Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh tai » thanh tai, hang tai, han tai
vanh tai » van tai, anh tai, vanh dai
cau luc » cau truc, cau phuc
van cau » van dau, van hau, van chat
tu sach » thu sach, te sach, tu cach
nang ma » tang ma, sang ma, nang cao
ty nang » ky nang, ty xang, ty hang
su sach » so sach, vu sach
ma hoi » mai hoi, xa hoi, ma hoa
luc va » duc va, tuc va, loc va
thiet » thieu

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 (su sach)) ty nang ma hoi. hieu van cau luc va ((vanh tai) or (hanh tai)) va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ty nang ma hoi. hieu van cau luc va ((vanh tai) OR (hanh tai)) va thiet.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ty nang ma hoi. hieu van cau luc va ((vanh tai) or (hanh tai)) va thiet*.