Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
thuoc va » thuc va, thuong va, thuoc tai
thuoc ma » hoc ma, duoc ma
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu va » hieu qua
cuu tre » cua tre, cau tren, cau treo
dan va » doan va, dan ca, ban va
va cuu » va cau, va chu, va huu

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

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