Perhaps you should try some spelling variations:
dan hanh » dang hanh, dan khanh, dan thanh
thuc dan » thuc hanh, hoc dan, thuc vat
cam thuc » am thuc, nam thuc, cam thu
so sach » so sanh, bo sach, co sach
hieu ve » hieu va, hieu van
vu sach » vu bach, su sach, vu khach
cua tre » cua te, cuu tre, cua triet
v nang » va nang, vu nang, van nang
ve cam » ve cham, ve cac, va cam
y nang » ky nang, ly nang, may nang
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: ((so sach) or (vu sach)) ((y nang) or (v nang)) xa hoi. hieu ve cam thuc dan hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (vu sach)) ((y nang) OR (v nang)) xa hoi. hieu ve cam thuc dan hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((so sach) or (vu sach)) ((y nang) or (v nang)) xa hoi. hieu ve cam thuc dan hanh vi cua tre*.