The Espacenet database, the largest database of patent data, has been improved in a couple of ways.
This database contains PDFs of patent specifications from numerous countries, going back to for example the USA (1836), Germany (1877) and Britain (1895). Many European countries are held from 1920 onwards. A certain amount can be searched for in English, especially in recent decades. It is best to learn how to use it by going to the "Get Assistance" tutorial in the Advanced Search format.
Formerly search terms were not highlighted in the results, but they now generally appear in yellow. This makes it much easier to spot the word you searched for within the summary.
The old "up to four terms" only in each field restriction seems to have vanished. This is useful if you have many keywords.
Formerly you could not sort the results. Now, provided there are fewer than 500 hits, they can be sorted by date, priority date, inventor, applicant or ECLA. Sorting by date is most useful for historians of technology as the earliest entries appear first. ECLA is based on the International Patent Classification, which is printed on patent specifications, but often provides much more precise classes, and goes back to 1877 for Germany and about 1909 for Britain (and 1920 for USA and many European countries). It does not cover Far Eastern countries.
Such definitions can then be requested by clicking in the box next to the definition and then clicking on Copy on the same page. This then sends the class to the search page (and wipes out any previous search).
And date limits can now be used. Hence in the date field using e.g. 1950:1970 restricts hits to any within those years.
I would suggest that this database is the best to start off with if you are looking for a particular invention, whether modern or old.