"scarce studies" is correct and usable in written English.
You can use it when you're referring to a lack of research or studies on a particular subject. For example, "There are very few studies that address the effects of climate change in this region."
Scarce studies on sAA in MDD produce confounded results and no data is available regarding baseline sAA activity.
Though hominin remains are scarce, studies focussing on the more abundant records of fossil land mammal communities can contribute greatly to our knowledge of the palaeoenvironmental circumstances that influenced and directed the global spread of hominins.
However, there are scarce studies on the relationships between growth and flowering of the young tree and the fruiting pattern, i.e. regular vs. alternate bearing, of the adult tree.
Of note, scarce studies of trauma centenarians are available [37].
These scarce studies revealed that outcomes of nonagenarians were not worse than those of octogenarians.
Since only scarce studies exist comparing both techniques directly, we decided to additionally include any study on MSA in which information on the applied technique, e.g. conventional or piezosurgery, was retrievable and additionally reporting on the incidence of membrane perforations.
Very scarce study has been made on the study of Bangham's model.
The strength of our research is that literature is extremely scarce on studies as our prospective study on free hand positioning without special aiming devices.
Studies on the effects of stump harvesting on forest biodiversity are scarce and studies on long-term effects are until now non-existent.
Studies focusing on risk factors of officially registered childhood offenders remain scarce and studies examining the risk factors of registered re-offending childhood offenders are even scarcer [ 13- 17].
However, the literature is scarce in studies describing the development of complete plants.
