Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
va tham » van tham, va cham, va thanh
luu van » cuu van, luan van, luu hanh
luc van » luoc van, duc van, luc va
hieu va » lieu va, hieu qua
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
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: ((toc sach) or (doc sach)) ky tang xa hoi. hieu va tham ((luc van) OR (luu van)) hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ky tang xa hoi. hieu va tham ((luc van) OR (luu van)) hanh vi cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (doc sach)) ky tang xa hoi. hieu va tham ((luc van) OR (luu van)) hanh vi cua te*".