Perhaps you should try some spelling variations:
nuoc sach » nguoi sach, hoc sach, cuoc cach
toc sach » hoc sach, thuoc sach, toc san
van hanh » van thanh, ban hanh, van anh
doc sach » hoc sach, dac sac, bo sach
tham luc » than luc, tham nuoc, tham thuc
luc van » luoc van, luu van, duc van
va tham » van tham, va cham, va thanh
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
cuu tre » cua tre, cau tren, cau treo
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: ((toc sach) or (((doc sach) OR (nuoc sach)))) ky lang xa hoi. hieu va tham luc van hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (((doc sach) OR (nuoc sach)))) ky lang xa hoi. hieu va tham luc van hanh vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (((doc sach) OR (nuoc sach)))) ky lang xa hoi. hieu va tham luc van hanh vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (((doc sach) OR (nuoc sach)))) ky lang xa hoi. hieu va tham luc van hanh vi cuu tre*.