全文获取类型
收费全文 | 8190篇 |
免费 | 90篇 |
国内免费 | 247篇 |
专业分类
安全科学 | 162篇 |
废物处理 | 408篇 |
环保管理 | 926篇 |
综合类 | 1373篇 |
基础理论 | 2010篇 |
污染及防治 | 2029篇 |
评价与监测 | 611篇 |
社会与环境 | 959篇 |
灾害及防治 | 49篇 |
出版年
2023年 | 60篇 |
2022年 | 132篇 |
2021年 | 106篇 |
2020年 | 68篇 |
2019年 | 101篇 |
2018年 | 146篇 |
2017年 | 155篇 |
2016年 | 214篇 |
2015年 | 161篇 |
2014年 | 265篇 |
2013年 | 707篇 |
2012年 | 286篇 |
2011年 | 381篇 |
2010年 | 316篇 |
2009年 | 349篇 |
2008年 | 400篇 |
2007年 | 409篇 |
2006年 | 314篇 |
2005年 | 297篇 |
2004年 | 293篇 |
2003年 | 282篇 |
2002年 | 275篇 |
2001年 | 346篇 |
2000年 | 218篇 |
1999年 | 118篇 |
1998年 | 87篇 |
1997年 | 85篇 |
1996年 | 107篇 |
1995年 | 127篇 |
1994年 | 97篇 |
1993年 | 86篇 |
1992年 | 90篇 |
1991年 | 92篇 |
1990年 | 80篇 |
1989年 | 71篇 |
1988年 | 71篇 |
1987年 | 75篇 |
1986年 | 52篇 |
1985年 | 64篇 |
1984年 | 63篇 |
1983年 | 59篇 |
1982年 | 58篇 |
1981年 | 66篇 |
1980年 | 47篇 |
1979年 | 46篇 |
1977年 | 38篇 |
1976年 | 37篇 |
1974年 | 34篇 |
1973年 | 44篇 |
1972年 | 51篇 |
排序方式: 共有8527条查询结果,搜索用时 15 毫秒
21.
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
22.
Changes in the survival parameters of the red fox were analyzed at different phases of the population cycle. It was found that the survival rate in all age classes, including newborns, drastically increased at the phase of population growth. The relationship between the general mortality rate and population size was determined. A hypothesis concerning the mechanism of these changes in the general mortality rate is suggested. 相似文献
23.
Long-term stationary studies on the ecology of the northern mole vole (Ellobius talpinus Pall.), performed by the mark–recapture method from 1985 to 1997, have provided original data on population dynamics and structure. The analysis shows that, to reveal cyclic fluctuations of population size in this species, the period of three years should be taken as a unit of time for estimating the duration of one phase. The 12-year population cycle in E. talpinus has four distinct phases: an increase, a peak, a decline, and a minimum. At each phase, the population is characterized by certain features of family structure, age composition, birth and death rates, and the composition of migrants. 相似文献
24.
V. I. Kolmakov N. A. Gaevskii E. A. Ivanova O. P. Dubovskaya I. V. Gribovskaya E. S. Kravchuk 《Russian Journal of Ecology》2002,33(2):97-103
In the periods of summer and autumn bloom of the Stephanodiscus hantzschii Crun. in recreational water bodies, studies on the vertical distribution of chlorophyll a, its contents per unit biomass, efficiency in using photosynthetically active radiation (EPhAR), and assimilative activity of microalgae were performed. The results confirmed the existence of two ecophysiological forms of St. hantzschii and provided evidence that both forms are typically autotrophic and can efficiently use low-intensity PhAR for photosynthesis. 相似文献
25.
Methodological Basis of Ecological Safety Standards for the Technogenic Impact of Mineral Resource Exploitation 总被引:1,自引:0,他引:1
A new methodological approach to the development of biological and technological safety standards for the impact of underground mining on the natural biota is proposed. 相似文献
26.
N. P. Kosykh N. P. Mironycheva-Tokareva A. M. Peregon E. K. Parshina 《Russian Journal of Ecology》2008,39(7):466-474
New experimental data on biological productivity of plant communities in oligotrophic and mesotrophic bogs of the middle taiga
subzone over the past five years are presented. The relationship between net primary production and the stock of live phytomass
is estimated. The stock of necromass in oligotrophic bog ecosystems increases from west to east, while the stock of live phytomass
and net primary production decrease. 相似文献
27.
N. O. Kin 《Russian Journal of Ecology》2008,39(4):254-260
Heavy metal accumulation by plant communities has been studied in different zones of impact of gas field development. The contents of heavy metals in different blocks of plant communities has proved to depend not only on the location of phytocenosis but also on its species composition. Communities dominated by species of the family Poaceae contain smaller amounts of heavy metals than those dominated by species of the family Asteraceae, especially of the genus Artemisia. The order of precedence in the accumulation of heavy metals in different blocks of plant communities has been revealed. 相似文献
28.
Studies on paleosols under an archaeological landmark of a rare type (a complex of kurgans with “whiskers”) dating from the Early Iron Age (the fourth century AD) have been performed in the steppe zone of the Transural Plateau. The size and shape of third-order soil polygons under stony ridges (“whiskers”) between the kurgans have been described in detail. The results have shown that the paleosol under the kurgans erected at the turn of the Late Sarmatian and Hun times (1600 years ago) is characterized by a higher humus content and deeper location of the carbonate horizon, compared to the recent soil. This indicates that an increase in atmospheric humidity took place in the fourth century AD. 相似文献
29.
A. Migné D. Davoult N. Spilmont D. Menu G. Boucher J.-P. Gattuso H. Rybarczyk 《Marine Biology》2002,140(4):865-869
This paper describes a closed-chamber method for measuring CO2 fluxes in intertidal soft sediments during periods of emersion. The method relies on closed-circuit incubations of undisturbed sediment and measurement of CO2 exchanges using an infrared gas analyser. The method was assessed during field experiments, both in light and dark conditions, on an exposed sandy beach and in an estuary. The rates of gross community production measured under moderate irradiance (4.2 mg C m-2 h-1 on the exposed sandy beach and 35 mg C m-2 h-1 in the estuary) are in good agreement with rates reported in the literature. In conjunction with appropriate sampling strategies, this method can be useful for estimating and comparing production of intertidal areas or for assessing factors that influence production. 相似文献
30.
Hiroshi Yamamoto Yudai Nakamura Yuki Nakamura Chise Kitani Tetsuya Imari Jun Sekizawa Yuji Takao Naoyuki Yamashita Narisato Hirai Shigeto Oda Norihisa Tatarazako 《Environmental sciences》2007,14(4):177-193
Eight pharmaceuticals were selected on the basis of their domestic consumption in Japan, the excretion ratio of the parent compound and the frequency of detection in the aquatic environment or wastewater treatment plant effluent. Toxicity tests on these pharmaceuticals were conducted using Japanese medaka (Oryzias latipes), daphnia (Daphnia magna), and green algae (Psuedokirchneriella subcapitata). Predicted no effect concentration (PNEC) was calculated using lethal or effect concentration 50 (LC50 or EC50) values and no effect concentration (NOEC) obtained in the toxicity tests for these compounds. Predicted environmental concentration (PEC) was also calculated from annual consumption, the excretion rate of the parent compound, and removal rate in the preliminary batch activated sludge treatment performed in this study. Maximum concentrations found in the aquatic environment or sewage effluent in Japan or foreign countries were also used for another calculation of PEC. Initial risk assessment on the selected pharmaceuticals was performed using the PEC/PNEC ratio. The results of initial risk assessment on the eight selected pharmaceuticals suggest neither urgent nor severe concern for the ecological risk of these compounds, but further study needs to be conducted using chronic toxicity tests, including reproduction inhibition and endocrine disruption assessments. 相似文献