Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
sach ty » sach y, sach tu, sach thu
duc van » duc va, duc tan, duc manh
hoc duc » hoc duoc, hoc nuoc, hoc thuc
hieu va » lieu va, hieu qua
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
sach uu » sach luu, sach tu, sach xu
va hoc » van hoc
vi cua » vai cua, di cua
cua su » qua su

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

• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ty) OR (sach uu)) ((nang ma) OR (tang ma)) hoi. hieu va hoc duc van hanh vi cua su~.
• Adding a wildcard symbol may retrieve word variants: te ((sach ty) or (sach uu)) ((nang ma) or (tang ma)) hoi. hieu va hoc duc van hanh vi cua su*.