全文获取类型
收费全文 | 9382篇 |
免费 | 1108篇 |
国内免费 | 292篇 |
专业分类
耳鼻咽喉 | 51篇 |
儿科学 | 148篇 |
妇产科学 | 102篇 |
基础医学 | 650篇 |
口腔科学 | 243篇 |
临床医学 | 770篇 |
内科学 | 1055篇 |
皮肤病学 | 103篇 |
神经病学 | 479篇 |
特种医学 | 213篇 |
外国民族医学 | 1篇 |
外科学 | 535篇 |
综合类 | 1478篇 |
预防医学 | 3155篇 |
眼科学 | 166篇 |
药学 | 868篇 |
3篇 | |
中国医学 | 283篇 |
肿瘤学 | 479篇 |
出版年
2024年 | 43篇 |
2023年 | 182篇 |
2022年 | 379篇 |
2021年 | 428篇 |
2020年 | 420篇 |
2019年 | 340篇 |
2018年 | 338篇 |
2017年 | 358篇 |
2016年 | 404篇 |
2015年 | 345篇 |
2014年 | 561篇 |
2013年 | 660篇 |
2012年 | 548篇 |
2011年 | 593篇 |
2010年 | 440篇 |
2009年 | 428篇 |
2008年 | 447篇 |
2007年 | 471篇 |
2006年 | 387篇 |
2005年 | 340篇 |
2004年 | 341篇 |
2003年 | 250篇 |
2002年 | 230篇 |
2001年 | 216篇 |
2000年 | 170篇 |
1999年 | 178篇 |
1998年 | 154篇 |
1997年 | 118篇 |
1996年 | 107篇 |
1995年 | 85篇 |
1994年 | 90篇 |
1993年 | 85篇 |
1992年 | 114篇 |
1991年 | 87篇 |
1990年 | 84篇 |
1989年 | 66篇 |
1988年 | 72篇 |
1987年 | 32篇 |
1986年 | 33篇 |
1985年 | 41篇 |
1984年 | 19篇 |
1983年 | 22篇 |
1982年 | 20篇 |
1981年 | 6篇 |
1980年 | 12篇 |
1979年 | 8篇 |
1978年 | 8篇 |
1977年 | 8篇 |
1976年 | 4篇 |
1974年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Vladimir Trubnikov Lubov Uvarova Margarita Alfimova Vera Orlova Natalia Ozerova Nickolai Abrosimov 《Behavior genetics》1993,23(5):455-459
Mathematical genetic analyses were performed on a sample of schizophrenic families (25 probands and 58 first-degree relatives). Heritability coefficients were estimated for EEG power spectrum parameters and their topography, and also for psychological test data on thought and speech process disorder, designed to assess altered selectivity in cognitive activity. Multiple regression equations for genetic counseling regarding the prognosis of mental illness were derived from the neurophysiological and psychological measures. 相似文献
32.
目的探讨影响幕上高血压脑出血(SICH)患者预后的相关因素,以指导临床治疗和评估预后。方法回顾性分析符合本研究纳入标准的幕上高血压脑出血324例完整病历。以一般资料、起病症状、入院查体、影像学资料、治疗方式、并发症等43项为自变量,以发病后1个月后功能独立性评定评分(functional independence measure,FIM)为因变量,建立多重线性回归模型,筛选出对预后有影响的因素,并比较各因素的影响大小。结果经统计学处理发现血肿体积、入院时收缩期血压、GCS评分、脑室是否积血、血肿体积扩大、是否并发肺部感染和应激性溃疡等7项对预后有显著性的影响。结论血肿体积、入院GCS评分和脑室是否积血对预后影响有重要意义,可作为SICH患者预后的关键性指标。 相似文献
33.
Krishnamoorthy V Latash ML Scholz JP Zatsiorsky VM 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2003,152(3):281-292
Movements by a standing person are commonly associated with adjustments in the activity of postural muscles to cause a desired shift of the center of pressure (COP) and keep balance. We hypothesize that such COP shifts are controlled (stabilized) using a small set of central variables (muscle modes, M-modes), while each M-mode induces changes in the activity of a subgroup of postural muscles. The main purpose of this study has been to explore the possibility of identification of muscle synergies in a postural task using the framework of the uncontrolled manifold (UCM) hypothesis employing the following three steps in data analysis: (i) Identification of M-modes: Subjects were asked to release a load from extended arms through a pulley system, resulting in a COP shift forward prior to load release. Electromyographic (EMG) activity of eleven postural muscles on one side of the body was integrated over a 100 ms interval corresponding to the early stage of the COP shift, and subjected to a principal component (PC) analysis across multiple repetitions of each task. Three PCs were identified and associated with a push-back M-mode, a push-forward M-mode and a mixed M-mode. (ii) Calculation of the Jacobian of the system, which relates changes in the magnitude of M-modes to COP shifts using regression techniques: Subjects performed three different tasks (releasing different loads at the back, voluntarily shifting body weight forward and backward, at different speeds) to verify if the relationship between magnitudes of M-modes and COP shifts is task or direction specific. (iii) UCM analysis: Three tasks were chosen (load release in the front, arm movement forward and backward) which were associated with an early shift in COP. A manifold was identified in the M-mode space corresponding to a certain average (across trials) shift of the COP and variance per degree of freedom within the UCM (VUCM) and orthogonal (VORT) to the UCM was computed. Across subjects, VUCM was significantly higher than VORT when analysis at the third step was performed using a Jacobian computed based on a set of tasks associated with a COP shift in the same direction but not in the opposite direction. This result confirms our hypothesis that the M-modes work together as a synergy to stabilize a desired shift of the COP. Forward and backward COP shifts are associated with different synergies based on the same three M-modes.An erratum to this article can be found at 相似文献
34.
职业紧张与冠心病的病例对照研究 总被引:12,自引:0,他引:12
目的 :(1)探讨男性列车乘务人员职业紧张与冠心病发病的关系。方法 :应用职业紧张因素测试量表 (OSI) ,对男性列车乘务人员中 3 9例冠心病患者进行 1:2的配比病例对照研究并进行多因素条件Logistic回归分析。结果 :(1)在控制和考虑了非职业紧张因素条件下 ,职业紧张与冠心病关系密切 (OR =2 18,95 %CI :1 15 -4 15 ) ,而且随着职业紧张程度的增加 ,患冠心病的危险性显著增加 ;(2 )以铁路乘务人员为对照时 (与病例同工种 ) ,职业紧张仍与冠心病发病有关联 (OR =4 43 ,95 %CI :1 60 -12 2 5 ) ,但其OR值明显低于以其他服务行业人员为对照时的OR值 (OR =9 75 ,95 %CI:3 18-2 9 92 )。结论 :职业紧张是引起男性列车乘务人员冠心病发病的重要危险因素之一。 相似文献
35.
生物学行为是影响胃癌预后的重要因素而核面积是影响因素中最重要一个。本文按生长方式对胃癌作了新的病理生物学分型的尝试,把胃癌分作膨胀型和浸润型,每型又依核面积大小分为大核型和小核型。结果表明,本文的分型较其他分型更能体现肿瘤的生物学特性,值得提倡。 相似文献
36.
企业员工应对方式与心理健康之间的关系 总被引:3,自引:2,他引:3
目的:验证不同应对方式对心理健康的单独与共同影响。方法:对4745名被试用分层回归的方法分析不同应对方式对心理健康的单独影响和交互作用。结论:单独使用“消极应对”的应对方式,对心理健康水平存在不利影响;而单独使用“积极应对”的应对方式能在一定程度上改善心理健康水平。“消极应对”与“积极应对”两种应对方式结合使用能显著改善心理健康水平,比单独使用这两种应对方式对心理健康更有利。 相似文献
37.
Gaëlle Dzangué-Tchoupou Kuberaka Mariampillai Loïs Bolko Damien Amelin Wladimir Mauhin Aurélien Corneau Catherine Blanc Yves Allenbach Olivier Benveniste 《Autoimmunity reviews》2019,18(4):325-333
Background
Myositis is a heterogeneous group of muscular auto-immune diseases with clinical and pathological criteria that allow the classification of patients into different sub-groups. Inclusion body myositis is the most frequent myositis above fifty years of age. Diagnosing inclusion body myositis requires expertise and is challenging. Little is known concerning the pathogenic mechanisms of this disease in which conventional suppressive-immune therapies are inefficacious.Objectives
Our aim was to deepen our understanding of the immune mechanisms involved in inclusion body myositis and identify specific biomarkers.Methods
Using a panel of thirty-six markers and mass cytometry, we performed deep immune profiling of peripheral blood cells from inclusion body myositis patients and healthy donors, divided into two cohorts: test and validation cohorts. Potential biomarkers were compared to myositis controls (anti-Jo1-, anti-3-hydroxyl-3-methylglutaryl CoA reductase-, and anti-signal recognition particle-positive patients).Results
Unsupervised analyses revealed substantial changes only within CD8+ cells. We observed an increase in the frequency of CD8+ cells that expressed high levels of T-bet, and containing mainly both effector and terminally differentiated memory cells. The senescent marker CD57 was overexpressed in CD8+T-bet+ cells of inclusion body myositis patients. As expected, senescent CD8+T-bet+ CD57+ cells of both patients and healthy donors were CD28nullCD27nullCD127null. Surprisingly, non-senescent CD8+T-bet+ CD57- cells in inclusion body myositis patients expressed lower levels of CD28, CD27, and CD127, and expressed higher levels of CD38 and HLA-DR compared to healthy donors. Using classification and regression trees alongside receiver operating characteristics curves, we identified and validated a frequency of CD8+T-bet+ cells >51.5% as a diagnostic biomarker specific to inclusion body myositis, compared to myositis control patients, with a sensitivity of 94.4%, a specificity of 88.5%, and an area under the curve of 0.97.Conclusion
Using a panel of thirty-six markers by mass cytometry, we identify an activated cell population (CD8+T-bet+ CD57- CD28lowCD27lowCD127low CD38+ HLA-DR+) which could play a role in the physiopathology of inclusion body myositis, and identify CD8+T-bet+ cells as a predominant biomarker of this disease. 相似文献38.
Immunolocalization of extracellular matrix proteins and integrins in sarcoid lymph nodes 总被引:1,自引:0,他引:1
K. Shigehara Noriharu Shijubo Michio Hirasawa Shosaku Abe Toshimitsu Uede 《Virchows Archiv : an international journal of pathology》1998,433(1):55-61
To improve our understanding of the role of extracellular matrix (ECM) proteins and integrins during the processes of granuloma
formation in sarcoidosis, we examined the distribution of ECM proteins and the expression of integrins in sarcoid lymph nodes
by immunohistochemical methods. We also examined the expression of transforming growth factor-β1 (TGF-β1), which is one of
major regulators for synthesis of ECM proteins. Most ECM proteins were detected in the periphery of the granulomas in a concentric
pattern, and fibronectin was diffusely detected from an early to a regressive stage. Compared with normal lymph nodes, most
β1-integrin subfamilies (α1, α4, α5 and α6) were more strongly expressed on lymphocytes around the granulomas. Epithelioid
cells exhibited strong expression of the α5 molecule. Fibroblasts exhibited the expression of the α2 and α5 molecules surrounding
ECM proteins. The α5β1 molecule had a distribution similar to that of fibronectin. TGF-β1 was detected in epithelioid cells
throughout the various evolutional stages and its expression was especially marked in mature granulomas. Interaction of fibronectin
and the α5β1 molecule may have an important role in the process of formation of sarcoid granuloma. The expression of TGF-β1
may be involved in the regression of sarcoid granuloma by initiating fibrosis and atrophy of epithelioid cells.
Received: 2 December 1997 / Accepted: 19 February 1998 相似文献
39.
利用脉搏波特征参数连续测量血压的方法研究 总被引:11,自引:0,他引:11
通过研究血压与脉搏波特征参数的关系,提出了一个选择多个与血压相关的脉搏波特征参数,通过回归分析建立适合不同人的特征方程,进行血压的连续测量的新方法,为了验证测量结果的准确性;研制了张力计。实验结果表明:该方法具有较高的测量精度,可以应用于临床危重病人的血压监护和一般医学研究中,经过进一步地改进和完善后可应用于载人航天和日常动态环境。 相似文献
40.
A. Bansal† J. M. Farnham† R. O. Crapo‡ D. C. Hughes† R. L. Jensen‡ L. A. Cannon-Albright† 《Clinical and experimental allergy》2001,31(5):756-760
BACKGROUND: Asthma is becoming increasingly prevalent and a number of research groups are investigating its genetic and environmental basis. OBJECTIVE: To produce a brief screening tool suitable for determining phenotype in asthma research. METHODS: The scores from eight questions on symptoms and history were obtained from 678 adults and 244 children from high asthma-incidence caucasian families. An independent physician diagnosis was also obtained with the use of a modified NHLBI-CSGA questionnaire and pulmonary function test. Stepwise logistic regression was applied to determine which of the eight questions had greatest predictive value for asthma, and the quality of the resultant models was evaluated using an independent set of 643 adults and 239 children. RESULTS: For adults, the most parsimonious model used responses from three of the eight questions. It had sensitivity and specificity of 0.94 and 0.96, respectively. For children, responses to two questions gave a model with sensitivity and specificity of 0.97. For both age groups, negative predictive values were above 0.87. Positive predictive values were 0.58 and 0.78 for adults and children respectively. The latter emphasize the need for conformation, by physician, of "affected" calls made by this initial screen. CONCLUSION: The brief questionnaires described are potentially useful in a research setting, as a preliminary screening mechanism of low cost. Their use will reduce the numbers of subjects that must undergo detailed phenotyping. 相似文献