Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thanh vi » hanh vi, thanh va, thanh ve
tru nang » tra nang, tri nang, truc nano
hieu van » thien van, lieu va, hieu ve
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
duc van » duc va, duc tan, duc manh
cau duc » cao duc, cau luc, chu duc
cuu tre » cua tre, cau tren, cau treo
tu nang » tu nong, tu nano, tu lang
vi cuu » vi luu, vinh cuu

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) OR (hieu va)) cau duc van thanh vi cuu 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) OR (hieu va)) cau duc van thanh vi cuu 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) OR (hieu va)) cau duc van thanh vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((tu nang) or (tru nang)) xa hoi. ((hieu van) OR (hieu va)) cau duc van thanh vi cuu tre*.