Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
va hanh » van hanh, va thanh, va danh
hieu va » lieu va, hieu qua
hieu ve » hieu van
cao hoi » cau hoi, co hoi, cao hoc
ho nang » thi nang, kha nang, cao nang
luu tre » luu tru, cuu tre, luy tre
xuc va » duc va, tuc va, luc va
vi luu » vi lua

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)) ho nang cao hoi. ((hieu ve) OR (hieu va)) cam xuc va hanh vi luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ho nang cao hoi. ((hieu ve) OR (hieu va)) cam xuc va hanh vi luu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (doc sach)) ho nang cao hoi. ((hieu ve) OR (hieu va)) cam xuc va hanh vi luu tre*".