Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
cac tren » ca tren, cau tren, rac tren
hieu van » hieu va, thien van, lieu va
tai cac » tai cuc
te sach » toc sach
nang xa » nang x, lang xa, nang ma
van cam » van nam, van lam, van cau
luc va » duc va, tuc va
loc va » hoc va

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 (thu hoach)) ky nang xa hoi. hieu van cam ((luc va) OR (loc va)) thanh tai cac tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (thu hoach)) ky nang xa hoi. hieu van cam ((luc va) OR (loc va)) thanh tai cac tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (thu hoach)) ky nang xa hoi. hieu van cam ((luc va) OR (loc va)) thanh tai cac tren".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (thu hoach)) ky nang xa hoi. hieu van cam ((luc va) OR (loc va)) thanh tai cac tren*.