Miriam Ashour will turn 18 in November and speaks English with only the slightest of accents. She has a scholarship to study for a college degree in business administration at Columbia College, affiliated with the United Methodist Church, in Columbia, S.C.

But she will miss at least the first semester. She is among some 670 Gazans enrolled in schools abroad who have been denied permission to leave the territory.

That number includes six Fulbright scholars. Another two students, including Ms. Ashour, are sponsored by the Hope Fund, and a third by the Open Society Institute. At least 35 are enrolled in American institutions, according to an Israeli lobbying group, Gisha, which has sued the Israeli Supreme Court on behalf of the students.

Ms. Ashour said she still hoped to be allowed to leave, “but I feel sad, because I may lose the scholarship.”

Israel and Egypt have tightened the movement of goods and people into and out of Gaza since Hamas routed Fatah in June and took control of Gaza. The main goods crossings are shut, as is the Rafah crossing to Egypt for people. Israel is trying to use only the crossing at Kerem Shalom, which it controls, but Hamas and other militants have been mortaring it intermittently and demanding that the other crossings be opened.

Israel has declared Gaza a “hostile entity” and is moving to reduce its supplies of energy to the territory, while maintaining imports of essentials for life, hoping to put economic pressure on Hamas to stop constant rocket attacks from Gaza into Israel. Gaza is thus isolated diplomatically and economically.

According to the United Nations, an average of 74 truckloads of goods a day entered Gaza in October, down from 253 truckloads a day in April. The consequences have meant a shrinking economy coupled with a severe increase in prices even for basic foodstuffs like flour, cooking oil and chicken.

The average income of nonrefugees in Gaza has dropped 22 percent since June and 70 percent of them are now existing on less than $1.20 a day, compared with 55 percent in June, according to the World Food Program.

Since June, wheat prices have increased 40 percent, bread prices 20 percent and rice 15 percent. But because of the inability to export, the prices of vegetables have fallen 30 percent or more, further undermining the agricultural sector.

“Israel won’t allow a humanitarian crisis,” said Miri Eisin, spokeswoman for Prime Minister Ehud Olmert. “But Hamas forcibly took over Gaza, and they are the rulers now, and we don’t have to work after a violent takeover with people who attack us every day.”

Asked if she understood Israeli policy, Ms. Ashour said: “Yes, I do understand. Maybe if I were in their place I would do the same thing. But my family is clean. I’m not a hazard to anyone.”

Ghassan Matar, 25, is a Fulbright scholar who has had to delay his studies in business information systems at Central Michigan University. “No such field of studies exists in Gaza,” he said. “My dream is to focus on outsourcing in software, so I can invest in Gaza’s human resources. Such a field can flourish even if the crossings are closed.”

But Mr. Matar, who was supposed to start school on Aug. 27, is stuck in Gaza. The university, he said, has agreed to let him begin in the spring semester, in January. “I’m afraid to lose this chance,” he said. “I’ve worked two years to get this scholarship.” He describes himself as apolitical. “I blame all the parties,” he said.

The issue of the students has embarrassed the Israeli government, which is facing lawsuits and bad publicity for denying ordinary Gazans the chance to study in the West.

Christopher Gunness, a spokesman for the United Nations Relief and Works Agency, dealing with Palestinian refugees, said, “It cannot be in Israel’s interest to shrink the intellectual space in which peace and moderation can grow in Gaza.”

He added: “The next generation must have a decent education, both as a bridge from this shut-down Gaza and over which different values can find their way in. We all need to step back and look at the bigger picture. Isolation risks driving the younger generation into the hands of the radicals.”

Mark Regev, a spokesman for the Israeli Foreign Ministry, said that Hamas mortars had complicated the exit of students and the infirm, but that the government wanted to solve the student issue. “We don’t want to keep students locked up inside Gaza,” Mr. Regev said. “It’s kind of a self-inflicted wound. We hope to have a solution shortly.”

Shlomo Dror, a spokesman for the army’s coordinating office that deals with Gaza, said the issue was complicated. The Erez crossing into Israel was problematic, in part because Jordan did not want to handle hundreds of students, he said, followed by as many as 4,000 people seeking medical attention abroad.

An earlier effort to bus Gazans through Erez to Nitzana into Egypt was dangerous and long, he said, so now Israel wants to use Kerem Shalom. But Hamas regularly mortars it, and the airport authority that ran it removed security equipment when it was shut. “We’re trying to find a way to get them out with a high level of security,” Mr. Dror said. “If Hamas stops attacking Kerem Shalom, we can move out several hundred people a day.”

But the problems of the students can seem minor compared to other restrictions. Marwan Sawafiri, 40, who runs the Sawafiri for Chicken shop in Gaza City, said the price of chicken has risen about 40 percent since the end of Ramadan in mid-October, when Israel stopped allowing special shipments for the holiday.

Gazans raise chickens, he said. But the chickens are hatched from fertilized eggs imported from Israel, and fed with Israeli chicken feed. “Now we get many fewer imports, so the prices go up,” he said.

Coca-Cola and packaged fruit juice have disappeared from shops, and a printer cartridge costs $60. Even the price of flour, considered a necessity by Israel, has gone up 40 percent, said Muhammad Hassouna, 30, who runs his family’s grocery.

Hamad Dahdar, 25, the chief butcher at a clean but nearly empty meat shop, has been told that he can work only 20 days a month, to save other jobs. His income has gone down by a third, to $200 a month, “and you can see, we’re just standing around,” he said.

Stewing beef has gone up a third in price, “and people who once bought a kilo buy only a half,” he said. Beef and lamb are also imported through Israel and quantities are down. But taxes are not. The Hamas administration in Gaza, cut off by the Fatah-appointed government in Ramallah, is taxing imports, from cigarettes to beef. “Now we have two governments,” Mr. Dahdar said. “And both of them want to collect taxes.”