Perhaps you should try some spelling variations:
thue thanh » hue thanh, thu thanh, thuc thanh
tham thuc » nham thuc, pham thuc, tam thuc
dau tren » dau tien, dat tren, dau tieng
thanh ca » thanh cha, thanh cac, thanh ha
hanh tai » thanh tai, hang tai, hinh tai
han tai » hang tai, nhan tai, van tai
so sach » so sanh, bo sach, hoc sach
thuc va » thuc vat, thuc dan, thuc day
hieu ve » hieu va, hieu van
co sach » bo sach, cuon sach, hoc sach
ve tham » va tham, ve cham, vi tham
ca hoi » cau hoi, cua hoi, xa hoi

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) OR (co sach)) thue thanh ca hoi. hieu ve tham thuc va ((hanh tai) or (han tai)) dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (co sach)) thue thanh ca hoi. hieu ve tham thuc va ((hanh tai) OR (han tai)) dau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sach) OR (co sach)) thue thanh ca hoi. hieu ve tham thuc va ((hanh tai) or (han tai)) dau tren".
• Adding a wildcard symbol may retrieve word variants: ((so sach) OR (co sach)) thue thanh ca hoi. hieu ve tham thuc va ((hanh tai) or (han tai)) dau tren*.