Perhaps you should try some spelling variations:
danh dien » dinh dien, danh kien, danh lien
dien cua » dieu cua, dien cuc, dien cu
trung va » truong va, trang va, trung ha
hieu van » hieu va, thien van, lieu va
truc va » thuc va, thuc vat
te sach » toc sach
sach ky » sac ky, sach y, sach ty
van dau » van dao, phan dau
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
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: te sach ky ((nang xa) or (lang xa)) hoi. hieu van dau ((truc va) OR (trung va)) danh dien cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky ((nang xa) OR (lang xa)) hoi. hieu van dau ((truc va) OR (trung va)) danh dien cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky ((nang xa) or (lang xa)) hoi. hieu van dau ((truc va) OR (trung va)) danh dien cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ky ((nang xa) or (lang xa)) hoi. hieu van dau ((truc va) OR (trung va)) danh dien cua tre*.