Perhaps you should try some spelling variations:
cau thuc » cau truc, cuu thuc, can thuc
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
hieu ve » hieu va, hieu van
su sach » so sach, vu sach
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
ve cau » ke cau, va cau, ve cac
vi va » vi van, vai va, bi va
vu va » vu van, tu va, su va

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 y ((nang xa) or (nang ma)) hoi. hieu ve cau thuc va hanh ((vi va) OR (vu va)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang xa) OR (nang ma)) hoi. hieu ve cau thuc va hanh ((vi va) OR (vu va)) triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((nang xa) or (nang ma)) hoi. hieu ve cau thuc va hanh ((vi va) OR (vu va)) triet*".