Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
huong doi » huong dan, dung doi
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu va » lieu va
cuu tre » cua tre, cau tren, cau treo
cac tu » cac thu, cach tu, cac du

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

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