首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   482篇
  免费   23篇
  国内免费   50篇
耳鼻咽喉   1篇
儿科学   19篇
妇产科学   23篇
基础医学   48篇
口腔科学   7篇
临床医学   75篇
内科学   110篇
皮肤病学   13篇
神经病学   16篇
特种医学   48篇
外科学   60篇
综合类   46篇
预防医学   24篇
眼科学   9篇
药学   51篇
中国医学   1篇
肿瘤学   4篇
  2018年   5篇
  2015年   6篇
  2014年   5篇
  2013年   14篇
  2012年   2篇
  2011年   2篇
  2010年   11篇
  2009年   10篇
  2008年   2篇
  2007年   33篇
  2006年   9篇
  2005年   7篇
  2004年   4篇
  2003年   3篇
  2001年   9篇
  2000年   6篇
  1999年   9篇
  1998年   14篇
  1997年   17篇
  1996年   17篇
  1995年   12篇
  1994年   10篇
  1993年   17篇
  1992年   7篇
  1991年   8篇
  1990年   10篇
  1989年   9篇
  1988年   7篇
  1987年   11篇
  1986年   3篇
  1985年   4篇
  1984年   4篇
  1982年   7篇
  1981年   4篇
  1980年   4篇
  1978年   4篇
  1977年   5篇
  1976年   4篇
  1975年   2篇
  1973年   2篇
  1959年   21篇
  1958年   32篇
  1957年   29篇
  1956年   34篇
  1955年   28篇
  1954年   18篇
  1949年   23篇
  1948年   29篇
  1946年   3篇
  1940年   2篇
排序方式: 共有555条查询结果,搜索用时 15 毫秒
1.
Most ureteral tumors are transitional cell neoplasms. Neuroendocrine tumors of the genitourinary tract are extremely rare. To our knowledge, only one ureteral carcinoid tumor has been reported before. We report a second case of ureteral carcinoid tumor found in a 70-year-old female.  相似文献   
2.
Background. It is estimated that over 100,000 new cases of squamous cell carcinoma are diagnosed in the United States annually. This number is compounded by an increasing concern over the ozone layer depletion and the continued sunbathing behavior of many individuals. This could be particularly acute in Hawaii, which may have the highest rates of skin cancer in the country. We believe the updated information on skin cancer is essential to address the magnitude of the problem. Methods. A prospective 5-year population-based incidence study was conducted on Kauai, Hawaii, between 1983 and 1987 to investigate the frequency of squamous cell carcinomas in resident Caucasians. Results. A total of 58 residents, 37 men and 21 women, were identified with an initial episode of squamous cell carcinoma during the 5-year period. The average annual incidence rate per 100,000 Kauai Caucasian residents, standardized to the 1980 U.S. white population, was 153 for men and 92 for women with a combined rate of 118. The average patient age was 66.4 years. The head and neck was the most common anatomic site, with the extremities second. Subsequent new squamous cell carcinoma occurred in 13.8% of patients. Only one patient (2%) developed a recurrence after treatment. Twenty-five patients (43%) had basal cell carcinoma simultaneously or at other earlier times. Conclusions. In Kauai the incidence rate of squamous cell carcinoma is the highest yet documented in the United States. No consistent trend in incidence rates was appreciated during this 5-year period.  相似文献   
3.
Over the past decade, the unfortunate reality is that the income gap has widened between Canadian families. Educational outcomes are one of the key areas influenced by family incomes. Children from low-income families often start school already behind their peers who come from more affluent families, as shown in measures of school readiness. The incidence, depth, duration and timing of poverty all influence a child’s educational attainment, along with community characteristics and social networks. However, both Canadian and international interventions have shown that the effects of poverty can be reduced using sustainable interventions. Paediatricians and family doctors have many opportunities to influence readiness for school and educational success in primary care settings.  相似文献   
4.
5.
6.
7.
8.
9.
The effectiveness of a sequential regimen consisting of mifepristone, 10 mg/day for 15 days, followed by nomegestrol acetate (NOMA), 5 mg/day for the next 13 days, for inhibiting ovulation and maintaining regular bleeding cycles was assessed in 10 surgically sterilized volunteers who were followed for one pretreatment and three treated cycles. Hormonal determinations in blood and urine, ovarian ultrasonography, bleeding records in all cycles and an endometrial biopsy taken on day 22-25 of the third treatment cycle were used to monitor the effects of treatment. During treatment, 24 monophasic (no sustained progesterone rise above 12 nmol/l) and six biphasic cycles were recorded. Nine follicular ruptures were detected echographically in these 30 treated cycles, five of which occurred in monophasic cycles. All follicular ruptures occurred on days 1-7 of NOMA treatment. Echographic and endocrine features of ovulatory cycles were both present in only four treated cycles (13.3%). Development of a secretory endometrium was achieved in all cases, but it was always irregular. Regular withdrawal bleeding occurred in all subjects and no adverse reactions were recorded. The ovarian and endometrial effects of this regimen justify testing its contraceptive effectiveness in phase 2 clinical trials.   相似文献   
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号