全文获取类型
收费全文 | 7572篇 |
免费 | 468篇 |
国内免费 | 123篇 |
专业分类
管理学 | 2826篇 |
劳动科学 | 1篇 |
民族学 | 9篇 |
人口学 | 103篇 |
丛书文集 | 333篇 |
理论方法论 | 418篇 |
综合类 | 3255篇 |
社会学 | 537篇 |
统计学 | 681篇 |
出版年
2024年 | 10篇 |
2023年 | 134篇 |
2022年 | 98篇 |
2021年 | 110篇 |
2020年 | 255篇 |
2019年 | 245篇 |
2018年 | 242篇 |
2017年 | 277篇 |
2016年 | 279篇 |
2015年 | 285篇 |
2014年 | 429篇 |
2013年 | 687篇 |
2012年 | 479篇 |
2011年 | 474篇 |
2010年 | 390篇 |
2009年 | 364篇 |
2008年 | 383篇 |
2007年 | 390篇 |
2006年 | 403篇 |
2005年 | 412篇 |
2004年 | 325篇 |
2003年 | 282篇 |
2002年 | 233篇 |
2001年 | 205篇 |
2000年 | 118篇 |
1999年 | 95篇 |
1998年 | 56篇 |
1997年 | 49篇 |
1996年 | 42篇 |
1995年 | 40篇 |
1994年 | 56篇 |
1993年 | 41篇 |
1992年 | 32篇 |
1991年 | 28篇 |
1990年 | 36篇 |
1989年 | 22篇 |
1988年 | 32篇 |
1987年 | 22篇 |
1986年 | 19篇 |
1985年 | 13篇 |
1984年 | 18篇 |
1983年 | 17篇 |
1982年 | 17篇 |
1981年 | 16篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有8163条查询结果,搜索用时 31 毫秒
91.
罗秀琴 《西南科技大学学报(哲学社会科学版)》2003,20(4):26-29
一直以来,企业的负债经营是企业经营中倍受关注的问题之一。究竟负债对企业的经营有何影响,在实践中又该如何降低偿债风险呢?本文从分析举债经营的利弊入手,初步探讨了经营企业的最佳负债率问题,并提出了较为行之有效的偿债保障机制,以期能对企业的负债经营有所借鉴意义。 相似文献
92.
在分析银行住房抵押贷款的各种风险因素的基础之上,提出模糊预警模型,给出预警结果。 相似文献
93.
Recently, we developed a GIS-Integrated Integral Risk Index (IRI) to assess human health risks in areas with presence of environmental pollutants. Contaminants were previously ranked by applying a self-organizing map (SOM) to their characteristics of persistence, bioaccumulation, and toxicity in order to obtain the Hazard Index (HI). In the present study, the original IRI was substantially improved by allowing the entrance of probabilistic data. A neuroprobabilistic HI was developed by combining SOM and Monte Carlo analysis. In general terms, the deterministic and probabilistic HIs followed a similar pattern: polychlorinated biphenyls (PCBs) and light polycyclic aromatic hydrocarbons (PAHs) were the pollutants showing the highest and lowest values of HI, respectively. However, the bioaccumulation value of heavy metals notably increased after considering a probability density function to explain the bioaccumulation factor. To check its applicability, a case study was investigated. The probabilistic integral risk was calculated in the chemical/petrochemical industrial area of Tarragona (Catalonia, Spain), where an environmental program has been carried out since 2002. The risk change between 2002 and 2005 was evaluated on the basis of probabilistic data of the levels of various pollutants in soils. The results indicated that the risk of the chemicals under study did not follow a homogeneous tendency. However, the current levels of pollution do not mean a relevant source of health risks for the local population. Moreover, the neuroprobabilistic HI seems to be an adequate tool to be taken into account in risk assessment processes. 相似文献
94.
This article presents a framework for using probabilistic terrorism risk modeling in regulatory analysis. We demonstrate the framework with an example application involving a regulation under consideration, the Western Hemisphere Travel Initiative for the Land Environment, (WHTI‐L). First, we estimate annualized loss from terrorist attacks with the Risk Management Solutions (RMS) Probabilistic Terrorism Model. We then estimate the critical risk reduction, which is the risk‐reducing effectiveness of WHTI‐L needed for its benefit, in terms of reduced terrorism loss in the United States, to exceed its cost. Our analysis indicates that the critical risk reduction depends strongly not only on uncertainties in the terrorism risk level, but also on uncertainty in the cost of regulation and how casualties are monetized. For a terrorism risk level based on the RMS standard risk estimate, the baseline regulatory cost estimate for WHTI‐L, and a range of casualty cost estimates based on the willingness‐to‐pay approach, our estimate for the expected annualized loss from terrorism ranges from $2.7 billion to $5.2 billion. For this range in annualized loss, the critical risk reduction for WHTI‐L ranges from 7% to 13%. Basing results on a lower risk level that results in halving the annualized terrorism loss would double the critical risk reduction (14–26%), and basing the results on a higher risk level that results in a doubling of the annualized terrorism loss would cut the critical risk reduction in half (3.5–6.6%). Ideally, decisions about terrorism security regulations and policies would be informed by true benefit‐cost analyses in which the estimated benefits are compared to costs. Such analyses for terrorism security efforts face substantial impediments stemming from the great uncertainty in the terrorist threat and the very low recurrence interval for large attacks. Several approaches can be used to estimate how a terrorism security program or regulation reduces the distribution of risks it is intended to manage. But, continued research to develop additional tools and data is necessary to support application of these approaches. These include refinement of models and simulations, engagement of subject matter experts, implementation of program evaluation, and estimating the costs of casualties from terrorism events. 相似文献
95.
This paper investigates how individuals evaluate delayed outcomes with risky realization times. Under the discounted expected utility (DEU) model, such evaluations depend only on intertemporal preferences. We obtain several testable hypotheses using the DEU model as a benchmark and test these hypotheses in three experiments. In general, our results show that the DEU model is a poor predictor of intertemporal choice behavior under timing risk. We found that individuals are averse to timing risk and that they evaluate timing lotteries in a rank-dependent fashion. The main driver of timing risk aversion is nothing but probabilistic risk aversion that stems from the nonlinear treatment of probabilities. 相似文献
96.
The benchmark dose (BMD) is an exposure level that would induce a small risk increase (BMR level) above the background. The BMD approach to deriving a reference dose for risk assessment of noncancer effects is advantageous in that the estimate of BMD is not restricted to experimental doses and utilizes most available dose-response information. To quantify statistical uncertainty of a BMD estimate, we often calculate and report its lower confidence limit (i.e., BMDL), and may even consider it as a more conservative alternative to BMD itself. Computation of BMDL may involve normal confidence limits to BMD in conjunction with the delta method. Therefore, factors, such as small sample size and nonlinearity in model parameters, can affect the performance of the delta method BMDL, and alternative methods are useful. In this article, we propose a bootstrap method to estimate BMDL utilizing a scheme that consists of a resampling of residuals after model fitting and a one-step formula for parameter estimation. We illustrate the method with clustered binary data from developmental toxicity experiments. Our analysis shows that with moderately elevated dose-response data, the distribution of BMD estimator tends to be left-skewed and bootstrap BMDL s are smaller than the delta method BMDL s on average, hence quantifying risk more conservatively. Statistically, the bootstrap BMDL quantifies the uncertainty of the true BMD more honestly than the delta method BMDL as its coverage probability is closer to the nominal level than that of delta method BMDL. We find that BMD and BMDL estimates are generally insensitive to model choices provided that the models fit the data comparably well near the region of BMD. Our analysis also suggests that, in the presence of a significant and moderately strong dose-response relationship, the developmental toxicity experiments under the standard protocol support dose-response assessment at 5% BMR for BMD and 95% confidence level for BMDL. 相似文献
97.
The paper considers simultaneous estimation of finite population means for several strata. A model-based approach is taken, where the covariates in the super-population model are subject to measurement errors. Empirical Bayes (EB) estimators of the strata means are developed and an asymptotic expression for the MSE of the EB estimators is provided. It is shown that the proposed EB estimators are “first order optimal” in the sense of Robbins [1956. An empirical Bayes approach to statistics. In: Proceedings of the Third Berkeley Symposium on Mathematical Statistics and Probability, vol. 1, University of California Press, Berkeley, pp. 157–164], while the regular EB estimators which ignore the measurement error are not. 相似文献
98.
Regina Thompson Paul H. Templet John K. Gamman Scott T. McCleary Margaret A. Reams 《Risk analysis》1994,14(5):857-861
The goal of Louisiana's 1990–1991 comparative risk project, also called the Louisiana Environmental Action Plan (LEAP), was to incorporate risk assessment into state environmental planning and policymaking. Scientists, government officials, and citizens were brought together to estimate the relative risk to human health, natural resources, and quality of life posed by 33 selected environmental issues. The issues were then ranked according to their relative estimated risks. It was hoped that this ranking of "comparative risks" would enable state policymakers to target the most important environmental problems and allocate scarce public resources more rationally and efficiently. As a result of the project, the governor issued an Executive Order forming a permanent Public Advisory Committee to continue this type of comparative risk assessment in Louisiana. 相似文献
99.
王家远 《深圳大学学报(人文社会科学版)》1994,(3)
本文分析了建设项目中专业技术服务的潜在风险,探讨了风险管理的内容、途径和方法,简述了专业责任保险的特点和原则,指出了在我国开展专业责任保险的紧迫性。 相似文献
100.
本文认为,风险投资机构在设立之初及再融资过程中面临着融资风险,而拓宽融资渠道是降低这类风险的关键。本文首先介绍了风险投资机构的融资来源有哪些,以及影响风险投资机构融资的各种因素。在此基础上,笔者提出了目前扩大我国风险投资机构融资来源、控制转移融资风险的各种措施。 相似文献