全文获取类型
收费全文 | 709篇 |
免费 | 50篇 |
国内免费 | 176篇 |
专业分类
安全科学 | 76篇 |
废物处理 | 45篇 |
环保管理 | 55篇 |
综合类 | 349篇 |
基础理论 | 98篇 |
污染及防治 | 222篇 |
评价与监测 | 34篇 |
社会与环境 | 36篇 |
灾害及防治 | 20篇 |
出版年
2023年 | 16篇 |
2022年 | 49篇 |
2021年 | 37篇 |
2020年 | 34篇 |
2019年 | 25篇 |
2018年 | 31篇 |
2017年 | 36篇 |
2016年 | 40篇 |
2015年 | 47篇 |
2014年 | 41篇 |
2013年 | 61篇 |
2012年 | 68篇 |
2011年 | 64篇 |
2010年 | 45篇 |
2009年 | 46篇 |
2008年 | 44篇 |
2007年 | 46篇 |
2006年 | 27篇 |
2005年 | 19篇 |
2004年 | 21篇 |
2003年 | 16篇 |
2002年 | 25篇 |
2001年 | 21篇 |
2000年 | 5篇 |
1999年 | 9篇 |
1998年 | 12篇 |
1997年 | 10篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有935条查询结果,搜索用时 78 毫秒
771.
Dongwei Kang Hongwei Yang Junqing Li Youping Chen 《Environmental science and pollution research international》2013,20(9):6290-6296
Conservation of surrogate species is expected to benefit co-occurring species with similar distributions that share the same habitat, yet the usefulness of this approach to protect nontarget species has been extensively challenged. In this study, we aimed to assess whether co-occurring species could be afforded protection under the conservation of two proposed surrogate species, the giant panda and the takin. We undertook a thorough study on the habitat requirements of these two endangered species, based on the analysis of their habitat preferences. The results revealed that the giant panda exhibits more specialized habitat preferences than does the takin and that habitat separation between these species mainly reflected differences in their dietary requirements and preferences. We suggest that these differences might facilitate their coexistence in sympatric areas. Meanwhile, results of a discriminant function analysis showed that protection of giant pandas would protect 82.1 % of the panda’s habitat, but only 25.4 % of the takin’s habitat and just 57.0 % of the joint habitats of these species. Importantly, our results also showed that a joint surrogate species approach to conservation would protect 86.9 % of the panda’s habitat, 53.7 % of the takin’s habitat, and 72.2 % of the joint habitats of these species. This is a higher degree of habitat protection than the single surrogate conservation of pandas. We conclude that the joint surrogate species approach should be adopted to improve biodiversity conservation. 相似文献
772.
Xin Zhou Xiaoya Ren Yu Chen Haopeng Feng Jiangfang Yu Kang Peng Yuying Zhang Wenhao Chen Jing Tang Jiajia Wang Lin Tang 《Frontiers of Environmental Science & Engineering》2023,17(3):29
773.
This study examined the mediating influence of protege‐initiated mentoring relationships on the relationship between personality and situational characteristics and mentoring received. Data were obtained from Hong Kong Chinese graduate employees (N=184) in their early career stage. Results of the regression analysis showed that protege‐initiated mentoring relationships mediated the relationship between the personality (extraversion) but not the situational (individual development culture and opportunities for interactions on the job) characteristics and mentoring received. In other words, extraversion was indirectly related to mentoring received through protege‐initiated mentoring relationships but individual development culture and opportunities for interactions on the job were directly related to mentoring received. Additionally, opportunities for interactions on the job indirectly influenced mentoring received through protege‐initiated mentoring relationships. Limitations of the study, implications of the findings and directions for future research are discussed. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
774.
775.
Zhiyuan Cong Shichang Kang Shuping Dong Xiande Liu Dahe Qin 《Environmental monitoring and assessment》2010,160(1-4):323-335
Atmospheric aerosols were collected during the scientific expedition to Mt. Qomolangma (Everest) in May–June, 2005. The elemental concentrations of the aerosols were determined by inductively coupled plasma mass spectrometry. This yielded data for the concentration of 14 elements: Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, and Pb. The mean elemental concentrations were generally comparable with those from central Asia and the Arctic, while much higher than those from Antarctic. Size, morphology, and chemical composition of 900 individual aerosol particles were determined by scanning electron microscopy and energy-dispersive X-ray microanalysis. Based on morphology and elemental composition, the particles were clustered into eight groups: soot (8%), tar ball (3%), alumosilicates/silica (55%), calcium sulfate (16%), Ca/Mg carbonate (2%), Fe/Ti-rich particles (3%), Pb-rich particles (1%), and biological particles (12%). The sampling site, located at 6,520 m in the Himalayas, is particularly remote and located at high altitude. Nonetheless, high aerosol enrichment factors for copper, chromium, lead, nickel, vanadium, and zinc all suggest the influence of long-range transported pollution, while enrichment in calcium and the presence of alumino-silicates in individual particle analyses indicates a distinct mineral dust influence. The backward air mass trajectories showed that the northwestern part of India may contribute to the atmospheric aerosol in the central high Himalayas. 相似文献
776.
为使注册安全工程师行业在初始阶段就纳入科学的管理,通过对注册安全工程师行业监管模式的探讨,在分析注册安全工程师执业资格制度基本特点及注册安全工程师执业定位的基础上,参照国外的发达国家和我国目前注册安全工程师发展现状,提出了3种监管模式,即政府监管模式、行业自律监管模式和政府监管与行业自律结合的监管模式。并且通过运用建立数学模型的方法和规律性分析,比较了3种不同的注册安全工程师行业监管模式效力的异同和利弊,最终得出应采用政府监管与自律监管结合模式的结论。并对完善和规范注册安全工程师执业资格制度方面进行了探讨。 相似文献
777.
778.
注册安全工程师执业资格制度是在市场经济条件下,加强企业安全与卫生工作的一项重要管理制度。我国注册安全工程师制度刚刚兴起,一个高效的行业监管模式尚未建立起来,因此有必要对这一新兴行业的监管开展先行研究。目前,国际上通行的注册安全工程师行业监管模式主要有行业自律和政府监管两种,并呈现出逐步向独立监管方向发展的趋势。不同监管模式具有不同的优缺点和不同的适应条件,中国注册安全工程师行业的监管既应借鉴国际先进经验,又必须着眼于中国的实际情况,分别从短期、中期和长期的综合监管绩效考虑,采纳混合监管模式不失为一种现实可行的抉择。 相似文献
779.
780.
通过对汶川8.0级地震发生后西安、成都地区(地震烈度为Ⅵ~Ⅶ度区)的高层建筑震害调查,以某小区震后建筑物非承重墙体裂缝为实例,给出了高层建筑震害易发生的部位和楼层,分析了非承重墙体裂缝产生的原因。震害调查表明:汶川地震中,在抗震设防烈度为Ⅵ~Ⅷ度区,当地震烈度为Ⅵ~Ⅶ度时,非承重墙抗震性能的表现不尽如人意。提出了应对非承重墙体制定设防目标,且非承重结构构件的抗震设防目标应与主体结构设防目标相适应,使建筑结构设计,对非承重墙的抗震设防有据可依,使灾后有可能对设计与施工的质量进行评估,通过有区别地加强非承重墙的抗震构造措施,减小建筑物的震害损失。 相似文献