Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
quoc ban » quoc bao, quoc quan, quoc binh
quoc lan » nuoc luan, quoc quan, quoc danh
cau theo » cau thi, cau tao
te sach » toc sach
xu lang » cu lang, tu lang, xu dang
van cam » van nam, van lam, van cau
vi cau » va cau, ve cau, di cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ((xu lang) or (truc nano)) xa hoi. hieu van cam ((quoc ban) OR (quoc lan)) hanh vi cau theo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((xu lang) OR (truc nano)) xa hoi. hieu van cam ((quoc ban) OR (quoc lan)) hanh vi cau theo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((xu lang) or (truc nano)) xa hoi. hieu van cam ((quoc ban) OR (quoc lan)) hanh vi cau theo".
• Adding a wildcard symbol may retrieve word variants: te sach ((xu lang) or (truc nano)) xa hoi. hieu van cam ((quoc ban) OR (quoc lan)) hanh vi cau theo*.