Baidu Inc reports that its first-quarter profit more than doubled in 2011.

Baidu Inc, the most popular search engine in China, introduced a service on Wednesday that will make it easier for customers to access content they have searched for on mobile devices.

The step is intended to fend off competition from rivals such as Tencent Holdings Ltd.

The mobile "box computing" service, as Baidu calls it, takes users directly to games, e-books, music or other content they have searched for instead of showing a list of Web pages containing links to that content. With it, Baidu is trying to bring a variety of Internet services to its basic search engine.

"Giving users better searching experiences with 'box computing' will help us gain more market share," said Yue Guofeng, general manager at Baidu's mobile Internet division.

Baidu is using the service to stay ahead of competitors such as Tencent Inc and the US-listed Qihoo 360 Technology Co, analysts said.

Tencent, which owns the instant-messaging service QQ - one of the most popular applications in China - has been working with software developers to add various Internet offerings to its main product. Qihoo has adopted a similar approach.

"The three companies all have a large number of users, and by providing diversified services on their own platforms, they can monetize their large user bases," said Fang Li, an analyst with the domestic research company Analysys International. She added that although Baidu provides search services, Tencent instant messaging, and Qihoo security, the companies compete with each other as Internet sites that offer diversified Internet services.

Baidu said earlier this month that it will invest $306 million in Qunar.com, a Chinese online travel website. Yue said the step is intended to add to the number of Internet services offered by Baidu.

Tencent has also poured billions of yuan into investments this year. The money has gone into e-commerce, online travel, movies and other products and services.

Similarly, the companies have all begun offering "open platforms" as a means of working with services providers and application developers to diversify the services found on their websites.

In the first quarter of the year, Baidu handled 36 percent of the Internet searches coming from mobile devices. Following it were Easou.com, which handled 19 percent of those searches, Tencent's Soso.com, which handled 14.7 percent and Google Inc, which handled 11.5 percent, according to Analysys International.

The company expects the number of searches though mobile phones will overtake those made through PCs in three to five years.

There has been speculation that Baidu is trying to devise an operating system for mobile phones that will be built on Google's Android system, but Yue declined to comment on the matter.