全文获取类型
收费全文 | 92篇 |
免费 | 1篇 |
专业分类
管理学 | 26篇 |
人口学 | 16篇 |
理论方法论 | 1篇 |
社会学 | 14篇 |
统计学 | 36篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 6篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2014年 | 3篇 |
2013年 | 29篇 |
2011年 | 2篇 |
2010年 | 2篇 |
2009年 | 6篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1969年 | 3篇 |
1966年 | 1篇 |
排序方式: 共有93条查询结果,搜索用时 15 毫秒
11.
Recently, there have been several reports from different parts of the World on the declining populations of the House Sparrow (Passer domesticus). In order to assess the population of this species in the National Capital Territory of Delhi-India, this study was conducted during June– August in 2007. Twenty-eight Fixed-Radius Point Count stations were established in five habitat types viz. High-density Urban Area, Medium-density Urban Area, Low-density Urban Area, Agriculture Area, and Forested Area, within the study area. The results show that the House Sparrow is still a dominant species in the agriculture area. However, its density is very low in the urban areas as compared to the other co-occurring common bird species viz. Rock Pigeon (Columba livia domestica), House Crow (Corvus splendens) and Common Myna (Acridotheres tristis). As, this study was conducted only over one season, the data is not sufficient to provide a clear picture of the population trend of the House Sparrow. Further studies are therefore required to investigate the relationship of the House Sparrow with other co-occurring common species, and to analyse the data on the type and quality of greenspaces and their relation with the House Sparrow in the study area. A long-term monitoring and conservation programme involving local people may be a good approach for maintaining the population of House Sparrow in the study area. 相似文献
12.
In this paper we develop a test based on the empirical distribution function for the alternative representing 'decreasing variance residual life1 property. The test is consistent with asymptotically normal test statistic and is shown to perform well in the Pitman's asymptotic relative efficiency sense. 相似文献
13.
Sudha Jain 《统计学通讯:理论与方法》2013,42(5-6):1871-1879
In this paper, the maximum likelihood estimates of the parameters for the M/Er /1 queueing model are derived when the queue size at each departure point is observed. A numerical example is generated by simulating a finite Markov chain to illustrate the methodology for estimating the parameters with variable Erlang service time distribution. The problem of hypothesis testing and simultaneous Confidence regions of the parameter is also investigated.0 相似文献
14.
Environmental scanning in U.S. corporations. 总被引:4,自引:0,他引:4
S C Jain 《Long Range Planning》1984,17(2):117-128
Environmental scanning is a new activity among corporations, because of its importance, corporations need to progress by stages to achieve a structured and formal system of scanning, and this takes time. This paper is based on a study examining the evolution and state of environmental scanning among corporations, and finds that the essential difference between scanning at the corporate and at the product/market level is not observed by all companies. Ideally, there should be a close liaison between the two levels so that each may reinforce the scanning effort of the other. 相似文献
15.
Research on interfirm alliances indicates that partner firms’ asymmetry in network centrality increases the likelihood of alliance dissolution because it gives rise to a power imbalance and opportunism in the partnership. We contend that this view of centrality asymmetry does not consider the binding force that network resource complementarity can provide in an alliance, which motivates partners to ally for the long term. We propose that centrality asymmetry can have both divisive and cohesive forces in an alliance, which – when considered together – lead to a prediction that centrality asymmetry has a U‐shaped relationship with alliance dissolution. Moderate levels of asymmetry lead to lower rates of dissolution than high and low levels of asymmetry. The degree of cooperation between partners and the degree of external competition reduce the effects of centrality asymmetry on alliance dissolution because they mitigate power imbalances while encouraging partners to strengthen the alliance to withstand competitive challenges. 相似文献
16.
In recent times, managerial applications of neural networks, especially in the area of financial services, has received considerable attention. In this paper, neural network models are developed for a new application: the pricing of Initial Public Offerings (IPOs). Previous empirical studies provide consistent evidence of considerable inefficiency in the pricing of new issues. Neural network models using publicly available financial data as inputs are developed to price IPOs. The pricing performance and the economic benefits of the neural network models are evaluated. Significant economic gains are documented with neural networks. Several tests to establish generalizability and robustness of the results are conducted. 相似文献
17.
When the development cycle for a product is longer than the development cycle for a core technology that is embedded in it, designers may need to modify the product̂s design to avail of upgrades in this core technology. We model optimal product positioning with regard to technology choice in this setting, using a stochastic dynamic programming framework. Under fairly general assumptions, we find that there are three possible optimal actions: to abandon the project, to maintain the current technology, or to reposition so as to use the best technology currently available. We characterize the optimal positioning sequence in different design environments, discussing throughout the practical implications of our model. Previous research and conventional wisdom suggest early finalization of product specifications if design flexibility is decreasing over time. In contrast, we find that in some design environments, repositioning late in the development cycle can be optimal. 相似文献
18.
19.
We model a supply chain consisting of a supplier and multiple retailers facing deterministic demand. We denote some retailers as strategic in the sense that given the supplier inventory information, they will implement the optimal stocking policy by incorporating such information. On the other hand, some retailers are denoted as naïve in the sense that they ignore supply information and resort to a simplistic ordering policy. Naïve retailers learn the optimal policy over time and adjust their orders accordingly. We study the dynamics of this game and investigate the impact of such strategic and naïve retailers on the cost, ordering pattern and stocking policies of all parties. We analyze the supply chain under two scenarios: the centralized supply chain where the objective is to minimize the total supply chain cost, and the decentralized supply chain where each self‐interested player minimizes its own cost in a Stackelberg game setting. We fully characterize the optimal policies under both centralized and decentralized scenarios and show that, surprisingly, the supply chain might be better off by virtue of naïve retailers. The result is driven by the fact that strategic and naïve players’ decisions shift the positioning of inventory in the supply chain with its final impact being determined by the relative costs of different retailer‐types. Our results also offer managerial insights into how access to supply information can improve supply chain performance. 相似文献
20.
Image models are useful in quantitatively specifying natural constraints and general assumptions about the physical world and the imaging process. This review paper explains how Gibbs and Markov random field models provide a unifying theme for many contemporary problems in image analysis. Random field models permit the introduction of spatial context into pixel labeling problems, such as segmentation and restoration. Random field models also describe textured images and lead to algorithms for generating textured images, classifying textures and segmenting textured images. In spite of some impressive model-based image restoration and texture segmentation results reported in the literature, a number of fundamental issues remain unexplored, such as the specification of MRF models, modeling noise processes, performance evaluation, parameter estimation, the phase transition phenomenon and the comparative analysis of alternative procedures. The literature of random field models is filled with great promise, but a better mathematical understanding of these issues is needed as well as efficient algorithms for applications. These issues need to be resolved before random field models will be widely accepted as general tools in the image-processing community. 相似文献