Perhaps you should try some spelling variations:
day tinh » may tinh, dac tinh, dao tinh
thuc day » thuc dan, thuc vat
hoc thuc » hoc huu
hieu van » thien van, lieu va, hieu ve
su sach » so sach
hieu va » lieu va, hieu qua
tinh va » tich va, trinh van, trinh vat
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, lang xa, nang ma
vu sach » vu bach, vu khach
va cua » va chua, via cua, ca 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) or (vu sach)) ky nang xa hoi. ((hieu van) or (hieu va)) hoc thuc day tinh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) ky nang xa hoi. ((hieu van) OR (hieu va)) hoc thuc day tinh va cua tre.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) ky nang xa hoi. ((hieu van) or (hieu va)) hoc thuc day tinh va cua tre*.