What are detailed differences between qualified and unqualified audit reports?

What does it mean by emphasis of matter? Give some examples

In an unqualified report, the auditors conclude that the financial statements of your business present fairly its affairs in all material aspects. 

However, a qualified report is one in which the auditor concludes that most matters have been dealt with adequately, except for a few issues. An auditor’s report is qualified when there is either a limitation of scope in the auditor’s work, or when there is a disagreement with management regarding application, acceptability or adequacy of accounting policies. For auditors an issue must be material or financially worth consideration to qualify a report. The issue should not be pervasive, that is, the issue should not misrepresent the factual financial position. If issues are material and pervasive, the auditor issues a disclaimer or adverse opinion. A qualified audit report does not mean that your business is suffering, and it doesn't mean that your financial statement isn't transparent. It merely reflects the auditor’s inability to give a clean report.

when an auditor "Usually CPA"  is working on financial statement for any business, he/ she usually give an "Opinion" about these financial statements. 

1) Unqualified opinion: when the auditor determines that the financial statements are clear of any misrepresentation.

2) Qualified opinion: this opinion is usually given when  there is a small mistakes but there is no misrepresentation.

For more info, you can read about auditing opinions.