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You are allowed to do so. In fact asking about help in finding primary and secondary sources is one of the purposes of this community.
As for the primary and secondary sources itself, it would help to narrow down what you are interested in since the secondary sources are numerous and tend to cover a variety of issues related to these experiments with the big question being whether you want to approach them from a historical perspective, specifically how these experiments fit within the history of Nazi Germany and Nazi ideology, or from a a more medical perspective, specifically discussing the ethics of engaging with these experiments and how they influenced modern medical and ethical considerations. One important provision: For a real in-depth look in secondary and especially primary sources, it pays off to be able to read German. While secondary sources in English are numerous, some of the best (which I'll discuss below) are in German and while published primary source in English do exist to a degree greater than this is the case for other subjects, any in-depth study of primary sources will eventually lead you to German documents.
With that out of the way, here it goes:
The best place to start on all of these as well as published primary sources in English is this bibliography courtesy of the USHMM, which even has the handy feature of linking to worldcat so that you can find these books in a library near you. The list is long but it mentions two standard works that deserve to be highlighted:
The late Ernst Klee (who died in 2013) was not a historian but a social worker and investigative journalist but can nonetheless be credited with reviving and pioneering the field of research into medical crimes of the Nazi regime. While the NMT doctors' trial had initially lead to great public interest in the medical crimes of the Nazi regime and had lead to various reforms of medicine ethics vis-á-vis human experiments as laid out in the Nuremberg code, it took until Klee's research in the 1980s to see renewed interest and to discover some of the full extent of these crimes.
Klee had been active in the emancipatory movement of handicapped people in the 1970s in Germany, which lead him to do his research on both Nazi medical crimes and the legacy of these crimes, mostly in form of doctors implicated in them still practicing in the 1970s/80s. In his research for the above mentioned book, which was finally published in 1997 after many years of research, Klee found and utilized sources that until that point had not been known/utilized, including the diary of Buchenwald physician Erwin Ding-Schuler and the first complete record of the Kältetagung in 1942 among them. While the book has been criticized in reviews for not utilizing earlier scholarship in English. But despite this flaw, the general consensus is that this book has advanced scholarship on the subject by many, many miles and counts among the standard work on the subject.
It is divided in sections on victims, perpetrators and medical activities and highlights one of Klee's greatest strengths: Biographical research. Klee, who also published the immensely useful Personenlexikon des Dritten Reiches is due to his journalistic background a veritable expert on digging up biographical detail of the involved doctors and goes into great detail concerning the careers of perpetrators in Nazi Germany and beyond in the Federal Republic.
Psychiatrist Robert Lifton wrote the other standard work in the field that given what sparked the recent interest in Nazi medical crimes – thanks Sam "scientific data can't be racist" Harris – is especially pertinent. Lifton's book deals only in smaller parts with the medical experiments themselves but is nonetheless a crucial read for it details the relationship between medicine, the Nazi state, and Nazi ideology in general.
Lifton through extensive interviews and source research highlights the importance of the euthanasia movement in Germany amog doctors and its staggering influence that manifested not just in the T4 killing program but also in the Holocaust itself. As Richard A. Koenigsberg in his review of Lifton's book summarizes this view:
Nazi ideology grew out of the fantasy of Germany as a gigantic organism—an actual body. Contained within this body were diseased cells threatening the life of the German organism. The Nazi’s killing projects (euthanasia, the Final Solution and war) revolved around the struggle to kill cells that were the source of defect and disease—in order to save the life of Germany. [...]
Lifton suggests that there was a single dynamic linking euthanasia, war and genocide. What’s more, he claims it was no accident that Hitler’s decree authorizing the destruction of life unworthy life was backdated to September 1, 1939—the date of Hitler’s declaration of war. Perhaps the killing of defective human beings, Jews, enemy soldiers, enemy civilians, German soldiers and German civilians represented a single purpose: the sacrifice of individuals for the “good of the state.” Nazism enacted—in a radical way—the idea that states have a “right to kill.”
A third work that is too recent to have already become a standard work on the subject that deserves a mention nonetheless is
Weindling is one of the foremost experts on the history of medicine in Nazi Germany and has previously written a triology of books that detail the evolvement of medicine and its social context in Germany from the 19th to the middle of the 20th century. In this book however he focuses specifically on the Nazi medical experiments. While some reviews have found it somewhat cumbersome, the fact that it is structured with each individual experiment receiving a section can make it a useful work in learning more about the experiments specifically. Though i too have found that doing it this way leads to some suffering of the scholarship because it doesn't leave enough space for the context, it can be useful as a reference work for specific experiments.
With these books all mentioned, let's talk about primary sources:
As you'll notice the book list by the USHMM includes several published primary source collections, among them Bernadac, Christian. Devil’s Doctors: Medical Experiments on Human Subjects in the Concentration Camps. Geneva: Ferni Publishing House, 1978; Koch, Peter-Ferdinand. Menschenversuche: die tödlichen Experimente deutscher Ärzte. München: Piper, 1996.; Nyiszli, Miklos. Auschwitz: A Doctor’s Eyewitness Account. New York: Fawcett Crest, 1961.; and Shelley, Lore. Criminal Experiments on Human Beings in Auschwitz and War Research Laboratories: Twenty Women Prisoners’ Accounts. San Francisco: Mellen Research University Press, 1991. – all very useful for historical researchers.
Further primary sources can be found at the Harvard Law School's online portal on the IMT and NMT trials. They do have, among other things, the complete transcript of NMT case v. Karl Brandt et. al., better known as the Nuremberg Doctor's Trial and have put a variety of the Nuremberg documents online, some of which directly concern the medical experiments.
One thing concerning the primary sources on Nazi medical experiments that is rather crucial and must be highlighted however is the simple fact that due to the destruction of documents near the end of the war, the raw data of these experiments is pretty much lost. The evidence for these experiments comes from synthesized reports of Nazi doctors to their superiors and to Himmler, from eye witness testimony, research grants by the SS and documentation from the Concentration Camps itself, while the raw data generated in these experiments and noted by the doctors who conducted these experiments is pretty much lost to historical research.
This is among the reasons why stuff like Sam Harris going on about the "truths" discovered during these experiments or people on this forum constantly citing the Dachau hypothermia experiments by Rascher as something that produced "useful" science is such a misconception of epic proportions. When discussing the Dachau experiments on hypothermia, one of the first things Robert Berger points out in his article on the subject is that what survives is a "a 56-page comprehensive report to Himmler on the Dachau experiments, signed by Drs. Holzloehner, Rascher, and Finke and dated October 21, 1942" but not the data that report is based on.