Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
cau theo » cau thi, cau tao
dang xay » dang van, van xay
hanh van » thanh van, khanh van, hanh va
hieu va » lieu va, hieu qua
van cau » van dau, van hau, van chat
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
hieu ve » hieu van
nang ma » tang ma, sang ma, nang cao

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ty ((dang xay) or (nang ma)) hoi. ((hieu ve) or (hieu va)) tham thuc va hanh van cau theo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((dang xay) OR (nang ma)) hoi. ((hieu ve) OR (hieu va)) tham thuc va hanh van cau theo.
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((dang xay) or (nang ma)) hoi. ((hieu ve) or (hieu va)) tham thuc va hanh van cau theo*.