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   127862篇
  免费   4045篇
  国内免费   1382篇
管理学   3632篇
劳动科学   26篇
民族学   1824篇
人才学   11篇
人口学   1802篇
丛书文集   16515篇
理论方法论   5419篇
综合类   90739篇
社会学   4104篇
统计学   9217篇
  2024年   199篇
  2023年   621篇
  2022年   988篇
  2021年   1131篇
  2020年   1452篇
  2019年   1447篇
  2018年   1559篇
  2017年   1966篇
  2016年   1978篇
  2015年   2605篇
  2014年   6005篇
  2013年   8216篇
  2012年   7637篇
  2011年   8848篇
  2010年   7279篇
  2009年   7461篇
  2008年   7906篇
  2007年   9806篇
  2006年   9888篇
  2005年   9112篇
  2004年   8649篇
  2003年   8316篇
  2002年   6791篇
  2001年   5682篇
  2000年   3350篇
  1999年   1060篇
  1998年   532篇
  1997年   449篇
  1996年   377篇
  1995年   318篇
  1994年   242篇
  1993年   201篇
  1992年   165篇
  1991年   148篇
  1990年   83篇
  1989年   73篇
  1988年   77篇
  1987年   28篇
  1986年   30篇
  1985年   108篇
  1984年   107篇
  1983年   80篇
  1982年   69篇
  1981年   60篇
  1980年   51篇
  1979年   55篇
  1978年   48篇
  1977年   16篇
  1976年   11篇
  1975年   7篇
排序方式: 共有10000条查询结果,搜索用时 500 毫秒
31.
《Risk analysis》2018,38(9):1988-2009
Harbor seals in Iliamna Lake, Alaska, are a small, isolated population, and one of only two freshwater populations of harbor seals in the world, yet little is known about their abundance or risk for extinction. Bayesian hierarchical models were used to estimate abundance and trend of this population. Observational models were developed from aerial survey and harvest data, and they included effects for time of year and time of day on survey counts. Underlying models of abundance and trend were based on a Leslie matrix model that used prior information on vital rates from the literature. We developed three scenarios for variability in the priors and used them as part of a sensitivity analysis. The models were fitted using Markov chain Monte Carlo methods. The population production rate implied by the vital rate estimates was about 5% per year, very similar to the average annual harvest rate. After a period of growth in the 1980s, the population appears to be relatively stable at around 400 individuals. A population viability analysis assessing the risk of quasi‐extinction, defined as any reduction to 50 animals or below in the next 100 years, ranged from 1% to 3%, depending on the prior scenario. Although this is moderately low risk, it does not include genetic or catastrophic environmental events, which may have occurred to the population in the past, so our results should be applied cautiously.  相似文献   
32.
Abstract

This paper focuses on the inference of suitable generally non linear functions in stochastic volatility models. In this context, in order to estimate the variance of the proposed estimators, a moving block bootstrap (MBB) approach is suggested and discussed. Under mild assumptions, we show that the MBB procedure is weakly consistent. Moreover, a methodology to choose the optimal length block in the MBB is proposed. Some examples and simulations on the model are also made to show the performance of the proposed procedure.  相似文献   
33.
最高人民法院、最高人民检察院《关于办理侵犯公民个人信息刑事案件适用法律若干问题的解释》第六条对为合法经营活动而侵犯公民个人信息行为进行独立规制,是新型犯罪罪状表述抽象化与罪状解释具体化、信息时代信息价值多元化与危害行为多样化、现代社会犯罪治理精细化与刑法评价精准化的内在要求.为合法经营活动而侵犯公民个人信息行为相关规范要素中的“为合法经营活动”应理解为主观超过要素,“获利五万元”应作严格解释,“曾因侵犯公民个人信息”应作广义解释,“其他情节严重”应包括信息数量标准.  相似文献   
34.
应用于交易领域的智能合约融入区块链技术,以代码形式表现,可实现合同履行的自动化和不可逆,超越了传统意义上的合同模式.自助行为说、代理说将智能合约视为对合同过程的外部增强,是侧面功能的法律阐释,并未完全捕捉到实质.智能合约并不一定跨越整个合同过程,也可仅是合同过程某个方面或某个阶段.法律意义上的智能合约不是合同新类型,而是合同关系形式的新发展,即当事人缔结和履行合同的新形式,合同性质未发生实质变化.智能合约满足特定要件构成特殊的书面形式,具有"书面形式+自动履行"功能的特质.民事主体通过智能合约形式订立合同应遵守《民法典》等现行法律的具体规则,以保证合同依法成立与生效.智能合约不等同于具有法律效力的合同,认定其效力应结合智能合约应用中的具体问题展开具体分析.从立法上确认智能合约,在符合国家现有法律、政策基础上编写和应用,实现形式的合法化、内容的规范化是该技术谋求长远发展的保障.技术起步的现阶段,纸质合同、一般电子合同与智能合约在不同方面发挥协作作用,会在未来一段时间内成为民事交往、商业交易的主要状态.  相似文献   
35.
系统总结了在伸展构造背景下,导致反映构造特征的地层倾角模式复杂化的多种因素。沉积相的不同、岩性变化、井眼状况和测井作业时间等多种因素都可能使地层倾角资料复杂化。进一步指出在拉张盆地中,进行倾角资料的构造解释,必须了解其构造样式的多样性和复杂性,解释存在的多解性。重点解剖了铲式断层在横剖面情况下,对于不同构造位置下的倾角模式。详细分析了一个倾角模式对应多种构造样式的倾角构造解释实例。倾角资料的构造解释应是综合解释,既要综合井筒的相关地质资料,又要综合测井与地质知识,还必须考虑综合地震资料。  相似文献   
36.
《一个人老了》写于1991年4月,彼时作者的生理年龄与诗中感悟分别处于跨度相距较远的不同生命时段,由此在形成诗歌内在张力的同时,也使阅读必须面对在“四月”与“衰老”之间存在的强烈反差,问题由此被提出。对这种反差的成因分析是从文本的抒情节奏、抒情肌理以及价值立场与生命观等方面的异质特征切入,解读其在诗歌渊源上与博尔赫斯、聂鲁达等世界诗人之间的互文关系,进而追溯至作者西川所代表的“知识分子写作”对阅读经验的习惯性倚重。  相似文献   
37.
We propose testing procedures for the hypothesis that a given set of discrete observations may be formulated as a particular time series of counts with a specific conditional law. The new test statistics incorporate the empirical probability-generating function computed from the observations. Special emphasis is given to the popular models of integer autoregression and Poisson autoregression. The asymptotic properties of the proposed test statistics are studied under the null hypothesis as well as under alternatives. A Monte Carlo power study on bootstrap versions of the new methods is included as well as real-data examples.  相似文献   
38.
19世纪末20世纪初,马克思的思想就传入了中国,梁启超在传统大同思想与社会主义贯通中对它进行解读;早期国民党人在批判资本主义,建构民生主义中对它进行评价;无政府主义在反传统中认同马克思的共产主义。虽然各有局限性,但又各有自身的意义。以十月革命的经验解读马克思主义,遮蔽了对马克思思想早期传播的研究,研究马克思主义在中国的早期传播,对认识马克思主义中国化有重要意义。  相似文献   
39.
Generally, the semiclosed-form option pricing formula for complex financial models depends on unobservable factors such as stochastic volatility and jump intensity. A popular practice is to use an estimate of these latent factors to compute the option price. However, in many situations this plug-and-play approximation does not yield the appropriate price. This article examines this bias and quantifies its impacts. We decompose the bias into terms that are related to the bias on the unobservable factors and to the precision of their point estimators. The approximated price is found to be highly biased when only the history of the stock price is used to recover the latent states. This bias is corrected when option prices are added to the sample used to recover the states' best estimate. We also show numerically that such a bias is propagated on calibrated parameters, leading to erroneous values. The Canadian Journal of Statistics 48: 8–35; 2020 © 2019 Statistical Society of Canada  相似文献   
40.
The landscape of political humor and satire is changing rapidly, and it is becoming an increasingly relevant aspect of our culture. Although scholars have been actively trying to capture this change, majority of the existing frameworks for understanding humor and satire in politics still reduce these phenomena to mere genres or rhetoric tools. In addition, they provide insufficient accounts concerning the reception of humor and satire, and neglect to interpret and explain what they communicate. In the article, a general understanding of humor and satire outside of a political context, followed by an overview of studies discussing humor and satire in politics through their applications in social movements, as leadership tools, and through their manifestations in mass media has been presented. Lastly, a cultural sociological perspective to the field has been introduced. It has been argued that approaching humor and satire in politics through a structural hermeneutic method of the Strong Program will enable us to recognize and treat political humor and satire as autonomous and complex cultural systems which carry an internal power to move people.  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