全文获取类型
收费全文 | 8180篇 |
免费 | 565篇 |
国内免费 | 300篇 |
专业分类
安全科学 | 1618篇 |
废物处理 | 138篇 |
环保管理 | 3069篇 |
综合类 | 2191篇 |
基础理论 | 815篇 |
环境理论 | 10篇 |
污染及防治 | 247篇 |
评价与监测 | 333篇 |
社会与环境 | 344篇 |
灾害及防治 | 280篇 |
出版年
2023年 | 104篇 |
2022年 | 134篇 |
2021年 | 192篇 |
2020年 | 251篇 |
2019年 | 193篇 |
2018年 | 166篇 |
2017年 | 223篇 |
2016年 | 310篇 |
2015年 | 261篇 |
2014年 | 318篇 |
2013年 | 467篇 |
2012年 | 454篇 |
2011年 | 577篇 |
2010年 | 385篇 |
2009年 | 494篇 |
2008年 | 362篇 |
2007年 | 476篇 |
2006年 | 469篇 |
2005年 | 361篇 |
2004年 | 396篇 |
2003年 | 297篇 |
2002年 | 278篇 |
2001年 | 270篇 |
2000年 | 270篇 |
1999年 | 205篇 |
1998年 | 132篇 |
1997年 | 135篇 |
1996年 | 108篇 |
1995年 | 105篇 |
1994年 | 49篇 |
1993年 | 62篇 |
1992年 | 57篇 |
1991年 | 47篇 |
1990年 | 33篇 |
1989年 | 28篇 |
1988年 | 34篇 |
1987年 | 35篇 |
1986年 | 27篇 |
1985年 | 23篇 |
1984年 | 27篇 |
1983年 | 18篇 |
1982年 | 22篇 |
1981年 | 18篇 |
1980年 | 24篇 |
1979年 | 33篇 |
1978年 | 21篇 |
1975年 | 14篇 |
1973年 | 14篇 |
1972年 | 16篇 |
1971年 | 14篇 |
排序方式: 共有9045条查询结果,搜索用时 15 毫秒
61.
概述了环境DNA技术目前的研究方向和分析原理,介绍了该技术在水生、土壤和植物生态系统中的应用进展,以及在监测畜舍环境、促进畜禽粪污无害化处理、检测动物营养与健康状况、调查动物群体遗传多样性、监测和预防畜禽疾病等动物生产管理中的应用前景。分析了环境DNA技术的优势与局限,并在此基础上提出了建立标准操作流程、提高检测精确度、积极推广应用环境DNA技术等建议。 相似文献
62.
新疆在长期边界资源开发的实践中形成了一套具有地方特色的陆地边界资源开发机制,成功地实现了对边界资源开发的有序管控。这些成功经验主要包括:对国家政策与地方政策进行相互配套,通过制度化建设将边界地区的资源开发服务于地方经济发展。在新形势下,边界资源开发出现了一些的新的动向与重点,其中包括在资源开发中注重环境保护问题,以及注重资源开发与边界地区经济发展相适应。总结以往经验,解决这些问题的关键是借助国家的一带一路建设,在实现边界地区安全稳定的基础上,以资源开发的可持续发展作为发展目标,通过经济发展促进边界地区的和谐、安全与稳定。 相似文献
63.
为从根本上降低煤矿从业人员实施不安全行为的概率,在充分考虑煤矿从业人员不安全个体状态是诱发其不安全行为的主要原因的基础上,设计开发一套矿工不安全状态智能检测系统。首先,对2007—2022年期间各高危行业安全事故调查报告和专家研究进行归纳,总结得出煤矿从业人员不安全状态的影响因素,构建包括生理状态、心理状态以及个体能力状态在内的3个一级指标和15个二级指标体系;其次,通过相应的表征模型对不安全状态影响因素进行深入剖析;最后,基于构建的从业人员不安全状态倾向数据库,建立煤矿岗前不安全状态智能检测系统。研究结果表明:在下井工作前对从业人员个体状态进行智能检测,能够实现矿工不安全状态“早发现、早干预”,能够有效地降低人因事故发生率,研究结果对煤炭行业安全管理具有重要的参考价值。 相似文献
64.
An integrated approach for performance assessment and management of safety barriers in a systemic manner is needed concerning the prevention and mitigation of major accidents in chemical process industries. Particularly, the effects of safety barriers on system risk reduction should be assessed in a dynamic manner to support the decision-making on safety barrier establishments and improvements. A simulation approach, named Simulink-based Safety Barrier Modeling (SSBM), is proposed in this paper to conduct dynamic risk assessment of chemical facilities with the consideration of the degradation of safety barriers. The main functional features of the SSBM include i) the basic model structures of SSBM can be determined based on bow-tie diagrams, ii) multiple data (periodic proof test data, continuous condition-monitoring data, and accident precursor data) may be combined to update barrier failure probabilities and initiating event probabilities, iii) SSBM is able to handle uncertainty propagation in probabilistic risk assessment by using Monte Carlo simulations, and iv) cost-effectiveness analysis (CEA) and optimization algorithms are integrated to support the decision-making on safety barrier establishments and improvements. An illustrative case study is demonstrated to show the procedures of applying the SSBM on dynamic risk-informed safety barrier management and validate the feasibility of implementing the SSBM for cost-effective safety barrier optimization. 相似文献
65.
We designed 3 image‐based field guides to tropical forest plant species in Ghana, Grenada, and Cameroon and tested them with 1095 local residents and 20 botanists in the United Kingdom. We compared users’ identification accuracy with different image formats, including drawings, specimen photos, living plant photos, and paintings. We compared users’ accuracy with the guides to their accuracy with only their prior knowledge of the flora. We asked respondents to score each format for usability, beauty, and how much they would pay for it. Prior knowledge of plant names was generally low (<22%). With a few exceptions, identification accuracy did not differ significantly among image formats. In Cameroon, users identifying sterile Cola species achieved 46–56% accuracy across formats; identification was most accurate with living plant photos. Botanists in the United Kingdom accurately identified 82–93% of the same Cameroonian species; identification was most accurate with specimens. In Grenada, users accurately identified 74–82% of plants; drawings yielded significantly less accurate identifications than paintings and photos of living plants. In Ghana, users accurately identified 85% of plants. Digital color photos of living plants ranked high for beauty, usability, and what users would pay. Black and white drawings ranked low. Our results show the potential and limitations of the use of field guides and nonspecialists to identify plants, for example, in conservation applications. We recommend authors of plant field guides use the cheapest or easiest illustration format because image type had limited bearing on accuracy; match the type of illustration to the most likely use of the guide for slight improvements in accuracy; avoid black and white formats unless the audience is experienced at interpreting illustrations or keeping costs low is imperative; discourage false‐positive identifications, which were common; and encourage users to ask an expert or use a herbarium for groups that are difficult to identify. Pruebas Empíricas de Guías de Campo de Plantas Hawthorne, Cable & Marshall 相似文献
66.
MATTHEW W. MCKOWN JOSHUA T. ACKERMAN COLLIN A. EAGLES‐SMITH BERNIE R. TERSHY DONALD A. CROLL 《Conservation biology》2014,28(4):1100-1108
Although wildlife conservation actions have increased globally in number and complexity, the lack of scalable, cost‐effective monitoring methods limits adaptive management and the evaluation of conservation efficacy. Automated sensors and computer‐aided analyses provide a scalable and increasingly cost‐effective tool for conservation monitoring. A key assumption of automated acoustic monitoring of birds is that measures of acoustic activity at colony sites are correlated with the relative abundance of nesting birds. We tested this assumption for nesting Forster's terns (Sterna forsteri) in San Francisco Bay for 2 breeding seasons. Sensors recorded ambient sound at 7 colonies that had 15–111 nests in 2009 and 2010. Colonies were spaced at least 250 m apart and ranged from 36 to 2,571 m2. We used spectrogram cross‐correlation to automate the detection of tern calls from recordings. We calculated mean seasonal call rate and compared it with mean active nest count at each colony. Acoustic activity explained 71% of the variation in nest abundance between breeding sites and 88% of the change in colony size between years. These results validate a primary assumption of acoustic indices; that is, for terns, acoustic activity is correlated to relative abundance, a fundamental step toward designing rigorous and scalable acoustic monitoring programs to measure the effectiveness of conservation actions for colonial birds and other acoustically active wildlife. La Actividad Vocal como un Índice Escalable y de Bajo Costo del Tamaño de Colonia de las Aves Marinas 相似文献
67.
Using empirical models of species colonization under multiple threatening processes to identify complementary threat‐mitigation strategies 下载免费PDF全文
Ayesha I.T. Tulloch Alessio Mortelliti Geoffrey M. Kay Daniel Florance David Lindenmayer 《Conservation biology》2016,30(4):867-882
Approaches to prioritize conservation actions are gaining popularity. However, limited empirical evidence exists on which species might benefit most from threat mitigation and on what combination of threats, if mitigated simultaneously, would result in the best outcomes for biodiversity. We devised a way to prioritize threat mitigation at a regional scale with empirical evidence based on predicted changes to population dynamics—information that is lacking in most threat‐management prioritization frameworks that rely on expert elicitation. We used dynamic occupancy models to investigate the effects of multiple threats (tree cover, grazing, and presence of an hyperaggressive competitor, the Noisy Miner (Manorina melanocephala) on bird‐population dynamics in an endangered woodland community in southeastern Australia. The 3 threatening processes had different effects on different species. We used predicted patch‐colonization probabilities to estimate the benefit to each species of removing one or more threats. We then determined the complementary set of threat‐mitigation strategies that maximized colonization of all species while ensuring that redundant actions with little benefit were avoided. The single action that resulted in the highest colonization was increasing tree cover, which increased patch colonization by 5% and 11% on average across all species and for declining species, respectively. Combining Noisy Miner control with increasing tree cover increased species colonization by 10% and 19% on average for all species and for declining species respectively, and was a higher priority than changing grazing regimes. Guidance for prioritizing threat mitigation is critical in the face of cumulative threatening processes. By incorporating population dynamics in prioritization of threat management, our approach helps ensure funding is not wasted on ineffective management programs that target the wrong threats or species. 相似文献
68.
针对目前我国非煤矿山在安全制度管理过程中常常出现刚性有余而柔性不足的缺陷,总结出非煤矿山在制订、执行和完善安全制度中存在的问题主要表现在安全制度的制订与实际符合度不高、安全制度的执行过程重形式轻实践、对安全制度的完善重视度不够3个方面。引入道家"自然无为"思想,分析了"自然无为"思想对安全制度的制订、执行和完善3个阶段的影响。提出在安全制度的制订时注重"道法自然";在安全制度的执行时强调"三和"观;在安全制度的完善时注重"顺道而为"。将道家"自然无为"思想与安全制度管理相融合,能有效增强安全制度管理的"人情味",使其更好地发挥基础保障作用。 相似文献
69.
BEN C. SCHEELE DAVID A. HUNTER LAURA F. GROGAN LEE BERGER JON E. KOLBY MICHAEL S. MCFADDEN GERRY MARANTELLI LEE F. SKERRATT DON A. DRISCOLL 《Conservation biology》2014,28(5):1195-1205
Wildlife diseases pose an increasing threat to biodiversity and are a major management challenge. A striking example of this threat is the emergence of chytridiomycosis. Despite diagnosis of chytridiomycosis as an important driver of global amphibian declines 15 years ago, researchers have yet to devise effective large‐scale management responses other than biosecurity measures to mitigate disease spread and the establishment of disease‐free captive assurance colonies prior to or during disease outbreaks. We examined the development of management actions that can be implemented after an epidemic in surviving populations. We developed a conceptual framework with clear interventions to guide experimental management and applied research so that further extinctions of amphibian species threatened by chytridiomycosis might be prevented. Within our framework, there are 2 management approaches: reducing Batrachochytrium dendrobatidis (the fungus that causes chytridiomycosis) in the environment or on amphibians and increasing the capacity of populations to persist despite increased mortality from disease. The latter approach emphasizes that mitigation does not necessarily need to focus on reducing disease‐associated mortality. We propose promising management actions that can be implemented and tested based on current knowledge and that include habitat manipulation, antifungal treatments, animal translocation, bioaugmentation, head starting, and selection for resistance. Case studies where these strategies are being implemented will demonstrate their potential to save critically endangered species. Intervenciones para Reducir el Riesgo de Extinción en Anfibios Amenazados por la Quitridiomicosis 相似文献
70.
The Southern Ocean is one of the most rapidly changing ecosystems on the planet due to the effects of climate change and commercial fishing for ecologically important krill and fish. Because sea ice loss is expected to be accompanied by declines in krill and fish predators, decoupling the effects of climate and anthropogenic changes on these predator populations is crucial for ecosystem‐based management of the Southern Ocean. We reviewed research published from 2007 to 2014 that incorporated very high‐resolution satellite imagery to assess distribution, abundance, and effects of climate and other anthropogenic changes on populations of predators in polar regions. Very high‐resolution imagery has been used to study 7 species of polar animals in 13 papers, many of which provide methods through which further research can be conducted. Use of very high‐resolution imagery in the Southern Ocean can provide a broader understanding of climate and anthropogenic forces on populations and inform management and conservation recommendations. We recommend that conservation biologists continue to integrate high‐resolution remote sensing into broad‐scale biodiversity and population studies in remote areas, where it can provide much needed detail. Aplicaciones de Imágenes de Muy Alta Resolución en el Estudio y Conservación de Grandes Depredadores en el Océano Antártico 相似文献