Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cam thuc » am thuc, nam thuc, can thuc
vu sach » vu bach, su sach, vu khach
cam thu » nam thu, cac thu, ca thu
danh di » danh du, xanh di, danh dien
cuu tre » cua tre, cau tren, cau treo
sach ty » sach y, sach tu, sach thu
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ty nang xa hoi. hieu van ((cam thuc) OR (cam thu)) dan ((hanh vi) or (danh di)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ty nang xa hoi. hieu van ((cam thuc) OR (cam thu)) dan ((hanh vi) OR (danh di)) cuu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ty nang xa hoi. hieu van ((cam thuc) OR (cam thu)) dan ((hanh vi) or (danh di)) cuu tre*".