Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
qua cac » cua cac
cac tru » ca tru, cac tro, cac thu
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
me hoi » le hoi
tru va » truc va, tu va, trung va
va dan » ca dan, va dao, va dau
ca cua » co 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 y nang ((me hoi) or (ma hoa)). hieu qua cac tru va dan ca cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((me hoi) OR (ma hoa)). hieu qua cac tru va dan ca cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((me hoi) or (ma hoa)). hieu qua cac tru va dan ca cua tre*.