Perhaps you should try some spelling variations:
sach ky » sac ky, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
hieu va » hieu qua
cac loc » cac lop, cac toc, cac hoc
cuu tre » cua tre, cau tren, cau treo
loc va » hoc va, luc va
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va
vi cuu » vi luu, vinh cuu

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