Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
sach tan » sach han, sach san, sach tai
tran van » luan van
doanh va » doan va, doanh tai, doanh cua
danh vai » danh sai, danh va, doanh van
vu sach » vu bach, su sach, vu khach
cuu tre » cau tren, cau treo
thuc va » thuc vat, thuc dan, thuc day
vi tham » vi pham, va tham, vi than
hieu vi » hieu voi, hieu va, hieu ve
van hoi » van hoa, van hoc, van hoe
cua tre » cua te, cua triet, dua tren

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach tan tran van hoi. hieu vi tham thuc va ((danh vai) or (doanh va)) ((cuu tre) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach tan tran van hoi. hieu vi tham thuc va ((danh vai) OR (doanh va)) ((cuu tre) OR (cua tre)).
• Adding a wildcard symbol may retrieve word variants: vu sach tan tran van hoi. hieu vi tham thuc va ((danh vai) or (doanh va)) ((cuu tre) or (cua tre))*.