全文获取类型
收费全文 | 20329篇 |
免费 | 651篇 |
国内免费 | 235篇 |
专业分类
管理学 | 2124篇 |
劳动科学 | 2篇 |
民族学 | 71篇 |
人才学 | 3篇 |
人口学 | 364篇 |
丛书文集 | 844篇 |
理论方法论 | 389篇 |
综合类 | 8263篇 |
社会学 | 592篇 |
统计学 | 8563篇 |
出版年
2024年 | 26篇 |
2023年 | 145篇 |
2022年 | 254篇 |
2021年 | 290篇 |
2020年 | 429篇 |
2019年 | 586篇 |
2018年 | 691篇 |
2017年 | 940篇 |
2016年 | 698篇 |
2015年 | 696篇 |
2014年 | 1030篇 |
2013年 | 3256篇 |
2012年 | 1499篇 |
2011年 | 1162篇 |
2010年 | 983篇 |
2009年 | 973篇 |
2008年 | 1068篇 |
2007年 | 1005篇 |
2006年 | 913篇 |
2005年 | 812篇 |
2004年 | 675篇 |
2003年 | 562篇 |
2002年 | 523篇 |
2001年 | 437篇 |
2000年 | 306篇 |
1999年 | 248篇 |
1998年 | 159篇 |
1997年 | 148篇 |
1996年 | 103篇 |
1995年 | 107篇 |
1994年 | 75篇 |
1993年 | 69篇 |
1992年 | 70篇 |
1991年 | 56篇 |
1990年 | 35篇 |
1989年 | 29篇 |
1988年 | 26篇 |
1987年 | 18篇 |
1986年 | 12篇 |
1985年 | 21篇 |
1984年 | 21篇 |
1983年 | 14篇 |
1982年 | 10篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1979年 | 7篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1976年 | 1篇 |
1975年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
191.
Robert Aslett Robert J. Buck Steven G. Duvall Jerome Sacks & William J. Welch 《Journal of the Royal Statistical Society. Series C, Applied statistics》1998,47(1):31-48
In electrical engineering, circuit designs are now often optimized via circuit simulation computer models. Typically, many response variables characterize the circuit's performance. Each response is a function of many input variables, including factors that can be set in the engineering design and noise factors representing manufacturing conditions. We describe a modelling approach which is appropriate for the simulator's deterministic input–output relationships. Non-linearities and interactions are identified without explicit assumptions about the functional form. These models lead to predictors to guide the reduction of the ranges of the designable factors in a sequence of experiments. Ultimately, the predictors are used to optimize the engineering design. We also show how a visualization of the fitted relationships facilitates an understanding of the engineering trade-offs between responses. The example used to demonstrate these methods, the design of a buffer circuit, has multiple targets for the responses, representing different trade-offs between the key performance measures. 相似文献
192.
应用交通流宏观连续模型,模拟上下游信号灯作异步周期变化的协调信号灯路段的交通流动,经数值计算比较,选择改进Murman格式求解.结果表明:改进Murman格式能准确捕捉交通流中无振荡“激波”位置. 相似文献
193.
Suen W 《Journal of population economics》1997,10(4):443-461
This paper provides an overview of retirement patterns in Hong Kong on the basis of limited data. A censored regression model
is used to infer the retirement age from people‘s current retirement status and their current age. This model is equivalent
to a restricted probit model, and the interpretation of parameters is straightforward. The results clearly show a negative
income effect on the retirement decision. The retirement age seems to be positively related to lifetime earnings but negatively
related to the rate of decline of earnings with age.
JEL classification: C24, J14, J26
Received May 6, 1996 / Accepted February 5, 1997 相似文献
194.
The maximum likelihood estimation for the critical points of the failure rate and the mean residual life function are presented
in the case of mixture inverse Gaussian model. Several important data sets are analyzed from this point of view. For each
of the data sets, Bootstrapping is used to construct confidence intervals of the critical points. 相似文献
195.
Dietary and Inhalation Intake of Lead and Estimation of Blood Lead Levels in Adults and Children in Kanpur, India 总被引:1,自引:0,他引:1
This research was initiated to study lead levels in various food items in the city of Kanpur, India, to assess the dietary intake of lead and to estimate blood lead (PbB) levels, a biomarker of lead toxicity. For this purpose, sampling of food products, laboratory analysis, and computational exercises were undertaken. Specifically, six food groups (leafy vegetables, nonleafy vegetables, fruits, pulses, cereals, and milk), drinking water, and lead air concentration were considered for estimating lead intake. Results indicated highest lead content in leafy vegetables followed by pulses. Fruits showed low lead content and drinking water lead levels were always within tolerable limits. It was estimated that average daily lead intake through diet was about 114 microg/day for adults and 50 microg/day in children; tolerable limit is 250 microg/day for adults and 90 microg/day for children. The estimated lead intakes were translated into the resultant PbB concentrations for children and adults using a physiologically-based pharmacokinetic (PBPK) model. Monte Carlo simulation of PbB level variations for adults showed that probability of exceeding the tolerable limit of PbB (i.e.,10 microg/dL) was 0.062 for the pre-unleaded and 0.000328 for the post-unleaded gasoline period. The probability of exceeding tolerable limits in PbB level was reduced by a factor of 189 in the post-unleaded scenario. The study also suggested that in spite of the introduction of unleaded gasoline, children continue to be at a high risk (probability of exceeding 10 microg/dL = 0.39) because of a high intake of lead per unit body weight. 相似文献
196.
我国财务危机公司投资行为的财务特征分析 总被引:9,自引:0,他引:9
在引入一个简化的理性财务危机公司投资模型的基础上,论文分析了企业陷入财务危机后,债权人与债务人之间在期权博弈过程中,企业在投资策略的选择上会偏离正常的投资行为的财务特征。在此基础上,重点分析了我国经济转轨时期财务危机公司严重地过度投资和在债务重组过程中的盲目性、短期性和功利性及其形成的主要原因。企业的过度投资是内部人控制和银行债权弱化的具体体现,虚假的债务重组是将危机转嫁给企业债权人的真正动因。 相似文献
197.
上海股票市场股票收益率因素研究 总被引:14,自引:3,他引:14
根据上海股票市场从1995 年7 月到2000 年6 月所有A 股股票的月收益率、价格、市值和
公司财务数据,利用Fama-Macbeth 回归分析方法及构造动态组合方法,分析总市值、流通市值、
价格、账面市值比、市盈率、账面资产负债比等因素对股票回报率的影响. 发现上海股票市场具
有显著的市值效应、账面市值比效应、市盈率效应和价格效应. 这些效应不能用股票的beta 值
来解释. 同时发现Fama- French 的三因子模型不能完全解释这些效应,但在三因子模型的基础
上再加上一个市盈率因子可以很好地解 相似文献
198.
199.
构造一种新的方法———岭- 偏最小二乘回归方法(它既有效消除了因素变量之间的多
重共线性,又克服了传统方法的不足,且使模型更加稳健,具有更强的预测和分析能力) ;并运
用广义岭- 偏最小二乘回归方法分析了我国经济增长的影响因素,为我国制订持续、快速增长
的经济政策提供了有益的参考. 相似文献
200.
Risk Modeling, Assessment, and Management of Lahar Flow Threat 总被引:1,自引:0,他引:1
The 1991 eruption of Mount Pinatubo in the Philippines is considered one of the most violent and destructive volcanic activities in the 20th century. Lahar is the Indonesian term for volcanic ash, and lahar flows resulting from the massive amount of volcanic materials deposited on the mountain's slope posed continued post-eruption threats to the surrounding areas, destroying lives, homes, agricultural products, and infrastructures. Risks of lahar flows were identified immediately after the eruption, with scientific data provided by the Philippine Institute of Volcanology, the U.S. Geological Survey, and other research institutions. However, competing political, economic, and social agendas subordinated the importance of scientific information to policy making. Using systemic risk analysis and management, this article addresses the issues of multiple objectives and the effective integration of scientific techniques into the decision-making process. It provides a modeling framework for identifying, prioritizing, and evaluating policies for managing risk. The major considerations are: (1) applying a holistic approach to risk analysis through hierarchical holographic modeling, (2) applying statistical methods to gain insight into the problem of uncertainty in risk assessment, (3) using multiobjective trade-off analysis to address the issue of multiple decisionmakers and stakeholders in the decision-making process, (4) using the conditional expected value of extreme events to complement and supplement the expected value in quantifying risk, and (5) assessing the impacts of multistage decisions. Numerical examples based on ex post data are formulated to illustrate applications to various problems. The resulting framework from this study can serve as a general baseline model for assessing and managing risks of natural disasters, which the Philippines' lead agency-the National Disaster Coordinating Council (NDCC)-and other related organizations can use for their decision-making processes. 相似文献