Perhaps you should try some spelling variations:
vu khach » vu khanh, vu khac, vay khach
nam thuc » nam thuoc, am thuc, nam thu
ca viet » va viet, hoa viet, san viet
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
hieu ve » hieu va, hieu van
sang ma » tang ma, nang ma, sang tao
ky sang » ky nang, ky dang, ky tang
so sach » so sanh, bo sach, co sach
co viet » so viet, o viet, hoc viet
ma hoi » mai hoi, xa hoi, ma hoa
ve nam » he nam, va nam, le nam

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((vu khach) or (so sach)) ky sang ma hoi. hieu ve nam thuc va hanh vi ((ca viet) or (co viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu khach) OR (so sach)) ky sang ma hoi. hieu ve nam thuc va hanh vi ((ca viet) OR (co viet)).
• Adding a wildcard symbol may retrieve word variants: ((vu khach) or (so sach)) ky sang ma hoi. hieu ve nam thuc va hanh vi ((ca viet) or (co viet))*.