Perhaps you should try some spelling variations:
dan hanh » dang hanh, dan khanh, dan thanh
thuc dan » thuc hanh, hoc dan, thuc vat
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cuu tre, cua triet
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
ve cam » ve cham, ve cai, ve cau
va cam » va cham, va cac, va cao
ve cac » va cac, vien cac
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: tu sach ky tang xa hoi. hieu ((((ve cam) OR (va cam))) or (ve cac)) thuc dan hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky tang xa hoi. hieu ((((ve cam) OR (va cam))) OR (ve cac)) thuc dan hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky tang xa hoi. hieu ((((ve cam) OR (va cam))) or (ve cac)) thuc dan hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky tang xa hoi. hieu ((((ve cam) OR (va cam))) or (ve cac)) thuc dan hanh vi cua tre*.