Scientific research emerges through analyzing data collected in experiments and observation. Researchers develop a research plan, which is rooted in identifying a question and possible answers and designing a program to test those answers. Almost certainly, this is not the first experiment or observation to answer the question; other researchers have worked on it, too. Instead, this set of experiments and observations provides a new design and offers a new interpretation of the data as part of a large conversation with researchers in the past and researchers on other continents, also offering new questions to future researchers.
Though new scientific research happens in the stages of experimentation and observation, it requires a knowledge of the conversation that has been happening all around it. Scientific fields are open to new interpretations, but they require new research to acknowledge existing research. In order to find these materials, you'll need to find both original research articles as well as scholarly reviews. Your research design may be identical to something another research did, but your interpretation of the data and the results may be significantly different. Alternately, you may create a completely different design to respond to the same question, as a way to find different results. But only by finding research that already exists can you expand the field.
Original research is new scholarship written to expand a field of knowledge. In the sciences, original research usually involves collecting data through experiments and observation to answer an important research question. Sometimes referred to as primary resources, original research is the first place the study has been discussed.
Review articles are discussions of the state of the field at the time the review was written. For example, climatologists in 2018 want to know about studies of glacial ice in the past twenty years, so they can avoid duplicating studies, and so they can position their own work to make a meaningful contribution to climate science. Review articles discuss many different studies, explaining how the field has changed, what areas the field has addressed thoroughly, and what areas of study are still missing.
A librarian can help you refine your search results to one of these.
Some resources for searching broadly within the sciences:
Use these resources to find books, both in Milne Library and from other universities.