Perhaps you should try some spelling variations:
cheng guan » cheng han, thong guan
human gene » human genome, human gender, human bone
cheng yan » cheng han, chen yang, zhang yan
gene yang » gene bank
yang thi » dang thi, yang chik, yang di
thi hong » tan hong
hong yu » wong yue

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: yuan ((cheng yan) OR (cheng guan)) human gene yang thi hong yu ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "yuan ((cheng yan) OR (cheng guan)) human gene yang thi hong yu ;*".