The sentence "difficulties in studying" is correct and usable in written English.
You can use it in a sentence to describe the challenges someone is facing in their academic pursuits. For example, you could say "Sam has been struggling with difficulties in studying this semester."
One of the difficulties in studying the relationship between gum disease and coronary artery disease is that the two conditions share many risk factors, like smoking, diabetes and high blood pressure.
Although inadequacies in quantifying personality traits and difficulties in studying estimates of time spans exceeding a few seconds have hampered scientific study, simple observation reveals marked individual differences in the ability to estimate time.
This creates difficulties in studying and designing affect in HCI.
Consequently, MD has difficulties in studying the feasibility of the proposed NEMS design in practical applications.
Before starting the research, let us first explain some mathematical difficulties in studying this problem.
One reason for such an imbalance involves the difficulties in studying roots in their heterogeneous and opaque environment.
This article reviews the difficulties in studying adverse effects of drugs during pregnancy on the fetus and newborn.
The inherent difficulties in studying a complex, low base rate behavior with negative connotations have stimulated methodological diversity.
The main difficulty in studying seal designs is that they were often conservative, especially since seals were often replaced with an exactly similar design.
Human studies using functional magnetic resonance imaging have implicated prefrontal-amygdala interactions in these processes, though the precise mechanisms remain poorly understood, in part owing to the difficulty in studying those processes in animal models.
The principal difficulty in studying DDEs lies in their special transcendental nature.
