全文获取类型
收费全文 | 8132篇 |
免费 | 654篇 |
国内免费 | 3266篇 |
专业分类
安全科学 | 778篇 |
废物处理 | 415篇 |
环保管理 | 619篇 |
综合类 | 5197篇 |
基础理论 | 1339篇 |
环境理论 | 2篇 |
污染及防治 | 2524篇 |
评价与监测 | 433篇 |
社会与环境 | 375篇 |
灾害及防治 | 370篇 |
出版年
2024年 | 39篇 |
2023年 | 195篇 |
2022年 | 434篇 |
2021年 | 433篇 |
2020年 | 426篇 |
2019年 | 336篇 |
2018年 | 398篇 |
2017年 | 459篇 |
2016年 | 462篇 |
2015年 | 545篇 |
2014年 | 600篇 |
2013年 | 842篇 |
2012年 | 752篇 |
2011年 | 719篇 |
2010年 | 615篇 |
2009年 | 569篇 |
2008年 | 544篇 |
2007年 | 505篇 |
2006年 | 476篇 |
2005年 | 327篇 |
2004年 | 227篇 |
2003年 | 265篇 |
2002年 | 274篇 |
2001年 | 216篇 |
2000年 | 202篇 |
1999年 | 192篇 |
1998年 | 177篇 |
1997年 | 135篇 |
1996年 | 131篇 |
1995年 | 127篇 |
1994年 | 112篇 |
1993年 | 75篇 |
1992年 | 71篇 |
1991年 | 47篇 |
1990年 | 43篇 |
1989年 | 25篇 |
1988年 | 14篇 |
1987年 | 10篇 |
1986年 | 13篇 |
1985年 | 8篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1977年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
32.
33.
朱辉 《防灾减灾工程学报》2012,(5):45-47
针对宁夏中宁发电有限责任公司斗轮堆取料机(简称斗轮机)斗轮轴胀套联接处粘死问题,进行分析、计算,将胀套联接方式改为花键联接方式。结果表明:斗轮机长期在超负荷工况下运行是造成斗轮轴胀套联接处粘死的主要原因;联接方式改进后,斗轮轴传动负荷能力增大,检修方便,达到了预期的改造效果。 相似文献
34.
农保制度实施中的问题分析农保制定在实施过程中,存在着不少矛盾关系,这些矛盾严重阻碍了农保工作的顺利开展,甚至可能危及制度的安全. 相似文献
35.
Miao Tian Heekwang Koo Qinwen Xu Jun Li 《International journal of occupational safety and ergonomics》2013,19(1):118-126
Effects of work boots and load carriage (6.4?kg and 12.8?kg) on gait pattern were investigated. The protective work boots were examined by comparison with running shoes through human performance tests with 15 male participants. The loads were carried symmetrically and asymmetrically on the shoulder and hand. Statistical data analysis showed a prolonged stance phase and decreased double support for work boots. A significantly increased ground reaction force was found in work boot conditions as the weight of loads increases. This study demonstrates that inflexible and heavy work boots restrict foot movement and require greater torque at the ankle to propel the body forward, which may increase physical strain and the risk of musculoskeletal injuries. Development of improved fixation methods for work boots, increased use of flexible protective layers and further study of anthropometry of human foot morphology for improved safety and work efficiency of industry workers are suggested. 相似文献
36.
Gas leakage from pipeline leads to significant environmental damages and industrial hazards, so small leakage detection for gas pipeline is essential to avoid these serious leakages. However, because of the high frequency component of leakage signal attenuates quickly, traditional detection method which inspects pressure or vibration signal has problem to get effective information from leakage signal. So, a novel detection method based on acoustic wave is proposed. This paper, firstly, researches on the phonation principle of pipeline leakage and the characteristic of sound source, and simulates the leakage acoustic field on the basis of aero acoustics. Secondly, using Wavelet Packet Transform method and Fuzzy Support Vector Machine pattern classification, the laboratory testing for identifying acoustic signal of gas pipeline leakage is presented. Finally, the field application demonstrates that the detection system could identify small gas leakage effectively and avoids false-alarms which caused by running conditions with a good prospect. 相似文献
37.
Vinasse has great pollution to the environment. A number of technologies have been explored for reducing the pollution of vinasse. Sustainability has become an important factor when discussing wastewater treatment techniques. Emergy analysis was used to evaluate the treatment of cassava vinasse in this paper. Cr (emergy consumption ratio) as a new emergy index was proposed to measure the impact of waste treatment to the society. Centrifugal solid–liquid separation, UASB (up-flow anaerobic sludge bed), and SBR (sequencing batch reactor activated sludge process) are used in the treatment process. The emergy indices for cassava vinasse treatment system were as follows: EYR (emergy yield ratio) was 6.20, ELR (environmental loading ratio) was 5.81, ESI (emergy sustainability index) was 1.07, and Cr was 4.60E+12 sej/m3. The emergy of coal electricity accounts for 46% of all purchased inputs. It is necessary to improve the treatment technology to reduce the electricity used. 相似文献
38.
为研究含地下采空区的岩质边坡在施工过程中的各种响应与稳定性,采用SURPAC建立某磷矿的三维地质模型。在边坡坡顶、坡角与采空区四周布置应力与位移监测点。利用接口程序将三维模型导入FLAC3D,计算露天边坡开挖过程中监测点的应力与位移。计算结果表明:坡顶与坡角水平位移与竖向反弹位移随着边坡开挖的进行越来越大,但每步开挖完成后新增的反弹位移越来越小,这与每步开挖的卸载量大小有关。坡顶监测点处于拉应力状态,坡角监测点处于压剪应力状态,在监测点所在位置开挖时,压应力显著变大。地下空区的开挖过程对空区的竖向位移与应力有极大影响,最大主应力在每步开挖完成时突然增加,且增幅很大。建议在施工过程中,加强对采空区与边坡坡顶及坡脚的位移与应力的量测,以确保施工安全。 相似文献
39.
40.