全文获取类型
收费全文 | 4183篇 |
免费 | 250篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 53篇 |
儿科学 | 110篇 |
妇产科学 | 32篇 |
基础医学 | 545篇 |
口腔科学 | 74篇 |
临床医学 | 491篇 |
内科学 | 718篇 |
皮肤病学 | 35篇 |
神经病学 | 395篇 |
特种医学 | 145篇 |
外科学 | 657篇 |
综合类 | 47篇 |
一般理论 | 5篇 |
预防医学 | 476篇 |
眼科学 | 74篇 |
药学 | 319篇 |
中国医学 | 4篇 |
肿瘤学 | 263篇 |
出版年
2023年 | 24篇 |
2022年 | 33篇 |
2021年 | 92篇 |
2020年 | 65篇 |
2019年 | 87篇 |
2018年 | 85篇 |
2017年 | 59篇 |
2016年 | 87篇 |
2015年 | 100篇 |
2014年 | 164篇 |
2013年 | 205篇 |
2012年 | 307篇 |
2011年 | 327篇 |
2010年 | 163篇 |
2009年 | 163篇 |
2008年 | 257篇 |
2007年 | 329篇 |
2006年 | 278篇 |
2005年 | 249篇 |
2004年 | 244篇 |
2003年 | 241篇 |
2002年 | 191篇 |
2001年 | 51篇 |
2000年 | 33篇 |
1999年 | 37篇 |
1998年 | 51篇 |
1997年 | 42篇 |
1996年 | 39篇 |
1995年 | 33篇 |
1994年 | 20篇 |
1993年 | 28篇 |
1992年 | 32篇 |
1991年 | 20篇 |
1990年 | 18篇 |
1989年 | 17篇 |
1988年 | 26篇 |
1987年 | 27篇 |
1986年 | 22篇 |
1985年 | 33篇 |
1984年 | 24篇 |
1983年 | 17篇 |
1982年 | 12篇 |
1981年 | 13篇 |
1980年 | 8篇 |
1979年 | 11篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 6篇 |
1974年 | 12篇 |
1973年 | 6篇 |
排序方式: 共有4443条查询结果,搜索用时 15 毫秒
101.
Yvette Wittenberg Alice de Boer Inger Plaisier Arnoud Verhoeff Rick Kwekkeboom 《Scandinavian journal of caring sciences》2019,33(4):1006-1016
The European policy emphasis on providing informal care at home causes caregivers and home care professionals having more contact with each other, which makes it important for them to find satisfying ways to share care. Findings from the literature show that sharing care between caregivers and professionals can be improved. This study therefore examines to what degree and why caregivers’ judgements on sharing care with home care professionals vary. To improve our understanding of social inequities in caregiving experiences, the study adopts an intersectional perspective. We investigate how personal and situational characteristics attached to care judgements are interwoven. Using data of the Netherlands Institute for Social Research, we conducted bivariate and multivariate linear regression analysis (N = 292). We combined four survey questions into a 1–4 scale on ‘caregiver judgement’ (α = 0.69) and used caregivers’ personal (such as gender and health status) and situational characteristics (such as the care recipient's impairment and type of care) as determinants to discern whether these are related to the caregivers’ judgement. Using a multiplicative approach, we also examined the relationship between mutually constituting factors of the caregivers’ judgement. Adjusted for all characteristics, caregivers who provide care to a parent or child with a mental impairment and those aged between 45 and 64 years or with a paid job providing care to someone with a mental impairment are likely to judge sharing care more negatively. Also, men providing care with help from other caregivers and caregivers providing care because they like to do so who provide domestic help seem more likely to be less satisfied about sharing care. This knowledge is vital for professionals providing home care, because it clarifies differences in caregivers’ experiences and hence induce knowledge how to pay special attention to those who may experience less satisfaction while sharing care. 相似文献
102.
103.
104.
Ganim RP Lewis WR Diercks DB Kirk D Sabapathy R Baker L Amsterdam EA 《Cardiology》2004,102(2):100-103
BACKGROUND: A number of innovative approaches have been investigated for their value in the early detection of acute ischemia or infarction in patients presenting to the emergency department (ED) with chest pain suggestive of a cardiac origin. Prior investigations have demonstrated the utility of adding right precordial and posterior chest leads to the standard 12-lead electrocardiogram (ECG) for identifying right ventricular and posterior wall infarctions in the ED. HYPOTHESIS: To assess the utility of additional ECG leads in low-risk patients presenting to the ED with symptoms suggestive of acute coronary syndromes who are managed in a chest pain evaluation unit (CPEU). METHODS: We studied low-risk patients who presented to the ED with chest pain compatible with myocardial ischemia. Low-risk patients were identified by a normal 12-lead ECG, no arrhythmias or hemodynamic instability, and one negative serum cardiac troponin I. Patients were admitted to the CPEU where a 16-lead ECG was recorded by the addition of 2 right-sided precordial leads (V4R, V5R) and 2 posterior leads (V8, V9) to the standard 12-lead ECG. RESULTS: The 16-lead ECG system was applied to 316 consecutive patients. The study group was a middle-aged population with equal numbers of men and women and an average of 2 cardiac risk factors per patient. The 16-lead ECG demonstrated evidence of myocardial injury in only 1 patient and no evidence of ischemia in any of the 316 patients. CONCLUSION: In patients presenting to the ED with chest pain and evidence of low clinical risk by our criteria, the addition of both right-sided precordial and posterior chest leads to the standard 12-lead ECG did not provide additional information for risk stratification. 相似文献
105.
Clinical use of a rapid collagen binding assay for von Willebrand factor cleaving protease in patients with thrombotic thrombocytopenic purpura 总被引:10,自引:0,他引:10
Rick ME Moll S Taylor MA Krizek DM White GC Aronson DL 《Thrombosis and haemostasis》2002,88(4):598-604
A simple collagen binding assay (CBA) for measuring activity of the von Willebrand factor cleaving protease in clinical samples is described, and results of fifty masked plasmapheresis samples rom patients with TTP/HUS and other diseases are presented. There was 97.5% concordance between the CBA and a multimer gel assay. The CBA identified low protease activity in 78% of patients who had a clinical syndrome consistent with TTP/HUS and in 2 of 10 sick controls, giving it a positive predictive value of 0.94. The heterogeneity regarding the presence or absence of vWF protease activity in patients with TTP/HUS was confirmed by finding a low negative predictive value of 0.50 with the CBA. The CBA detected inhibitors of the protease in 26 of 29 patients (90%) with TTP/HUS and low protease activity levels. The CBA is a useful clinical assay for examining von Willebrand factor protease activity and detecting inhibitors against the protease. 相似文献
106.
A normally transient cross-modal thalamocortical projection from the magnocellular subdivision of the medial geniculate nucleus (MGm) to the primary somatosensory (SI) cortex of rats was found to remain unchanged throughout adulthood following unilateral removal of whiskers in newborn animals. The normal MGm projection to the auditory cortex is not lost in these neonatally whisker-deprived adults rats but some of the MGm neurons send collaterals to both primary auditory and SI cortices. Parallel electrophysiological experiments demonstrated the multimodal character of some MGm neurons, since they responded to both auditory and cutaneous stimulation. These results suggest that the areal distribution in the cortex of thalamocortical projections arising from a multimodal thalamic nucleus, such as the MGm, may be determined during early postnatal development by the normal flow of sensory information from the periphery to the thalamus and that an early postnatal somatosensory deprivation may prevent the normal withdrawal of a cross-modal projection from the MGm to the SI. 相似文献
107.
108.
Gordon GR Baimoukhametova DV Hewitt SA Rajapaksha WR Fisher TE Bains JS 《Nature neuroscience》2005,8(8):1078-1086
Glial cells actively participate in synaptic transmission. They clear molecules from the synaptic cleft, receive signals from neurons and, in turn, release molecules that can modulate signaling between neuronal elements. Whether glial-derived transmitters can contribute to enduring changes in postsynaptic efficacy, however, remains to be established. In rat hypothalamic paraventricular nucleus, we demonstrate an increase in the amplitude of miniature excitatory postsynaptic currents in response to norepinephrine that requires the release of ATP from glial cells. The increase in quantal efficacy, which likely results from an insertion of AMPA receptors, is secondary to the activation of P2X(7) receptors, an increase in postsynaptic calcium and the activation of phosphatidylinositol 3-kinase. The gliotransmitter ATP, therefore, contributes directly to the regulation of postsynaptic efficacy at glutamatergic synapses in the CNS. 相似文献
109.
Intranasal vaccination induces protective immunity against intranasal infection with virulent Francisella tularensis biovar A 下载免费PDF全文
The inhalation of Francisella tularensis biovar A causes pneumonic tularemia associated with high morbidity and mortality rates in humans. Exposure to F. tularensis usually occurs by accident, but there is increasing awareness that F. tularensis may be deliberately released in an act of bioterrorism or war. The development of a vaccine against pneumonic tularemia has been limited by a lack of information regarding the mechanisms required to protect against this disease. Vaccine models for F. tularensis in inbred mice would facilitate investigations of the protective mechanisms and significantly enhance vaccine development. Intranasal vaccination with the attenuated live vaccine strain (LVS) of F. tularensis reproducibly protected BALB/c mice, but not C57BL/6 mice, against intranasal and subcutaneous challenges with a virulent clinical isolate of F. tularensis biovar A (NMFTA1). The resistance of LVS-vaccinated BALB/c mice to intranasal NMFTA1 challenge was increased 100-fold by boosting with live NMFTA1 but not with LVS. The protective response was specific for F. tularensis and required both CD4 and CD8 T cells. The vaccinated mice appeared outwardly healthy for more than 2 months after NMFTA1 challenge, even though NMFTA1 was recovered from more than half of the vaccinated mice. These results show that intranasal vaccination induces immunity that protects BALB/c mice from intranasal infection by F. tularensis biovar A. 相似文献
110.
An antimetastatic role for decorin in breast cancer 总被引:1,自引:0,他引:1
Goldoni S Seidler DG Heath J Fassan M Baffa R Thakur ML Owens RT McQuillan DJ Iozzo RV 《The American journal of pathology》2008,173(3):844-855
Decorin, a member of the small leucine-rich proteoglycan gene family, down-regulates members of the ErbB receptor tyrosine kinase family and attenuates their signaling, leading to growth inhibition. We investigated the effects of decorin on the growth of ErbB2-overexpressing mammary carcinoma cells in comparison with AG879, an established ErbB2 kinase inhibitor. Cell proliferation and anchorage-independent growth assays showed that decorin was a potent inhibitor of breast cancer cell growth and a pro-apoptotic agent. When decorin and AG879 were used in combination, the inhibitory effect was synergistic in proliferation assays but only additive in both colony formation and apoptosis assays. Active recombinant human decorin protein core, AG879, or a combination of both was administered systemically to mice bearing orthotopic mammary carcinoma xenografts. Primary tumor growth and metabolism were reduced by approximately 50% by both decorin and AG879. However, no synergism was observed in vivo. Decorin specifically targeted the tumor cells and caused a significant reduction of ErbB2 levels in the tumor xenografts. Most importantly, systemic delivery of decorin prevented metastatic spreading to the lungs, as detected by novel species-specific DNA detection and quantitative assays. In contrast, AG879 failed to have any effect. Our data support a role for decorin as a powerful and effective therapeutic agent against breast cancer due to its inhibition of both primary tumor growth and metastatic spreading. 相似文献