Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
dau xua » dau cua, dao xuan, dau luan
dau xuc » dau xac, dau nuoc
hieu va » lieu va, hieu qua
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
cuu tre » cua tre, cau tren, cau treo
sach 2 » sach y
vi cuu » vi luu, vinh cuu

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 2 ((nang xa) OR (lang xa)) hoi. hieu va ((dau xuc) or (dau xua)) van hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach 2 ((nang xa) OR (lang xa)) hoi. hieu va ((dau xuc) OR (dau xua)) van hanh vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach 2 ((nang xa) OR (lang xa)) hoi. hieu va ((dau xuc) or (dau xua)) van hanh vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach 2 ((nang xa) OR (lang xa)) hoi. hieu va ((dau xuc) or (dau xua)) van hanh vi cuu tre*.