Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
sach cay » sach cap, sach hay, sach nay
dau tren » dau tien, dat tren, dau tieng
mang xa » lang xa, dang xay, mang cua
cau xuc » cam xuc, cau luc, cau truc
xuc van » duc van, luc van, vuc van
hieu va » lieu va
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: thu sach cay ((mang xa) or (mang may)) hoi. ((hieu va) OR (hieu qua)) cau xuc van hanh vi dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach cay ((mang xa) OR (mang may)) hoi. ((hieu va) OR (hieu qua)) cau xuc van hanh vi dau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach cay ((mang xa) or (mang may)) hoi. ((hieu va) OR (hieu qua)) cau xuc van hanh vi dau tren".
• Adding a wildcard symbol may retrieve word variants: thu sach cay ((mang xa) or (mang may)) hoi. ((hieu va) OR (hieu qua)) cau xuc van hanh vi dau tren*.