Perhaps you should try some spelling variations:
tranh nghien » trinh nghien, tron nghien, trong nghien
danh nghien » doanh nghiep, dau nghien, dung nghien
sach tranh » canh tranh
sach danh » sach dao, sach dung, sach kinh
nghien d » nghiem d, nghien o, nghiem de
so sach » so sanh, bo sach, co sach
cuu hoc » cua hoc, cuu thuoc, cuu khoa
su sach » vu sach
d hoc » du hoc, ad hoc, de hoc

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

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