"has shown clearly" is a correct and usable part of a sentence in written English.
You can use it to emphasize that someone or something has demonstrated a specific idea or point clearly. Example: The scientific research data has shown clearly that climate change is a serious global issue.
"The long consultation process, now complete, has shown clearly what customers want and expect from their banks.
A wide body of evidence has shown clearly that our emotions often play a role in illness.
The torture scandal has shown clearly that we are too polite, deferential or powerless to stop US interests trumping our own.
No one has shown clearly where Mattel's and Lee Der's supply chain broke down but such uncertainty is common in China, too.
The IPCC has shown clearly that those who once doubted the science and now fashionably claim that we should "just adapt" to climate change are plain wrong.
It has shown clearly that you do not have to embrace "western" culture in order to modernise your economy and prosper.
A Department of Health spokesperson said: "Recent reports have shown clearly that we need safe numbers on wards and a supportive culture in the NHS.
The recent report of the Brussels Commission, he said, had shown clearly that membership of the EEC was incompatible with the economy of Britain, with her chronic deficiency in balance of payments.
Academic studies of all of the big merger waves of this century have shown clearly that, although shareholders of acquired firms have tended to benefit, those in the acquiring firm have lost.
The results have shown clearly that only Zn2+ could be efficiently detected using the dendrimer of second generation.
Numerical simulations have shown clearly that using an impact damper may significantly improve the performance of a conventional vibration absorber at its first natural frequency.
