Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dang xay » dang van, van xay
danh dai » danh dau, danh di, danh sai
nang xa » nang x, lang xa, nang ma
thi van » thi lan, thi hanh, thi nang
van cau » van dau, van hau, van chat
truc va » thuc va, thuc vat, trung va
va danh » va dinh, va dan, va hanh
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 y ((nang xa) or (dang xay)) hoi. thi van cau truc va danh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y ((nang xa) OR (dang xay)) hoi. thi van cau truc va danh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach y ((nang xa) or (dang xay)) hoi. thi van cau truc va danh dai cua tre*.