Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
sach thu » sach thue, sach thieu, sach tham
hieu van » hieu va, thien van, lieu va
nang ma » tang ma, sang ma, nang cao
ban dat » ban dan, dan dat, ban dau
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach thu ((nang ma) or (mang may)) hoi. hieu van ban dat va hanh di cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach thu ((nang ma) OR (mang may)) hoi. hieu van ban dat va hanh di cua vat.
• Adding a wildcard symbol may retrieve word variants: thu sach thu ((nang ma) or (mang may)) hoi. hieu van ban dat va hanh di cua vat*.