Will adding positive items reduce the affect of negative listsings in report and help to have high score?

Negative listings can't be removed from your credit report before 7 years and 180 days. However, when you add positive listings on your credit report, they make a positive impact on your credit report. That is true. The negative impact becomes less with time.

The negative listing will stay for 7 years. However, adding positive points will help you to increase your credit score with time.

Of course. Adding positive item i your credit report will definitely help you to grow your credit score. But You should also try to remove errors from your credit report by disputing them.