Perhaps you should try some spelling variations:
trinh thiet » trinh viet
tham nghiem » trac nghiem, thuc nghiem, thi nghiem
nghiem ban » nghiem van, nghiem xuan, nghiep bang
trinh thi » trinh tai, dinh thi, trinh tu
sach tham » sach nha
te sach » toc sach
tu sach » thu sach, su sach, tu cach
ban hoc » bang hoc, van hoc, bai 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 thiet) or (trinh thi)) dai hoc ) or ( tu sach tham nghiem ban hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach ((trinh thiet) OR (trinh thi)) dai hoc ) OR ( tu sach tham nghiem ban hoc )).
• Adding a wildcard symbol may retrieve word variants: (( te sach ((trinh thiet) or (trinh thi)) dai hoc ) or ( tu sach tham nghiem ban hoc ))*.