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, cau treo
tu sach » thu sach, su sach, te sach
cac vuc » cac nuoc, cac vung, cac cuoc
vuc van » duc van, luc van, thuc van
ca tren » cu tren, la tren, co tren
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
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 ve cac vuc van nhanh thanh ((cau tren) OR (ca tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((o hoc) OR (o hai)). hieu ve cac vuc van nhanh thanh ((cau tren) OR (ca tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((o hoc) or (o hai)). hieu ve cac vuc van nhanh thanh ((cau tren) OR (ca tren))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((o hoc) or (o hai)). hieu ve cac vuc van nhanh thanh ((cau tren) OR (ca tren))*.