Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
ve tham » va tham, ve cham, vi tham
sach ky » sac ky, sach ty, sach kem
thuc va » thuc vat, thuc dan, thuc day
dan vi » doan vi, don vi, gan vi
dan va » doan va, dan ca, ban va
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuat ((sach ky) OR (sach y)) nang ma hoa. hieu ve tham thuc va ((dan vi) or (dan va)) cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat ((sach ky) OR (sach y)) nang ma hoa. hieu ve tham thuc va ((dan vi) OR (dan va)) cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat ((sach ky) OR (sach y)) nang ma hoa. hieu ve tham thuc va ((dan vi) or (dan va)) cua te".
• Adding a wildcard symbol may retrieve word variants: thuat ((sach ky) OR (sach y)) nang ma hoa. hieu ve tham thuc va ((dan vi) or (dan va)) cua te*.