Perhaps you should try some spelling variations:
vat danh » va danh, van danh, luat danh
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
sach thu » sach thue, sach thieu, sach tham
cau tren » cu tren, dau tren, ca tren
lang xa » lang ha, dang xay, lang van
sach ty » sach y, sach tu, xach tay
danh va » doanh va, hanh va, anh va
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc ((sach ty) or (sach thu)) lang xa hoi. hieu van nam thuc vat danh va ((cua tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc ((sach ty) OR (sach thu)) lang xa hoi. hieu van nam thuc vat danh va ((cua tre) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: toc ((sach ty) or (sach thu)) lang xa hoi. hieu van nam thuc vat danh va ((cua tre) or (cau tren))*.