Perhaps you should try some spelling variations:
hanh dai » hanh tai, hanh dao, vanh dai
sach thu » sach thue, sach thieu, sach tham
thuc dan » thuc hanh, hoc dan, thuc vat
hieu van » hieu va, thien van, lieu va
van bao » van ban, van dao
sach ty » sach y, sach tu, xach tay
nang xa » nang x, lang xa, nang ma
luc va » duc va, tuc va, loc va
cua te » cua tu

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 ty) OR (sach thu)) nang xa hoi. hieu van bao ((luc va) or (thuc dan)) hanh dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ty) OR (sach thu)) nang xa hoi. hieu van bao ((luc va) OR (thuc dan)) hanh dai cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ty) OR (sach thu)) nang xa hoi. hieu van bao ((luc va) or (thuc dan)) hanh dai cua te*".