Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
cau tren » cu tren, dau tren, ca tren
sach ty » sach tu, sach thu, xach tay
thuc va » thuc vat, thuc dan, thuc day
va danh » va dinh, va dan, va hanh
danh ve » dinh ve, hanh ve, anh ve
ve cau » ke cau, va cau, ve cac
x hoi » o hoi, x ho, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ty) or (sach y)) nang ((x hoi) or (xa hoi)). hieu van nam thuc va danh ve cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sach y)) nang ((x hoi) OR (xa hoi)). hieu van nam thuc va danh ve cau tren.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ty) or (sach y)) nang ((x hoi) or (xa hoi)). hieu van nam thuc va danh ve cau tren*.