全文获取类型
收费全文 | 8190篇 |
免费 | 572篇 |
国内免费 | 271篇 |
专业分类
安全科学 | 1630篇 |
废物处理 | 142篇 |
环保管理 | 3092篇 |
综合类 | 2167篇 |
基础理论 | 810篇 |
环境理论 | 10篇 |
污染及防治 | 204篇 |
评价与监测 | 342篇 |
社会与环境 | 355篇 |
灾害及防治 | 281篇 |
出版年
2023年 | 85篇 |
2022年 | 108篇 |
2021年 | 182篇 |
2020年 | 248篇 |
2019年 | 192篇 |
2018年 | 166篇 |
2017年 | 224篇 |
2016年 | 310篇 |
2015年 | 254篇 |
2014年 | 323篇 |
2013年 | 465篇 |
2012年 | 458篇 |
2011年 | 581篇 |
2010年 | 392篇 |
2009年 | 499篇 |
2008年 | 360篇 |
2007年 | 475篇 |
2006年 | 470篇 |
2005年 | 363篇 |
2004年 | 395篇 |
2003年 | 301篇 |
2002年 | 283篇 |
2001年 | 277篇 |
2000年 | 273篇 |
1999年 | 208篇 |
1998年 | 134篇 |
1997年 | 138篇 |
1996年 | 109篇 |
1995年 | 106篇 |
1994年 | 50篇 |
1993年 | 64篇 |
1992年 | 57篇 |
1991年 | 48篇 |
1990年 | 33篇 |
1989年 | 27篇 |
1988年 | 34篇 |
1987年 | 33篇 |
1986年 | 29篇 |
1985年 | 23篇 |
1984年 | 28篇 |
1983年 | 17篇 |
1982年 | 23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9033条查询结果,搜索用时 15 毫秒
991.
西部管道工程HSE一体化绩效管理应用研究 总被引:1,自引:0,他引:1
分析了我国管道工程项目HSE绩效管理存在问题,运用绩效管理理论,结合“PMT(业主)+PMC(监理)+EPC(施工总承包方)”一体化模式及西部管道工程,阐述了HSE一体化绩效管理体系的建立及应用情况。 相似文献
992.
993.
994.
The assessment of the frequencies of release from piping due to losses of containment is an essential step in the preparing Safety Reports, drawn up as required by the so-called “Seveso” Directive. These are usually calculated starting from the frequencies of random rupture included in international databases and are not plant-specific, furthermore, the quantification of the effect of the safety management system of the facility is not easy. A simple and flexible approach quantifying technical and management characteristics of the plant has been proposed by Milazzo and co-workers in 2010; it is based on the modification of the frequency taken from literature, through the use of the percentages of failure causes actually possible in that plant, and the judgment about their management. The data about the failure causes are taken from the literature and modified by using corrective factors to adapt them to the industrial context. To make possible the application of the method to a large number of major-hazard industry types, some aspects of the approach needed to be improved; these have been identified during a development project coordinated by RINA Consulting, on behalf of Saipem, with the collaboration of the University of Messina. The improvement of the approach focused on two main points, the development of a method to calculate the corrective factors for the failure causes associated with corrosion and erosion phenomena and the strengthening of the methodology for the formulation of the judgment about the safety management. This paper illustrates the fully improved method, as well as an application to a typical gas storage plant. 相似文献
995.
针对大型场所疏散出口通行能力不均衡现象,以某大型体育场馆为对象,建立Pathfinder疏散模型,通过不断改变行人出口选择,得到行人疏散分区优化模型。结果表明:通过对比优化前后疏散时间、疏散过程及疏散出口利用差异,得到疏散时间优化效率10.55%,各出口疏散时间标准差优化效率为90.78%。分区优化能够均衡各出口疏散时间,提高疏散出口利用效率,有效缓解大型场所拥堵问题,为实现大型场所安全疏散提供理论参考。 相似文献
996.
为更好地比较不同领导风格对员工安全行为的影响,采用元分析方法,基于34篇独立实证研究的15 032个样本,对常见的领导风格与员工安全行为关系进行定量分析。结果表明:对于安全遵守,相关系数从低到高分别为伦理型领导、变革型领导、领导-成员交换以及交易型领导;对于安全参与,相关系数从低到高分别为伦理型领导、变革型领导、交易型领导、领导-成员交换;年龄、经济发展水平、行业以及研究设计调节了领导风格与员工安全行为之间的关系。 相似文献
997.
Ekaterina Nikitina 《Journal of Environmental Planning and Management》2019,62(5):779-796
When ecosystem services value estimates are applied in the economic assessment of environmental policies, high accuracy of these estimates is required. One of the directions in the scientific discussion on biases in stated preference (SP) valuation surveys builds on dual-process theories of judgment. The paper contributes to this literature by presenting an experiment where two types of judgment were induced via separate versus joint valuation of environmental goods. The results demonstrated that policy relevance of environmental issues, e.g. the need for conservation measures increases emotional response, causing a larger bias in the separate design as it involves ‘valuation by feeling.’ This finding suggests that the context of a specific policy, which is often the reason for conducting SP surveys, influences the answers, thereby making the results less reliable for use in cost–benefit analysis. 相似文献
998.
John S. McLaren Todd V. Royer Robert W. Van Kirk Melissa L. Muradian 《Journal of the American Water Resources Association》2019,55(5):1323-1334
This study seeks to improve understanding of temperature patterns in reservoir outflows. We examined water temperatures in an irrigation storage reservoir, Island Park Reservoir, and its outflow, Henry’s Fork of the Snake River in eastern Idaho. Our objectives were to (1) quantify the extent to which daily temperature ranges in the reservoir outflow deviated from other reaches of the Henry’s Fork, and (2) test whether the reservoir’s net volume change during the summer — expressed as the volume of water remaining in the reservoir on September 1 — predicted mean summer temperature in the outflow. Two years of temperature data showed dampened diel temperature cycles in the reservoir outflow. Model selection with 17 years of climatic, hydrologic, and reservoir management variables found mean summer temperature in the outflow was best predicted by September 1 reservoir volume and average summer air temperature. Two years of weekly reservoir thermal profiles indicated large changes in reservoir volume eliminated cool hypolimnetic water and encouraged mixing, allowing warm epilimnetic water to be discharged into the outflow. Increases in future drought frequency and severity and increases in summer air temperatures could increase the frequency of occurrence of high mean summertime water temperatures in the outflow. Our study provides important information for local managers by quantifying influences on outflow temperatures and the downstream river ecosystem. 相似文献
999.
Mark E. Eiswerth G. Cornelis van Kooten 《Journal of the American Water Resources Association》2019,55(5):1335-1348
Given the expansion of payments for water‐based ecosystem services (PWES) worldwide, two relevant issues are as follows: (1) determination of efficient allocations of payments among land managers, and (2) how this might change when paying one manager to implement a best management practice (BMP) to enhance an ecosystem service impacts the cost‐effectiveness of BMPs considered by other land managers not currently involved in PWES. Such externalities may be negative if diminishing returns dominate, or positive if mechanisms such as “social diffusion” dominate. We analyze how a planner should optimally allocate payments, depending on whether the expected externalities are negligible, negative, or positive. We employ (1) an optimal control model to gain insights on the problem’s dynamics, and (2) stochastic dynamic programming to determine optimal funding strategies using a specific application. The study contributes to the literature by identifying dynamically optimal PWES payment patterns, and illustrates how they should change when one accounts for externalities induced by the program. Because such impacts have not been addressed previously in a rigorous way, this treatment provides useful value added for PWES design and implementation. 相似文献
1000.
Brenda DeZiel Lori Krider Brad Hansen Joseph Magner Bruce Wilson Geoff Kramer John Nieber 《Journal of the American Water Resources Association》2019,55(1):154-188
Water quality and stream habitat in agricultural watersheds are under greater scrutiny as hydrologic pathways are altered to increase crop production. Ditches have been traditionally constructed to remove water from agricultural lands. Little attention has been placed on alternative ditch designs that are more stable and provide greater habitat diversity for wildlife and aquatic species. In 2009, 1.89 km of a conventional drainage ditch in Mower County, Minnesota, was converted to a two‐stage ditch (TSD) with small, adjacent floodplains to mimic a natural system. Cross section surveys, conducted pre‐ and post‐construction, generally indicate a stable channel with minor adjustments over time. Vegetation surveys showed differences in species composition and biomass between the slopes and the benches, with changes ongoing. Longitudinal surveys demonstrated a 12‐fold increase in depth variability. Fish habitat quality improved with well‐sorted gravel riffles and deeper pool habitat. The biological response to improved habitat quality was investigated using a Fish Index of Biological Integrity (FIBI). Our results show higher FIBI scores post‐construction with scores more similar to natural streams. In summary, the TSD demonstrated improvements in riparian and instream habitat quality and fish communities, which showed greater fish species richness, higher percentages of gravel spawning fish, and better FIBI scores. This type of management tool could benefit ditches in other regions where gradient and geology allow. 相似文献