Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
gia hanh » gia thanh, giao hanh, gia anh
cau tren » cu tren, dau tren, ca tren
nang xa » nang x, lang xa, nang ma
hieu ve » hieu van
sach ty » sach y, sach tu, sach thu
cam luc » cau luc
ty nang » ky nang, ty xang, ty hang
hieu va » lieu va, hieu qua
vi cau » va cau, ve cau, di cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ty nang xa hoi. ((hieu ve) or (hieu va)) ((cam luc) or (cam xuc)) gia hanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ty nang xa hoi. ((hieu ve) OR (hieu va)) ((cam luc) OR (cam xuc)) gia hanh vi cau tren.
• Adding a wildcard symbol may retrieve word variants: doc sach ty nang xa hoi. ((hieu ve) or (hieu va)) ((cam luc) or (cam xuc)) gia hanh vi cau tren*.