Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
so sanh » do sanh
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
ve cham » va cham, ve chat, vu cham
ve nham » ve nha
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
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 sanh) or (hoc sach)) ky nang ma hoi. hieu ((ve nham) OR (ve cham)) thuc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sanh) OR (hoc sach)) ky nang ma hoi. hieu ((ve nham) OR (ve cham)) thuc va hanh vi cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sanh) or (hoc sach)) ky nang ma hoi. hieu ((ve nham) OR (ve cham)) thuc va hanh vi cua tre*".