Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
dau tren » dau tien, dat tren, dau tieng
va thanh » gia thanh, ban thanh, le thanh
hieu van » hieu va, thien van, lieu va
tai dau » tac dau, tai du, thi dau
va tinh » may tinh
tu sach » thu sach, su sach, te sach
cam tuc » cam xuc, cam tu, nam thuc
van cam » van nam, van lam, van cau
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 ((va thanh) OR (va tinh)) 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 ((va thanh) OR (va tinh)) 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 ((va thanh) OR (va tinh)) tai dau tren".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thuat sach)) ky nang o hoi. hieu van cam tuc ((va thanh) OR (va tinh)) tai dau tren*.