Perhaps you should try some spelling variations:
tinh hoc » sinh hoc, tin hoc, hinh hoc
cua tre » cua te, cuu tre, cua triet
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
hieu va » lieu va, hieu qua
va tinh » may tinh
ta hoi » tao hoi, tay hoi, tai hoi
sac ky » sai ky
anh ta » anh tu, anh va, anh tuan
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 ((sac ky) OR (cac ky)) anh ta hoi. hieu va tinh hoc ((va hanh) or (va danh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sac ky) OR (cac ky)) anh ta hoi. hieu va tinh hoc ((va hanh) OR (va danh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sac ky) OR (cac ky)) anh ta hoi. hieu va tinh hoc ((va hanh) or (va danh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sac ky) OR (cac ky)) anh ta hoi. hieu va tinh hoc ((va hanh) or (va danh)) vi cua tre*.