全文获取类型
收费全文 | 358569篇 |
免费 | 28623篇 |
国内免费 | 10710篇 |
专业分类
耳鼻咽喉 | 2914篇 |
儿科学 | 4986篇 |
妇产科学 | 5019篇 |
基础医学 | 52720篇 |
口腔科学 | 6397篇 |
临床医学 | 25843篇 |
内科学 | 55562篇 |
皮肤病学 | 4668篇 |
神经病学 | 25666篇 |
特种医学 | 10301篇 |
外国民族医学 | 53篇 |
外科学 | 26829篇 |
综合类 | 48454篇 |
现状与发展 | 41篇 |
一般理论 | 14篇 |
预防医学 | 23375篇 |
眼科学 | 4146篇 |
药学 | 51880篇 |
94篇 | |
中国医学 | 19641篇 |
肿瘤学 | 29299篇 |
出版年
2024年 | 723篇 |
2023年 | 5588篇 |
2022年 | 11558篇 |
2021年 | 16917篇 |
2020年 | 13081篇 |
2019年 | 12005篇 |
2018年 | 11832篇 |
2017年 | 12492篇 |
2016年 | 12610篇 |
2015年 | 13223篇 |
2014年 | 17872篇 |
2013年 | 22859篇 |
2012年 | 19355篇 |
2011年 | 22710篇 |
2010年 | 16789篇 |
2009年 | 17146篇 |
2008年 | 18209篇 |
2007年 | 18276篇 |
2006年 | 16779篇 |
2005年 | 15101篇 |
2004年 | 12770篇 |
2003年 | 11388篇 |
2002年 | 9047篇 |
2001年 | 7810篇 |
2000年 | 6584篇 |
1999年 | 5758篇 |
1998年 | 4870篇 |
1997年 | 4759篇 |
1996年 | 4343篇 |
1995年 | 3807篇 |
1994年 | 3569篇 |
1993年 | 2965篇 |
1992年 | 2626篇 |
1991年 | 2481篇 |
1990年 | 2099篇 |
1989年 | 1730篇 |
1988年 | 1658篇 |
1987年 | 1438篇 |
1986年 | 1322篇 |
1985年 | 2013篇 |
1984年 | 1722篇 |
1983年 | 1245篇 |
1982年 | 1297篇 |
1981年 | 1084篇 |
1980年 | 985篇 |
1979年 | 779篇 |
1978年 | 512篇 |
1977年 | 433篇 |
1976年 | 410篇 |
1975年 | 289篇 |
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
991.
(张明敏)(刘沛霖)(叶望云)EffectofTripterygiumVilfordiionAdrenalCortexinRatwithAdjuvantArthritis¥ZHANGMing-min;LIUPei-lin;YEWang-yun(Tongji... 相似文献
992.
(沈张悦)(邵静芳)(王晓林)(朱慧芬)ExperimentalStudyonAnti-tumorEffectofSplenocytesInducedbyAnti-CD3McAb,PHAandIL-2¥SHENGuan-xin,WANGXiao-li... 相似文献
993.
Alcohol and Platelet Function 总被引:3,自引:0,他引:3
Epidemiological studies have shown that moderate consumption of alcoholic beverages is inversely related to the incidence of the complications of coronary artery disease. The protective effect of ethanol may be partially attributable to an inhibitory effect of ethanol on platelets. This article summarizes the experimental observations that ethanol inhibits platelet responses to specific physiological agonists. In alcoholics, various platelet defects have been observed, but these may be influenced by metabolic factors rather than the presence of ethanol alone. The acute effects of ethanol on platelet functions both in vivo and ex vivo will be reviewed. Evidence will be presented demonstrating that ethanol added acutely in vitro inhibits phospholipase A2 in stimulated platelets. The interaction of ethanol with other signal transduction pathways will also be discussed. 相似文献
994.
Michael P. Recht Josef Kramer Cheryl A. Petersilge Joseph Yu Mini Pathria Debra Trudell David J. Sartoris Donald Resnick 《Journal of magnetic resonance imaging : JMRI》1994,4(2):173-177
Although magnetic resonance (MR) images of the glenohumeral joint frequently demonstrate intraarticular fluid, no specific criteria have, to the authors' knowledge, been published that allow accurate assessment of the amount of fluid present. Also, despite the increasing use of MR arthrography of the shoulder, the optimal amount of intra-articular fluid that should be used with this technique has not been determined. The authors progressively distended the glenohumeral joint in six cadaveric shoulder specimens with a dilute gadopentetate dimeglumine solution and obtained MR images after injection of 2, 5, 10, 15, and 20 mL of the solution. The pattern of fluid distribution was evaluated, and these results were then used to estimate the amount of fluid that was present in the glenohumeral joint on MR images of 20 shoulders obtained in 12 asymptomatic volunteers. In 14 of these shoulders, intraarticular fluid was present; however, in none was more than 2 mL evident. Results of the cadaveric study also indicated that 15 mL of intraarticular fluid appears to be the optimal amount for MR arthrography. 相似文献
995.
996.
微型无线收发器在中央监护系统中的应用 总被引:3,自引:0,他引:3
中央监护系统能够实现对病人的生理或生化参数连续、长时间、自动、实时监测,并经分析、处理后实现多类别自动报警、自动记录及对诊断结果进行综合判断等。传统的多参数生理监护系统主要是通过各种专用电缆来实现网络化,在增加产品成本的同时也加大了施工的难度。本文在分析了无线收发芯片XE1201的工作原理基础上,重点介绍了应用其开发无线收发模块的原理和方法,并利用此模块构建了无线中央监护系统,继而对整个系统的性能进行了测试。该系统已在实验室中实现,并对心电(ECG)、无创血压、血氧饱和度(SPO2)等多生理参数进行实时监护,将信息提供给医院内的网络,以供访问使用。 相似文献
997.
北京市1989~2002年疫苗相关麻痹型脊髓灰质炎病例的监测 总被引:13,自引:2,他引:11
北京市急性弛缓性麻痹 (AFP)病例监测系统 1989~ 2 0 0 2年共诊断疫苗相关麻痹型脊髓灰质炎 (脊灰 )(VAPP) 2 0例 ,其中首次服苗VAPP 18例 ,接触服苗VAPP 2例。所有病例均 <2岁 ,<6月龄病例占 85 %。男女发病之比为 9∶1。每年VAPP发生率无明显季节性高峰和地区差异。VAPP总发生率为 1 2 0 / 10 0万剂口服脊灰减毒活疫苗 (OPV)投放量或 1 5 9/ 10 0万剂OPV接种量 ,首次服苗VAPP发生率为 13 18/ 10 0万剂首次服苗量 ,接触服苗VAPP发生率为 0 16 / 10 0万剂OPV接种量。监测结果表明 ,北京市VAPP发生的危险性高于中国其它省份和其它许多国家与地区 ;免疫缺陷和 /或肛门周围脓肿可能是VAPP重要的危险因素。在中国当前尚未改变脊灰疫苗免疫策略的情况下 ,为减少和避免VAPP的发生 ,必须加强接种前儿童病史询问和体检 ,严格掌握接种禁忌证 ;同时要加强对VAPP的监测工作。 相似文献
998.
CO2激光治疗尿道肉阜105例报告 总被引:1,自引:0,他引:1
在局麻下用CO2激光在门诊对105例尿道肉阜者行切除术或直接汽化。结果:术中出血少,手术时间短,术后伤口愈合好,随访5年无复发。 相似文献
999.
Eric K. Outwater Katsuyoshi Ito Evan Siegelman C. Edwin Martin Manoj Bhatia Donald G. Mitchell 《Journal of magnetic resonance imaging : JMRI》1997,7(6):1033-1039
The purpose of this study is to describe a subset of atypical hepatic hemangiomas that enhance rapidly and diffusely and to determine whether heavily T2-weighted images could distinguish between atypically enhancing liver hemangiomas and hypervascular malignancies. A retrospective search of MR records identified seven patients with liver hemangiomas that demonstrated diffuse early enhancement and 23 patients with biopsy-proven malignant liver lesions that were hypervascular on dynamic gadolinium-enhanced MR images. Quantitative analysis of signal intensity measurements was performed on the T2-weighted images, heavily T2-weighted (TE < 140), and dynamic gadolinium-enhanced images. Blinded reader comparison of the T2-weighted images and gadolinium-enhanced images was performed. Hypervascular hemangiomas enhanced to a greater degree than hypervascular malignant liver lesions on the early phase gadolinium-enhanced images. Perilesional parenchymal enhancement was demonstrated in five cases of rapidly enhancing hemangiomas. Signal intensity and contrast-to-noise ratios on the heavily T2-weighted images of the hemangiomas were significantly greater than that of the hypervascular malignant lesions (P < .05). Hemangiomas were differentiated from the hypervascular malignant liver lesions with high accuracy (97–100%) by three blinded readers based on the T2-weighted images. A subset of hemangiomas have atypical rapid diffuse enhancement on dynamic gadolinium-enhanced images. These atypical hemangiomas can be distinguished from hypervascular malignant liver lesions on T2-weighted MR images. 相似文献
1000.
A. Gregory Sorensen Andrew L. Tievsky Leif Ostergaard Robert M. Weisskoff Bruce R. Rosen 《Journal of magnetic resonance imaging : JMRI》1997,7(1):47-55
Contrast agents have greatly expanded the role of MR imaging (MRI) to allow assessment of physiologic, or “functional,” parameters. Although activation mapping generally does not require contrast agents, other forms of functional MRI, including mapping of cerebral hemodynamics (eg, perfusion imaging), are best done with the use of contrast agents. Serial echo planar images are obtained after bolus injection of lanthanide chelates. Application of susceptibility contrast physics and standard tracer kinetic principles permits generation of relative cerebral blood volume maps. Deconvolution of cerebral blood flow and mean transit time parameters is also possible within technical limitations. By using diffusion and perfusion pulse sequences, an imaging correlate to the ischemic penumbra can be identified. Functional MRI perfusion imaging of intraaxial tumors is analogous to positron emission tomography for delineation of metabolic activity, yet may be even more sensitive to neovascularity and possesses improved image quality. Clinical applications include biopsy site selection and postirradiation follow-up. Further improvements in data analysis and map generation techniques may improve diagnostic accuracy and utility. 相似文献