Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dan hanh » dang hanh, dan khanh, dan thanh
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
cau hoc » cau hoi, cau hoa, cao hoc
ve cau » ke cau, va cau, ve cac
vi cua » vai cua
di cua » dai cua, doi cua, de cua

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 hoi. hieu ve cau hoc dan hanh ((vi cua) OR (di cua)) tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky nang xa hoi. hieu ve cau hoc dan hanh ((vi cua) OR (di cua)) tu*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ky nang xa hoi. hieu ve cau hoc dan hanh ((vi cua) OR (di cua)) tu*".