Perhaps you should try some spelling variations:
chieu sach » chiet tach, chieu sang, chieu xanh
hanh trinh » canh tranh, hanh chinh
luat quang » luat quan, xuat quang, chat quang
thuong dan » huong dan, thuong han, thuong dam
luat dung » suat dung, luat chung, thuat dung
dan toan » van toan, dan than, manh toan
toan cau » toan cao, toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((chieu sach) or (chinh sach)) - hanh trinh ((luat dung) OR (luat quang)) thuong dan toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sach) OR (chinh sach)) - hanh trinh ((luat dung) OR (luat quang)) thuong dan toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu sach) or (chinh sach)) - hanh trinh ((luat dung) OR (luat quang)) thuong dan toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu sach) or (chinh sach)) - hanh trinh ((luat dung) OR (luat quang)) thuong dan toan cau*.