Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
van dinh » van minh, van dich, va dinh
dinh sai » dinh tai, danh sai, dinh hai
va trien » va truyen, va thiet, va tuyen
ty lang » tay lang, ty hang, tu lang
nam xuc » cam xuc, nam xua, nam thuc
xuc van » duc van, luc van, vuc van
cua tu » cua tuc, cua su, cua cu

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 ((ty lang) or (ty xang)) xa hoi. hieu van nam xuc van dinh sai ((va trien) or (cua tu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ty lang) OR (ty xang)) xa hoi. hieu van nam xuc van dinh sai ((va trien) OR (cua tu)).
• Adding a wildcard symbol may retrieve word variants: toc sach ((ty lang) or (ty xang)) xa hoi. hieu van nam xuc van dinh sai ((va trien) or (cua tu))*.