entence stems to introduce existing research in the field

The increasing interest in … by (field of scholarship) has heightened
the need for … .

Of particular interest to (field of scholarship) is …

Recently, there has been growing interest in the field of … in … .

The development of … has led … to the hope that … .

… has become a favourite topic of analysis in the field of … .

The study of … has become an important aspect of … .

A central issue in (field of scholarship) is … .

The question of … has been extensively studied in recent years.

Many recent studies have focused on … .

Previous research has concentrated on … .

Most studies have been content to … .

So far, investigations have been confined to … .
Sentence stems for summarising a 'gap' in the literature
Indicate a gap in the previous research by raising a question about it, or
extending previous knowledge in some way:

However, there is little information/attention/work/data/research on
….

However, few studies/investigations/researchers/attempt to … .
Often steps two and three blend together in the same sentence, as in the
sentence stems below.
Sentence stems which both introduce research in the field (what
is 'known') and summarise a 'gap'

The research has tended to focus on …(introduce existing field foci),
rather than on … ('gap').

These studies have emphasised that … …(introduce what is known),
but it remains unclear whether … ('gap').

Although considerable research has been devoted to … (introduce
field areas), rather less attention has been paid to … ('gap').