Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
may nang » may nong, ky nang, cam nang
hieu van » hieu va, thien van, lieu va
van hac » van hoc, van ha, van hai
hac dat » hoc dat, tac dat, hoach dat
va hanh » van hanh, va thanh, va danh
v nang » va nang, vu nang, van nang
ma hoi » mai hoi, xa hoi, ma hoa
vi cua » vai cua, di 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 ((may nang) or (v nang)) ma hoi. hieu van hac dat va hanh vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((may nang) OR (v nang)) ma hoi. hieu van hac dat va hanh vi cua vat.
• Adding a wildcard symbol may retrieve word variants: thu sach ((may nang) or (v nang)) ma hoi. hieu van hac dat va hanh vi cua vat*.