Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
lam duoc » nam duoc, luat duoc, lam thuoc
danh vai » danh sai, danh va, doanh van
hieu van » hieu va, thien van, lieu va
ca viet » va viet, hoa viet, san viet
ma danh » va danh, ma dan, mo danh
duoc ma » duoc lam
van lam » van nam
ky dang » ky nang, ky danh
ky lang » ky nang, ky tang, tay lang
co viet » so viet, o viet, hoc viet

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 ((ky lang) or (ky dang)) xa hoi. hieu van lam duoc ma danh vai ((ca viet) OR (co viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ky lang) OR (ky dang)) xa hoi. hieu van lam duoc ma danh vai ((ca viet) OR (co viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ky lang) or (ky dang)) xa hoi. hieu van lam duoc ma danh vai ((ca viet) OR (co viet))".
• Adding a wildcard symbol may retrieve word variants: toc sach ((ky lang) or (ky dang)) xa hoi. hieu van lam duoc ma danh vai ((ca viet) OR (co viet))*.