Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dien cuc » dien tu, dieu cua, vien cac
dien cuu » dien cu, dien cua, dien chu
hieu su » hieu sau, tieu su, hieu so
va danh » va dinh, va dan, va hanh
nang xa » nang x, lang xa, nang ma
hieu vu » hieu va, hieu ve, dieu vu
sach v » sach va, sach y, sach 2
cham o » cham soc
v nang » va nang, vu nang, van nang
o va » do va, so va, co va

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 nang xa hoi. ((hieu vu) or (hieu su)) cham o va danh ((dien cuu) OR (dien cuc)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach v nang xa hoi. ((hieu vu) OR (hieu su)) cham o va danh ((dien cuu) OR (dien cuc)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach v nang xa hoi. ((hieu vu) or (hieu su)) cham o va danh ((dien cuu) OR (dien cuc)) tre".
• Adding a wildcard symbol may retrieve word variants: toc sach v nang xa hoi. ((hieu vu) or (hieu su)) cham o va danh ((dien cuu) OR (dien cuc)) tre*.