Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
dan thanh » dang thanh, danh thanh, ban thanh
cua viet » ca viet, hoa viet, cua vat
thuc dan » thuc hanh, hoc dan, thuc vat
hieu van » hieu va, thien van, lieu va
vai cua » dai cua, hai cua, lai cua
su sach » vu sach
ky dang » ky nang, ky danh
ky lang » ky nang, ky tang, tay lang
so sach » so sanh, bo sach, co sach
van am » van nam, van lam, van dam

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) or (so sach)) ((ky lang) OR (ky dang)) xa hoi. hieu van am thuc dan thanh vai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) ((ky lang) OR (ky dang)) xa hoi. hieu van am thuc dan thanh vai cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sach)) ((ky lang) OR (ky dang)) xa hoi. hieu van am thuc dan thanh vai cua viet".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) ((ky lang) OR (ky dang)) xa hoi. hieu van am thuc dan thanh vai cua viet*.