Perhaps you should try some spelling variations:
thien van » thi van
nam thuc » nam thuoc, am thuc, nam thu
cau tren » cu tren, dau tren, ca tren
sach thu » sach thue, sach thieu, sach tham
lang xa » lang ha, dang xay, lang van
sach ty » sach y, sach tu, xach tay
thuc va » thuc vat, thuc dan, thuc day
va danh » va dinh, va dan, va hanh
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. thien van nam thuc va 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. thien van nam thuc va danh va ((cua tre) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: toc ((sach ty) or (sach thu)) lang xa hoi. thien van nam thuc va danh va ((cua tre) or (cau tren))*.