The phrase "a main problem in" is correct and usable in written English.
It can be used when discussing a significant issue or challenge within a specific context or field.
Example: "One main problem in the education system is the lack of resources for underfunded schools."
Alternatives: "a major issue in" or "a key challenge in".
Tendon engineering still represents a main problem in rotator cuff repair.
Complexity of components extensibility is a main problem in the ETL area, because ETL components are tightly-coupled to each others in the current ETL framework.
Substrate wetting has been a main problem in the use of water-based inks for printing in non-porous substrates, and to achieve successful substrate wetting, the surface tension of the ink must be lower than the surface energy of the substrate to be printed on [3].
However, a main problem in QSPR is to investigate relationships between molecular structure and physicochemical properties, e.g., the topological complexity of chemical structures [7], [13], [14], [11].
A main problem in HIV-1 vaccine research is the generation of cross-subtype neutralizing antibodies, which is due to the fact that HIV-1 employs a number of strategies to evade the immune response.
In keeping with global trends, a shortage in the nursing workforce in PHC was identified as a main problem in the current study.
A main problem encountered in control engineering is the estimation of unknown parameters appearing in the plant equations.
A main problem addressed in this series concerns the use of previous results on orbital flatness of a model for single substance crystallization.
A main problem with studies in vivo is the accessibility of the affected organ to the drug.
A main problem is bubble formation in microelectrodes which has an impact on the electrical properties of the electrode and thus it influences the quality of the recording.
The Seattle Times Kay McFadden also found a main problem of the show in the characters, believing that the pilot was more focused on plot development than it was on character development.
