Perhaps you should try some spelling variations:
thieu sang » chieu sang, thieu khang, thieu quang
hanh trinh » canh tranh, hanh chinh
quang dung » quang trung, ung dung, cuong dung
trong hach » trong mach, trong cach, trong hanh
hoc thieu » toc thieu, hoc hien
quan dung » quan duong, qua dung, quan dong
toan tai » toan tap, doanh tai, toan cao
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 - hanh trinh ((quan dung) OR (quang dung)) trong hach ((toan tai) or (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thieu sang - hanh trinh ((quan dung) OR (quang dung)) trong hach ((toan tai) OR (toan ban)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thieu sang - hanh trinh ((quan dung) OR (quang dung)) trong hach ((toan tai) or (toan ban))".
• Adding a wildcard symbol may retrieve word variants: hoc thieu sang - hanh trinh ((quan dung) OR (quang dung)) trong hach ((toan tai) or (toan ban))*.