Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
cac truc » cau truc, cac tru, cac trung
hieu ve » hieu va, hieu van
truc va » thuc va, thuc vat, trung va
va hanh » van hanh, va thanh, va danh
ve cac » va cac, vien cac
vi cua » vai cua, di cua
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: hoc sach y ((nang x) or (nang cao)) hoi. hieu ve cac truc va hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach y ((nang x) OR (nang cao)) hoi. hieu ve cac truc va hanh vi cua te*.