President Bush advised college graduates on Saturday to use technology but not become enslaved by it.

"Science offers the prospect of eventual cures for terrible diseases — and temptations to manipulate life and violate human dignity," Bush said during commencement exercises at Oklahoma State University. "With the Internet, you can communicate instantly with someone halfway across the world — and isolate yourself from your family and your neighbors."

The nation's young generation will wrestle to resolve these dilemmas, he said.

"My advice: Harness the promise of technology without becoming slaves to technology. My advice is that science serves the cause of humanity and not the other way around," the president said.

Bush highlighted recent economic gains and told the graduates that an improving job market is giving them more job opportunities.

"The job market for college graduates is the best it has been in years," he said. "This economy of ours is strong and so you'll have more jobs to choose from than previous classes and your starting salaries will be higher. And the opportunities beyond are only limited by the size of your dreams."

Graduates in the 2,700-member class assembled in Boone Pickens Stadium wore plastic slickers to keep their gowns dry from drizzle. Bush spoke from a covered platform to a crowd of about 20,000 people, many of whom wore orange raincoats made available to those in the stadium. Protesters staged a peaceful demonstration outside.

Laughter and applause greeted Bush's reference to the university's cowboy mascot: "If you read the papers, you know that when some want to criticize me, they call me a cowboy. ... This cowboy is proud to be standing amidst of a lot of other cowboys."

Bush urged the graduates not to become isolationists but, instead, to help enhance education and foster technological advances the United States needs to compete with the world's economic powers.

"We are also seeing the rise of new competitors like China and India, and this competition creates uncertainty," he said.

"Some look at the changes taking place all around us, and they worry about our future. Their reaction is to wall America off from the world, and to retreat into protectionism. This is a sure path to stagnation and decline," he said.

"I ask you to reject this kind pessimism," he said. "We should welcome competition because it makes our country stronger and more prosperous."

Noting that 27 lieutenants were receiving their Army and Air Force commissions along with their degrees, Bush recalled Oklahoma State graduate Luke James. After he earned his commission in 2004, James was deployed to Iraq as a member of the Army's 82nd Airborne Division and died shortly after arriving there. The husband and father of one was awarded the Bronze Star and buried at Arlington National Cemetery.

"While no soldier wants war, he understood the necessity of war — that it can ensure the freedoms we enjoy in America," Bush said. "Luke James is part of a generation who are every bit as selfless and dedicated to liberty as any that has come before, and our future is better because of the character of young Americans like Luke James."

The speech was one of four Bush is delivering this commencement season. He will speak on Thursday at Mississippi Gulf Coast Community College, which was hit by Hurricane Katrina; on May 27 at the U.S. Military Academy in West Point, N.Y.; and on June 19 at the U.S. Merchant Marine Academy.

About 250 protesters held signs and chanted anti-Bush slogans a block from the OSU stadium. One protester held a sign that read, "Worst President Ever."

"If he's coming to my town, I'm going to let him know he's not welcome here and that Oklahomans are not as bright as they think," said Laurie Keeley, 25, a protester from Tulsa.