Perhaps you should try some spelling variations:
van nhanh » van thanh, van hanh, van khanh
tu sach » thu sach, su sach, te sach
tri cuu » tri cua, tra cuu, trinh cuu
van anh » van thanh, tuan anh, van minh
cuu tre » cua tre, cau tren, cau treo
cac xuc » cam xuc, cac nuoc, chat xuc
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
co hai » co dai, co hoi, so hai
ve cac » va cac, vien cac
o hai » so hai, o lai, _ hai

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 ky nang ((o hai) OR (co hai)). hieu ve cac xuc ((van nhanh) or (van anh)) tri cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((o hai) OR (co hai)). hieu ve cac xuc ((van nhanh) OR (van anh)) tri cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((o hai) OR (co hai)). hieu ve cac xuc ((van nhanh) or (van anh)) tri cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((o hai) OR (co hai)). hieu ve cac xuc ((van nhanh) or (van anh)) tri cuu tre*.