Perhaps you should try some spelling variations:
truc van » truc va, thuc van, truc dan
truc ban » thuc ban, truc dan, truoc bang
vanh dai » van dai, vanh tai, lanh dao
cua viet » ca viet, hoa viet, cua vat
su sach » so sach, vu sach
ty nang » ky nang, ty hang, ly nang
va dau » va dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ((ty nang) or (ty xang)) xa hoi. lieu va dau ((truc van) OR (truc ban)) vanh dai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ty nang) OR (ty xang)) xa hoi. lieu va dau ((truc van) OR (truc ban)) vanh dai cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ty nang) or (ty xang)) xa hoi. lieu va dau ((truc van) OR (truc ban)) vanh dai cua viet".
• Adding a wildcard symbol may retrieve word variants: su sach ((ty nang) or (ty xang)) xa hoi. lieu va dau ((truc van) OR (truc ban)) vanh dai cua viet*.