Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
cac dat » cac dan, cac dac, cac hat
cac dai » cac dan, cac bai, can dai
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: thuat sach ky nang ma hoi. hieu van ((((cac dat) OR (cai dat))) or (cac dai)) van hanh vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach ky nang ma hoi. hieu van ((((cac dat) OR (cai dat))) OR (cac dai)) van hanh vi cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach ky nang ma hoi. hieu van ((((cac dat) OR (cai dat))) or (cac dai)) van hanh vi cua vat".
• Adding a wildcard symbol may retrieve word variants: thuat sach ky nang ma hoi. hieu van ((((cac dat) OR (cai dat))) or (cac dai)) van hanh vi cua vat*.