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   188253篇
  免费   12247篇
  国内免费   1652篇
耳鼻咽喉   2767篇
儿科学   3466篇
妇产科学   4341篇
基础医学   27776篇
口腔科学   3786篇
临床医学   17627篇
内科学   36580篇
皮肤病学   5075篇
神经病学   14023篇
特种医学   9303篇
外国民族医学   3篇
外科学   25539篇
综合类   2843篇
现状与发展   5篇
一般理论   94篇
预防医学   10995篇
眼科学   5252篇
药学   15971篇
  3篇
中国医学   1875篇
肿瘤学   14828篇
  2023年   1170篇
  2022年   3270篇
  2021年   5666篇
  2020年   2908篇
  2019年   4231篇
  2018年   5207篇
  2017年   3789篇
  2016年   4857篇
  2015年   6582篇
  2014年   8081篇
  2013年   9700篇
  2012年   14615篇
  2011年   14349篇
  2010年   8476篇
  2009年   7138篇
  2008年   10777篇
  2007年   10555篇
  2006年   9673篇
  2005年   9238篇
  2004年   8182篇
  2003年   7246篇
  2002年   6376篇
  2001年   5097篇
  2000年   4662篇
  1999年   3869篇
  1998年   1559篇
  1997年   1219篇
  1996年   1143篇
  1995年   1021篇
  1994年   887篇
  1993年   737篇
  1992年   1870篇
  1991年   1802篇
  1990年   1608篇
  1989年   1498篇
  1988年   1396篇
  1987年   1230篇
  1986年   1198篇
  1985年   1044篇
  1984年   794篇
  1983年   678篇
  1982年   481篇
  1981年   455篇
  1980年   411篇
  1979年   649篇
  1978年   489篇
  1977年   458篇
  1976年   389篇
  1974年   415篇
  1973年   377篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Originally described by Rosen in 1983, syringomatous nipple adenoma (SAN) is a tumor of disputed histogenesis, which can be problematic both diagnostically and therapeutically. 1 It is a benign primary tumor of breast epithelium with histology similar to that of the syringoma. In the current case, we describe a 40-year-old female with this lesion occurring within a supernumerary breast. This case represents, to our knowledge, the first such reported case, and represents a significant finding as its presence could lend some confusion as to whether or not this represents a benign primary process of breast or a potentially infiltrative tumor of the skin.  相似文献   
32.
33.
34.
Background/aims: The objective and quantitative assessment of the skin is important in medical and cosmeceutical research. Assessment of color is an important element for analyzing the surface of the skin, which is usually determined subjectively by a doctor or using color analysis devices. These devices, however, cannot provide correct color information because color is construed from the mean value of the observation region, and analysis of color distribution is impossible. The purpose of this paper is to develop an objective analysis method to permit skin color measurement of each pixel unit of an image and analyze the distribution of skin surface color. Methods: The Skin Color Distribution Analyzer (SCDA) is an analysis method newly developed at the Research Institute for Skin Image at Korea University. The SCDA system presented in this paper performed a novel form of quantitative and objective analysis of skin color distribution using each pixel color model parameter found in image wavelength information. In this paper, distribution analysis was conducted on normal skin and skin lesions and skin affected by artificially induced irritant contact dermatitis and pigmented nevous. The method selected a grade using a color model parameter. Twenty healthy Korean males participated in this study. A comparative study of the eight anatomical areas was performed, including the exposure and non‐exposure parts and the medial aspect and the lateral aspect of the forearm. A reliability test for the SCDA system was also conducted with a spectrometer (SPEC) using the color analysis method. Results: Each skin lesion was precisely segmented by grade and each parameter hada different statistical significance for results of analysis of distribution in pigmented nevous and the artificially induced irritant contact dermatitis. Parameters L*, b*, a*, and EI showed salient traits. Showed resemble measured result in the SCDA system and the SPEC of normal skin. The exposed site, in comparison with the non‐exposed site, showed a notable difference in the L* parameter and a significant statistical difference in the x and z parameters, except b*. The comparison of the medial and lateral aspects of the forearm showed a notable difference in the L* parameter and a significant statistical difference in the parameters except y and b*. In the reliability test result using the SCDA system and the SPEC, the SCDA system was highly reliabile in terms of the CV value in all color model parameters. Conclusions: The color distribution analysis method using the SCDA system has revealed an aspect that the existent method of medical research has not shown, and is considered to be more reliable than other methods. This method can provide better study findings because it can be applied to other fields in addition to the medical science field and the ripple effect is thought to be bigger in other science field too.  相似文献   
35.
36.
37.
38.
The purpose of this study was to examine the levels of anxiety of mothers with children in pediatric intensive care units with different types of visitation policies, both structured and individualized Forty subjects were obtained from two children's hospitals A comparative research design was used Data showed that mothers who experienced individualized visitation had significantly lower anxiety scores (p < 005) than mothers who experienced structured visitation Findings also revealed that mothers viewed their child's illness as less severe when individualized visitation was permitted as opposed to structured visitation.  相似文献   
39.
In medical studies with censored data Kaplan and Meier's product limit estimator has frequent use as the estimate of the survival function. Simultaneous confidence intervals for the survival function at various time points constitute a useful addition to the analysis. This study compares several such methods. We consider in a simulation investigation two whole curve confidence bands and four methods based on the Bonferroni inequality. The results show that three Bonferroni-type methods are essentially equivalent, all being better than the other methods when the number of time points is small (3 or 5).  相似文献   
40.
The first‐order kernel analysis in multifocal electroretinogram (mfERG) using low contrast stimulation is suggested as a way to detect the inner retinal responses in animal studies. In this case report, this protocol is applied to human patients with glaucoma to demonstrate the possibility of using mfERG as a tool to detect glaucomatous damage. Two patients with glaucoma were recruited and had mfERG measurements with the 103‐scaled hexagonal stimulus pattern at low (50 per cent) contrast. Their responses were analysed and compared with those from normal subjects with the mfERG measured under the same condition. In the normal subjects, there were obvious oscillatory components on the ascending and descending limbs of the first‐order kernel response to 50 per cent contrast. In the glaucomatous patients, the oscillatory component on the descending limb was obviously diminished. In addition, this component was significantly diminished in the quadrant with a glaucomatous visual field defect. This suggests that the low‐contrast stimulation condition in mERG measurement may provide a good way to detect glaucomatous damage and this may help in clinical diagnosis of glaucoma.  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