"extensive examination of" is correct and can be used in written English.
It is typically used to describe a thorough and detailed analysis or investigation of something. Example: The scientists conducted an extensive examination of the data to determine the cause of the anomaly.
State regulators soon conducted an extensive examination of the company and found that it was not complying with the rules.
Amnesty International conducted an extensive examination of the case, documenting the many recantations, inconsistencies, contradictions and unanswered questions.
Mr. Dixon's lawyers have suggested in court that an extensive examination of his past conducted for them by a social worker had indicated learning difficulties and emotional problems.
White House officials, led by Mr. Bush's chief political adviser, Karl Rove, are in the midst of an extensive examination of the history of previous re-election campaigns.
The second request for information means regulators will do a more extensive examination of the deal, rather than approving it immediately.
"A year ago we renewed his contract for another term and we had a fairly extensive examination of what he has done," he noted.
The officials said the report would portray a more complicated and detailed picture, based on a far more extensive examination of suspected Iraqi weapons sites and records, as well as the debriefings.
Despite the parents' instructions, Professor Dick van Velzen, 55, carried out an "extensive" examination of the teenager's organs, excluding only the brain, and kept fragments in the Liverpool children's hospital, the General Medical Council (GMC) heard.
The latest and most extensive examination of electoral irregularities, released in November by the nonpartisan research institute Demos, determined that voter fraud was "very rare," and every other respectable study has reached the same conclusion.
Through a patient and extensive examination of local as well as national archives, Thompson had uncovered details about workshop customs and rituals, failed conspiracies, threatening letters, popular songs, and union club cards.
The National Transportation Safety Board concluded, after an extensive examination of wreckage, that a stray spark of undetermined origin set off a flammable mixture of gases in the nearly empty center fuel tank of the T.W.A. plane, a Boeing 747.
