Perhaps you should try some spelling variations:
diem cau » dieu can
van hanh » van thanh, ban hanh, van anh
sach ky » sach y, sach ty, sach kem
diem ca » diem can, diem cap, diem cua
duc van » duc va, duc tan, duc manh
cam duc » cam xuc, cao duc, pham duc
va cam » va cham, va cac, va cao
nang o » nang co, nang ho, nang ro
sac ky » cac ky, sai ky
o hoi » co hoi, o hoc, o hai

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 o hoi. lieu va cam duc van hanh ((diem ca) OR (diem cau)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) nang o hoi. lieu va cam duc van hanh ((diem ca) OR (diem cau)) tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sac ky)) nang o hoi. lieu va cam duc van hanh ((diem ca) OR (diem cau)) tre*".