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