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   9396篇
  免费   609篇
  国内免费   50篇
耳鼻咽喉   49篇
儿科学   301篇
妇产科学   323篇
基础医学   1361篇
口腔科学   121篇
临床医学   921篇
内科学   2185篇
皮肤病学   177篇
神经病学   889篇
特种医学   130篇
外科学   948篇
综合类   68篇
一般理论   8篇
预防医学   1030篇
眼科学   266篇
药学   666篇
中国医学   39篇
肿瘤学   573篇
  2024年   7篇
  2023年   69篇
  2022年   182篇
  2021年   344篇
  2020年   201篇
  2019年   283篇
  2018年   298篇
  2017年   219篇
  2016年   237篇
  2015年   314篇
  2014年   409篇
  2013年   499篇
  2012年   796篇
  2011年   834篇
  2010年   462篇
  2009年   392篇
  2008年   678篇
  2007年   686篇
  2006年   611篇
  2005年   562篇
  2004年   461篇
  2003年   424篇
  2002年   422篇
  2001年   64篇
  2000年   40篇
  1999年   57篇
  1998年   62篇
  1997年   39篇
  1996年   28篇
  1995年   38篇
  1994年   28篇
  1993年   30篇
  1992年   28篇
  1991年   28篇
  1990年   25篇
  1989年   19篇
  1988年   18篇
  1987年   19篇
  1986年   13篇
  1985年   17篇
  1984年   17篇
  1983年   10篇
  1982年   9篇
  1981年   13篇
  1980年   5篇
  1979年   5篇
  1978年   7篇
  1977年   8篇
  1973年   4篇
  1970年   4篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Thymolipoma is a rare thymic tumor; His frequency is estimated at 2 at 9% of all thymic tumors. His diagnosis usually easy, can be difficult with an unusual radio clinic pattern, but actually get benefice from progress in radiologic investigations especially MRI. We reported a case of a 36-year old woman, admitted for a left pleuro-pneumopathy investigation. Evolution, after antibiotic treatment and pleural effusion draining, was well. However, patient developed systolic aortic murmur and a chest-X-ray cardiomegaly supposing cardiologic dysfunction. But the normality of cardiac sonography, the ascension of diaphragma and non-specific thoracic sonographic pattern, guided to thoracic MRI. This exploration demonstrated a giant thymolipoma, which was confirmed by the histologic examination of a resected mass.  相似文献   
992.
Background: The ProSeal(TM) Laryngeal Mask Airway (PLMA) (Laryngeal Mask Company, Henley-on-Thames, United Kingdom) is a new laryngeal mask with a modified cuff designed to improve its seal and a drain tube for gastric tube placement. Similarly, the Laryngeal Tube Suction (LTS) (VBM Medizintechnik Gmbh, Sulz a.N, Germany) is a new laryngeal tube that also has an additional channel for gastric tube placement. This study compared the placement and functions of these two devices.

Methods: One hundred fifty patients undergoing general anesthesia for elective surgery were randomly allocated to the PLMA (n = 75) or LTS (n = 75). Oxygenation and ventilation, ease of insertion, fiberoptic view, oropharyngeal leak pressure, ventilatory data, ease of gastric tube insertion, and postoperative airway morbidity were determined.

Results: After successful insertion of the devices in 96% of patients with the PLMA and in 94.4% with the LTS it was possible to maintain oxygenation, ventilation, and respiratory mechanics during the entire duration of surgery. Successful first and second attempt insertion rates were 57 patients (76%) and 15 patients (20%), respectively, for the PLMA and 60 patients (80%) and 11 patients (14.6%), respectively, for the LTS. Airway placement was unsuccessful with the PLMA in three patients and with the LTS in four patients. Time to achieve an effective airway was 36 +/- 24 s with the PLMA versus 34 +/- 25 s with the LTS. Gastric tube insertion was possible in 97.3% of patients with the PLMA and in 96% with the LTS.  相似文献   

993.
994.
The influence of gonadal steroids on the ultrastructure of glial cells and on the immunoreactivity for the specific astrocytic marker glial fibrillary acidic protein (GFAP) has been assessed in the neuroendocrine hypothalamus. The following parameters were analyzed in the arcuate nucleus of adult female rats: the number and the surface density of cells immunoreactive for GFAP, the number of glial profiles showing bundles of glial filaments, the size of the bundles of glial filaments, and the proportion of neuronal perikaryal membrane apposed by glial processes. These parameters were studied during the different phases of the estrous cycle, after ovariectomy, and after the administration of estradiol or progesterone to ovariectomized rats. No significant differences were detected in the number of GFAP-immunoreactive cells among the different experimental groups. The surface density of GFAP-immunoreactive material, the number of glial profiles in the neuropil, and the proportion of neuronal perikaryal membrane covered by glia were increased in the afternoon of proestrus and in the morning of estrus compared with other phases of the estrous cycle or to ovariectomized rats and showed a rapid (5 h) and reversible increase in ovariectomized rats injected with 17β estradiol, with a maximal effect by 24 h after the administration of the hormone. In contrast, the size of the bundles of glial filaments was decreased in the afternoon of proestrus, in the morning of estrus, and by the administration of estradiol to ovariectomized rats. The parameters studied were not affected by the administration of progesterone. However, progesterone (300 μg/rat) blocked the effects of 17β estradiol (1, 10, and 300 μg). The results suggest that glial cells may be actively involved in the modulation of neuroendocrine events by the hypothalamus. © 1994 Wiley-Liss, Inc.  相似文献   
995.
996.
Clusters of Parkinson's disease (PD) among healthcare professionals have been interpreted as evidence of an infectious etiology. Anesthetic gases have also been associated with parkinsonism symptoms and PD among patients undergoing general anesthesia. We investigated PD mortality among large cohorts of male U.S. anesthesiologists (n = 33,040) and internal medicine physicians (n = 33,044). PD mortality for any mention on a death certificate was lower than rates in U.S. men during 1979-1995 for both groups, although anesthesiologists had a significantly elevated risk for PD as underlying cause of death for 10-year follow-up. Direct comparisons of mortality between the two cohorts indicated excess PD mortality in anesthesiologists for >10-year follow-up for any mention and for underlying cause of death. These findings lend some support to the hypothesis that infectious agents or anesthetic gases may be associated etiologically with PD.  相似文献   
997.
998.
Even today major hepatic trauma remains a formidable surgical challenge with considerable deaths from exsanguination. Apart from conservative operative techniques that allow successful management in most cases, liver transplantation may be indicated in a more severe injury. This is a report on a patient with massive, unsalvageable liver trauma on whom the first two-staged procedure was successfully performed. After total hepatectomy as the first step and a prolonged anhepatic period of more than 14 hours, liver replacement by an allograft was carried out in a second operation. The patient recovered completely from the potentially lethal hepatic trauma and is alive more than 17 months later.  相似文献   
999.
Chronic inflammation during rheumatoid arthritis and degenerative processes during osteoarthritis eventually result in joint destruction. Anti-inflammatory therapies facilitate the inhibition or delay of progressing joint cartilage and bone loss, but do not regenerate these tissues. Surgical procedures are quite unsatisfactory in long-term evaluation and often lead to endoprothetic joint replacement. Present tissue engineering technologies offer new strategies for the treatment of cartilage and bone defects. Here, beyond implantation of cell suspensions, biomaterials combined with tissue-specific cells or mesenchymal stem cells are clinically applied. This review focuses on state-of-the-art and future in situ mesenchymal stem cell-based tissue engineering approaches for joint repair in patients with rheumatic diseases.  相似文献   
1000.
Mesenchymal stem cells (MSCs) are multipotent cells with a number of potential therapeutic applications. At present, they are being used in a clinical trial for the treatment of myocardial infarction and are being studied as a therapy for other vascular disorders. Treatments of neurologic disorders and anticancer therapy with MSCs have progressed in light of the migratory properties of MSCs to brain injury and tumors. The osteogenic potential of MSCs is being exploited in work investigating their use in bone regeneration therapy, and the immunomodulatory function of MSCs is being evaluated as a possible therapy for graft-versus-host disease. Here, the authors review recent work contributing to the knowledge of MSC biology and the advances in gene therapy and tissue regeneration using MSCs.  相似文献   
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