This thesis examines the optionality of Russian genitive case under negation, using native-speaker data and online resources, such as Internet search engines and linguistic corpora. Of special interest is assessing the role of negative intensifier phrases in selecting genitive or other grammatical case forms. The paper includes a discussion of the pros and cons of relying on online resources in linguistic research, as well as an overview of the use of the Russian National Corpus, a highly robust linguistics research tool.