Perhaps you should try some spelling variations:
dau thai » dau thau, da thai, dao thai
thai cuu » thai cua, tai cuc, thi cuc
sach ky » sach y, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
hieu va » hieu qua
dat duc » dat duoc, dao duc, dat doc
cuu tre » cua tre, cau tren, cau treo
sac ky » cac ky, sai ky
va dau » va dao

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) OR (sac ky)) nang xa hoi. ((hieu va) or (lieu va)) dat duc va dau thai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ky) OR (sac ky)) nang xa hoi. ((hieu va) OR (lieu va)) dat duc va dau thai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ky) OR (sac ky)) nang xa hoi. ((hieu va) or (lieu va)) dat duc va dau thai cuu tre".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ky) OR (sac ky)) nang xa hoi. ((hieu va) or (lieu va)) dat duc va dau thai cuu tre*.