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   600篇
  免费   21篇
  国内免费   5篇
管理学   49篇
民族学   4篇
人口学   8篇
丛书文集   16篇
理论方法论   6篇
综合类   293篇
社会学   17篇
统计学   233篇
  2023年   3篇
  2022年   2篇
  2021年   6篇
  2020年   9篇
  2019年   12篇
  2018年   9篇
  2017年   17篇
  2016年   12篇
  2015年   18篇
  2014年   23篇
  2013年   113篇
  2012年   51篇
  2011年   30篇
  2010年   31篇
  2009年   19篇
  2008年   38篇
  2007年   31篇
  2006年   20篇
  2005年   38篇
  2004年   28篇
  2003年   28篇
  2002年   14篇
  2001年   9篇
  2000年   12篇
  1999年   11篇
  1998年   6篇
  1997年   5篇
  1996年   6篇
  1995年   8篇
  1994年   4篇
  1993年   2篇
  1992年   1篇
  1991年   1篇
  1990年   2篇
  1989年   3篇
  1988年   1篇
  1983年   1篇
  1980年   1篇
  1975年   1篇
排序方式: 共有626条查询结果,搜索用时 46 毫秒
31.
Objectives: To investigate frailty as a predictor of surgical outcome in elderly patients undergoing penile prosthesis implantation.

Material and methods: A total of 54 elderly patients, above 60 years of age, underwent penile prosthesis implantation between 2012 and 2014. Their data were collected and retrospectively analyzed. A modified frailty index (mFI) was calculated for each patient based on 11 risk factors from the Canadian Study of Health and Aging Frailty Index. The 1-year adverse outcomes were correlated with mFI, patients’ and procedure’s risk factors.

Results: Mean age was 64.9?±?5.2 years. No mortality was reported in our patients, however, one-year adverse outcomes were encountered in 43 (79.6%) patients. Among all studied variables, the 1-year adverse outcomes was not significantly association with mFI, but with preoperative glycosylated hemoglobin A1c (HbA1c) (p?=?0.031) and associated Peyronie’s disease (PD) (p?=?0.000). HbA1c, dyslipidemia, hypertension, PD and duration of the procedure were predictive of infection complications (p?Conclusions: mFI is not a predictive of post-penile prosthesis implantation adverse outcomes in elderly patients with impotence. Degree of diabetic control and association with PD was associated with the 1-year adverse outcomes and infection complications.  相似文献   
32.
自贸区对所属城市创新能力具有直接推动作用。选取福建省为评价对象,应用改进熵值法,实证分析自贸区所属城市创新驱动发展要素及互动关系,指出科技进步、政策支撑、产业参与和环境匹配是区域创新的重要因素,在资源秉赋差异明显的情况下,应着力推进科研投入与措施创新,并加快人才培育和产业集聚。  相似文献   
33.
Abstract. This paper considers the integration problems associated with incorporating production planning and control (PP&C) systems within CIM; these problems are typically not differentiated from functionally related problems, and have in the past received relatively little attention. The on-going emergence of a number of standards relevant to manufacturing software systems provides an opportunity to assess the current situation with regard to proprietary PP&C systems and to suggest ways forward towards ‘seamless’ integration of PP&C within the CIM environment. The problems arising from conventional integration approaches are briefly described, and the concept of a simplifying ‘integration platform’ is introduced; the three-schema information architecture is presented as part of this ‘integration simplification’ approach. Current and developing PP&C systems are assessed against a number of information system integration criteria, and the results of a small survey of proprietary packages are presented. The paper concludes that information must be regarded as an enterprise-wide asset, rather than belonging to individual software applications, and that the adoption of relevant standards will enable seamless integration within a three-schema architecture. An increasing number of proprietary packages are adopting standards and methodologies which ease the integration problem significantly.  相似文献   
34.
A new discrete distribution defined over all the positive integers and with the name of Geeta distribution is described. It is L-shaped like the logarithmic series distribution, Yule distribution and the discrete Pareto distribution but is far more versatile than them as it has two parameters. It belongs to the classes of location parameter distributions, modified power series distributions, Lagrange series distributions and exponential distributions. Its mean fi, variance a2 and two recurrence formulae for higher central moments are obtained. Convolution theorem and variations in the model with changes in the parameters have been considered. ML estimators, MVU estimators and estimators based of mean and variance and on mean and first frequency have been derived.  相似文献   
35.
A new class of statistical tests for uniformity based on sample ranges is proposed to detect a uniform density contaminated by a density with one or more high peaks. These kinds of alternatives occur quite frequently, especially in physics. It is shown that the proposed tests arc consistent and have high Pitman asymptotic relative efficiencies. Results of a Monte Carlo power study indicate that they, compared with other tests of uniformity, possess good power properties.A comparative study of various tests is also conducted using real data. An effcient algorithm for computing out test statistic and a table of percentage points are given, providing a practical guide for using the new test.  相似文献   
36.
For testing that the population correlations coefficientp Q, Tiku and Balakrishnan1986) developed a robust test. This test is extended here to situcitions where one wants to test that p p , p being a specified non-zero value of p. o o  相似文献   
37.
38.
A gamma regression model with an exponential link function for the means Is considered. Moment properties of the deviance statistics based on maximum likelihood and weighted least squares fits are used to define modified deviance statistics which provide alternative global goodness of fit tests. The null distribution properties of the deviances and modified deviances are compared with those of the approximating chi-square distribution and It is shown that the use of the modified deviances gives much better control over the significance levels of the tests.  相似文献   
39.
Josef Kozák 《Statistics》2013,47(3):363-371
Working with the linear regression model (1.1) and having the extraneous information (1.2) about regression coefficients the problem exists how to build estimators (1.3) with the risk (1.4) which enable to utilize the known information in order to reduce their risk as compared with the risk (1.6) of the LSE (1.5). Solution of this problem is known for the positive definite matrix T, namely in form for estimators (1.8) and (1.10).First, it is shown that the proposed estimators (2.6),(2.9) and (2.16) based on psedoinversions of the matrix L represent the solution of the problem of the positive semidefinite matrix T=L'L.Further, the problem of interpretability of estimators in the sense of the inequality (3.1) exists; it is shown that all mentioned estimators are at least partially interpretable in the sense of requirements (3.2) or (3.10).  相似文献   
40.
作为一类征收主体,征收关系人的范围是非常广泛的,但我国现行法规就征收关系人的范围并未做出系统规定,这是我国未来统一征收立法必须解决的一个问题。根据立法通例,登记并非成为适格的征收关系人的必要条件。对于预告登记权利人的关系人地位,应分不同情形作具体分析。  相似文献   
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