Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cu tren » tu tren, dua tren
hieu ve » hieu va, hieu van
cam tuc » cam xuc, cam tu, nam thuc
cao hoi » cau hoi, co hoi, cao hoc
va dan » va dao, va dau, va dap
ca dan » cac dan, ca dao
ve cam » ve cham, ve cac, va cam

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 cao hoi. hieu ve cam tuc ((va dan) or (ca dan)) bac ((dau tren) or (cu tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang cao hoi. hieu ve cam tuc ((va dan) OR (ca dan)) bac ((dau tren) OR (cu tren)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang cao hoi. hieu ve cam tuc ((va dan) or (ca dan)) bac ((dau tren) or (cu tren))*.