全文获取类型
收费全文 | 28153篇 |
免费 | 4848篇 |
国内免费 | 29779篇 |
专业分类
安全科学 | 2431篇 |
废物处理 | 1461篇 |
环保管理 | 2338篇 |
综合类 | 37674篇 |
基础理论 | 4922篇 |
环境理论 | 9篇 |
污染及防治 | 10103篇 |
评价与监测 | 2046篇 |
社会与环境 | 735篇 |
灾害及防治 | 1061篇 |
出版年
2024年 | 7篇 |
2023年 | 306篇 |
2022年 | 916篇 |
2021年 | 748篇 |
2020年 | 1162篇 |
2019年 | 2382篇 |
2018年 | 2679篇 |
2017年 | 2827篇 |
2016年 | 2540篇 |
2015年 | 3094篇 |
2014年 | 3892篇 |
2013年 | 4491篇 |
2012年 | 3995篇 |
2011年 | 3805篇 |
2010年 | 3224篇 |
2009年 | 3307篇 |
2008年 | 3105篇 |
2007年 | 2806篇 |
2006年 | 2329篇 |
2005年 | 1751篇 |
2004年 | 1469篇 |
2003年 | 1312篇 |
2002年 | 1131篇 |
2001年 | 1051篇 |
2000年 | 1209篇 |
1999年 | 1143篇 |
1998年 | 879篇 |
1997年 | 843篇 |
1996年 | 838篇 |
1995年 | 735篇 |
1994年 | 502篇 |
1993年 | 423篇 |
1992年 | 418篇 |
1991年 | 353篇 |
1990年 | 280篇 |
1989年 | 231篇 |
1988年 | 164篇 |
1987年 | 82篇 |
1986年 | 85篇 |
1985年 | 56篇 |
1984年 | 58篇 |
1983年 | 44篇 |
1982年 | 47篇 |
1981年 | 35篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1972年 | 7篇 |
1971年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 406 毫秒
21.
Zhang Jing Feng Zhiming Yang Yanzhao 《中国人口.资源与环境(英文版)》2006,4(2):33-40
The article puts forward the process and means of regional water and land balance research, and then from two scenarios which are the balances under natural regulation and human intervention, calculated and analysed the balance between water and land on Ningxia Plain. For the balance under natural regulation named farmland water balance, using farmland water resource balance equation, the research estimated the monthly farmland" water balance of 8 major crops for all of the 12 counties on Ningxia Plain in the period of 1960-2001; for the balance under human intervention, the research estimated land-use water balance equation of the counties in 2000, and calculated the balance between land use and water resources including irrigating water of all the 12 counties on Ningxia Plain. Results showed that ①precipitation can not meet the water demand of the crops for growth and development on Ningxia Plain, and water shortage is the primary character of farmland water balance under natural regulation. ②the diversity of water and land balance of different counties is distinctly influenced by the crop structure, water quantity for irrigation and irrigation level. ③Irrigation water could meet the crop water demand on Ningxia Plain in 2000, but there was not much space to expand irrigating cultivated land. 相似文献
22.
长江中游平原湖区农业开发地域分工与农产品专业化生产研究 总被引:6,自引:1,他引:5
农业生产地域分工与农产品专业化生产是使农业从自然经济阶段向以市场为导向的商品农产品生产转变的一个标志。本文在分析该区农业布局现状及其存在问题的基础上,提出了农业总体布局的设想与不同类型地域农业开发的主攻方向与对策,并对市场经济体制下粮食、棉花、猪、禽、水产品等农产品生产基地的地域选择、建设规模与技术措施等进行了探讨。 相似文献
23.
Dynamics and Causation of Environmental Equity, Locally Unwanted Land Uses, and Neighborhood Changes
Feng Liu 《Environmental management》1997,21(5):643-656
/ Why are some environmental risks distributed disproportionately in the neighborhoods of the minorities and the poor? A hypothesis was proposed in a recent study that market dynamics contributed to the current environmental inequity. That is, locally unwanted land uses (LULUs) make the host communities home to more poor people and people of color. This hypothesis was allegedly supported by a Houston case study, whereby its author analyzed the postsiting changes of the socioeconomic characteristics of the neighborhoods surrounding solid waste facilities. I argue that such an analysis of postsiting changes alone is insufficient to test the causation hypothesis. Instead, I propose a conceptual framework for analysis of environmental equity dynamics and causation. I suggest that the presiting neighborhood dynamics and the characteristics of control neighborhoods be analyzed as the first test for the causation hypothesis. Furthermore, I present theories of neighborhood change and then examine alternative hypotheses that these theories offer for explaining neighborhood changes and for the roles of LULUs in neighborhood changes. These alternative hypotheses should be examined when analyzing the relationship between LULUs and neighborhood changes in a metropolitan area. Using this framework of analysis, I revisited the Houston case. First, I found no evidence that provided support for the hypothesis that the presence of LULUs made the neighborhoods home to more blacks and poor people, contrary to the conclusion made by the previous study. Second, I examined alternative hypotheses for explaining neighborhood changes-invasion-succession, other push forces, and neighborhood life-cycle; the former two might offer better explanation.KEY WORDS: Environmental equity and justice; Locally unwanted lane uses; Siting; Market dynamics; Invasion-succession; Neighborhood changes 相似文献
24.
Lei Jun & Zhang Xiaolei Xinjiang Institute of Ecology Geography Chinese Academy of Sciences Urumqi China Institute of Geography Science Natural Resources Research Chinese Academy of Sciences Beijing .China 《中国人口.资源与环境(英文版)》2005,3(3)
As a special basic economic region in China, Xinjiang is situated in the arid area in the Northwest China. Oasis agriculture is the basis of the national economy. The development of oasis agriculture helps to accelerate the development of economy, social and environment. After 50 years of practice, from 1949 to 2002, oasis agriculture in Xinjiang enhanced rapidly the scale of agricultural industry and had great changes in its structure. The amount of cultivated area rose from 120.97*102 ha t… 相似文献
25.
关中地区飑线天气的预测及灾害对策探讨 总被引:1,自引:0,他引:1
对1961~1990年发生在陕西省关中地区的飑线天气及其灾害进行了统计分析,并从天气形势背景方面对飑线的发生发展进行了研究和分析,同时就飑线的预测和防灾对策进行了探讨。 相似文献
26.
Zhang Yuqing Zhan Chengcheng Wang Hui Gao Ya 《Environment, Development and Sustainability》2022,24(8):9777-9808
Environment, Development and Sustainability - This study analyzes the evolution of the land use structure, demographic reconstruction, and social reconstruction of Dachangshan Island, Changhai... 相似文献
27.
Jiao Youzhou Xue Huizan He Chao Wang Zigang Ma Xiaoran Liu Xinxin Liu Liang Chang Chun Petracchini Francesco Li Panpan 《Environment, Development and Sustainability》2022,24(4):4709-4726
Environment, Development and Sustainability - Anaerobic digestion (AD) is an attractive straw resource treatment technology as it can improve the utilization efficiency of straw resource. Raw straw... 相似文献
28.
Feng Jingchun Tang YunQing Xue Song Zhang Ke 《Environment, Development and Sustainability》2022,24(1):138-155
Environment, Development and Sustainability - The PPP mode of rural water environment governance was conducive to attracting social capital for giving full play to the decisive role of the market... 相似文献
29.
30.
Russian Journal of Ecology - The aim of this study is to explore the effects of the litter cover thickness and cleaning methods on seed germination and seedling growth of Pinus densata. The overall... 相似文献