Close the vacancy with bases the data itself is a search engine is simple enough. All that is needed – to know where to begin and where the "hit". Take, for example, databases that are in communication with the active output of enterprises in the network are updated regularly replenished and structured. The most important are targeted and reference systems. Send "addresses phones" in Yandex you get to issue the results of a long list of various "yellow pages". And the very first link leads you a great opportunity not to look for the address information in the vast network, and get ready for use. Multi-level index in industries and activities, as well as regional filters can significantly reduce the time for selection of interesting for you, "the companies-donors", whose employees are potentially those who you want. The most recent nesting level Categorization – card company.
All that is needed – go to a link to web-resource companies, make inquiries and find a corporate email address from which you will need for further work only the second part. The next step – search of traces, which the company has left the network. Request the "Company + @ -.ru (instead of Yandex, you can use a more precise queries in the context Google.ru) will give you at least an extensive compendium of information about employees of the company desired, lit by the nature of themselves and their e-mail of tenders, exhibitions, seminars and other industry events. This may be information on the registration lists and name badges, left feedback, news articles and press releases, interviews or commercial offers.