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   1879篇
  免费   117篇
  国内免费   6篇
耳鼻咽喉   56篇
儿科学   82篇
妇产科学   75篇
基础医学   200篇
口腔科学   35篇
临床医学   217篇
内科学   296篇
皮肤病学   12篇
神经病学   259篇
特种医学   122篇
外科学   289篇
综合类   60篇
预防医学   98篇
眼科学   44篇
药学   82篇
肿瘤学   75篇
  2022年   12篇
  2021年   39篇
  2020年   21篇
  2019年   29篇
  2018年   44篇
  2017年   28篇
  2016年   26篇
  2015年   26篇
  2014年   58篇
  2013年   70篇
  2012年   84篇
  2011年   81篇
  2010年   75篇
  2009年   72篇
  2008年   80篇
  2007年   73篇
  2006年   84篇
  2005年   74篇
  2004年   99篇
  2003年   70篇
  2002年   71篇
  2001年   43篇
  2000年   51篇
  1999年   49篇
  1998年   38篇
  1997年   32篇
  1996年   34篇
  1995年   37篇
  1994年   21篇
  1993年   10篇
  1992年   30篇
  1991年   20篇
  1990年   25篇
  1989年   42篇
  1988年   34篇
  1987年   34篇
  1986年   30篇
  1985年   26篇
  1984年   22篇
  1983年   18篇
  1982年   12篇
  1981年   18篇
  1980年   14篇
  1979年   9篇
  1978年   10篇
  1977年   10篇
  1975年   14篇
  1974年   13篇
  1973年   12篇
  1972年   8篇
排序方式: 共有2002条查询结果,搜索用时 15 毫秒
91.
The brain is highly dynamic, reorganizing its activity at different interacting spatial and temporal scales, including variation within and between brain networks. The chronnectome is a model of the brain in which nodal activity and connectivity patterns change in fundamental and recurring ways over time. Most literature assumes fixed spatial nodes/networks, ignoring the possibility that spatial nodes/networks may vary in time. Here, we introduce an approach to calculate a spatially fluid chronnectome (called the spatial chronnectome for clarity), which focuses on the variations of networks coupling at the voxel level, and identify a novel set of spatially dynamic features. Results reveal transient spatially fluid interactions between intra‐ and internetwork relationships in which brain networks transiently merge and separate, emphasizing dynamic segregation and integration. Brain networks also exhibit distinct spatial patterns with unique temporal characteristics, potentially explaining a broad spectrum of inconsistencies in previous studies that assumed static networks. Moreover, we show anticorrelative connections to brain networks are transient as opposed to constant across the entire scan. Preliminary assessments using a multi‐site dataset reveal the ability of the approach to obtain new information and nuanced alterations that remain undetected during static analysis. Patients with schizophrenia (SZ) display transient decreases in voxel‐wise network coupling within visual and auditory networks, and higher intradomain coupling variability. In summary, the spatial chronnectome represents a new direction of research enabling the study of functional networks which are transient at the voxel level, and the identification of mechanisms for within‐ and between‐subject spatial variability.  相似文献   
92.
Three-dimensional volume rendering of spiral CT data: theory and method.   总被引:58,自引:0,他引:58  
Three-dimensional (3D) medical images of computed tomographic (CT) data sets can be generated with a variety of computer algorithms. The three most commonly used techniques are shaded surface display, maximum intensity projection, and, more recently, 3D volume rendering. Implementation of 3D volume rendering involves volume data management, which relates to operations including acquisition, resampling, and editing of the data set; rendering parameters including window width and level, opacity, brightness, and percentage classification; and image display, which comprises techniques such as "fly-through" and "fly-around," multiple-view display, obscured structure and shading depth cues, and kinetic and stereo depth cues. An understanding of both the theory and method of 3D volume rendering is essential for accurate evaluation of the resulting images. Three-dimensional volume rendering is useful in a wide variety of applications but is just now being incorporated into commercially available software packages for medical imaging. Although further research is needed to determine the efficacy of 3D volume rendering in clinical applications, with wider availability and improved cost-to-performance ratios in computing, 3D volume rendering is likely to enjoy widespread acceptance in the medical community.  相似文献   
93.
Coexistence of gallbladder disease and morbid obesity   总被引:5,自引:0,他引:5  
To further investigate the relationship between gallbladder disease and morbid obesity, 92 morbidly obese patients underwent routine cholecystectomy at the time of their bariatric procedures. The preoperative ultrasonographic findings were positive in only 20 patients. Of the 92 patients who underwent cholecystectomy, 87 (95 percent) had pathologic evidence of gallbladder disease. This included cholecystitis, cholesterolosis, cholelithiasis, or some combination of the three. The incidence of postoperative cholecystitis, the technical difficulty of reoperation, the unnecessary expense and exposure to a second hospitalization and a second operation are all completely eliminated when routine cholecystectomy is performed in concert with elective bariatric procedures.  相似文献   
94.
Indian Journal of Thoracic and Cardiovascular Surgery -  相似文献   
95.
BACKGROUND: Controversy exists regarding axillary dissection (ALND) for sentinel node (SLN) metastases detected as isolated tumor cells (ITC). We hypothesized that the number of positive non-SLNs is low and ALND is unnecessary for most patients with ITC. METHODS: From 1995 to 1999, 634 breast cancer patients underwent SLND. SLNs were examined using immunohistochemistry if hematoxylin and eosin was negative. ALND was recommended for ITC-positive SLNs. RESULTS: Seventy-eight patients (12.3%) with ITC-positive SLNs were offered ALND. Sixty-one consented, whereas 17 refused. Fifty-eight (95.1%) had negative non-SLNs. Three (4.9%) had non-SLN metastases. One patient (1.6%) had macrometastatic disease, whereas 2 (3.3%) had micrometastases. No ITC-only-positive SLN patient experienced axillary recurrence. CONCLUSIONS: When ALND was performed for ITC, 1.6% of non-SLNs harbored macrometastases and 3.3% had micrometastases. When ALND was not performed, axillary recurrence was not seen. The low risk of non-SLN disease in this study fails to support the routine use of ALND for ITC-positive SLNs.  相似文献   
96.
The present study investigated the effects of the age of a victim on social reactions to a rape incident. The findings indicated limited but reliable effects of age on the way respondents reacted to the rape episode. There was a greater tendency for the characteristics and the behavior of the victim to be viewed as factors in causing the rape when the victim was in the middle age ranges than when she was in the extreme age range (six-years-old or 76-years-old). Respondents also favored more severe punishment for the assailant when the victim was at the extremes of the age distribution.  相似文献   
97.
98.
Occlusal splints have been widely used in dentistry for treating craniomandibular disorders, yet the precise effect that splints have on symptoms is still undetermined. When the available research evidence is closely scrutinized it is found to be weak and generally unsupported. Most studies are lacking in sound research design and often draw conclusions that are unsubstantiated. Recognizing these weaknesses, this article proposes a research design that will effectively evaluate treatment effects through rigid, well-controlled, and accurately documented experimentation. Using this research design clinically may be a difficult task. However, incorporation of one or more of the suggested parameters will help to strengthen any research proposal.  相似文献   
99.
100.
There are several articles in the literature reporting laparoscopic surgery in patients with ventriculoperitoneal shunts (VPSs). Although the majority of these conclude that a pneumoperitoneum in these patients is safe, there are other reports indicating possible complications of the insufflation. This is the first known report of a robotic-assisted hysterectomy performed on a patient with a VPS and the management of the shunt during the procedure.  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