Perhaps you should try some spelling variations:
van quang » van quan, tran quang, van tuan
van nang » van ban, van dong, van dung
cau thuc » cau truc, cuu thuc, can thuc
so sach » so sanh, bo sach, co sach
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
hieu ve » hieu va, hieu van
de cua » te cua, dieu cua
le cua » ly cua
ve cau » ke cau, va cau, ve cac
x hoi » xa hoi, o hoi, x ho

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 ((van nang) OR (van quang)) x hoi. hieu ve cau thuc va hanh ((de cua) or (le cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ((van nang) OR (van quang)) x hoi. hieu ve cau thuc va hanh ((de cua) OR (le cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ((van nang) OR (van quang)) x hoi. hieu ve cau thuc va hanh ((de cua) or (le cua)) tre".
• Adding a wildcard symbol may retrieve word variants: so sach ((van nang) OR (van quang)) x hoi. hieu ve cau thuc va hanh ((de cua) or (le cua)) tre*.