Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
su tien » su kien, su hien, tu tieng
ve cam » ve cham, ve cac, va cam
cam tu » cam thu, nam tu, dam tu
x hoi » xa hoi, o hoi, x ho
vi su » va su, ve su, ki su

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) ky nang x hoi. hieu ve cam tu va hanh vi su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky nang x hoi. hieu ve cam tu va hanh vi su tien*.