Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thu sach » tu sach, thuat sach, thu hoach
hieu van » hieu va, thien van, lieu va
cac truc » cau truc, cac tru, cac trung
nang xa » nang x, lang xa, nang ma
van cac » van hac, van cau, van bac
truc va » thuc va, thuc vat, trung va
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
va dan » ca dan, va dao, va dau
dan di » danh di, dan da, dan de

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