Perhaps you should try some spelling variations:
va trien » va truyen, va thiet, va tuyen
va hanh » van hanh, va thanh, va danh
cam duc » cam xuc, cao duc, pham duc
hieu va » lieu va, hieu qua
su sach » vu sach
nang xa » nang x, lang xa, mang xa
so sach » so sanh, bo sach, co sach
nang ma » tang ma, sang ma, nang cao
va cam » va cham, va cac, va cao
vi va » vi van, vai va, vu va

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (so sach)) ty ((nang xa) or (nang ma)) hoi. hieu va cam duc va hanh vi va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) ty ((nang xa) OR (nang ma)) hoi. hieu va cam duc va hanh vi va trien.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) ty ((nang xa) or (nang ma)) hoi. hieu va cam duc va hanh vi va trien*.