Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van cam » van nam, van lam, van cau
truc va » thuc va, thuc vat, trung va
han mai » han tai, ban mai, han mac
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
x hoi » xa hoi, o hoi, x ho
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 sac ky nang x hoi. hieu van cam ((truc va) or (tuc xa)) han mai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky nang x hoi. hieu van cam ((truc va) OR (tuc xa)) han mai va thiet.
• Adding a wildcard symbol may retrieve word variants: tu sac ky nang x hoi. hieu van cam ((truc va) or (tuc xa)) han mai va thiet*.