Perhaps you should try some spelling variations:
tan thanh » tran thanh, tang thanh, toan thanh
kho tang » cao tang
hieu van » hieu va, thien van, lieu va
van pham » san pham, van phan, van phat
pham duy » pham duc
thanh vi » hanh vi, thanh va, thanh ve
duy tan » duy tuan, duc tan, duy van
cua tre » cua te, cuu tre, cua triet
tang ma » mang may, tang van
san kho » san khoa, san cho, lan kho
cua tu » cua tuc, cua cu, cua te
tu san » thu san, tu ban, tu can
ma hoi » mai hoi, xa hoi, ma hoa
cua su » qua su

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu san kho tang ma hoi. hieu van pham duy tan thanh vi ((cua tre) or (((cua tu) OR (cua su))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu san kho tang ma hoi. hieu van pham duy tan thanh vi ((cua tre) OR (((cua tu) OR (cua su)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu san kho tang ma hoi. hieu van pham duy tan thanh vi ((cua tre) or (((cua tu) OR (cua su))))".
• Adding a wildcard symbol may retrieve word variants: tu san kho tang ma hoi. hieu van pham duy tan thanh vi ((cua tre) or (((cua tu) OR (cua su))))*.