Perhaps you should try some spelling variations:
thieu khang » chieu khong, thieu quang
thieu sang » chieu sang, thieu quang, hieu lang
hanh trinh » canh tranh, hanh chinh
trinh quan » tinh quang, trinh luat, trinh han
trong hach » trong mach, trong cach, trong hanh
quan dung » quang dung, quan duong, qua dung
toan cau » toan cao, toan tap, toan tai
toan ban » van ban

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

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