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   31848篇
  免费   2943篇
  国内免费   2380篇
耳鼻咽喉   235篇
儿科学   258篇
妇产科学   330篇
基础医学   3759篇
口腔科学   491篇
临床医学   4689篇
内科学   4646篇
皮肤病学   249篇
神经病学   1711篇
特种医学   1071篇
外国民族医学   21篇
外科学   2898篇
综合类   5424篇
现状与发展   5篇
一般理论   2篇
预防医学   1817篇
眼科学   1190篇
药学   3583篇
  26篇
中国医学   1899篇
肿瘤学   2867篇
  2024年   100篇
  2023年   518篇
  2022年   1446篇
  2021年   1762篇
  2020年   1356篇
  2019年   1214篇
  2018年   1123篇
  2017年   1158篇
  2016年   1000篇
  2015年   1590篇
  2014年   1853篇
  2013年   1532篇
  2012年   2335篇
  2011年   2543篇
  2010年   1517篇
  2009年   1184篇
  2008年   1583篇
  2007年   1564篇
  2006年   1625篇
  2005年   1820篇
  2004年   999篇
  2003年   865篇
  2002年   784篇
  2001年   682篇
  2000年   653篇
  1999年   761篇
  1998年   531篇
  1997年   503篇
  1996年   390篇
  1995年   368篇
  1994年   305篇
  1993年   213篇
  1992年   233篇
  1991年   214篇
  1990年   191篇
  1989年   143篇
  1988年   146篇
  1987年   102篇
  1986年   99篇
  1985年   66篇
  1984年   29篇
  1983年   24篇
  1982年   11篇
  1981年   19篇
  1980年   9篇
  1979年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
191.
High-frequency deep brain stimulation (DBS) of the subthalamic nucleus (STN) improves the motor symptoms of Parkinson's disease (PD). Opposite changes in mood, such as mania or depression, have been reported after surgery, but it is not known whether these side effects are specifically related to STN DBS. To learn whether STN DBS also influences the limbic loop, we investigated acute subjective psychotropic effects related to levodopa or bilateral STN DBS. After a median postoperative follow-up of 12 months, 50 PD patients completed the Addiction Research Center Inventory (ARCI), assessing subjective psychotropic effects in four conditions: off-drug/on-stimulation; off-drug/off-stimulation; on-drug/off-stimulation; and on-drug/on-stimulation. Both levodopa and STN DBS improved all the ARCI subscales, indicating subjective feelings of well being, euphoria, increase in motivation, and decrease in fatigue, anxiety, and tension. A suprathreshold dose of levodopa was significantly more effective than STN DBS, using the same electrical parameters as for chronic stimulation, on four of the five ARCI subscales. We concluded that 1) both STN DBS and levodopa have synergistic acute beneficial psychotropic effects in PD, 2) the psychotropic effects of both treatments need to be considered in the long-term management of chronic STN DBS, and 3) the results indicate an involvement of the limbic STN in mood disorders of PD.  相似文献   
192.
A modified exeimer laser energy delivery system was used to irradiate 100 segments of normal and fibrous aorta in vitro. The laser beam was scanned into 8 fiber bundles consisting of 50 fibers each resulting in a reduction of the applied pulse energy. The total repetition rate was increased to 150 Hz in order to keep the repetition rate per fiber bundle close to 20 Hz and to minimize thermal injury. The results demonstrate that effective ablation (etch rate per 8 pulses > 2.0 μm) occurred at an energy fluency of 50 mJ/mm2 in both normal and fibrous aorta. Tissue damage (carbonization, tissue separation, fissures, cracks, and vacuolization) was in a range of 100 ± 28 to 152 ± 30 μm for normal aorta and in a range of 57 ± 35 to 110 ± 39 μm for fibrous aorta. We conclude that effective ablation of normal and fibrous human aorta can be achieved by the application of smooth excimer laser coronary angioplasty. This improvement of excimer laser technology may result in a reduction of shock wave- and cavitation-induced damage leading to a reduction of tissue injury. However, this awaits further in vitro and in vivo confirmation. © 1993 Wiley-Liss, Inc.  相似文献   
193.
Radiologic and pathologic mani;estations of 30 peripheral pulmonary masses around l.5-3 cm in dia- meter were compared to the pathologic basis of va- cuole sign and small node sign on tomogram. Stati stics of 100 conventional X-ray tomograms of peri- pheral pulmonary masses about l-3 cm in diameter suggested that the vacuole sign and small node sign, more common in early peripheral lung cancer than in tuberculoma, are valuable for differentiating early peripheral lung cancer from tuberculoma.  相似文献   
194.
随着螺旋CT成像技术的不断发展,螺旋CT扫描对腹部及腹膜后等疾病的显示,特别是对肝脏等实质部分的显示,是传统X线摄影所不及的。肝脏螺旋CT检查技术已经日益成为肝癌等肝脏占位性病变的常规检查方法,如何提高螺旋CT扫描的图像质量以满足临床诊断是需要进一步解决的问题。笔者通过实践,对如何合理地优化扫描参数,得到高质量的图像有一些经验体会,现总结如下。  相似文献   
195.
All mammalian metallothionaln genes studied to dare have several metal responsive elements (MRE) with consensus sequences of TGCRCNC (R, purlne) in their regulatory region. MRE-11ke sequeaees were also found in many other metal-related genes. To see whether there is also such a sequence at the genetic locus (13q14. 3) d Wilstm disease, which is a genetic disorder d copper metabolisa‘‘n, junction-trapping method baaed on the MRE sequence was used. A fragment containing MRE and MRE-like sequences from YAC 27D8 at the WND locus was successfully cloned and mapped back to the YAC by PC, R, Presence of such a sequence in the copper transporter gene at the W‘‘D locus might imply that it has a possible interesting role in the regulation of WD gene expression.  相似文献   
196.
目的进一步研究声带小结与息肉的治疗手段。方法采用日本OlimpusBFp20型纤支镜和国产FF-99光电子内窥镜显示仪,配合间接万向喉钳治疗声带小结和息肉57例。结果治愈率92%,病人痛苦小。结论纤支镜配合间接喉钳手术治疗声带小结和息肉效果良好。  相似文献   
197.
本文观察了频率为20Hz、振幅为0.67mm和作用时间为40min的振动预处理对急性缺氧小鼠肺损伤的影响。结果发现实验组的肺组织匀浆脂质过氧化物LghdPeroxde(LPO)、支气管肺泡灌洗液(BALF)中蛋白含量和白细胞数明显低于对照组(P<0.05)。这表明在特定率数的振动作用下能明显减轻急性缺氧小鼠肺的损伤。  相似文献   
198.
对10名男性受试者单剂量po240mgVer缓释片药代动力学及心电图变化进行研究。血药浓度—时间数据用零级吸收过程的一室模型拟合,其药代动力学参数:Tmax5.9±1.6h;Cmax118.9±37.2μg·L-1;T1 5.4±1.5h;k030.5±17.5μg·L-1·h-1;T1/210.8±4.9h。PR间期延长有显著意义,血药浓度与PR间期变化满足S 型模型,其药效学参数:EC50 64.6±16.9μg·L-1; Emax54±11ms;s 1.68±0.66。  相似文献   
199.
用Multiquadric方法实现医学图像的弹性配准   总被引:3,自引:1,他引:2  
目的改进医学图像弹性配准的精确度和配准方法的稳定性,并简化配准操作。方法 利用Multiquadric插值方法的可平滑性质,将其与一种半自动标记点选择方法结合。建立一种新配准方法。结果 运用此方法进行医学图像的弹性配准,实现了标准图像与变形图像的快速,准确配准,结论 我们建立的配准方法是一种准确。简便和稳定的方法。  相似文献   
200.
We describe the first case of orofacial abnormal movements induced by adrafinil, a vigilance promoting agent of the same pharmacological class as modafinil. The dyskinesias did not spontaneously recover despite adrafinil withdrawal for a 4-month period. They were secondly dramatically improved by tetrabenazine, a presynaptic dopaminergic depleting drug which was introduced after the 4-month adrafinil-free period.  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