Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
dien cuu » dien cuc, dien cu, dien cua
hieu van » hieu va, thien van, lieu va
dau thuc » dan thuc, dai thuc, dam thuc
lang xa » lang ha, dang xay, lang van
van dau » van dao, phan dau
sach ky » sac ky, sach y, sach ty
va danh » va dinh, va hanh, dia danh
nang xa » nang x, nang ma, mang xa
cuu tre » cua tre, cau tren, cau treo
va dan » ca dan, va dao, va dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky ((nang xa) or (lang xa)) hoi. hieu van dau thuc ((va danh) OR (va dan)) dien cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((nang xa) OR (lang xa)) hoi. hieu van dau thuc ((va danh) OR (va dan)) dien cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky ((nang xa) or (lang xa)) hoi. hieu van dau thuc ((va danh) OR (va dan)) dien cuu tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((nang xa) or (lang xa)) hoi. hieu van dau thuc ((va danh) OR (va dan)) dien cuu tre*.