全文获取类型
收费全文 | 35041篇 |
免费 | 3247篇 |
国内免费 | 1418篇 |
专业分类
耳鼻咽喉 | 146篇 |
儿科学 | 368篇 |
妇产科学 | 334篇 |
基础医学 | 3135篇 |
口腔科学 | 359篇 |
临床医学 | 3771篇 |
内科学 | 6359篇 |
皮肤病学 | 403篇 |
神经病学 | 6406篇 |
特种医学 | 1150篇 |
外国民族医学 | 10篇 |
外科学 | 3101篇 |
综合类 | 5499篇 |
现状与发展 | 6篇 |
一般理论 | 6篇 |
预防医学 | 1284篇 |
眼科学 | 1269篇 |
药学 | 3074篇 |
11篇 | |
中国医学 | 1745篇 |
肿瘤学 | 1270篇 |
出版年
2024年 | 144篇 |
2023年 | 669篇 |
2022年 | 902篇 |
2021年 | 1232篇 |
2020年 | 1339篇 |
2019年 | 1339篇 |
2018年 | 1245篇 |
2017年 | 1262篇 |
2016年 | 1274篇 |
2015年 | 1312篇 |
2014年 | 2084篇 |
2013年 | 2582篇 |
2012年 | 1891篇 |
2011年 | 2023篇 |
2010年 | 1806篇 |
2009年 | 1752篇 |
2008年 | 1839篇 |
2007年 | 1820篇 |
2006年 | 1718篇 |
2005年 | 1588篇 |
2004年 | 1343篇 |
2003年 | 1217篇 |
2002年 | 1106篇 |
2001年 | 844篇 |
2000年 | 724篇 |
1999年 | 537篇 |
1998年 | 493篇 |
1997年 | 450篇 |
1996年 | 405篇 |
1995年 | 368篇 |
1994年 | 293篇 |
1993年 | 248篇 |
1992年 | 246篇 |
1991年 | 242篇 |
1990年 | 158篇 |
1989年 | 156篇 |
1988年 | 137篇 |
1987年 | 127篇 |
1986年 | 102篇 |
1985年 | 144篇 |
1984年 | 99篇 |
1983年 | 70篇 |
1982年 | 76篇 |
1981年 | 94篇 |
1980年 | 44篇 |
1979年 | 45篇 |
1978年 | 34篇 |
1977年 | 24篇 |
1976年 | 18篇 |
1975年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Kumasaka T Mitani K Izumi H Miyamoto H Takahashi K Fukuchi Y Suda K 《Histopathology》2003,43(2):189-193
AIMS: We investigated a rare case of small vessel vasculitis (SVV) limited to pleuropulmonary manifestations, possibly induced by endotoxin, to determine the activation of immuno-mediated cells and endothelia in the pleuropulmonary circulation. METHODS AND RESULTS: A 44-year-old man with a high fever was X-rayed, revealing bilateral pleural effusion and atelectasis in the chest. His laboratory data were within normal limits except for a high white blood cell count and a high C-reactive protein level. Autoantibodies including anti-neutrophil cytoplasmic antibody were negative. Endotoxin was detected in his sera, but repeated cultures of sputa, urine, blood and the pleural effusion were negative for bacteria. Video-assisted thoracic surgery was performed and lung and parietal pleura specimens were obtained. Histology showed arterioles or small arteries infiltrated by monocytes or neutrophils with fibrinoid necrosis and acute or chronic venulitis. A diagnosis of SVV in the lung and pleura was made. Immunohistochemistry revealed that interleukin (IL)-1beta was expressed in monocytes and vascular cell adhesion molecule (VCAM)-1 on endothelial cells in the vasculitic lesions in the lung. CONCLUSIONS: Endotoxin possibly induced the inflammation in this apparently unique case of pleuropulmonary small vessel vasculitis. Immunohistochemistry revealed the expression of IL-1beta and VCAM-1 which may have caused activation of monocytes and endothelial cells within the vasculitic lesions. 相似文献
82.
D. W. Cheung 《Pflügers Archiv : European journal of physiology》1984,400(3):335-337
Stimulation of the perivascular nerves elicited two types of electrical responses in the rat tail artery—excitatory junction potentials (e.j.p.s) and slow depolarization—and two types of mechanical responses—fast and slow contractions. Fast phasic contractions were triggered whenever action potentials were generated from either the e.j.p. or the slow depolarization reaching threshold. Slow tonic contractions and slow depolarizations were sensitive to -adrenergic blockade. However the slow contraction always preceded the slow depolarization. Bolus doses of exogenous noradrenaline also induced slow contraction and slow depolarization and the development of tension also preceded the membrane potential change. Increasing the external KCl also induced membrane depolarization however, contractions were not observed until the membrane was depolarized positive of –49 mV. In contrast, tension developed readily with membrane potential more negative than –49 mV with exogenous noradrenaline and neural stimulation, suggesting that the action of noradrenaline was not mediated by electromechanical coupling. It was concluded that vascular activity in the rat tail artery could be regulated by the e.j.p., the slow depolarization and also by pharmacomechanical coupling. 相似文献
83.
Krämer J Aguirre-Arteta AM Thiel C Gross CM Dietz R Cardoso MC Leonhardt H 《Journal of molecular medicine (Berlin, Germany)》1999,77(2):294-298
Studies on smooth muscle cell differentiation and those on vascular development in mouse and humans have long been hampered
by the lack of suitable markers. Here we describe a novel, large isoform of smoothelin, a structural protein of differentiated,
contractile smooth muscle cells. The protein, which is highly conserved in mouse and humans, shows homology with other cytoskeleton-associated
smooth muscle cell proteins and contains an actinin-type actin-binding domain. Northern blot analysis from various mouse organs
identified short and long smoothelin mRNA forms, which exhibit distinct tissue expression patterns. The short form is highly
expressed in visceral muscle tissues such as intestine and stomach and is not detectable in brain, while the long mRNA form
is expressed in all vascularized organs. These results may provide new tools and approaches to study both smooth muscle cell
differentiation and proliferative vascular disease.
Received: 25 August 1998 / Accepted: 19 October 1998 相似文献
84.
Kiseleva EP Krylov AV Lyudyno VI Suvorov AN 《Bulletin of experimental biology and medicine》2005,139(5):576-579
Vascular endothelial growth factor is not only angiogenic, but also immunoregulatory factor. For evaluation of the possibility of its direct interaction with mouse thymocytes we studied the effect of vascular endothelial growth factor on proliferation and apoptosis of thymocytes and expression of genes for the corresponding receptor on these cells. Vascular endothelial growth factor modulated mitogen-induced proliferation of thymocytes and stimulated spontaneous apoptosis in intact thymus cells. Thymocytes express mRNA of type 2, but not type 1 vascular endothelial growth factor receptors.__________Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 139, No. 5, pp. 533–537, May, 2005 相似文献
85.
Martin Griebe Michael Daffertshofer Mark Stroick Magdalena Syren Parviz Ahmad-Nejad Michael Neumaier Juergen Backhaus Michael G. Hennerici Marc Fatar 《Neuroscience letters》2007
Biological markers play an evolving role in the diagnosis of Alzheimer disease (AD). We compare conventional measurements of cerebrospinal fluid (CSF) tau and β-amyloid1–42 proteins to a novel approach – Fourier transformed infrared (FT-IR) spectroscopy – a simple technique derived from chemical and physical sciences that characterizes intramolecular bonds. For automatic diagnostic analysis, we developed an artificial neural network (ANN). We examined 71 patients with a clinical diagnosis of AD and 66 controls. β-Amyloid1–42 was decreased (sensitivity 80% and specificity 78%); tau was elevated (sensitivity 76% and specificity 88%) in CSF of AD patients. The combined tau/β-amyloid1–42 quotient was able to distinguish healthy from diseased subjects with 99% sensitivity and 86% specificity. The ANN could separate FT-IR spectroscopy data with 88.5% sensitivity and 80% specificity. FT-IR spectroscopy proved to be cost-effective and simple to perform. Diagnostic sensitivity and specificity is in the range of CSF tau and β-amyloid1–42 protein analysis. Larger sample numbers for ANN training and validation could increase diagnostic accuracy and thus prove to be a useful screening tool. 相似文献
86.
Biomarkers for neurodegenerative diseases should reflect the central pathogenic processes of the diseases. The field of clinical proteomics is especially well suited for discovery of biomarkers in cerebrospinal fluid (CSF), which reflects the proteins in the brain under healthy conditions as well as in several neurodegenerative diseases. Known proteins involved in the pathology of neurodegenerative diseases are, respectively, normal tau protein, beta-amyloid (1-42), synaptic proteins, amyloid precursor protein (APP), apolipoprotein E (apoE), which previously have been studied by protein immunoassays. The objective of this paper was to summarize results from proteomic studies of differential protein patterns in neurodegenerative diseases with focus on Alzheimer's disease (AD). Today, discrimination of AD from controls and from other neurological diseases has been improved by simultaneous analysis of both beta-amyloid (1-42), total-tau, and phosphorylated tau, where a combination of low levels of CSF-beta-amyloid 1-42 and high levels of CSF-tau and CSF-phospho-tau is associated with an AD diagnosis. Detection of new biomarkers will further strengthen diagnosis and provide useful information in drug trials. The combination of immunoassays and proteomic methods show that the CSF proteins express differential protein patterns in AD, FTD, and PD patients, which reflect divergent underlying pathophysiological mechanisms and neuropathological changes in these diseases. 相似文献
87.
心脑血管病患者微血栓与D-2聚体、血小板聚集的相互关系 总被引:4,自引:0,他引:4
观察20例急性脑梗塞,30例冠心病在微循环中微血栓的变化,同时检测血小板聚集率、D-2聚体。结果表明微血栓阳性组血小板聚集率、D-2聚体均高于微血栓阴性组。治疗后二组血小板聚集、D-2聚体明显减少。提示微血栓、D-2聚体及血小板聚集率可作为评定冠心病、脑梗塞病情变化的一种指标 相似文献
88.
G. P. Cantore R. Delfini A. Mariottini A. Santoro P. Cascone 《Acta neurochirurgica》1987,86(1-2):56-60
Summary Anterior displacement of the mandible (ADM) was performed in 34 patients undergoing surgery for malformations or atheromatous lesions of the distal segment of the extracranial internal carotid artery (ICA). This procedure greatly facilitates surgical access to the upper cervical region and has several advantages over mandibulotomy-mandibulectomy, namely: A shorter operating time, sparing of the inferior alveolar nerve and of the mandibular branch of cranial nerve VII, with no need for post-operative immobilization of the mandible. ADM permits the correction of ICA lesions extending as far as the first cervical vertebra. For lesions extending into the carotid canal ADM needs to be supplemented by various other procedures via the base of the skull. 相似文献
89.
90.
Calogera Pisano Daniele Polisano Carmela Rita Balistreri Claudia Altieri Paolo Nardi Fabio Bertoldo Daniele Trombetti Laura Asta Maria Sabrina Ferrante Dario Buioni Calogero Foti Giovanni Ruvolo 《Nutrients》2021,13(2)
Frailty is the major expression of accelerated aging and describes a decreased resistance to stressors, and consequently an increased vulnerability to additional diseases in elderly people. The vascular aging related to frail phenotype reflects the high susceptibility for cardiovascular diseases and negative postoperative outcomes after cardiac surgery. Sarcopenia can be considered a biological substrate of physical frailty. Malnutrition and physical inactivity play a key role in the pathogenesis of sarcopenia. We searched on Medline (PubMed) and Scopus for relevant literature published over the last 10 years and analyzed the strong correlation between frailty, sarcopenia and cardiovascular diseases in elderly patient. In our opinion, a right food intake and moderate intensity resistance exercise are mandatory in order to better prepare patients undergoing cardiac operation. 相似文献