Perhaps you should try some spelling variations:
vao truc » vao thuc, cau truc, bao thuc
su sach » so sach, vu sach
hanh va » hang va, hanh vi
va hanh » van hanh, va thanh, va danh
dao tuc » dao duc
su tien » su kien, su hien, tu tieng
doc hai » hoc hai, duc hai, do hai
doc hoi » duoc hoi, hoc hoi, doi hoi
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang

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: su sach v nang ((doc hoi) OR (doc hai)). lieu va ((vao truc) OR (dao tuc)) va hanh va su tien~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach v nang ((doc hoi) OR (doc hai)). lieu va ((vao truc) or (dao tuc)) va hanh va su tien~".
• Adding a wildcard symbol may retrieve word variants: su sach v nang ((doc hoi) OR (doc hai)). lieu va ((vao truc) or (dao tuc)) va hanh va su tien*.