The phrase "a big evidence" is not correct in standard written English.
The word "evidence" is an uncountable noun, so it should not be preceded by "a" or "big."
Example: "There is substantial evidence to support the theory."
Alternatives: "strong evidence" or "significant evidence."
A small study of retired NFL players finds big evidence of head trauma.
Labor's announcement, then, is big – evidence, Shorten says, that Labor "will fight with every ounce of our energy to defend and save Medicare".
The first big evidence of the upcoming political upheaval generated by Hispanics came over a decade ago in the aftermath of 1994's GOP-sponsored Proposition 187 in California that denied public services to illegal immigrants.
It may not be big evidence, because I know people are looking for the big evidence,… we don't have that type of evidence we are still generating.
(Policymaker) It may not be big evidence, because I know people are looking for the big evidence,… we don't have that type of evidence we are still generating.
It was a big deal giving evidence to Leveson, because you're in that paradoxical position of trying to stick up for your privacy whilst slightly invading your own privacy.
The writer examines the evidence--a big stack of Herald Tribunes.
Zainab stayed four days with us on that first visit, and left us a big list of evidence she wanted, and exactly how she wanted it packaged up".
It provides a big dollop of evidence in support of an emerging idea that artificial sweeteners are not directly bad for people (humans cannot even digest most of them).
But most studies suggest that those differences don't play a big part when evidence is inherently strong or weak, meaning that most juries will wind up in the same place.
