全文获取类型
收费全文 | 4296篇 |
免费 | 240篇 |
国内免费 | 35篇 |
专业分类
管理学 | 1149篇 |
民族学 | 6篇 |
人才学 | 1篇 |
人口学 | 60篇 |
丛书文集 | 218篇 |
理论方法论 | 274篇 |
综合类 | 2161篇 |
社会学 | 550篇 |
统计学 | 152篇 |
出版年
2024年 | 6篇 |
2023年 | 58篇 |
2022年 | 28篇 |
2021年 | 49篇 |
2020年 | 106篇 |
2019年 | 105篇 |
2018年 | 123篇 |
2017年 | 147篇 |
2016年 | 118篇 |
2015年 | 149篇 |
2014年 | 274篇 |
2013年 | 533篇 |
2012年 | 242篇 |
2011年 | 299篇 |
2010年 | 241篇 |
2009年 | 224篇 |
2008年 | 222篇 |
2007年 | 252篇 |
2006年 | 258篇 |
2005年 | 196篇 |
2004年 | 178篇 |
2003年 | 146篇 |
2002年 | 131篇 |
2001年 | 80篇 |
2000年 | 73篇 |
1999年 | 55篇 |
1998年 | 29篇 |
1997年 | 27篇 |
1996年 | 20篇 |
1995年 | 20篇 |
1994年 | 37篇 |
1993年 | 15篇 |
1992年 | 21篇 |
1991年 | 16篇 |
1990年 | 9篇 |
1989年 | 11篇 |
1988年 | 16篇 |
1987年 | 16篇 |
1986年 | 9篇 |
1985年 | 5篇 |
1984年 | 9篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 6篇 |
排序方式: 共有4571条查询结果,搜索用时 251 毫秒
81.
Risk Assessment of Human Listeriosis from Semisoft Cheeses Made from Raw Sheep's Milk in Lazio and Tuscany (Italy) 下载免费PDF全文
Roberto Condoleo Ziad Mezher Selene Marozzi Antonella Guzzon Roberto Fischetti Matteo Senese Stefania Sette Luca Bucchini 《Risk analysis》2017,37(4):661-676
Semisoft cheese made from raw sheep's milk is traditionally and economically important in southern Europe. However, raw milk cheese is also a known vehicle of human listeriosis and contamination of sheep cheese with Listeria monocytogenes has been reported. In the present study, we have developed and applied a quantitative risk assessment model, based on available evidence and challenge testing, to estimate risk of invasive listeriosis due to consumption of an artisanal sheep cheese made with raw milk collected from a single flock in central Italy. In the model, contamination of milk may originate from the farm environment or from mastitic animals, with potential growth of the pathogen in bulk milk and during cheese ripening. Based on the 48‐day challenge test of a local semisoft raw sheep's milk cheese we found limited growth only during the initial phase of ripening (24 hours) and no growth or limited decline during the following ripening period. In our simulation, in the baseline scenario, 2.2% of cheese servings are estimated to have at least 1 colony forming unit (CFU) per gram. Of these, 15.1% would be above the current E.U. limit of 100 CFU/g (5.2% would exceed 1,000 CFU/g). Risk of invasive listeriosis per random serving is estimated in the 10?12 range (mean) for healthy adults, and in the 10?10 range (mean) for vulnerable populations. When small flocks (10–36 animals) are combined with the presence of a sheep with undetected subclinical mastitis, risk of listeriosis increases and such flocks may represent a public health risk. 相似文献
82.
Land subsidence risk assessment (LSRA) is a multi‐attribute decision analysis (MADA) problem and is often characterized by both quantitative and qualitative attributes with various types of uncertainty. Therefore, the problem needs to be modeled and analyzed using methods that can handle uncertainty. In this article, we propose an integrated assessment model based on the evidential reasoning (ER) algorithm and fuzzy set theory. The assessment model is structured as a hierarchical framework that regards land subsidence risk as a composite of two key factors: hazard and vulnerability. These factors can be described by a set of basic indicators defined by assessment grades with attributes for transforming both numerical data and subjective judgments into a belief structure. The factor‐level attributes of hazard and vulnerability are combined using the ER algorithm, which is based on the information from a belief structure calculated by the Dempster‐Shafer (D‐S) theory, and a distributed fuzzy belief structure calculated by fuzzy set theory. The results from the combined algorithms yield distributed assessment grade matrices. The application of the model to the Xixi‐Chengnan area, China, illustrates its usefulness and validity for LSRA. The model utilizes a combination of all types of evidence, including all assessment information—quantitative or qualitative, complete or incomplete, and precise or imprecise—to provide assessment grades that define risk assessment on the basis of hazard and vulnerability. The results will enable risk managers to apply different risk prevention measures and mitigation planning based on the calculated risk states. 相似文献
83.
郭栋 《北京航空航天大学学报(社会科学版)》2012,25(3):62-70
国外立法例对侵权法中作为义务的规制模式不尽相同,中国台湾地区和大陆地区理论界对作为义务的研究在结合中国司法实践方面略显不足。对于侵权法中作为义务的探究,应当将国外立法例、中国理论界的研究成果与司法实践情况结合起来。中国侵权法中作为义务的设计应当遵循如下思路:无须在一般条款中明确作为义务;合同约定不应成为侵权法中作为义务的来源;不应当规定一般救助义务;作为义务来源应当具有层级性,且该层级性应当以重塑安全保障义务为中心。 相似文献
84.
Using In Vitro High‐Throughput Screening Data for Predicting Benzo[k]Fluoranthene Human Health Hazards 下载免费PDF全文
Today there are more than 80,000 chemicals in commerce and the environment. The potential human health risks are unknown for the vast majority of these chemicals as they lack human health risk assessments, toxicity reference values, and risk screening values. We aim to use computational toxicology and quantitative high‐throughput screening (qHTS) technologies to fill these data gaps, and begin to prioritize these chemicals for additional assessment. In this pilot, we demonstrate how we were able to identify that benzo[k]fluoranthene may induce DNA damage and steatosis using qHTS data and two separate adverse outcome pathways (AOPs). We also demonstrate how bootstrap natural spline‐based meta‐regression can be used to integrate data across multiple assay replicates to generate a concentration–response curve. We used this analysis to calculate an in vitro point of departure of 0.751 μM and risk‐specific in vitro concentrations of 0.29 μM and 0.28 μM for 1:1,000 and 1:10,000 risk, respectively, for DNA damage. Based on the available evidence, and considering that only a single HSD17B4 assay is available, we have low overall confidence in the steatosis hazard identification. This case study suggests that coupling qHTS assays with AOPs and ontologies will facilitate hazard identification. Combining this with quantitative evidence integration methods, such as bootstrap meta‐regression, may allow risk assessors to identify points of departure and risk‐specific internal/in vitro concentrations. These results are sufficient to prioritize the chemicals; however, in the longer term we will need to estimate external doses for risk screening purposes, such as through margin of exposure methods. 相似文献
85.
蔡海霞 《北京理工大学学报(社会科学版)》2016,18(4):9-18
基于多维效应的能源效率评估使人们在达到经济增长目的的同时兼顾能源安全、竞争力、环境、社会和技术的可持续性。论述能源效率内涵演化发展的路径,在此基础上将能源效率的内涵扩展至多维效应。以非参数DEA(Data Envelopment Analysis)方法为例,研究基于多维效应的能源效率评估方法的演化与发展趋势。研究结果显示:采用DEA方法对基于多维效应的能源效率进行评估的发展趋势主要有以下3点:能源效率的内涵不断延伸;DEA模型向非导向非径向模型转变;能源效率评估的研究维度不断扩展。对多维效应的能源效率综合指标评价体系和评价方法还需做深入研究。 相似文献
86.
As part of the process of examining their theory of change (TOC) and reflecting on grant making activity, one Midwestern foundation employed a multipronged strategy to assess 209 community-based mental health grants across seven years of funding. This article details the evaluation approach, which comprised these areas of the TOC: grantees’ use of evidence-based interventions, cultural competency, quality improvement, community collaboration, and use of integrated care. Inductive analyses identified grantees’ use of innovative practices, trauma-informed care, and use of validated instruments. In an iterative exercise spanning multiple years, the foundation and researchers found ways to gather information about community capacity and impact while simultaneously minimizing grantee data collection/reporting burden. Findings revealed that community agencies were improving in their uptake of evidence-based interventions and use of validated instruments. Community grantee use of trauma informed care also improved over the study period. Grantee desire to collaborate and coordinate services within the community was also strong. The research also revealed that in multiple domains (such as technology and non-profit operating costs) grantees needed support in building agency capacity. These findings shed light on which aspects of the foundation’s TOC were being addressed through funding, and which areas of the community needed additional support. 相似文献
87.
Laura López-Sanders 《Journal of ethnic and migration studies》2017,43(12):2072-2088
ABSTRACTBrokerage is a prominent mechanism that explains access for Latino immigrants to many American institutions. However, few studies examine the dual nature of brokerage in answering questions on access to health care for undocumented Latino immigrants. The growing importance of Federally Qualified Health Centers (FQHCs) and ethnic navigators connecting immigrants to health care under the 2010 Affordable Care Act calls attention to the duality of brokers and its role in access. The study draws from 44 in-depth interviews with providers, clinic directors, navigators, and immigrant patients and two years of fieldwork in FQHCs in California’s San Francisco Bay Area (2011–2013). Results show that brokers enable access through coaching and myth-busting but they also hinder it through scrutiny and bureaucratic filtering. The widespread dependence on brokerage, I argue, leads to ersatz brokerage, such as when providers navigate the health-care system for the undocumented without the appropriate linguistic resources or coordination. Furthermore, the study shows that the duality in brokerage generates misinformation, churning, and alienation. Understanding the relational processes that both include and exclude vulnerable populations from needed services enhances theories of immigrant integration and can help design more efficient policies and address inequalities related to documentation status. 相似文献
88.
Yi Mou 《Chinese Journal of Communication》2014,7(3):319-334
The affordance of microblogging services has made them an ideal tool for communicating risk and crisis. However, research on social media and risk communication is still in its infancy. This study, following the uses and gratifications framework, attempts to give some insight into the way micro-bloggers communicate about risk by investigating food safety communications on the microblogging service in China. A content analysis was conducted on 6186 microblog posts relating to 12 recent food safety incidents in China. A series of bivariate chi-square tests was conducted to test the association between micro-bloggers and gratifications. The results indicate that different types of micro-bloggers gratify different needs. Compared to other types of micro-bloggers, the general public tends to use microblogging to express opinions on food safety incidents, regulation and/or policy, rather than simply disseminating information; members of the public enjoy fewer multimedia affordances in their microblog posting but express more negative feelings. Although we anticipate growth in the use of social media in environmental health communication, caution is still needed: communication in China still follows a traditional top-down pattern. 相似文献
89.
90.