The phrase "a proper knowledge of" is correct and usable in written English.
It can be used when discussing the importance of having an adequate understanding or expertise in a particular subject or field.
Example: "To succeed in this industry, a proper knowledge of market trends is essential."
Alternatives: "an adequate understanding of" or "a thorough grasp of".
The old examination system, which admitted to the civil service only men with a proper knowledge of Confucian philosophy, had lapsed, and customary restraints on absolutism and arbitrary rule, such as would have been imposed by the censorate (a body that scrutinized the conduct of officials) and a professional public service, were lacking.
A proper knowledge of BAEs is indispensable to achieve an adequate management of psychiatric conditions.
A proper knowledge of these properties may permit the design of proper anti-pathogen drugs.
To understand and assess the potentially harmful effects of NPs a proper knowledge of their physicochemical properties is required.
A proper knowledge of polymer drug interactions can aid in the designing of polymers for various drug-delivery applications.
By considering wide applications of composite materials, having a proper knowledge of them under dynamic loading is necessary.
To warrant election, the candidate must prove that he uses the wines of Burgundy, must demonstrate, in the course of a severe oral examination, a proper knowledge and appreciation of wines.
Since timber is a combustible material, its safe use in construction will depend on a proper knowledge and modelling of the physical and chemical reactions involved in the pyrolysis, that affect the temperature growth and thus the performance of timber in fire.
The aim of this new subject was to provide a proper knowledge in the field of the regional issues of the world in addition to their future training as tourism specialists.
English will emphasise "grammar and punctuation, clarity on the essentials of clear composition and a requirement for proper knowledge of pre-20th-Century literature".
In addition, discussion of the decision-making process depended on HCP-related factors: their religious backgrounds, their attitude to religious objections to vaccination and their communication skills, see Table 4. Especially an orthodox Protestant background, or at least proper knowledge of the orthodox Protestant religion, was reported to be important.
