Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thanh hai » thanh phan, thanh hoa, thanh san
cam thuc » am thuc, nam thuc, can thuc
vu khach » vu khanh, vu khac, vay khach
tu sach » thu sach, su sach, te sach
hai cua » thai cua, dai cua, hoi cua
cam thu » nam thu, cac thu, ca thu
hieu va » lieu va, hieu qua
dang ma » dang mau, dang mam, dang mat
ky dang » ky nang, ky danh
ma hoi » mai hoi, xa hoi, ma hoa
cua tu » cua tuc, cua su, cua cu

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) or (vu khach)) ky dang ma hoi. hieu va ((cam thuc) OR (cam thu)) van thanh hai cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (vu khach)) ky dang ma hoi. hieu va ((cam thuc) OR (cam thu)) van thanh hai cua tu*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (vu khach)) ky dang ma hoi. hieu va ((cam thuc) OR (cam thu)) van thanh hai cua tu*".