Perhaps you should try some spelling variations:
nhanh hai » nhanh thai, thanh hai, nhanh ha
toc sach » hoc sach, doc sach, thuoc sach
hanh hai » thanh hai, hang hai, hanh tai
hieu van » hieu va, thien van, lieu va
van tham » van thanh, van tuan, van chat
tru nang » tra nang, tri nang, truc nano
cao hoi » cau hoi, co hoi, cao hoc
tham du » thap du, tham do, pham duc
tu nang » tu nong, tu nano, tu lang
cua tre » cua te, cuu tre, cua triet
du va » dau va, tu va, su 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 ((tu nang) OR (tru nang)) cao hoi. hieu van tham du va ((hanh hai) or (nhanh hai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((tu nang) OR (tru nang)) cao hoi. hieu van tham du va ((hanh hai) OR (nhanh hai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((tu nang) OR (tru nang)) cao hoi. hieu van tham du va ((hanh hai) or (nhanh hai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ((tu nang) OR (tru nang)) cao hoi. hieu van tham du va ((hanh hai) or (nhanh hai)) cua tre*.