Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
van tuan » van quan, van ban, anh tuan
thuc van » thuc vat, thuc dan, thuc va
cam thuc » am thuc, nam thuc, cam thu
tang ma » mang may, tang van
sach ty » sach y, sach tu, sach thu
sang ma » nang ma, sang tao, mang may
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ty ((sang ma) OR (tang ma)) hoi. hieu ve cam thuc van tuan ((ki su) or (ky su)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty ((sang ma) OR (tang ma)) hoi. hieu ve cam thuc van tuan ((ki su) OR (ky su)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty ((sang ma) OR (tang ma)) hoi. hieu ve cam thuc van tuan ((ki su) or (ky su)) triet".
• Adding a wildcard symbol may retrieve word variants: thu sach ty ((sang ma) OR (tang ma)) hoi. hieu ve cam thuc van tuan ((ki su) or (ky su)) triet*.