Perhaps you should try some spelling variations:
van nhanh » van thanh, van khanh, van nhan
cau tren » cu tren, dau tren, ca tren
chat xuc » chat huu, cam xuc, chao xu
thai cau » thai cao, toan cau, thai van
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
ve chat » va chat, van chat
o hai » co hai, so hai, o lai
o hoi » co hoi, o hoc, o hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang ((o hoi) or (o hai)). hieu ve chat xuc ((van nhanh) OR (van hanh)) thai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((o hoi) OR (o hai)). hieu ve chat xuc ((van nhanh) OR (van hanh)) thai cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((o hoi) or (o hai)). hieu ve chat xuc ((van nhanh) OR (van hanh)) thai cau tren".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((o hoi) or (o hai)). hieu ve chat xuc ((van nhanh) OR (van hanh)) thai cau tren*.