Generally, patent documents for the full text of major foreign patent searching can be performed through the databases of individual patenting authorities. Most major patenting authorities such as the United States, United Kingdom, EPO, France, Germany, Japan, Korea, and WIPO provide online access to their databases of patent documents for searching.
While performing a patent search, the searcher should be aware of the ranges of dates that individual foreign patent authority databases cover, as many of these databases only cover full text searching for patent documents starting from last few 1years.
Further, English-language records of foreign patent documents are rarely available. The exceptions are patents granted by the EPO and patents filed by the PCT, which will have English-language titles and claims, and occasionally are written in full-text English, or for that matter, Great Britain (GB), Canadian, and Australian patents which are also published in English.
Furthermore, the primary challenge presented by text searching in foreign patents is constructing useful search queries using foreign language keywords. For example, a two-word concept or phrase for search strings in English, may have a different word order of query when translated to the concerned language.
One approach that may be used to finding whole foreign phrases in their proper form is to query a database of EP or PCT documents with an English search string and to restrict your search to the title, abstract, and claims’ fields. If the results list includes documents originally published in the language of interest, the searcher may be able to identify the foreign equivalents of your search string text by skimming the foreign language title and claims.
Another strategy to search non-native language foreign patents is to search abstract-only databases. When performing such a search, you will need to format your query correctly; this is not always the same query you might use when searching full text.
One another way to go is using Web-based subscription services which provide full-text searches of some collections of foreign documents. Usually such resources are convenient for searching in multiple collections at once, and often include advance capabilities to make the search process simpler and more exhaustive, but generally comes at a steep cost.