Perhaps you should try some spelling variations:
sach cam » sach cap, mach cam, sach tham
cam thuc » am thuc, cam thu, can thuc
nam thuc » nam thuoc, am thuc, nam thu
su sach » so sach, vu sach
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
vi su » ve su, ki su, oi 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 cam nang xa hoi. hieu va ((cam thuc) or (nam thuc)) va hanh ((vi su) OR (va su)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach cam nang xa hoi. hieu va ((cam thuc) OR (nam thuc)) va hanh ((vi su) OR (va su)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach cam nang xa hoi. hieu va ((cam thuc) or (nam thuc)) va hanh ((vi su) OR (va su)) triet".
• Adding a wildcard symbol may retrieve word variants: su sach cam nang xa hoi. hieu va ((cam thuc) or (nam thuc)) va hanh ((vi su) OR (va su)) triet*.