Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
va trien » va truyen, va thiet, va tuyen
vu sach » vu bach, su sach, vu khach
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
cac vuc » cac nuoc, cac vung, cac cuoc
vuc van » duc van, luc van, thuc van
ve cac » va cac, vien cac
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: ((toc sach) or (vu sach)) ky nang xa hoi. hieu ve cac vuc van hanh vi va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (vu sach)) ky nang xa hoi. hieu ve cac vuc van hanh vi va trien.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (vu sach)) ky nang xa hoi. hieu ve cac vuc van hanh vi va trien*.