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61.
Benjamin GC 《Physician executive》2002,28(5):64-66
As a result of the 2001 anthrax attacks, the U.S. government is trying to forge a plan to handle something much worse: an outbreak of smallpox due to terrorist activity. Here's a look at where the debate stands today. 相似文献
62.
More on insurance as a Giffen good 总被引:2,自引:1,他引:1
In this article, we generalize the Hoy and Robson (1981) analysis and provide a necessary and sufficient condition for insurance not to be a Giffen good. The condition gives a bound for the variation of absolute risk aversion that permits the wealth effect to be always dominated by the substitution effect. 相似文献
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66.
This paper proposes a hierarchical Bayes estimator for a panel data random coefficient model with heteroskedasticity to assess
the contribution of R&D capital to total factor productivity. Based on Hall (1993) data for 323 US firms over 1976–1990, we find that there appear to have substantial unobserved heterogeneity and heteroskedasticity
across firms and industries that support the use of our Bayes inference procedure. We find much higher returns to R&D capital
and a more pronounced downswing for the 1981–1985 period, followed by a more pronounced upswing than those yielded by the
conventional feasible generalized least squares estimators or other estimates. The estimated elasticities of R&D capital are
0.062 for 1976–1980, 0.036 for 1981–1985 and 0.081 for 1986–1990, while the estimated elasticities of ordinary capital are
much more stable over these periods. 相似文献
67.
Chang-Chia Liu Panos M. Pardalos W. Art Chaovalitwongse Deng-Shan Shiau Georges Ghacibeh Wichai Suharitdamrong J. Chris Sackellares 《Journal of Combinatorial Optimization》2008,15(3):276-286
Epilepsy is a brain disorder characterized clinically by temporary but recurrent disturbances of brain function that may or
may not be associated with destruction or loss of consciousness and abnormal behavior. Human brain is composed of more than
10 to the power 10 neurons, each of which receives electrical impulses known as action potentials from others neurons via
synapses and sends electrical impulses via a sing output line to a similar (the axon) number of neurons. When neuronal networks
are active, they produced a change in voltage potential, which can be captured by an electroencephalogram (EEG). The EEG recordings
represent the time series that match up to neurological activity as a function of time. By analyzing the EEG recordings, we
sought to evaluate the degree of underlining dynamical complexity prior to progression of seizure onset. Through the utilization
of the dynamical measurements, it is possible to classify the state of the brain according to the underlying dynamical properties
of EEG recordings. The results from two patients with temporal lobe epilepsy (TLE), the degree of complexity start converging
to lower value prior to the epileptic seizures was observed from epileptic regions as well as non-epileptic regions. The dynamical
measurements appear to reflect the changes of EEG’s dynamical structure. We suggest that the nonlinear dynamical analysis
can provide a useful information for detecting relative changes in brain dynamics, which cannot be detected by conventional
linear analysis. 相似文献
68.
Dorean Nabukalu Georges Reniers Kathryn A. Risher Sylvia Blom Emma Slaymaker Chodziwadziwa Kabudula 《Population studies》2020,74(1):93-102
There are limited data on the impact of antiretroviral therapy (ART) on population-level adult mortality in sub-Saharan Africa. We analysed data for 2000–14 from the Rakai Community Cohort Study (RCCS) in Uganda, where free ART was scaled up after 2004. Using non-parametric and parametric (Weibull) survival analysis, we estimated trends in average person-years lived between exact ages 15 and 50, per capita life-years lost to HIV, and the mortality hazards of people living with HIV (PLHIV). Between 2000 and 2014, average adult life-years lived before age 50 increased significantly, from 26.4 to 33.5?years for all women and from 28.6 to 33.8?years for all men. As of 2014, life-years lost to HIV had declined significantly, to 1.3?years among women and 0.4?years among men. Following the roll-out of ART, mortality reductions among PLHIV were initially larger in women than men, but this is no longer the case. 相似文献
69.
Reniers G 《Demography》2008,45(2):417-438
In a setting where the transmission of HIV occurs primarily through heterosexual contact and where no cure or vaccine is available, behavioral change is imperative for containing the epidemic. Abstinence, faithfulness, and condom use most often receive attention in this regard. In contrast, this article treats marriage as a resource for HIV risk management via mechanisms of positive selection (partner choice) and negative selection (divorce of an adulterous spouse). Retrospective marriage histories and panel data provide the evidence for this study and results indicate that men and women in Malawi increasingly turned to union-based risk-avoidance strategies during the period that the threat of HIV/AIDS materialized. Although both sexes strategize in a similar fashion, men are better equipped than women to deploy these strategies to their advantage. The article concludes with reflections on the long-term and population-level implications of these coping mechanisms. 相似文献
70.
Let \(G = (V,E)\) be a finite graph and let \((\mathbb {A},+)\) be an abelian group with identity 0. Then G is \(\mathbb {A}\)-magic if and only if there exists a function \(\phi \) from E into \(\mathbb {A} - \{0\}\) such that for some \(c \in \mathbb {A}, \sum _{e \in E(v)} \phi (e) = c\) for every \(v \in V\), where E(v) is the set of edges incident to v. Additionally, G is zero-sum \(\mathbb {A}\)-magic if and only if \(\phi \) exists such that \(c = 0\). We consider zero-sum \(\mathbb {A}\)-magic labelings of graphs, with particular attention given to \(\mathbb {A} = \mathbb {Z}_{2j}^k\). For \(j \ge 1\), let \(\zeta _{2j}(G)\) be the smallest positive integer c such that G is zero-sum \(\mathbb {Z}_{2j}^c\)-magic if c exists; infinity otherwise. We establish upper bounds on \(\zeta _{2j}(G)\) when \(\zeta _{2j}(G)\) is finite, and show that \(\zeta _{2j}(G)\) is finite for all r-regular \(G, r \ge 2\). Appealing to classical results on the factors of cubic graphs, we prove that \(\zeta _4(G) \le 2\) for a cubic graph G, with equality if and only if G has no 1-factor. We discuss the problem of classifying cubic graphs according to the collection of finite abelian groups for which they are zero-sum group-magic. 相似文献