Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
nam truc » nam truoc, nam thuc, nam trung
truc van » truc va, thuc van, truc ban
van hanh » van thanh, ban hanh, van anh
cau tren » dau tren, ca tren, cau treo
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
cao hoi » cau hoi, co hoi, cao hoc
cu tren » tu tren, dua tren

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky nang cao hoi. hieu van nam truc van hanh vi ((cau tren) or (cu tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang cao hoi. hieu van nam truc van hanh vi ((cau tren) OR (cu tren)).
• Adding a wildcard symbol may retrieve word variants: so sach ky nang cao hoi. hieu van nam truc van hanh vi ((cau tren) or (cu tren))*.