If you're looking for a mention of a specific title, person, or company in any Comichron article or sales chart, the Google Custom Search box above may help; it searches the entire site, including blog posts, and may be helpful for searches where the searched name is relatively unique. "Bat Mite" will yield more useful results than "Batman."
Comichron is currently designed to present distributor sales charts in the manner they were released in — the entire month at once. At present, Comichron does not offer a searchable database of all comics data on the site, whereby individual issues can be found.
There are, however, a couple of tricks that can be used for Diamond Comic Distributors and other distributors' sales reports: visit the Grand Comics Database and search for an individual issue. Look for the release date — and then click on that month in the Monthly Comics Sales page. Then you can use the search box in the sales table to locate the individual issue. If only a cover date is known, search two or three months before that date.
If a comic book is likely to have been a top seller, then find the year of release and search the Yearly Comics Sales pages, which in the 2010s includes the top several hundred comics for each year.
If you're looking for circulations for individual variants, you will not find much of help in the Direct Market distributor charts. Diamond Comic Distributors merges all versions of a comic book that have the same cover price into single entries in its charts.
So sales on individual variants are generally not available, except in cases where a comic book went back to press for a later printing with a new cover later and it's clear that those copies are not part of the original sale. Even then, there might be sales of copies of the original mixed in; there's no way to know.
A caveat is necessary, as well, about trying to reverse-engineer the number of copies of a variant from known ordering threshholds. If 50 copies of a comic book must be ordered in order for a single copy of a specific variant to become available, that does not mean that on a total sale of 51,000 copies, that 1,000 copies must be the variant. Instead, that number is the maximum possible. In fact the true number is going to be much smaller, because the number of retailers large enough to order 50 copies isn't that big.
A caution regarding individual issue data
Be advised: If you're looking to compile a list of a single comic book title's sales across time, note that that information will not be reliable for that purpose. The Diamond shipping charts only capture the number of comics it shipped of a title in the United States and Canada in a single calendar month, a figure which is highly volatile depending on the shipping calendar. You may see month-to-month swings of 10% or more which do not actually exist, because a comic book came out in, say, Week 1 in July and Week 5 in August. There's a reason we don't present such trendlines ourselves!
The better use of figures on individual issues is as intended: in context of an overall month, as a general relative indicator.