Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, van anh, van ban
ban hanh » ban hang
nang xa » nang x, lang xa, nang ma
sach ky » sac ky, sach y, sach ty
di cua » dai cua, doi cua, de cua
ve cac » va cac, vien cac
ve cam » ve cham, va cam, ve cai
cua te » cua tu

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: toc sach ky nang xa hoi. hieu ((ve cam) OR (ve cac)) duc ((van hanh) OR (ban hanh)) di cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky nang xa hoi. hieu ((ve cam) OR (ve cac)) duc ((van hanh) or (ban hanh)) di cua te~".
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang xa hoi. hieu ((ve cam) OR (ve cac)) duc ((van hanh) or (ban hanh)) di cua te*.