Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
thanh tai » thanh hai, thanh toan, doanh tai
dau tren » dau tien, dat tren, dau tieng
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
tai dau » tac dau, tai du, thi dau
cam tuc » cam xuc, nam thuc, dam thuc
tu sach » thu sach, su sach, te sach
cam tu » cam thu, nam tu, dam tu
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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

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