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
cao hoi » cau hoi, co hoi, cao hoc
cac dat » cai dat, cac dai, cac dac
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 cao hoi. hieu van ((((cac dat) OR (cac dan))) or (can dai)) van hanh vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach ky nang cao hoi. hieu van ((((cac dat) OR (cac dan))) OR (can dai)) van hanh vi cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach ky nang cao hoi. hieu van ((((cac dat) OR (cac dan))) or (can dai)) van hanh vi cua vat".
• Adding a wildcard symbol may retrieve word variants: thuat sach ky nang cao hoi. hieu van ((((cac dat) OR (cac dan))) or (can dai)) van hanh vi cua vat*.