Mrs.Mirjana Gurinovic, you need apply for F visa,
F visa is issued to those who are invited to China for a business visit, an investigation, a lecture, scientific-technological & cultural exchanges, short-term furthering studies or intern practice less than six months.

Please submit the following requirments for application:
1. your passport with blank visa pages and at least 6 months validity left before expiration.
2. A truly and completely filled application form attached with one passport-sized photo
3. Invitation letter issued by the organizer of the Scientific Conference
4. air ticket or hotel reservation if available