Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
cam tuc » cam xuc, cam tu, nam thuc
van cam » van nam, van lam, van cau
ty nang » ky nang, ty hang, ly nang
cuu tre » cua tre, cau tren, cau treo
tuc va » thuc va, truc va, tuc xa
dan va » doan va, ban va, han va

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

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