Perhaps you should try some spelling variations:
trinh nghien » trinh nghe, kinh nghiem, trinh thiet
thai nghien » thai nguyen, thi nghiem, phap nghien
sach trinh » sach tranh, hanh trinh, sach kinh
khach thai » khach trai, khac trai, nhanh thai
nghien dau » nghiem dau, nghiep dau, nghiep cau
tu khach » vu khach, tu hach, cua khach
te sach » toc sach
cuu hoc » cua hoc, cuu thuoc, cuu khoa
dau hoc » dai hoc, du hoc, dan hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( te sach trinh nghien cuu hoc ) or ( tu khach thai nghien dau hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach trinh nghien cuu hoc ) OR ( tu khach thai nghien dau hoc ))*.