Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
cau tren » cu tren, dau tren, ca tren
ky dang » ky nang, ky danh
dang xa » dang xay, lang xa, dang ha
hieu ve » hieu va, hieu van
cac xuc » cam xuc, cac nuoc, chat xuc
xuc van » duc van, luc van, vuc van
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: ((toc sach) or (thu hoach)) ky dang xa hoi. ((hieu ve) or (lieu va)) cac xuc van hanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (thu hoach)) ky dang xa hoi. ((hieu ve) OR (lieu va)) cac xuc van hanh vi cau tren.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (thu hoach)) ky dang xa hoi. ((hieu ve) or (lieu va)) cac xuc van hanh vi cau tren*.