Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cau theo » cau thi, cau tao
dang xay » dang van, van xay
xay hoi » xa hoi, tay hoi, cay phoi
hieu va » lieu va, hieu qua
cac duc » cac du, cao duc, cac dac
hanh di » hanh vi, hanh de, hang di
cua tre » cuu tre, cua triet, dua tren
va hanh » van hanh, va thanh, va danh
v dang » vu dang, va dang, 2 dang
sach v » sach va, sach y, sach 2
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach v dang xay hoi. hieu va cac duc va hanh di ((((cua tre) OR (cua te))) or (cau theo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach v dang xay hoi. hieu va cac duc va hanh di ((((cua tre) OR (cua te))) OR (cau theo)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach v dang xay hoi. hieu va cac duc va hanh di ((((cua tre) OR (cua te))) or (cau theo))".
• Adding a wildcard symbol may retrieve word variants: toc sach v dang xay hoi. hieu va cac duc va hanh di ((((cua tre) OR (cua te))) or (cau theo))*.