Perhaps you should try some spelling variations:
luat duoc » luat tuc
toc sach » hoc sach, doc sach, thuoc sach
nam duoc » nam thuoc, dat duoc, nam moc
cua viet » ca viet, hoa viet, cua vat
hieu van » hieu va, thien van, lieu va
lang xa » lang ha, dang xay, lang van
sach xu » sach xa, cach xu, mach xu
xu lang » cu lang, tu lang, xu dang
da duoc » tao duoc, hoa duoc
va hanh » van hanh, va thanh, va danh
vi cua » vai cua, di cua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach xu lang xa hoi. hieu van ((luat duoc) OR (((nam duoc) OR (da duoc)))) va hanh vi cua viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach xu lang xa hoi. hieu van ((luat duoc) or (((nam duoc) OR (da duoc)))) va hanh vi cua viet~".
• Adding a wildcard symbol may retrieve word variants: toc sach xu lang xa hoi. hieu van ((luat duoc) or (((nam duoc) OR (da duoc)))) va hanh vi cua viet*.