Perhaps you should try some spelling variations:
sach kha » sach nha, sach ha, sach tham
kha nang » phap nang, ky nang, ki nang
van hanh » van thanh, ban hanh, van anh
nam thuc » nam thuoc, am thuc, nam thu
cam thuc » am thuc, cam thu, can thuc
su sach » so sach, vu sach
hanh ki » hanh vi, hanh ky, hanh kien
su viet » so viet
hieu va » lieu va, hieu qua
hieu ve » hieu van
nang xa » nang x, lang xa, nang ma
ki su » ky su

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 kha nang xa hoi. ((hieu ve) or (hieu va)) ((cam thuc) or (nam thuc)) van hanh ki su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach kha nang xa hoi. ((hieu ve) OR (hieu va)) ((cam thuc) OR (nam thuc)) van hanh ki su viet.
• Adding a wildcard symbol may retrieve word variants: su sach kha nang xa hoi. ((hieu ve) or (hieu va)) ((cam thuc) or (nam thuc)) van hanh ki su viet*.