Perhaps you should try some spelling variations:
trinh nghien » trinh nghe, kinh nghiem, trinh thiet
tranh nghien » tron nghien, trong nghien, truong nghien
sanh trinh » hanh trinh, anh trinh, sinh trinh
duoc hoc » quoc hoi
nghien d » nghiem d, nghien o, nghiem de
tu canh » thu canh, tu chanh, tu can
so sanh » do sanh
de hoc » te hoc, du hoc, dien hoc
d hoc » du hoc, ad hoc, y hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu canh tranh nghien ((de hoc) or (duoc hoc)) ) or ( so sanh trinh nghien d hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu canh tranh nghien ((de hoc) OR (duoc hoc)) ) OR ( so sanh trinh nghien d hoc )).
• Adding a wildcard symbol may retrieve word variants: (( tu canh tranh nghien ((de hoc) or (duoc hoc)) ) or ( so sanh trinh nghien d hoc ))*.