Perhaps you should try some spelling variations:
quang phap » quang phat, quan phap, quang phan
thieu qua » hieu qua, thieu cua, thieu quang
trinh tac » trinh tai, trinh tam, trinh cac
tac quang » thac quang, tac quan, tai quang
tieng han » tieng anh
dung dan » dung dat, dung san, tung dan
tin » tinh

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tin dung dan toc thieu qua ) or ( trinh tac quang phap tieng han ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tin dung dan toc thieu qua ) OR ( trinh tac quang phap tieng han )).
• Adding a wildcard symbol may retrieve word variants: (( tin dung dan toc thieu qua ) or ( trinh tac quang phap tieng han ))*.