Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
van hanh » van thanh, ban hanh, van anh
sach hay » sach han, sach ha, sach nay
hieu van » hieu va, thien van, lieu va
sach cay » sach cap, sach nay, sach vay
xuc van » duc van, luc van, vuc van
cau xuc » cam xuc, cau luc, cau truc
van cau » van dau, van hau, van chat
mang xa » lang xa, dang xay, mang cua
vi dau » vi dai, va dau, bi dau

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 cay) OR (sach hay)) ((mang xa) or (mang may)) hoi. hieu van cau xuc van hanh vi dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach cay) OR (sach hay)) ((mang xa) OR (mang may)) hoi. hieu van cau xuc van hanh vi dau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach cay) OR (sach hay)) ((mang xa) or (mang may)) hoi. hieu van cau xuc van hanh vi dau tren".
• Adding a wildcard symbol may retrieve word variants: tu ((sach cay) OR (sach hay)) ((mang xa) or (mang may)) hoi. hieu van cau xuc van hanh vi dau tren*.