Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
cac vo » cac co, cac vi, cac bo
vi cua » vai cua, di cua
cua te » cua tu

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 xa) or (lang xa)) hoi. hieu ve cac vo van hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky ((nang xa) OR (lang xa)) hoi. hieu ve cac vo van hanh vi cua te.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ky ((nang xa) or (lang xa)) hoi. hieu ve cac vo van hanh vi cua te*.