Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh dai » hanh tai, hanh dao, vanh dai
thuc dan » thuc hanh, hoc dan, thuc vat
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
van cac » van hac, van cau, van bac
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
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 ky ((nang xa) OR (nang ma)) hoi. hieu van cac ((luc va) or (thuc dan)) hanh dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang xa) OR (nang ma)) hoi. hieu van cac ((luc va) OR (thuc dan)) hanh dai cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang xa) OR (nang ma)) hoi. hieu van cac ((luc va) or (thuc dan)) hanh dai cua te*".