Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
thu sach » tu sach, thuoc sach, thu hoach
va thanh » ban thanh, va tinh, le thanh
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
tac dat » tac da, tac dao, tac dau
ma hoi » mai hoi, xa hoi, ma hoa
va tac » va cac
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 (thuat sach)) ky nang ma hoi. hieu va tac dat ((va thanh) OR (gia thanh)) vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuat sach)) ky nang ma hoi. hieu va tac dat ((va thanh) OR (gia thanh)) vi cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (thuat sach)) ky nang ma hoi. hieu va tac dat ((va thanh) OR (gia thanh)) vi cua vat".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (thuat sach)) ky nang ma hoi. hieu va tac dat ((va thanh) OR (gia thanh)) vi cua vat*.