Perhaps you should try some spelling variations:
hinh hoc » sinh hoc, tin hoc, benh hoc
tu sach » thu sach, te sach, tu cach
anh hoc » sinh hoc, benh hoc, anh khoa
dua ban » dia ban, cua ban, qua ban
cam dua » ca dua, cay dua, chay dua
cua tre » cua te, cuu tre, cua triet
su sach » so sach, vu sach
nang o » nang co, nang ho, nang ro
va cam » va cham, va cac, va cao
o lai » o lao

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) or (su sach)) ky nang o lai. lieu va cam dua ban ((anh hoc) OR (hinh hoc)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky nang o lai. lieu va cam dua ban ((anh hoc) OR (hinh hoc)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) ky nang o lai. lieu va cam dua ban ((anh hoc) OR (hinh hoc)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky nang o lai. lieu va cam dua ban ((anh hoc) OR (hinh hoc)) cua tre*.