Greyliterature is a kind of important and valuable information recourse.
灰色文献是一种具有重要情报价值的信息源。
2
The most common types of greyliterature were abstracts (55%) and unpublished data (30%).
灰色文献最常见的型式为摘要(55%)及未出版的资料(30%)。
3
To review systematically research studies, which have investigated the impact of greyliterature in meta-analyses of randomized trials of health care interventions.