Perhaps you should try some spelling variations:
ban hanh » ban hang
hieu van » hieu va, thien van, lieu va
hai truc » hai trac, hang truc, thai thuc
dai truc » dai thuc, doan truc, dai trung
su sach » so sach, vu sach
nang ma » tang ma, sang ma, nang cao
sach ky » sac ky, sach y, sach ty
vi cua » vai cua, di cua
ma hoi » mai hoi, xa hoi, ma hoa
cua tu » cua tuc, cua su, cua cu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang ma hoi. hieu van ((hai truc) or (dai truc)) ((ban hanh) or (van ban)) vi cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ma hoi. hieu van ((hai truc) OR (dai truc)) ((ban hanh) OR (van ban)) vi cua tu.
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ma hoi. hieu van ((hai truc) or (dai truc)) ((ban hanh) or (van ban)) vi cua tu*.