全文获取类型
收费全文 | 23007篇 |
免费 | 353篇 |
国内免费 | 375篇 |
专业分类
安全科学 | 836篇 |
废物处理 | 1028篇 |
环保管理 | 3413篇 |
综合类 | 3591篇 |
基础理论 | 6463篇 |
环境理论 | 11篇 |
污染及防治 | 5606篇 |
评价与监测 | 1342篇 |
社会与环境 | 1284篇 |
灾害及防治 | 161篇 |
出版年
2023年 | 98篇 |
2022年 | 188篇 |
2021年 | 199篇 |
2020年 | 208篇 |
2019年 | 174篇 |
2018年 | 454篇 |
2017年 | 428篇 |
2016年 | 655篇 |
2015年 | 432篇 |
2014年 | 529篇 |
2013年 | 1641篇 |
2012年 | 1093篇 |
2011年 | 1226篇 |
2010年 | 801篇 |
2009年 | 917篇 |
2008年 | 984篇 |
2007年 | 1063篇 |
2006年 | 900篇 |
2005年 | 1204篇 |
2004年 | 1360篇 |
2003年 | 1183篇 |
2002年 | 644篇 |
2001年 | 729篇 |
2000年 | 585篇 |
1999年 | 379篇 |
1998年 | 248篇 |
1997年 | 268篇 |
1996年 | 253篇 |
1995年 | 299篇 |
1994年 | 243篇 |
1993年 | 239篇 |
1992年 | 196篇 |
1991年 | 211篇 |
1990年 | 191篇 |
1989年 | 194篇 |
1988年 | 167篇 |
1987年 | 152篇 |
1986年 | 168篇 |
1985年 | 162篇 |
1984年 | 203篇 |
1983年 | 166篇 |
1982年 | 187篇 |
1981年 | 183篇 |
1980年 | 142篇 |
1979年 | 158篇 |
1978年 | 100篇 |
1977年 | 105篇 |
1975年 | 91篇 |
1974年 | 100篇 |
1972年 | 103篇 |
排序方式: 共有10000条查询结果,搜索用时 968 毫秒
31.
Yaping Zhong Michael R. Overcash Arnold L. McPeters 《Environmental geochemistry and health》1994,16(3-4):235-240
Studies were conducted to understand 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) behaviour in the near surface zone in relation to the operating conditions: UV-intensity, temperature and exposure modes. Comparisons have been made between Oriel lamp exposure tests and sunlight exposure tests. Under Oriel lamp exposure, the convective transport of TCDD, which depends on operating temperature, was the limiting factor in the cleanup process. The product differences between Oriel exposure tests and sunlight exposure tests probably result from the difference of UV-intensities. 相似文献
32.
33.
34.
This work, carried out within the framework of the PRISMA II project, aims at evaluating the effects of the Po River flow on primary productivity, measured by C with in situ sample incubations. A total of four cruises was carried out in late winter and early summer (1996-1998) along transects from the coast offshore. In both seasons, the highest primary productivity was found in the most oligohaline stations. The effects of the Po River inputs were therefore clearly evident in the westernmost area, both in high productivity values and in the shape of productivity profiles. In late winter, extensive blooms of Skeletonema costatum and Pseudo-nitzschia delicatissima resulted in productivity values that were sometimes higher than in early summer. In early summer 1996, greatly reduced river flow clearly influenced productivity which was much lower than in 1997. 相似文献
35.
36.
Although many conventional physical remediation methods are viewed as proven, they often only relocate wastes to other sites or into the air. How do the emerging biological and chemical in situ methods perform in the same applications? This article reviews their results (much of it in the laboratory) as well as their promise of more complete neutralization of hazardous wastes, lower capital costs, and longer-duration cleanup processes. The optimal method may be a combination of chemical and biological in situ techniques with physical pump-and-treat methods. 相似文献
37.
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
38.
N. L. Ivanova 《Russian Journal of Ecology》2002,33(2):125-129
Environmental conditions in cooling ponds of thermal power plants are favorable for marsh frogs. Their populations inhabiting Verkhne-Tagil and Reftinskoe reservoirs differ in some traits, such as size and age composition, growth rate after metamorphosis, spawning type, fecundity, and characteristics of larval development. Differentiation in body size manifests itself at the early stages of terrestrial life and progresses at later stages. As a consequence, larger individuals may reach maturity and participate in reproduction at an earlier age. 相似文献
39.
40.
On-going population growth and resulting domestic demand for water require rapid and effective decision-making as regards groundwater management and control of the various sources of salinization and pollution in Coastal aquifers. Sustainability of water resources for utilization by future generations must therefore be a high priority, not only for the purpose of fulfilling needs for water usage but also for bringing people into harmony with their ambient natural environment.The objective of this paper is to propose an empirical approach for prioritization of the needs involved for sustainable aquifer management. The approach involves a schematic format to:(1) develop a global understanding of an aquifer's hydrological and environmental properties in order to delineate appropriate eco-hydrological scenarios and recommend corresponding operational management activities; and(2) emphasize the importance of educating and increasing the awareness of the population involved as to the need for and viability of socially acceptable measures for sustainable management of groundwater and other resources.The psychologist Abraham Maslow utilized a pyramid to illustrate that until people's most basic needs were fulfilled, higher levels of needs would remain irrelevant. This paper postulates a comparable pyramid prioritizing hydrological needs required for progressing towards sustainable groundwater resources. Two sub-regions of Israel's Coastal aquifer in the Sharon region have been presented as representative areas, each characterized by different stress of exploitation. In assessing these sub-regions situation, specific measures have been recommended for achieving and/or maintaining sustainable groundwater resources in light of the ambient environment, and the level of the population on the pyramidal hierarchy of groundwater needs. 相似文献