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61.
论述了推动篮球技术模式的因素——攻守对抗矛盾、技战术矛盾、规则与技战术矛盾、训练学因素、现代科学技术、实践与认识等几个部分,用系统论的观点探讨了推动篮球运动的技术模式和篮球运动技术的发展模式,以指导篮球教学与训练。  相似文献   
62.
A mechanistic model is presented describing the clearance of a compound in a precision-cut liver slice that is incubated in a culture medium. The problem of estimating metabolic rate constants in PBPK models from liver slice experiments is discussed using identifiability analysis. From the identifiability problem analysis, it appears that in addition to the clearance, the compound's free fraction in the slice and the diffusion rate of the exchange of the compound between culture medium and liver slice should be identified. In addition, knowledge of the culture medium volume, the slice volume, the compound's free fraction, and octanol-water-based partition between medium and slice is presupposed. The formal solution for identification is discussed from the perspective of experimental practice. A formally necessary condition for identification is the sampling of parent compound in liver slice or culture medium. However, due to experimental limitations and errors, sampling the parent compound in the slice together with additional sampling of metabolite pooled from the medium and the slice is required for identification in practice. Moreover, it appears that identification results are unreliable when the value of the intrinsic clearance exceeds the value of the diffusion coefficient, a condition to be verified a posteriori.  相似文献   
63.
Existential, or existential-phenomenological philosophical approaches to the social psychology of risk perception provide a novel framework for understanding issues that are common to all humanity, such as fear of death, freedom and responsibility, isolation and meaninglessness, as these anxieties are a function of existing, or being-in-the-world. These fundamental anxieties can be related theoretically to the ways people perceive risks within social and cultural milieus, and can also be used practically within case studies, as demonstrated in the three examples presented, which examine perceptions of climate change, food-related risks, and environmental awareness via a mixture of quantitative and qualitative techniques. The discussion focuses on the possible insights that can be gained from taking an existential perspective on risk perception, and relates notions of contemporary technologically-oriented societies to the existential challenges faced by individuals and societies in the contemporary world.  相似文献   
64.
65.
周恒彤 《统计研究》1993,10(6):60-62
近年来,我国的社会经济统计学工作者努力把数理统计学的理论与方法应用于解决社会经济统计学的各种研究课题,在这方面取得了许多有价值的成果。但也还有一些值得进一步探讨的问题。其中之一是,数理统计学有其特定的研究对象和研究任务。社会经济统计学中的课题,有的属于这种研究范畴,有的则不属于。对于前者,自然可以而且也应当用数理统  相似文献   
66.
Recent studies have shown that group differences in marital stability and satisfaction can be predicted based on premarital relationship quality. There is also a growing literature indicating that there are distinct types of relationships, both premaritally and developmentally over time. This study examined the relationship between the four premarital types (Vitalized, Harmonious, Traditional, and Conflicted) identified by Fowers and Olson (1992) and relationship outcome over a 3-year period with 393 couples. A substantial relationship was found, with conflicted couples being the most likely to separate or divorce. Vitalized couples had the highest levels of satisfaction, followed by Harmonious, Traditional, and Conflicted couples. Traditional couples were less likely to have divorced than Harmonious couples, even though Harmonious couples had higher premarital relationship satisfaction scores.  相似文献   
67.
This paper presents the results of a study that identified how often a probabilistic risk assessment (PRA)should be updated to accommodate the changes that take place at nuclear power plants. Based on a 7-year analysis of design and procedural changes at one plant, we consider 5 years to be the maximum interval for updating PRAs. This conclusion is preliminary because it is based on the review of changes that occurred at a single plant, and it addresses only PRAs that involve a Level 1 analysis (i.e., a PRA including calculation of core damage frequency only). Nevertheless, this conclusion indicates that maintaining a useful PRA requires periodic updating efforts. However, the need for this periodic update stems only partly from the number of changes that can be expected to take place at nuclear power plants–changes that individually have only a moderate to minor impact on the PRA, but whose combined impact is substantial and necessitates a PRA update. Additionally, a comparison of two generations of PRAs performed about 5 years apart indicates that PRAs must be periodically updated to reflect the evolution of PRA methods. The most desirable updating interval depends on these two technical considerations as well as the cost of updating the PRA. (Cost considerations, however, were beyond the scope of this study.)  相似文献   
68.
69.
Beryllium is the strongest of the lightweight metals. Used primarily in military applications prior to the end of the Cold War, beryllium is finding new applications in many commercial products, including computers, telecommunication equipment, and consumer and automotive electronics. The use of beryllium in nondefense consumer applications is of concern because beryllium is toxic. Inhalation of beryllium dust or vapor causes a chronic lung disease in some individuals at concentrations as low as 0.01 microg/m3 in air. As beryllium enters wider commerce, it is prudent to ask what risks this might present to the general public and to workers downstream of the beryllium materials industry. We address this question by evaluating the potential for beryllium exposure from the manufacturing, use, recycle, and disposal of beryllium-containing products. Combining a market study with a qualitative exposure analysis, we determine which beryllium applications and life cycle phases have the largest exposure potential. Our analysis suggests that use and maintenance of the most common types of beryllium-containing products do not result in any obvious exposures of concern, and that maintenance activities result in greater exposures than product use. Product disposal has potential to present significant individual risks, but uncertainties concerning current and future routes of product disposal make it difficult to be definitive. Overall, additional exposure and dose-response data are needed to evaluate both the health significance of many exposure scenarios, and the adequacy of existing regulations to protect workers and the public. Although public exposures to beryllium and public awareness and concern regarding beryllium risks are currently low, beryllium risks have psychometric qualities that may lead to rapidly heightened public concern.  相似文献   
70.
实验用健康青紫兰家兔,麻醉后暴露颈部左侧迷走神经,一组电刺激迷走神经;另一组耳静脉注射阿托品后10min再刺激迷走神经.于刺激前及刺激后不同时间采血.检测外周血中T细胞百分率和PHA诱导的淋巴细胞转化率,结果表明:电刺激迷走神经能显著提高外围血中T细胞百分率和淋巴细胞转化率,而注射阿托品后,外周血T细胞百分率在刺激后4h才有升高,而淋巴细胞转化率在4h内无显著变化.提示:迷走神经兴奋后可显著增强机体的细胞免疫功能.而这一作用可能是通过M受体实现的.  相似文献   
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