Technical terms? That's hard as every field has its own vocabulary, sometimes even reusing terms from other fields to mean something completely unrelated. If you study the field, you should pick it up naturally. E.g., an introductory course will explain a great deal of the most common technical terms. Otherwise, I recommend trying to find an encyclopedia (just search for "encyclopedia of" + field name, for example if you want to read papers about birds, "encyclopedia of ornithology") and searching the web a lot.