Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
thanh va » thanh van, hanh va, thanh ha
sach ky » sach y, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
van cau » van dau, van hau, van chat
truc va » thuc va, thuc vat, trung va
cuu tre » cua tre, cau tren, cau treo
sac ky » cac ky, sai ky

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

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