Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thu sach » tu sach, thuat sach, thu hoach
nang ma » tang ma, sang ma, nang cao
van cac » van cau, van bac, dan cac
van hac » van hoc, van ha, van hai
va hanh » van hanh, va thanh, va danh
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) OR (thuoc sach)) ky nang ma hoi. hieu ((van cac) or (van hac)) dat va hanh vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuoc sach)) ky nang ma hoi. hieu ((van cac) OR (van hac)) dat va hanh vi cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) OR (thuoc sach)) ky nang ma hoi. hieu ((van cac) or (van hac)) dat va hanh vi cua vat".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) OR (thuoc sach)) ky nang ma hoi. hieu ((van cac) or (van hac)) dat va hanh vi cua vat*.