Abstract indexing is a method used to summarize the content of research articles and other documents in a way that allows them to be easily discoverable and searchable. It is an important tool for researchers, librarians, and other professionals who need to be able to locate and access relevant research materials quickly.

There are several reasons why abstract indexing is necessary for research journals:

1. It helps researchers find articles relevant to their work: By including relevant keywords in the abstract, researchers can use search engines and abstract databases to locate articles relevant to their research interests.

2. It allows for the organization and classification of research materials: Abstract indexing allows for the systematic organization and classification of research articles, making it easier for researchers to find and access materials that are relevant to their work.

3. It enables the creation of bibliographies and literature reviews: Abstract indexing is often used to create bibliographies and literature reviews, which are essential tools for researchers who need to review existing research on a particular topic.

4. It helps to increase the visibility and impact of research: By making research articles more discoverable and searchable, abstract indexing helps to increase the visibility and impact of the research being published in a particular journal.

Overall, abstract indexing is an important tool for researchers and other professionals who need to access and use research materials in their work and is essential for the effective functioning of research journals.