Detectives who seek to establish what happened come up against serious cognitive obstacles.

"Keep plugging away - even when you come up against obstacles."

But such an effort would have run up against formidable practical and political obstacles.

They say a new relief effort, against daunting obstacles, is needed.

You'll regularly come up against obstacles that can only be passed by working with your teammates.

It was the tendency for a person to persist against obstacles.

But private enterprise has run up against obstacles set deep in the Soviet system and psychology.

He was never one to hit his head against obstacles greater than himself, he notes.

At that point, the only strategy against obstacles is avoidance.

Yet across the city, the small schools labored against innumerable obstacles.