Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » thien van, lieu va, hieu ve
su sach » so sach, vu sach
ly nang » ky nang, ly hang, ly vang
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cau duc » cao duc, cau luc, chu duc
va danh » va dinh, va dan, va hanh
danh vi » hanh vi, dinh vi, danh di
vi cua » vai cua, di cua
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) or (su sach)) ly nang xa hoi. ((hieu van) or (hieu va)) cau duc va danh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (su sach)) ly nang xa hoi. ((hieu van) OR (hieu va)) cau duc va danh vi cua te.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (su sach)) ly nang xa hoi. ((hieu van) or (hieu va)) cau duc va danh vi cua te*.