全文获取类型
收费全文 | 18281篇 |
免费 | 977篇 |
国内免费 | 389篇 |
专业分类
耳鼻咽喉 | 237篇 |
儿科学 | 119篇 |
妇产科学 | 120篇 |
基础医学 | 4752篇 |
口腔科学 | 1719篇 |
临床医学 | 920篇 |
内科学 | 2220篇 |
皮肤病学 | 761篇 |
神经病学 | 2553篇 |
特种医学 | 573篇 |
外国民族医学 | 1篇 |
外科学 | 1261篇 |
综合类 | 1200篇 |
预防医学 | 682篇 |
眼科学 | 791篇 |
药学 | 1250篇 |
3篇 | |
中国医学 | 180篇 |
肿瘤学 | 305篇 |
出版年
2023年 | 140篇 |
2022年 | 215篇 |
2021年 | 608篇 |
2020年 | 415篇 |
2019年 | 431篇 |
2018年 | 447篇 |
2017年 | 411篇 |
2016年 | 440篇 |
2015年 | 511篇 |
2014年 | 806篇 |
2013年 | 1198篇 |
2012年 | 718篇 |
2011年 | 773篇 |
2010年 | 640篇 |
2009年 | 750篇 |
2008年 | 717篇 |
2007年 | 740篇 |
2006年 | 602篇 |
2005年 | 570篇 |
2004年 | 605篇 |
2003年 | 555篇 |
2002年 | 465篇 |
2001年 | 370篇 |
2000年 | 339篇 |
1999年 | 349篇 |
1998年 | 390篇 |
1997年 | 354篇 |
1996年 | 412篇 |
1995年 | 341篇 |
1994年 | 350篇 |
1993年 | 288篇 |
1992年 | 312篇 |
1991年 | 303篇 |
1990年 | 301篇 |
1989年 | 267篇 |
1988年 | 285篇 |
1987年 | 221篇 |
1986年 | 235篇 |
1985年 | 267篇 |
1984年 | 224篇 |
1983年 | 174篇 |
1982年 | 185篇 |
1981年 | 166篇 |
1980年 | 161篇 |
1979年 | 125篇 |
1978年 | 138篇 |
1977年 | 109篇 |
1976年 | 64篇 |
1975年 | 47篇 |
1973年 | 24篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
《Radiography》2020,26(4):e195-e200
IntroductionAdverse events in radiology are quite rare, but they do occur. Radiation safety regulations and the law obligate organizations to report certain adverse events, harm and near misses, especially events related to patients' health and safety. The aim of this study was to describe and analyse incidents related to radiation safety issues reported in Finland.MethodsThe data were collected from incident reports documented by radiology personnel concerning notifications of abnormal events in medical imaging made to the Radiation and Nuclear Safety Authority between 2010 and 2017. During these eight years, 312 reports were submitted. Only events reported from radiology departments were included; nuclear medicine, radiotherapy and animal radiology cases were excluded. The final number of reports was 293 (94%).ResultsThe majority of the 293 approved reports were related to computed tomography (CT, 68.3%) and to X-ray examinations (27.6%). Altogether 82.9% of those irradiated were adults, most of whom were exposed to unnecessary radiation through CT (86.5%), 5.5% were children, and 4.4% pregnant women. The most common effective dose of unnecessary radiation was 1 mSv or less (89.7% of all examinations). The highest effective doses were reported in CT (from under 1 mSv–20 mSv and above). The reasons for the adverse events were incorrect identification (32%), incorrect procedure, site or side (30%); and human errors or errors of knowledge (20%).ConclusionAdverse events occurred especially in CT examinations. It is important to collect and analyse incident data, assess the harmful events, learn from them and aim to reduce adverse events.Implications for practiceThis study emphasizes the need for radiological personnel to obtain evidence-based information on adverse events and focus on training to improve patient safety. 相似文献
13.
社会办医作为我国基层卫生服务的重要组成部分,可以弥补基层卫生机构发展总量与质量不足等问题,对于推进整个基层卫生服务高质量发展也是有着重大裨益。文章从物理学的"力"出发,运用支持力,推力,引力,阻力,摩擦力五种"力"探讨社会资本参与基层卫生服务的动力形成机制,并构建动力斜坡图,针对存在问题,提出加大支持力和引力,合理利用推力,减少摩擦力,消除阻力等优化建议,以期助力社会资本参与基层卫生服务建设平稳进行。 相似文献
14.
采用流变学法测定了亚麻籽胶溶液的胶凝点、熔化点,并采用质构仪、扫描电镜和原子力显微镜等手段研究了影响亚麻籽胶凝胶强度的因素,结果表明亚麻籽胶具有胶凝性,它能形成一种热可逆的冷致凝胶,亚麻籽胶溶液的胶凝点低于其凝胶的熔化点,且亚麻籽胶溶液的胶凝点及其凝胶的熔化点均随冷却的起始温度的升高而升高。亚麻籽胶浓度、溶解温度、pH、NaCl、CaCl2及复合磷酸盐能影响亚麻籽胶的凝胶强度,亚麻籽胶的凝胶强度随着浓度的增加及溶解温度的升高而增强;在pH6~9的范围内,亚麻籽胶的凝胶强度达到最大;NaCl和复合磷酸盐可以降低亚麻籽胶的凝胶强度,低浓度(〈0.3%)的CaCl2可以增强亚麻籽胶的凝胶强度,而高质量分数(〉0.3%)的CaCl2能降低亚麻籽胶的凝胶强度。 相似文献
15.
Birger Ragnarson Göran Örnung Ole P Ottersen Gunnar Grant Brun Ulfhake 《Journal of neuroscience methods》1998,80(2):42-136
Choleragenoid (cholera toxin B-fragment; CTB) is an anterograde, retrograde and transganglionic neuronal tracer. We describe a method for detecting CTB-labeled neuronal cell bodies, neurites and boutons at the ultrastructural level, using postembedding immunogold techniques on freeze-substituted Lowicryl HM20™ embedded nervous tissue. Primary afferents and motoneurons were labeled by injection of CTB in the dorsal ramus of the C2 spinal nerve of the rat. Following fixation with paraformaldehyde (4%) and glutaraldehyde (0.25%), tissue sections from the spinal cord C2 segment were freeze-substituted and embedded in Lowicryl HM20™ and subsequently processed with postembedding immunocytochemistry for CTB and glutamate. Immunogold particles indicating CTB immunoreactivity were found over primary afferents and motoneurons. In primary afferents in the central cervical nucleus (CCN) and motor nuclei, immunogold labeling was seen in boutons over vesicle-containing axoplasm and to a lesser extent over axoplasm devoid of vesicles, but not over mitochondria or axolemma. In motoneurons, immunogold particles were seen over the Golgi apparatus in the soma and over lysosomes in both soma and dendrites. Quantification of glutamate-like immunoreactivity in 20 CTB-labeled and 20 CTB-negative boutons in the neuropil was found similar, indicating that CTB does not interfere with the immunocytochemical detection of neuronal epitopes such as the transmitter substance glutamate. 相似文献
16.
17.
18.
K. Dorovini-Zis A. P. Zis 《Journal of neural transmission (Vienna, Austria : 1996)》1991,84(1-2):75-84
Summary Autonomic innervation of the adrenal cortex has been demonstrated in several species. Detailed ultrastructural studies on the innervation of the zona fasciculata of the normal human adrenal cortex are lacking. We report herein our observations on the pattern of innervation of the cells of the zona fasciculata of the normal adult human cortex at both the light and electron microscope levels. Postganglionic unmyelinated fibers were observed to descend from a dense capsular meshwork and to be distributed as delicate branches among the columns of endocrine cells. Immunoperoxidase staining confirmed the presence of nerve fibers in the zona fasciculata in a distribution similar to that observed after staining with silver impregnation methods. Ultrastructural findings lent further support to these observations by the demonstration of bundles of unmyelinated fibers with focal enlargements containing terminal boutons with both clear and dense core vesicles in close approximation with the endocrine cells. 相似文献
19.
20.
G.E. ORLANDINI S. ZECCHI ORLANDINI A.F. HOLSTEIN R. EVANGELISTI and R. PONCHIETTI 《Andrologia》1987,19(3):315-321
The human prostatic urethra has been investigated by means of scanning electron microscopy. On the posterior wall of the urethra, the seminal colliculus with the orifices of the ejaculatory ducts is clearly detectable. The upper portion of the prostatic urethra shows a typical transitional epithelium with large superficial cells of a ruffled appearance. In the lower portion of the organ (underneath the openings of the ejaculatory ducts), the apical pattern of the cells varies considerably. Four main aspects are recognizable: apices provided with microvilli, dome-shaped apices with an almost smooth surface, large apices with labyrinthic microplicae and ciliated apices. Also, apices showing intermediate characteristics can be noted. The functional significance of the morphological patterns as well as the possibility of a transition among the various types of surface structures are discussed. 相似文献