Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
hieu van » hieu va, thien van, hieu ve
cau tren » cu tren, dau tren, ca tren
nam tuc » nam thuc, nam truc, nam tu
va dinh » van dinh, va kinh, va tinh
dinh ve » dinh ket, dinh van
tuc va » thuc va, truc va, tuc xa
ve cau » ke cau, va cau, ve cac

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu cac) or (thuat sach)) ky nang x ho. ((hieu van) OR (lieu va)) nam tuc va dinh ve cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cac) OR (thuat sach)) ky nang x ho. ((hieu van) OR (lieu va)) nam tuc va dinh ve cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu cac) or (thuat sach)) ky nang x ho. ((hieu van) OR (lieu va)) nam tuc va dinh ve cau tren".
• Adding a wildcard symbol may retrieve word variants: ((tu cac) or (thuat sach)) ky nang x ho. ((hieu van) OR (lieu va)) nam tuc va dinh ve cau tren*.