Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
thanh van » thanh san, thanh toan, thanh phan
toc sach » hoc sach, doc sach, thuoc sach
vien cac » vien bach, vien dai, vien da
ly nang » ly hang, ly vang, ly quang
van cua » vang cua, ban cua, dan cua
cua tre » cua te, cuu tre, cua triet
du va » dau va, tu va, vu va
su va » su van, tu va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ((ly nang) or (ky nang)) ma hoa. hieu vien cac ((du va) OR (su va)) thanh van cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ly nang) OR (ky nang)) ma hoa. hieu vien cac ((du va) OR (su va)) thanh van cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ly nang) or (ky nang)) ma hoa. hieu vien cac ((du va) OR (su va)) thanh van cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ((ly nang) or (ky nang)) ma hoa. hieu vien cac ((du va) OR (su va)) thanh van cua tre*.