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231.
232.
Demographic crisis: The impact of the Bangladesh civil war (1971) on births and deaths in a rural area of Bangladesh 总被引:1,自引:0,他引:1
Summary In Matlab Bazaar Thana the Cholera Research Laboratory has registered the births, deaths and migrations in a population of approximately 125,000 since 1966. Although this rural area was not the scene of any significant armed encounters, striking changes in birth and death rates were registered during and after the conflict. Birth rates did not change during the relatively brief period of the civil war, but a small decline was registered for one year after the war. Fertility rates which had been declining slightly and irregularly in the pre-war baseline period may have increased slightly during the war and fell substantially in all age groups in the year following the war. The crude death rate, which rose by 37 per cent during the war, was a very sensitive reflection of the administrative and economic problems. Overall infant mortality rose by only 15 per cent over pre-war levels because all of the increase was observed in the post-neo-natal component, which traditionally accounts for less than one-third of the total infant mortality in Bangladesh. Children and older adults accounted for the majority of excess deaths which were largely attributed to acute diarrhoeas and other gastro-intestinal causes. The death rate at ages 1-4 rose by 43 per cent and at ages 5-9 soared to 208 per cent above pre-war baseline rates. All increases in age-specific mortality rates fell to baseline levels during the year following the war, except the 5-9-year age group, in which rates continued to be high largely because of deaths due to dysentery. 相似文献
233.
234.
品牌资产及其测量中的概念解析 总被引:18,自引:0,他引:18
品牌资产(品牌权益)是近年来营销领域中研究的热点问题,然而对于其基本概念的曲解却阻碍了对这个重要问题的进一步研究。本文针对品牌资产涉及的几个概念(品牌资产、品牌权益、品牌价值)及其相互关系加以解释,并将主要的品牌资产的测量方法进行分类,目的是澄清人们对于品牌资产基本概念的模糊认识,为进一步深入研究指明方向。 相似文献
235.
品牌延伸:资产价值转移与理论模型创建 总被引:5,自引:1,他引:5
本文通过对品牌延伸(Brand Extension)的研究综述和实证研究,提出决定品牌延伸的三大因子,并在此基础上构成品牌资产价值(Brand Asset Value),进而研究其在品牌延伸过程中的价值转移,从而构成了评估品牌延伸成败的标准,最终将各种因子和评估标准进行整合,提出了品牌延伸的理论模型。 相似文献
236.
Optimization Model and Algorithm for Crew Management During Airline Irregular Operations 总被引:4,自引:0,他引:4
Airline irregular operations have long been a realm where human experience and judgement are the most important tools to utilize. Crew management during irregular operations is usually the bottleneck of the whole system-recovering process due to complicated crew schedules and restrictive crew legalities as well as the size and scope of the hub-and-spoke networks adopted by major carriers. A system-wide multi-commodity integer network flow model and a heuristic search algorithm for the above purpose are presented and discussed in this paper. The computational experiences show that the algorithm is efficient enough to solve problems of realistic size and also has the flexibility to accommodate practical business requirements. 相似文献
237.
The Determinants of Trust and Credibility in Environmental Risk Communication: An Empirical Study 总被引:8,自引:1,他引:8
This study examines a key component of environmental risk communication; trust and credibility. The study was conducted in two parts. In the first part, six hypotheses regarding the perceptions and determinants of trust and credibility were tested against survey data. The hypotheses were supported by the data. The most important hypothesis was that perceptions of trust and credibility are dependent on three factors: perceptions of knowledge and expertise; perceptions of openness and honesty; and perceptions of concern and care. In the second part, models were constructed with perceptions of trust and credibility as the dependent variable. The goal was to examine the data for findings with direct policy implications. One such finding was that defying a negative stereotype is key to improving perceptions of trust and credibility. 相似文献
238.
Compliance Versus Risk in Assessing Occupational Exposures 总被引:1,自引:0,他引:1
Rogelio Tornero-Velez Elaine Symanski Hans Kromhout Rong C. Yu Stephen M. Rappaport 《Risk analysis》1997,17(3):279-292
Assessments of occupational exposures to chemicals are generally based upon the practice of compliance testing in which the probability of compliance is related to the exceedance [γ, the likelihood that any measurement would exceed an occupational exposure limit (OEL)] and the number of measurements obtained. On the other hand, workers’ chronic health risks generally depend upon cumulative lifetime exposures which are not directly related to the probability of compliance. In this paper we define the probability of “overexposure” (θ) as the likelihood that individual risk (a function of cumulative exposure) exceeds the risk inherent in the OEL (a function of the OEL and duration of exposure). We regard θ as a relevant measure of individual risk for chemicals, such as carcinogens, which produce chronic effects after long-term exposures but not necessarily for acutely-toxic substances which can produce effects relatively quickly. We apply a random-effects model to data from 179 groups of workers, exposed to a variety of chemical agents, and obtain parameter estimates for the group mean exposure and the within- and between-worker components of variance. These estimates are then combined with OELs to generate estimates of γ and θ. We show that compliance testing can significantly underestimate the health risk when sample sizes are small. That is, there can be large probabilities of compliance with typical sample sizes, despite the fact that large proportions of the working population have individual risks greater than the risk inherent in the OEL. We demonstrate further that, because the relationship between θ and γ depends upon the within- and between-worker components of variance, it cannot be assumed a priori that exceedance is a conservative surrogate for overexposure. Thus, we conclude that assessment practices which focus upon either compliance or exceedance are problematic and recommend that employers evaluate exposures relative to the probabilities of overexposure. 相似文献
239.
Estimation from Zero-Failure Data 总被引:2,自引:0,他引:2
Robert T. Bailey 《Risk analysis》1997,17(3):375-380
When performing quantitative (or probabilistic) risk assessments, it is often the case that data for many of the potential events in question are sparse or nonexistent. Some of these events may be well-represented by the binomial probability distribution. In this paper, a model for predicting the binomial failure probability, P , from data that include no failures is examined. A review of the literature indicates that the use of this model is currently limited to risk analysis of energetic initiation in the explosives testing field. The basis for the model is discussed, and the behavior of the model relative to other models developed for the same purpose is investigated. It is found that the qualitative behavior of the model is very similar to that of the other models, and for larger values of n (the number of trials), the predicted P values varied by a factor of about eight among the five models examined. Analysis revealed that the estimator is nearly identical to the median of a Bayesian posterior distribution, derived using a uniform prior. An explanation of the application of the estimator in explosives testing is provided, and comments are offered regarding the use of the estimator versus other possible techniques. 相似文献
240.
Power assignment for wireless ad hoc networks is to assign a power for each wireless node such that the induced communication
graph has some required properties. Recently research efforts have focused on finding the minimum power assignment to guarantee
the connectivity or fault-tolerance of the network. In this paper, we study a new problem of finding the power assignment such that the induced communication graph is a spanner for the original communication graph when all nodes have the maximum power. Here, a spanner means that the length of the
shortest path in the induced communication graph is at most a constant times of the length of the shortest path in the original
communication graph. Polynomial time algorithm is given to minimize the maximum assigned power with spanner property. The
algorithm also works for any other property that can be tested in polynomial time and is monotone. We then give a polynomial time approximation method to minimize the total transmission radius of all nodes. Finally, we
propose two heuristics and conduct extensive simulations to study their performance when we aim to minimize the total assigned
power of all nodes.
The author is partially supported by NSF CCR-0311174. 相似文献