全文获取类型
收费全文 | 102451篇 |
免费 | 6334篇 |
国内免费 | 465篇 |
专业分类
耳鼻咽喉 | 1119篇 |
儿科学 | 2663篇 |
妇产科学 | 1809篇 |
基础医学 | 12720篇 |
口腔科学 | 1827篇 |
临床医学 | 10841篇 |
内科学 | 20619篇 |
皮肤病学 | 1391篇 |
神经病学 | 10135篇 |
特种医学 | 4077篇 |
外国民族医学 | 3篇 |
外科学 | 16639篇 |
综合类 | 1132篇 |
一般理论 | 132篇 |
预防医学 | 8370篇 |
眼科学 | 2121篇 |
药学 | 6564篇 |
中国医学 | 107篇 |
肿瘤学 | 6981篇 |
出版年
2023年 | 576篇 |
2022年 | 946篇 |
2021年 | 2107篇 |
2020年 | 1342篇 |
2019年 | 2109篇 |
2018年 | 2597篇 |
2017年 | 1873篇 |
2016年 | 2028篇 |
2015年 | 2332篇 |
2014年 | 3524篇 |
2013年 | 4837篇 |
2012年 | 7620篇 |
2011年 | 8021篇 |
2010年 | 4671篇 |
2009年 | 4229篇 |
2008年 | 7167篇 |
2007年 | 7514篇 |
2006年 | 7237篇 |
2005年 | 6934篇 |
2004年 | 6759篇 |
2003年 | 6072篇 |
2002年 | 5744篇 |
2001年 | 867篇 |
2000年 | 580篇 |
1999年 | 928篇 |
1998年 | 1322篇 |
1997年 | 1013篇 |
1996年 | 848篇 |
1995年 | 745篇 |
1994年 | 666篇 |
1993年 | 621篇 |
1992年 | 471篇 |
1991年 | 435篇 |
1990年 | 343篇 |
1989年 | 341篇 |
1988年 | 317篇 |
1987年 | 320篇 |
1986年 | 274篇 |
1985年 | 311篇 |
1984年 | 326篇 |
1983年 | 264篇 |
1982年 | 355篇 |
1981年 | 298篇 |
1980年 | 238篇 |
1979年 | 101篇 |
1978年 | 134篇 |
1977年 | 115篇 |
1976年 | 92篇 |
1975年 | 78篇 |
1973年 | 71篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Aim: To examine the evidence of benefit in initiating immediate chemotherapy in patients with newly diagnosed asymptomatic metastatic incurable cancer, compared with delaying chemotherapy until symptomatic progression. Methods: Through an extensive review of published reports, we examined the biological, clinical, psychological and ethical background of the issue and reported on the available clinical trial evidence in a variety of tumor types. Results: Only a limited number of clinical trials have directly examined the role of immediate versus delayed chemotherapy in patients with incurable asymptomatic metastatic cancer. Small studies in mesothelioma, colorectal cancer, breast cancer, myeloma, and low‐grade lymphoma suggest no survival benefit for the immediate initiation of chemotherapy. However, there was no evidence in other tumor types. Conclusion: The appropriate timing of chemotherapy initiation in an asymptomatic patient with metastatic cancer remains a substantial question in oncology. Many factors are likely to impact on the decision. However, little if any evidence demonstrates a clear advantage in the immediate initiation of chemotherapy in this setting. 相似文献
63.
Stem cells and periodontal regeneration 总被引:10,自引:0,他引:10
64.
65.
Alfred E Buxton Hugh Calkins David J Callans John P DiMarco John D Fisher H Leon Greene David E Haines David L Hayes Paul A Heidenreich John M Miller Athena Poppas Eric N Prystowsky Mark H Schoenfeld Peter J Zimetbaum Paul A Heidenreich David C Goff Frederick L Grover David J Malenka Eric D Peterson Martha J Radford Rita F Redberg 《Journal of the American College of Cardiology》2006,48(11):2360-2396
66.
Kevin O'Brien Jean Wright Frances Conboy YeWeng Sanjie Nicky Mandall Stephen Chadwick Ivan Connolly Paul Cook David Birnie Mark Hammond Nigel Harradine David Lewis Cathy McDade Laura Mitchell Alison Murray Julian O'Neill Mike Read Stephen Robinson Dai Roberts-Harry Jonathan Sandler Ian Shaw 《American journal of orthodontics and dentofacial orthopedics》2003,124(3):234-43; quiz 339
This study evaluated the effectiveness of early orthodontic treatment with the Twin-block appliance for the developing Class II Division 1 malocclusion. This multicenter trial was carried out in the United Kingdom. A total of 174 children, aged 8 to 10 years old, with Class II Division 1 malocclusion were randomly allocated to receive treatment with a Twin-block appliance or to an untreated, control group. Data were collected at the start of the study and 15 months later. Results showed that early treatment with Twin-block appliances resulted in reduction of overjet, correction of molar relationships, and reduction in severity of malocclusion. Most of this correction was due to dentoalveolar change, but some was due to favorable skeletal change. Early treatment with the Twin-block appliance is effective in reducing overjet and severity of malocclusion. The small change in the skeletal relationship might not be considered clinically significant. 相似文献
67.
Leonardo Bonilha MD PhD Paulien M. de Vries Diana J. Vincent MD PhD Chris Rorden MD PhD Paul S. Morgan Mark W. Hurd PhD Nada Besenski MD Kenneth J. Bergmann MD Vanessa K. Hinson MD PhD 《Movement disorders》2007,22(8):1110-1116
We investigated whether structural white matter abnormalities, in the form of disruption of axonal coherence and integrity as measured with diffusion tensor imaging (DTI), constitute an underlying pathological mechanism of idiopathic dystonia (ID), independent of genotype status. We studied seven subjects with ID: all had cervical dystonia as their main symptom (one patient also had spasmodic dysphonia and two patients had concurrent generalized dystonia, both DYT1‐negative). We compared DTI MR images of patients with 10 controls, evaluating differences in mean diffusivity (MD) and fractional anisotropy (FA). ID was associated with increased FA values in the thalamus and adjacent white matter, and in the white matter underlying the middle frontal gyrus. ID was also associated with increase in MD in adjacent white matter to the pallidum and putamen bilaterally, left caudate, and in subcortical hemispheric regions, including the postcentral gyrus. Abnormal FA and MD in patients with ID indicate that abnormal axonal coherence and integrity contribute to the pathophysiology of dystonia. These findings suggest that ID is not only a functional disorder, but also associated with structural brain changes. Impaired connectivity and disrupted flow of information may contribute to the impairment of motor planning and regulation in dystonia. © 2006 Movement Disorder Society 相似文献
68.
Human C-reactive protein increases cerebral infarct size after middle cerebral artery occlusion in adult rats. 总被引:14,自引:0,他引:14
Ramanjit Gill John A Kemp Caroline Sabin Mark B Pepys 《Journal of cerebral blood flow and metabolism》2004,24(11):1214-1218
Human C-reactive protein (CRP), the classic acute phase plasma protein, increases in concentration after myocardial infarction and stroke. Human CRP binds to ligands exposed in damaged tissue and can then activate complement and its proinflammatory functions. In contrast, rat CRP, which binds to similar ligands, does not activate complement. In the present study, systemic complement depletion with cobra venom factor in adult rats subjected to middle cerebral artery occlusion did not affect cerebral infarct size, indicating that circulating complement does not contribute to injury in this model. However, we have previously reported that administration of human CRP to rats undergoing coronary artery ligation caused a marked increase in size of the resulting myocardial infarction, associated with codeposition of human CRP and rat complement in the infarcts. In the present study, we show that adult rats subjected to middle cerebral artery occlusion and then treated with human CRP similarly developed significantly larger cerebral infarcts compared with control subjects receiving human serum albumin. Human CRP can thus contribute to ischemic tissue damage in the brain as well as in the heart, and inhibition of CRP binding may therefore be a promising target for tissue protective acute therapeutic intervention in stroke as well as in myocardial infarction. 相似文献
69.
70.