Trademark protects identifiers (logos, names, slogans, etc.) that are used to identify the source of a commercial good or service. They are administered by the USPTO and they last as long as they remain in active use.
Trade Secrets protect secret information, often information that isn't patentable or is too sensitive to patent. They only last as long as they're secret, and are protected by legal documents like non-disclosure agreements.
This European Patent Office (EPO) database has international coverage and includes an excellent Cooperative Patent Classifcation (CPC) search tool. Patent information is provided by more than 82 patent-granting organizations. Machine translations are available for many languages. Espacenet also does an excellent job of making connections between patent filings in different countries, identifying "patent families" that share claims.
This database covers international patents and rewrites the titles in easier-to-read language. Most topics go back to the 1960s. Chemical structure searching is available. This is a subscription database for Purdue users, and not open to the general public. Derwent is recommended for researchers and students, but is not the best choice for a formal patentability search.
This database features Google's easy-to-use search interface, but Google's search algorithm can be inconsistent when dealing with legal-technical patent language. You can use it for doing a first pass when patentability searching, but make sure to use other resources as well.
Scifinder covers chemical patents as well as journal articles, conference papers, and book chapters on chemistry and chemistry-related topics. It is licensed for Purdue users only and requires an additional registration.