Perhaps you should try some spelling variations:
sach duoc » sach nuoc, sach dao, sach dung
tang van » dang van, hoang van, trong van
sach duy » sach dung, sach dao, sach dat
cam thuc » am thuc, nam thuc, cam thu
dan dai » dat dai, can dai, dan dat
thuc ca » thuc cua, thuc can, thuc cao
hieu ve » hieu va, hieu van
sang ma » tang ma, nang ma, sang tao
ve cam » ve cham, ve cac, va cam
ca dan » cac dan, ca dao
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: su ((sach duy) OR (sach duoc)) ((sang ma) or (tang van)) hoi. hieu ve cam thuc ca dan dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach duy) OR (sach duoc)) ((sang ma) OR (tang van)) hoi. hieu ve cam thuc ca dan dai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach duy) OR (sach duoc)) ((sang ma) or (tang van)) hoi. hieu ve cam thuc ca dan dai cua te".
• Adding a wildcard symbol may retrieve word variants: su ((sach duy) OR (sach duoc)) ((sang ma) or (tang van)) hoi. hieu ve cam thuc ca dan dai cua te*.