Perhaps you should try some spelling variations:
nha thuoc » nha nuoc, nhan thuc, nha hoc
hieu van » thien van, lieu va, hieu ve
thuoc va » thuc va, thuoc ma, thuong va
tu sach » thu sach, su sach, te sach
ca viet » va viet, hoa viet, san viet
hanh di » hanh vi, hanh de, hang di
va hanh » van hanh, va thanh, va danh
co viet » so viet, o viet, hoc viet
sach ho » sach hoi, sach ha, sach lo
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
ho nang » thi nang, kha nang, cao nang

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ho nang xa hoi. ((hieu van) or (hieu va)) nha thuoc va hanh di ((ca viet) OR (co viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ho nang xa hoi. ((hieu van) OR (hieu va)) nha thuoc va hanh di ((ca viet) OR (co viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ho nang xa hoi. ((hieu van) or (hieu va)) nha thuoc va hanh di ((ca viet) OR (co viet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ho nang xa hoi. ((hieu van) or (hieu va)) nha thuoc va hanh di ((ca viet) OR (co viet))*.