Perhaps you should try some spelling variations:
thien cac » thien cau, thieu cac, trien cac
hien cac » vien cac, hieu cac, dien cac
dinh dai » dinh dat, sinh dai, dinh dao
va dinh » van dinh, va kinh, va tinh
su sach » so sach, vu sach
ly nang » ky nang, ly hang, ly vang
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, v nang, may nang
bo va » bao va, do va, so va

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 ((y nang) or (ly nang)) xa hoi. hieu ((hien cac) OR (thien cac)) bo va dinh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((y nang) OR (ly nang)) xa hoi. hieu ((hien cac) OR (thien cac)) bo va dinh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((y nang) or (ly nang)) xa hoi. hieu ((hien cac) OR (thien cac)) bo va dinh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ((y nang) or (ly nang)) xa hoi. hieu ((hien cac) OR (thien cac)) bo va dinh dai cua tre*.