全文获取类型
收费全文 | 95466篇 |
免费 | 1232篇 |
国内免费 | 1166篇 |
专业分类
安全科学 | 3861篇 |
废物处理 | 3530篇 |
环保管理 | 14421篇 |
综合类 | 21410篇 |
基础理论 | 27023篇 |
环境理论 | 76篇 |
污染及防治 | 16979篇 |
评价与监测 | 5799篇 |
社会与环境 | 4169篇 |
灾害及防治 | 596篇 |
出版年
2022年 | 833篇 |
2021年 | 845篇 |
2020年 | 671篇 |
2019年 | 889篇 |
2018年 | 1266篇 |
2017年 | 1271篇 |
2016年 | 2257篇 |
2015年 | 1868篇 |
2014年 | 2618篇 |
2013年 | 9299篇 |
2012年 | 2502篇 |
2011年 | 2867篇 |
2010年 | 3415篇 |
2009年 | 3513篇 |
2008年 | 2403篇 |
2007年 | 2300篇 |
2006年 | 2597篇 |
2005年 | 2514篇 |
2004年 | 2775篇 |
2003年 | 2653篇 |
2002年 | 2216篇 |
2001年 | 2665篇 |
2000年 | 2202篇 |
1999年 | 1607篇 |
1998年 | 1416篇 |
1997年 | 1392篇 |
1996年 | 1516篇 |
1995年 | 1608篇 |
1994年 | 1504篇 |
1993年 | 1358篇 |
1992年 | 1363篇 |
1991年 | 1323篇 |
1990年 | 1278篇 |
1989年 | 1241篇 |
1988年 | 1065篇 |
1987年 | 1006篇 |
1986年 | 1002篇 |
1985年 | 1072篇 |
1984年 | 1167篇 |
1983年 | 1174篇 |
1982年 | 1179篇 |
1981年 | 1105篇 |
1980年 | 947篇 |
1979年 | 939篇 |
1978年 | 827篇 |
1977年 | 725篇 |
1976年 | 643篇 |
1975年 | 622篇 |
1973年 | 647篇 |
1972年 | 643篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
The occurrence and impact of psychological contract violations were studied among graduate management alumni (N = 128) who were surveyed twice, once at graduation (immediately following recruitment) and then two years later. Psychological contracts, reciprocal obligations in employment developed during and after recruitment, were reported by a majority of respondents (54.8 per cent) as having been violated by their employers. The impact of violations are examined using both quantitative and qualitative data. Occurrence of violations correlated positively with turnover and negatively with trust, satisfaction and intentions to remain. 相似文献
52.
53.
54.
55.
56.
Pyrite ash is created as waste from the roasting of pyrite ores during the production of sulphuric acid. These processes generate great amounts of pyrite ash waste that is generally land filled. This creates serious environmental pollution due to the release of acids and toxic substances. Pyrite ash waste can be utilized in the iron production industry as a blast furnace feed to process this waste and prevent environmental pollution. The essential parameters affecting the pelletization process of pyrite ash were studied using bentonite as a binder. Experiments were then carried out using bentonite and a mixture of bentonite with calcium hydroxide and calcium chloride in order to make the bentonite more effective. The metallurgical properties of pyrite ash, bentonite, calcium hydroxide, calcium chloride, a mixture of these and sintered pellets were studied using X-ray analysis. The crushing strength tests were carried out to investigate the strength of pyrite ash waste pellets. The results of these analyses showed that pyrite ash can be agglomerated to pellets and used in the iron production industry as a blast furnace feed. The crushing strength of the pellets containing calcium hydroxide and calcium chloride in addition to bentonite was better than the strength of pellets prepared using only bentonite binder. 相似文献
57.
58.
59.
Critical loads offer a unique way of evaluating impacts of acid deposition by quantifying environmental sensitivity. The critical loads of acidity for UK peat soils have been based upon an arbitrary reduction in pH of 0.2 units. This chemical shift needs to be better related to adverse effects on sensitive biological receptors. It is known that effective precipitation pH equates closely to soil solution pH, and the latter is directly linkable to biotic effects of pH change. On continuation of a long-term experiment assessing impacts of simulated acid rain on peat microcosms in a realistic outdoor environment, Calluna vulgaris continued to flourish at acid deposition loads well above the existing critical load. Calluna plants were harvested and analysed, and acid deposition treatments to the microcosms continued to allow natural vegetation to regenerate. A diverse mixture of moorland plants and bryophytes established at acidity treatments well above the existing critical load, and only a very high acid load resulted in no natural regeneration. A critical effective rain pH value of 3.6 is suggested as a basis for setting critical loads. At this pH, Calluna grows well, and a healthy diverse vegetation community re-establishes when harvested. It is suggested that the peat critical load should be set at the acid load that, at any specific site, would result in a mean effective precipitation pH of 3.6. 相似文献
60.