Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
van hanh » ban hanh, van anh, van ban
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
cao hoi » cau hoi, co hoi, cao hoc
ty nang » ky nang, ty hang, ly nang
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao
vi cua » vai cua, di cua

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

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