DURRES, Albania — With each piece of rubble pulled off the twisted pile of steel and concrete that used to be a four-story home, Luca Martino and his rescue dog, Foglia, were called into action.

“If there is room for air to come to the outside, the dog can smell it,” Mr. Martino, a rescue worker from Italy, said during a break on Thursday. “If someone is alive, Foglia will bark.”

On this day, the dog had not barked .

It was slow, arduous work, repeated at numerous sites in Albania in the aftermath of a 6.4-magnitude earthquake that struck on Tuesday, leaving at least 47 people dead. And in this Adriatic coast city, where many buildings were leveled and many more were dangerously damaged, the rescuers knew that hopes were fading.

“There is still time,” Mr. Martino said. Nine members of the Lala family had been in the home when it collapsed. Four had died, one had already been rescued, but four remained beneath the rubble.