Perhaps you should try some spelling variations:
cau triet » cau trieu, su triet, cua triet
cau treo » cau theo, cau tren, cau trieu
danh hai » dang hai, lanh hai, manh hai
hieu van » hieu va, thien van, lieu va
va danh » va dinh, va dan, va hanh
tu sach » thu sach, su sach, te sach
van cam » van nam, van lam, van cau
cao hoi » cau hoi, cao hoc, tao hoi
cam tuc » cam xuc, cam tu, nam thuc
y nang » ky nang, ly nang, v nang
tuc va » thuc va, truc va, tuc xa
co hoi » co hoc, co loi

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 y nang ((cao hoi) OR (co hoi)). hieu van cam tuc va danh hai ((cau treo) or (cau triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((cao hoi) OR (co hoi)). hieu van cam tuc va danh hai ((cau treo) OR (cau triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang ((cao hoi) OR (co hoi)). hieu van cam tuc va danh hai ((cau treo) or (cau triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((cao hoi) OR (co hoi)). hieu van cam tuc va danh hai ((cau treo) or (cau triet))*.