首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   4945篇
  免费   442篇
  国内免费   130篇
耳鼻咽喉   24篇
儿科学   80篇
妇产科学   31篇
基础医学   386篇
口腔科学   238篇
临床医学   494篇
内科学   432篇
皮肤病学   16篇
神经病学   173篇
特种医学   249篇
外国民族医学   2篇
外科学   313篇
综合类   703篇
预防医学   984篇
眼科学   47篇
药学   876篇
  11篇
中国医学   308篇
肿瘤学   150篇
  2024年   16篇
  2023年   81篇
  2022年   228篇
  2021年   258篇
  2020年   223篇
  2019年   167篇
  2018年   176篇
  2017年   178篇
  2016年   202篇
  2015年   186篇
  2014年   308篇
  2013年   384篇
  2012年   293篇
  2011年   344篇
  2010年   250篇
  2009年   245篇
  2008年   259篇
  2007年   260篇
  2006年   226篇
  2005年   200篇
  2004年   147篇
  2003年   130篇
  2002年   68篇
  2001年   92篇
  2000年   68篇
  1999年   63篇
  1998年   37篇
  1997年   43篇
  1996年   42篇
  1995年   31篇
  1994年   22篇
  1993年   31篇
  1992年   23篇
  1991年   30篇
  1990年   20篇
  1989年   10篇
  1988年   15篇
  1987年   22篇
  1986年   13篇
  1985年   19篇
  1984年   19篇
  1983年   10篇
  1982年   18篇
  1981年   10篇
  1980年   10篇
  1979年   9篇
  1978年   7篇
  1977年   6篇
  1976年   7篇
  1974年   5篇
排序方式: 共有5517条查询结果,搜索用时 15 毫秒
71.
72.
73.
The objective of this study was to evaluate the in vitro behavior of different clarithromycin granular suspensions based on a developed in vitro-in vivo correlation model, using one reference and two test formulations. In vitro release rate data were obtained for each product using the USP apparatus II, operated at 50?rpm under different pH conditions. The dissolution efficiency was used to analyze the dissolution data. In vivo study was performed on six healthy male volunteers under fasting condition. Correlation was made between in vitro release and in vivo absorption. A linear model was developed using percent absorbed data versus percent dissolved data from the three products. Dissolution condition of 0.1N HCl for 1?h and then phosphate buffer at pH 6.8 was found to be the most discriminating dissolution method. Rate of absorption for the reference as estimated by Wagner-Nelson deconvolution was correlated with in vitro release with a correlation coefficient of 0.99. The in vivo results for the two test products were compared to the predicted values using the reference model with a correlation coefficient of 0.94. Furthermore, multiple level C correlations were obtained for some pharmacokinetic parameters with the corresponding in vitro kinetic parameters with correlation coefficients exceeding 0.90. Moreover, the interpretation of the in vitro and in vivo data with reference to formulations was discussed.  相似文献   
74.
The purpose of this study was to measure the effects of a seven-week therapeutic horseback riding program and to determine if changes were retained after therapeutic riding was discontinued. A repeated-measures within-participants design was used to assess performance on the Gross Motor Function Measure and timed 10-meter walk in seven developmentally delayed children. A statistically significant improvement in gross motor function was found in post-intervention measures. Improvements were maintained seven weeks after therapeutic riding had ended. No considerable difference in gait speed was noted. This study indicates that therapeutic riding may lead to improvement in gross motor function in developmentally delayed children and that these improvements remain once therapeutic riding ceases.  相似文献   
75.
We investigate the impact of baseline covariates on the efficiency of statistical analyses of crossover designs. For practical considerations, we contemplate two different baseline methods: study baselines and period‐dependent baselines. For each baseline method, we establish analytical upper bounds for the relative efficiency of a large class of crossover designs, the totally balanced designs, under a model with the baseline covariates as compared with the model without the baseline covariates. We present numerical details based on these bounds for assorted scenarios and reveal implications of these results. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
76.
Cancer has emerged as a global threat with challenges for safe chemotherapeutics. Most of the currently available anti-cancer drugs exhibit significant toxicity. Amongst novel agents, interferons have exhibited anti-proliferative and cytoprotective roles. However, due to stability drawbacks of interferons, we have identified an interferon inducer DEAE-Dextran, which resolves the stability issues. Based on the previous history of toxicity pertaining to the current chemotherapeutic agents, it is equally essential to determine the safety of DEAE-Dextran. In the present study, repeated dose 28 day oral toxicity of DEAE-Dextran has been evaluated in accordance to OECD-407. We found absence of any CNS behavioral changes related to self-mutilation, walking backwards, aggressiveness on handling or tonic-clonic seizures during the 28 day study. Neither the motor activity nor grip strength was altered during the treatment duration with DEAE-Dextran implying absence of any effect on the skeletal muscles. Interestingly, we also found that treatment with DEAE-Dextran did not present any significant cardiac, hepatic, renal, gastrointestinal, lymphatic or reproductive system toxicity or alteration in the body's normal physiology based upon the various organ function tests. Henceforth, it may be concluded that DEAE-Dextran is a safe anti-cancer agent devoid of any sub-acute toxicity.  相似文献   
77.
78.
目的研究高校教育管理人员工作满意的现状及其影响因素。方法采用自编的教育管理人员工作满意度问卷对310名高校教育管理人员进行问卷调查。结果高校教育管理人员的工作满意度处于中等偏上水平,其中晋升发展的满意度最低(x珋=2.78),同事关系的满意度最高(x珋=3.91)。不同性别、年龄、职务、月收入水平的高校教育管理人员的工作满意度得分差异显著;工作满意度与工作效率具有显著的正相关(r=-0.362,P0.01),回归分析表明,在控制了人口统计变量之后,工作本身的满意度可以显著正向预测工作效率(β=0.353,P0.001)。结论高校教育管理人员对晋升发展的满意度偏低;性别、年龄、职务、月收入等显著影响高校教育管理人员的工作满意度;教育管理人员对教育管理工作本身的满意可以显著正向预测工作效率。  相似文献   
79.
Developing a better method for the metallization of silicon solar cells is integral part of realizing superior efficiency. Currently, contact realization using screen printing is the leading technology in the silicon based photovoltaic industry, as it is simple and fast. However, the problem with metallization of this kind is that it has a lower aspect ratio and higher contact resistance, which limits solar cell efficiency. The mounting cost of silver pastes and decreasing silicon wafer thicknesses encourages silicon solar cell manufacturers to develop fresh metallization techniques involving a lower quantity of silver usage and not relying pressing process of screen printing. In recent times nickel/copper (Ni/Cu) based metal plating has emerged as a metallization method that may solve these issues. This paper offers a detailed review and understanding of a Ni/Cu based plating technique for silicon solar cells. The formation of a Ni seed layer by adopting various deposition techniques and a Cu conducting layer using a light induced plating (LIP) process are appraised. Unlike screen-printed metallization, a step involving patterning is crucial for opening the masking layer. Consequently, experimental procedures involving patterning methods are also explicated. Lastly, the issues of adhesion, back ground plating, process complexity and reliability for industrial applications are also addressed.  相似文献   
80.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号