For your PubMed Article Assignment, remember to NOT use Review/Systematic Reviews as article types. Also, if you add the keyword United States to your search string, that will help find articles written by authors in the USA.
Sometimes (due to term mapping or truncation) PubMed searches for terms that you did not intend. The Search Details feature allows you to see what is actually being searched, which is sometimes different from what you entered.
To access the Search Details for one of the lines in your History, click the downward arrow under the "Details" column. This will expand the fields to show you all the different terms searched in that line.
In the search below, the only terms entered were lung cancer (no quotes):
Instead of only searching for the phrase lung cancer, PubMed also searched for "lung neoplasms"[MeSH] as well as other synonyms. These additional terms were searched because of PubMed's term mapping. If the phrase had been entered as "lung cancer" the term mapping would have been disabled.
The Search Details feature is one of the most powerful advanced search features in PubMed.
