I mentioned earlier. It was an MCLOS system - Manual Command to Line of Sight - meaning the operator had to guide the missile to the target manually, and required a Line of Sight on the target for accurate guidance. It was designed to knock out lightly-armoured vessels, and had relative success - the biggest loss-of-life being one HS 293 which sunk the troop transport HMT Rohna, which had over 1,000 men aboard who all perished.

The 'Fritx X' system was the bigger brother of the Hs 293. Rather than light-armour, the Fritz-X was designed to pierce heavily armoured battleships and cruisers. It was controlled by the same system as the Hs 293 - Funkgerät (FuG 203) Kehl -and saw limited service under Kampfgeschwader 100 'Wiking'. [This is the aftermath of a Fritz-X direct hit on the Savannah] (http://upload.wikimedia.org/wikipedia/commons/a/aa/USS_Savannah_%28CL-42%29_is_hit_by_a_German_guided_bomb%2C_off_Salerno%2C_11_September_1943.jpg). The bombs worked well when they scored a direct hit - One put the HMS Warspite out of action for 9 months - it penetrated 6 decks through the ship, and detonated inside Boiler Room No#4. Here's a German WW2 produced video about the Fritz X.

SAM's. Germany, again, had the first, and SAM's are still an essential part of anti-air coverage today. Germany produced the Wasserfall Ferngelenkte FlaRakete, or the Waterfall Remote-Controlled A-A Rocket. Similar to the V2, but around 1/4 the size and rather than a 2,000kg warhead, it carried a 306kg Flak warhead designed to explode mid-air. This warhead would spread shrapnel into Allied bomber wings, decimating them. It was guided by a (now) primitive, but fairly advanced 'Rheinland' Radar system, of which was later trialled on the V2 system. Again, the design team got shipped off to the USA and began working on Project Nike - the US' post 1945 guided SAM project.

Air-to-Air missiles, now a vital and totally indispensable part of design for Aircraft, originated in.. once again, Nazi Germany. The Ruhrstahl X-4, despite not being used in actual operational service, was designed as a wire-guided AA missile. Since it was wire-guided, it was fairly unsuited to fast-paced air-to-air duels, so the British especially took the concept and turned it into what we have today as TOWs. The British/Australian Malkara used quite a bit of research from the X-4, and from them improvements were made to the concept.

1. Stealth. The Horten Ho 229 was the first flying wing with jet engine propulsion, and has been cited as the first steps towards a 'stealth bomber', due to it's similarity in looks to the American B-2 Spirit. It had some ~80% less radar signature than the BF 109, and was predicted it could be over London and drop its payload, only having been detected by radar some ~5 minutes before it could drop it's load. This made it incredibly hard to intercept, coupled with it's speed of ~600mph, only jets could intercept it. The work that went into the Ho 229 by the Horten Brothers would definitely have been studied by Northrop Grumman, who produced the YB-49 Flying Wing. The Skunk Works, Lockheed's development centre for Stealth aircraft such as the U-2, SR-71, F-117 & the F-22 have reportedly been down to view the Ho 229 in person at the National Air & Space Museum. It's impossible to accurately say how much influence went into the B-2 & Flying Wing prototypes, but since the Ho229, Northrop produced a lot more flying wings.

Sources:

J.R. Smith, Antony L. Kay, E.J. Creek. German Aircraft of the Second World War. London: Putnam, 1985. 44.

Fitzsimons, Bernard, general editor. The Encyclopedia of 20th Century Weapons and Warfare (London: Phoebus Publishing Company, 1978), Volume 24, p.2602-3, "X-4, Ruhrstahl".

Myhra, David. The Horten Brothers and Their All-wing Aircraft. London: Bushwood Books, 1997

Neufeld, Michael J (1995). The Rocket and the Reich: Peenemünde and the Coming of the Ballistic Missile Era. New York: The Free Press