Perhaps you should try some spelling variations:
can cau » van cau, ban cau, ca cau
cac cau » cac mau, bac cau, ca cau
sach ky » sach y, sach ty, sach kem
hieu ve » hieu va, hieu van
cao hoc » co hoc, cho hoc, chat hoc
cam tuc » cam xuc, cam tu, nam thuc
ve cam » ve cham, ve cac, va cam
tuc va » thuc va, truc va, tuc xa
va dan » ca dan, va dao, va dau
sac ky » cac ky, sai ky

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) OR (sac ky)) nang cao hoc. hieu ve cam tuc va dan ((cac cau) or (can cau)) tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) nang cao hoc. hieu ve cam tuc va dan ((cac cau) OR (can cau)) tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) OR (sac ky)) nang cao hoc. hieu ve cam tuc va dan ((cac cau) or (can cau)) tren".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) OR (sac ky)) nang cao hoc. hieu ve cam tuc va dan ((cac cau) or (can cau)) tren*.