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
su triet » su viet, su tien, ve triet
duy can » duy van
ty sang » ty xang, ty hang, duy sang
tuan vi » quan vi, luan vi, quans vi
ma hoi » mai hoi, xa hoi, ma hoa
va cam » va cham, va cac, va cao
ve cam » ve cham, ve cac, ve cai
vi su » va su, ve su, ki su

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