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   690篇
  免费   46篇
  国内免费   8篇
耳鼻咽喉   2篇
儿科学   52篇
妇产科学   5篇
基础医学   71篇
口腔科学   14篇
临床医学   101篇
内科学   183篇
皮肤病学   2篇
神经病学   22篇
特种医学   138篇
外科学   34篇
综合类   8篇
预防医学   23篇
眼科学   5篇
药学   48篇
中国医学   2篇
肿瘤学   34篇
  2023年   3篇
  2022年   8篇
  2021年   13篇
  2020年   4篇
  2019年   5篇
  2018年   9篇
  2017年   5篇
  2016年   3篇
  2015年   6篇
  2014年   10篇
  2013年   17篇
  2012年   19篇
  2011年   23篇
  2010年   14篇
  2009年   16篇
  2008年   18篇
  2007年   25篇
  2006年   20篇
  2005年   25篇
  2004年   13篇
  2003年   16篇
  2002年   13篇
  2001年   14篇
  2000年   10篇
  1999年   10篇
  1998年   39篇
  1997年   59篇
  1996年   41篇
  1995年   32篇
  1994年   34篇
  1993年   25篇
  1992年   16篇
  1991年   10篇
  1990年   6篇
  1989年   19篇
  1988年   19篇
  1987年   17篇
  1986年   21篇
  1985年   20篇
  1984年   9篇
  1983年   7篇
  1982年   11篇
  1981年   6篇
  1980年   9篇
  1978年   6篇
  1977年   8篇
  1976年   5篇
  1975年   5篇
  1972年   1篇
排序方式: 共有744条查询结果,搜索用时 15 毫秒
101.
5-Phenyl-1,2,3,4,5,6-hexahydroazepino[4,5-b]indole (3a) and five derivatives have been prepared and screened for neuroleptic activity. None of the compounds antagonized methamphetamine aggregate toxicity in mice. A number of compounds, including 3a and its 3-methyl derivative 3d, showed activity in the antidepressant screens.  相似文献   
102.
103.
104.
105.
The Mark IV system for radionuclide computed tomography of the brain   总被引:5,自引:0,他引:5  
  相似文献   
106.
The radiopharmaceutical iodine 131 metaiodobenzylguanidine (I-131 MIBG) has been shown to locate pheochromocytomas scintigraphically with a false-negative rate of approximately 13%. To improve image quality and reduce the false-negative rate, I-123 was examined as a radioactive label for MIBG, as it has many advantages over I-131, including superior dosimetry and better detection efficiency. Diagnostic doses of 0.5 mCi (18.5 MBq) I-131 MIBG and 10.0 mCi (370.0 MBq) I-123 MIBG with nearly equivalent radiation dosimetries were compared in 18 patients with known or suspected pheochromocytomas. Images of superior quality were obtained with I-123 MIBG in 18 of 18 patients, and in eight cases lesions not visualized on I-131 MIBG scintigraphy were portrayed. A further advantage of I-123 MIBG is that it permits single photon emission computed tomography (SPECT). This was performed in six cases and provided additional information in three cases. The adrenal medullae were definitely visualized using I-123 scintigraphy in eight of 14 patients still possessing adrenal glands, whereas I-131 MIBG images portrayed the adrenal medulla in only one of 14 cases. Five remaining patients had multiple abdominal tumor deposits that were difficult to differentiate from normal adrenal medullae.  相似文献   
107.
Localized phosphorus-31 magnetic resonance (MR) spectroscopy in humans has previously been accomplished with surface coils by means of depth-resolved surface coil spectroscopy or rotating frame experiments, in which the extent of tissue sampled critically depends on surface coil placement. The authors' goal was to modify the surface coil image-selected in vivo spectroscopy (ISIS) experiment to accomplish three-dimensional volume selection through application of selective pulses in the presence of B0 gradients. Advantages of ISIS include the ability to use proton images to define the volume of interest (VOI) and reduced dependence on exact positioning of the surface coil. However, rapid replication of the surface coil ISIS experiment can cause spectral contamination from signals originating outside the VOI. A modified version of the ISIS experiment was developed to alleviate contamination under conditions of rapid replication. Applications of localized P-31 MR spectroscopy for observation of high-energy phosphorus metabolites are presented in human liver, heart, and transplanted and normal kidney.  相似文献   
108.
Endoscopic retrograde biliary drainage   总被引:1,自引:0,他引:1  
Marks  WM; Freeny  PC; Ball  TJ; Gannan  RM 《Radiology》1984,152(2):357
  相似文献   
109.
110.
Melanin-concentrating hormone (MCH) is a cyclic, nonadecapeptide expressed in the CNS of all vertebrates that regulates feeding behavior and energy homeostasis via interaction with the central melanocortin system. Regulation of this interaction results in modulation of food intake and body weight gain, demonstrating significant therapeutic potential for the treatment of obesity. The MCH-1 receptor (MCH-R1) has been identified as a key target in MCH regulation, as small molecule antagonists of MCH-R1 have demonstrated activity in vivo. Herein, we document our research in a bicyclo[3.1.0]hexyl urea series with particular emphasis on structure-activity relationships and optimization of receptor occupancy, measured both in vitro and via an ex vivo binding assay following an oral dosing regimen. Several compounds have been tested in vivo and exhibit oral efficacy in relevant acute rodent feeding models. In particular, 24u has proven efficacious in chronic rodent models of obesity, showing a statistically significant reduction in food intake and body weight over a 28 day study.  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