Perhaps you should try some spelling variations:
thanh cau » thanh chau, thanh mau, nhanh cau
sach thu » sach thue, sach tham, cach thuc
nam thuc » nam thuoc, am thuc, nam thu
vat hanh » vat thanh, van hanh, va hanh
hanh tai » thanh tai, hang tai, han tai
so triet » su triet, so thiet, bo triet
qua nam » quan nam, cua nam, quang nam
tai so » tai sao, dai so, tai co

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach thieu) or (sach thu)) thanh cau hoi. hieu qua nam thuc vat hanh tai so triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach thieu) OR (sach thu)) thanh cau hoi. hieu qua nam thuc vat hanh tai so triet.
• Adding a wildcard symbol may retrieve word variants: tu ((sach thieu) or (sach thu)) thanh cau hoi. hieu qua nam thuc vat hanh tai so triet*.