Perhaps you should try some spelling variations:
thanh van » thanh san, thanh toan, thanh phan
tru nang » tra nang, tri nang, truc nano
thanh va » hanh va, thanh ha, thanh ve
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
luc van » luoc van, luu van, duc van
van cau » van dau, van hau, van chat
cau luc » cau truc, cau phuc
tu nang » tu nong, tu nano, tu lang
cao tre » cho tre, choi tre

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((tu nang) or (tru nang)) xa hoi. hieu van cau luc van ((thanh va) OR (thanh van)) cao tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((tu nang) OR (tru nang)) xa hoi. hieu van cau luc van ((thanh va) OR (thanh van)) cao tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((tu nang) or (tru nang)) xa hoi. hieu van cau luc van ((thanh va) OR (thanh van)) cao tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((tu nang) or (tru nang)) xa hoi. hieu van cau luc van ((thanh va) OR (thanh van)) cao tre*.