Los Angeles ? Google Inc.’s YouTube said Thursday it is vastly expanding its library of full-length movies and TV shows it offers online, while also launching a new advertising service and adding about a dozen new content partners.

The long-form videos will be housed on a unique page at www.youtube.com/shows and get a “Shows” tab on the main YouTube site.

The offering, which was due to go live late Thursday, marks a further departure from the fuzzy homemade clips that made the Web site popular and is the latest move in YouTube’s attempt to boost sales and profits.

Last week, YouTube announced it was teaming up with Universal Music Group to create an online music video venture.

“It’s a first step in a long commitment,” said Shiva Rajaraman, a YouTube senior product manager, in a conference call with reporters.

The company hopes to add to its movie and show content over time. The titles available at launch are mostly older fare that are already available elsewhere on the Web. It will offer for free hundreds of TV show titles including “Beverly Hillbillies” and “Married With Children,” and hundreds of movies, including “Casino Royale” and “Cliffhanger.”

The service expands on YouTube’s existing partnership with several studios, whose parents include Sony Corp., Lions Gate Entertainment Corp., CBS Corp., Metro-Goldwyn-Mayer Inc. and Liberty Media Corp.

On Thursday it also announced new partnerships with 13 smaller companies such as Discovery Communications Inc., National Geographic and SnagFilms LLC.

Advertising revenue will be shared with the content providers.