Serious question - why wouldn’t you search for the algorithm you need (or the problem statement) on Google scholar these days? I have the books but if I ever found myself reaching for them at work, I would consult most recent literature
Consider, as an example, Fascicle 5b, Introduction to Backtracking. His citations in the first 25 pages are from 1899, 1918, 2017, 1957, 1967, 1963, 1900, 1947, 1882, 1848, 1849, 1850, and 1960. Had he somehow managed to write this chapter in 01968 instead of 02019 he would only have been missing one of them, though surely the illustrations and experimental results of his own he reports would not have been as excellent, and surely the overall framing of the section benefits from the additional 61 years of hindsight.
In fact, although enormous progress has been made in backtracking in recent years, it hasn't affected the introductory aspects of the question. But clearly you can learn an enormous amount about backtracking without straying into the literature of the current millennium.
Of course other resources exist, many of which cite TAOCP or are derived from it