Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
cham duc » pham duc, cham soc, pham duy
ban hanh » ban hang
su sach » so sach, vu sach
hieu su » hieu sau, tieu su, hieu so
hieu vu » hieu va, hieu ve, dieu vu
nang ma » tang ma, sang ma, nang cao
su viet » so viet
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang

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 v nang ma hoa. ((hieu vu) OR (hieu su)) cham duc ((van thanh) or (ban hanh)) va su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach v nang ma hoa. ((hieu vu) OR (hieu su)) cham duc ((van thanh) OR (ban hanh)) va su viet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach v nang ma hoa. ((hieu vu) OR (hieu su)) cham duc ((van thanh) or (ban hanh)) va su viet*".