全文获取类型
收费全文 | 379659篇 |
免费 | 35287篇 |
国内免费 | 26298篇 |
专业分类
耳鼻咽喉 | 2897篇 |
儿科学 | 4995篇 |
妇产科学 | 4230篇 |
基础医学 | 41563篇 |
口腔科学 | 6186篇 |
临床医学 | 53379篇 |
内科学 | 51328篇 |
皮肤病学 | 4201篇 |
神经病学 | 18350篇 |
特种医学 | 13998篇 |
外国民族医学 | 224篇 |
外科学 | 33697篇 |
综合类 | 71152篇 |
现状与发展 | 87篇 |
一般理论 | 32篇 |
预防医学 | 28057篇 |
眼科学 | 10767篇 |
药学 | 41221篇 |
442篇 | |
中国医学 | 24737篇 |
肿瘤学 | 29701篇 |
出版年
2024年 | 1295篇 |
2023年 | 5515篇 |
2022年 | 14564篇 |
2021年 | 18580篇 |
2020年 | 14641篇 |
2019年 | 11939篇 |
2018年 | 12323篇 |
2017年 | 11826篇 |
2016年 | 10967篇 |
2015年 | 17072篇 |
2014年 | 21237篇 |
2013年 | 19383篇 |
2012年 | 28776篇 |
2011年 | 32266篇 |
2010年 | 21819篇 |
2009年 | 17785篇 |
2008年 | 21718篇 |
2007年 | 21385篇 |
2006年 | 20383篇 |
2005年 | 19434篇 |
2004年 | 12895篇 |
2003年 | 12491篇 |
2002年 | 10210篇 |
2001年 | 8693篇 |
2000年 | 8433篇 |
1999年 | 8450篇 |
1998年 | 5339篇 |
1997年 | 5133篇 |
1996年 | 3974篇 |
1995年 | 3723篇 |
1994年 | 3145篇 |
1993年 | 2031篇 |
1992年 | 2435篇 |
1991年 | 2136篇 |
1990年 | 1796篇 |
1989年 | 1560篇 |
1988年 | 1286篇 |
1987年 | 1187篇 |
1986年 | 956篇 |
1985年 | 679篇 |
1984年 | 369篇 |
1983年 | 271篇 |
1982年 | 143篇 |
1981年 | 169篇 |
1980年 | 116篇 |
1979年 | 158篇 |
1978年 | 74篇 |
1977年 | 56篇 |
1974年 | 43篇 |
1972年 | 37篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
121.
血液尿素氮是肾功能最重要的观测指标之一,是临床常规和急诊不可缺少的检验项目.尿素氮的测定方法,长期以来采用湿化学分析。如二乙酰—肟法,脲酶—吲哚酚法、脲酶—谷氨酸脱氢酶偶联法等.这些方法有足够的精确性和准确性,但需昂贵的仪器设备和专业技术人员,且操作繁琐又不能应急.干化学试剂以其用血微量、操作简便、快速、易于掌握和无需特殊仪器设备等优点有效地补充了湿试剂法之不足.国外已有尿素氮试纸法报道.50-93494专利技术是以脲酶、pH指示剂和屏障体组成的尿素氮试纸.此技术的特点是不用pH缓冲剂,而用多种高分子物质组成的屏障体来控制血液pH的影响.缺点是在试纸表面形成一坚硬的甲膜,使血样不易渗入试剂层,反应产生的颜色较浅,肉眼不易分辨. 相似文献
122.
观察发育阶段不同的鸡和大鼠的小脑标本外形,并在光学显微镜和电子显微镜下观察了结构。鸡卵在孵育的第6天,小脑原基出现。第15天小脑皮质形成,普肯野氏细胞(普氏细胞)排成一层。新生鸡小脑皮质发育近成年状态,普氏细胞发育基本完成。大鼠在生后第5天小脑皮质形成,第20天发育成熟。在生后第5天普氏细胞排成一层,第20天接近成熟状态,此时在电子显微镜下显示为粗面内质网和多聚核蛋白体区域性集中分布。鸡小脑比大鼠小脑发育早,这是种属差异。 相似文献
123.
随着教育制度的改革,中职院校的学生面貌发生了巨大变化。面对新形势,我们应科学借鉴先进的教育理念,合理设置教育目标,为职业教育改革注入新的理念和活力。 相似文献
124.
目的 提高护理质量,提高护理对象的满意度,减少医疗护理纠纷的发生。方法 产前有计划的开办孕妇学校;住院后根据个体化需要,制定标准的教育计划、优化服务环境、营造良好的人文化氛围;分娩过程中人性化护理、工休座谈会人文化的有效沟通;出院产妇送温连心卡及随访等。结果 收到良好的效果,环境的人文化管理,使护理对象感到如同家的感觉,满意度大大提高,产程的人文化实施,更体现了人性化护理。结论 产科人文化护理的实施,不但密切了护患关系,提高护理管理水平和护理质量,还使护士完善了社会形象,提高了社会地位,实现了自我价值。 相似文献
125.
126.
127.
This paper describes the results of the application of linear solvation energy relationships (LSERs) to quantitatively characterize the properties of adhesives and to evaluate the degree of drug-adhesive interaction in transdermal drug delivery formulations. Probe solutions were prepared in acetonitrile (ACN) for a set of probe compounds with different physicochemical properties, and were used to swell the adhesives for subsequent probe molecule-adhesive interactions. The degree of the interactions was measured by the 'sorbed' amount of probe molecules. Based on LSERs, the 'sorbed' amounts were linearly correlated with their properties. The corresponding coefficients reflect the differential interactions of these molecules with the adhesive and ACN, and are quantitative indications of the adhesive properties. Two different transdermal acrylate adhesives (isooctyl acrylate/acrylamide/vinyl acetate in the weight ratios of 75/5/20 and isooctyl acrylate/2-hydroxyethyl acrylate/vinyl acetate in the weight ratios of 58/20/18) were selected for the evaluation of the methodology. It is concluded that the first adhesive is more basic and hydrophobic, which is consistent with the use of acrylamide monomer and significant amount of isooctyl acrylate. The second adhesive is more acidic and polarizable due to a relatively high amount of the 2-hydroxyethyl acrylate. Additionally, the 'sorbed' amount can be regarded as an interaction parameter or index between a drug molecule and the adhesive. Finally, this parameter is expected to correlate with the thermodynamic properties of transdermal formulations such as drug solubility, diffusion coefficient, release rate, and maybe skin permeation rate. 相似文献
128.
高等医学院校医学化学教材改革的几点思考 总被引:2,自引:1,他引:1
医学的发展已进入分子水平,医学生必须具有扎实的化学基础才能适应专业学习及临床、科研工作的需要。现行医学化学教材大多沿用几十年前的模式,部分内容陈旧滞后,实用性不强。面对现实,改革势在必行。我们认为,突出重点、注重实用、体现医学特色应作为改革的方向。 相似文献
129.
持续压力超负荷对兔左心室细胞凋亡的影响 总被引:3,自引:1,他引:2
OBJECTIVE: To study the effect of chronic pressure overload on the apoptosis of the left ventricle myocytes in rabbits. METHODS: Rabbit models of chronic pressure overload-induced heart failure were prepared in which dynamic changes of apoptotic myocytes in the left ventricle were observed by way of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay. RESULTS: Only a few apoptotic cells was observed in the sham-operated group, while in the experimental group, the apoptotic left ventricle myocytes significantly increased after operation, presenting a peak level between day 3 and day 7. Seven days after the operation, the apoptotic myocytes began to decrease and till day 14, the apoptotic cell number had been smaller than that measured on day 1. When signs of heart failure set in, the apoptotic myocytes were again increased (P<0.001). CONCLUSION: During chronic pressure overload, myocyte apoptosis in the left ventricle is elevated at the early stages and undulates subsequently, with the peak occurring before hypertrophy is obvious. 相似文献
130.
R. P. Iacono M. D. F.A.C.S. J. D. Carlson S. M. Kuniyoshi Y. J. Li A. S. Mohamed G. Maeda 《Acta neurochirurgica》1997,139(5):433-441
Summary The current interest in stereotactic posteroventral pallidotomy (PVP) for treating Parkinson's disease and the variability of published results have raised questions regarding techniques for target localization. In our technique the probe is guided to the optimum target at the most ventral pallidum and ansa lenticularis by macroelectrode stimulation of the internal capsule and optic tract from within the globus pallidus, with the thresholds providing a relative measure of the electrode proximity to these structures. We have characterized these localizing macroelectrode stimulation parameters in 57 posteroventral pallidotomies with consistent anatomic lesion placement, excellent outcome, and no complications.Using a 1.8 × 2.0 mm radiofrequency electrode for macroelectrode stimulation (RFG-3C, Radionics Inc.), minimum voltages (thresholds) to activate motor (at a frequency of 2 Hz) or visual (at a frequency of 100 Hz) responses as well as impedance measurements were obtained at the final target (Tf) and at distances proximal to Tf along the electrode trajectory. The visual and motor threshold voltages at Tf via our standard approach angles (50 ° above base plane, 20 ° from the sagittal plane), had a range of 1.0 to 1.5 V, and 2.0 to 3.5 V respectively. We also found that as the probe approaches Tf there is a significant decrease in voltage thresholds for motor (P<.0001) and visual (P<.0001) responses in an individual patient indicating that the probe is converging on these structures. Increases in impedance between Tf, 2–3 mm, and 4–5 mm proximal to Tf were also statistically significant (P<.0001). Microelectrode recording of electrophysiological neuronal activity at various points along the trajectory towards the target showed distinct firing patters providing identification of the globus pallidus externus and internus, ansa lenticularis, and optic tract.Macroelectrode electrophysiological stimulation within the target volume, inducing threshold responses in the internal capsule and optic tract, provides for accurate localization of the most effective PVP target in the ansa lenticularis. In unresponsive patients, the utilization of microelectrode recording for the identification of the pallidal borders and the optic tract improves safety. 相似文献