Perhaps you should try some spelling variations:
nhanh thanh » phan thanh, nhanh tinh
van nhanh » van thanh, van hanh, van khanh
cau tren » cu tren, dau tren, ca tren
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
cac vuc » cac nuoc, cac vung, cac cuoc
vuc van » duc van, luc van, thuc van
van cac » van hac, van cau, van bac
sach ky » sac ky, sach y, sach ty
co tren » cu tren, do tren, ca tren
o hai » co hai, so hai, o lai
o hoc » co hoc, mo hoc, so hoc

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 hoc) or (o hai)). hieu van cac vuc van nhanh thanh ((cau tren) or (co tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((o hoc) OR (o hai)). hieu van cac vuc van nhanh thanh ((cau tren) OR (co tren)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((o hoc) or (o hai)). hieu van cac vuc van nhanh thanh ((cau tren) or (co tren))*.