Perhaps you should try some spelling variations:
trinh nghien » trinh nghe, kinh nghiem, trinh thiet
nghien thuoc » nghiem thuoc, nghiem thuc, nghiep thuc
sach trinh » sach tranh, hanh trinh, sach kinh
xa nghiem » xet nghiem, van nghiem, va nghien
thuoc hoc » thuoc ho, thuoc nhom, thuong hoc
su sach » so sach, vu sach
sach xa » sach dao, sach nha, sach bai

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

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