Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
sach thu » sach thue, sach thieu, sach tham
hieu van » hieu va, thien van, lieu va
van pham » san pham, van phan, van phat
vat hanh » vat thanh, van hanh, va hanh
hanh vai » hanh vi, hanh va, hanh tai
co sach » bo sach, cuon sach, hoc sach
nang ma » tang ma, sang ma, mang may
vai cua » dai cua, hai cua, lai cua
cua tu » cua tuc, cua su, cua cu

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

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