Perhaps you should try some spelling variations:
nhanh thai » nhanh thi, nhanh thanh, nhanh thang
van nhanh » van thanh, van hanh, van khanh
cao tren » ca tren, cau tren, co tren
thai cao » tai cao, thoai cac, thuat cao
duc van » duc va, duc tan, duc manh
cac duc » cac du, cao duc, cac dac
hieu ve » hieu va, hieu van
tu sach » thu sach, su sach, te sach
vu sach » vu bach, su sach, vu khach
ve cac » va cac, vien cac
o hoi » co hoi, o hoc, o hoa
o hai » co hai, so hai, o lai

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) or (vu sach)) ky nang ((o hoi) or (o hai)). hieu ve cac duc van nhanh thai cao tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (vu sach)) ky nang ((o hoi) OR (o hai)). hieu ve cac duc van nhanh thai cao tren.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (vu sach)) ky nang ((o hoi) or (o hai)). hieu ve cac duc van nhanh thai cao tren*.