Perhaps you should try some spelling variations:
cau theo » cau thi, cau tao
lanh hai » manh hai, thanh hai, lang chai
danh hai » dang hai, manh hai, danh hau
hieu van » hieu va, thien van, lieu va
cam thuc » nam thuc, cam thu, can thuc
so sach » so sanh, bo sach, co sach
sach ly » sach y, sach lo, sach ty
hang ma » hang va, hang ca, tang ma
ly hang » ly quang
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ly hang ma hoi. hieu van ((cam thuc) or (am thuc)) va ((danh hai) or (lanh hai)) cau theo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ly hang ma hoi. hieu van ((cam thuc) OR (am thuc)) va ((danh hai) OR (lanh hai)) cau theo.
• Adding a wildcard symbol may retrieve word variants: so sach ly hang ma hoi. hieu van ((cam thuc) or (am thuc)) va ((danh hai) or (lanh hai)) cau theo*.