全文获取类型
收费全文 | 29118篇 |
免费 | 204篇 |
国内免费 | 233篇 |
专业分类
安全科学 | 647篇 |
废物处理 | 1194篇 |
环保管理 | 3689篇 |
综合类 | 5456篇 |
基础理论 | 7763篇 |
环境理论 | 13篇 |
污染及防治 | 6611篇 |
评价与监测 | 2009篇 |
社会与环境 | 2024篇 |
灾害及防治 | 149篇 |
出版年
2022年 | 222篇 |
2021年 | 196篇 |
2019年 | 179篇 |
2018年 | 816篇 |
2017年 | 778篇 |
2016年 | 886篇 |
2015年 | 431篇 |
2014年 | 626篇 |
2013年 | 1779篇 |
2012年 | 938篇 |
2011年 | 1666篇 |
2010年 | 1162篇 |
2009年 | 1339篇 |
2008年 | 1523篇 |
2007年 | 1762篇 |
2006年 | 924篇 |
2005年 | 917篇 |
2004年 | 773篇 |
2003年 | 855篇 |
2002年 | 842篇 |
2001年 | 1002篇 |
2000年 | 679篇 |
1999年 | 438篇 |
1998年 | 279篇 |
1997年 | 299篇 |
1996年 | 313篇 |
1995年 | 353篇 |
1994年 | 345篇 |
1993年 | 275篇 |
1992年 | 274篇 |
1991年 | 318篇 |
1990年 | 300篇 |
1989年 | 281篇 |
1988年 | 256篇 |
1987年 | 199篇 |
1986年 | 225篇 |
1985年 | 207篇 |
1984年 | 226篇 |
1983年 | 216篇 |
1982年 | 225篇 |
1981年 | 214篇 |
1980年 | 171篇 |
1979年 | 199篇 |
1978年 | 163篇 |
1977年 | 150篇 |
1976年 | 149篇 |
1974年 | 160篇 |
1973年 | 146篇 |
1972年 | 146篇 |
1967年 | 154篇 |
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
61.
The components of an environmental decision support system (EDSS) were outlined in Part 1 of this paper. Here, an example application is given using a range of data from the database in order to assess the utility of one specific model chosen from the modelbase: the one-dimensional thermal stratification model, EDD1. The model is applied to a range of lake types worldwide. 相似文献
62.
63.
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
64.
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
65.
Although stewardship has been widely defined and used in environmental management and planning, there is a dearth of studies
that describe how the lay public perceives this concept. A national sample of residents in 14 states who live near DOE nuclear
facilities were interviewed to delineate public understanding and awareness of the stewardship program of the U.S. Department
of Energy (DOE). This study discusses the findings of the survey and discusses how institutional trust influences public participation
and resident’s choices of potential stewards. Almost 40% of the respondents could not define stewardship; those who did, believed
that ‘responsibility,’ ‘management,’ and ‘accountability’ are key elements of stewardship. In addition, about a third of the
respondents identified Federal groups and the DOE as potential stewards.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue 相似文献
66.
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
67.
S. Savas S. Eraslan S. Kantarci B. Karaman D. Acarsoz T. Tükel O. Cogulu F. Ozkinay S. Basaran K. Aydınlı M. Yuksel-Apak B. Kirdar 《黑龙江环境通报》2002,22(8):703-709
Childhood-onset spinal muscular atrophy (SMA) is one of the most common neurodegenerative genetic disorders. SMN1 is the SMA-determining gene deleted or mutated in the majority of SMA cases. There is no effective cure or treatment for this disease yet. Thus, the availability of prenatal testing is important. Here we report prenatal prediction for 68 fetuses in 63 Turkish SMA families using direct deletion analysis of the SMN1 gene by restriction digestion. The genotype of the index case was known in 40 families (Group A) but unknown in the remaining 23 families (Group B). A total of ten fetuses were predicted to be affected. Eight of these fetuses were derived from Group A and two of these fetuses were from Group B families. Two fetuses from the same family in Group A had the SMNhyb1 gene in addition to homozygous deletion of the NAIP gene. One fetus from Group A was homozygously deleted for only exon 8 of the SMN2 gene, and further analysis showed the presence of both the SMN1 and SMNhyb1 genes but not the SMN2 gene. In addition, one carrier with a homozygous deletion of only exon 8 of the SMN1 gene was detected to have a SMNhyb2 gene, which was also found in the fetus. To our knowledge, these are the first prenatal cases with SMNhyb genes. Follow-up studies demonstrated that the prenatal predictions and the phenotype of the fetuses correlated well in 33 type I pregnancies demonstrating that a careful molecular analysis of the SMN genes is very useful in predicting the phenotype of the fetus in families at risk for SMA. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
68.
Environmental factors have long been shown to influence species distributions, with range limits often resulting from environmental
stressors exceeding organism tolerances. However, these abiotic factors may differentially affect species with multiple life-history
stages. Between September 2004 and January 2006, the roles of temperature and nutrient availability in explaining the southern
distributions of two understory kelps, Pterygophora californica and Eisenia arborea (Phaeophyceae, Laminariales), were investigated along the coast of California, USA and the Baja California Peninsula, Mexico,
by limiting either: (a) tissue nitrogen uptake and storage by adult sporophytes during periods of elevated temperature, and/or
(b) production of embryonic sporophytes by microscopic gametophytes. Results suggest that while adult sporophytes of both
species are tolerant of high temperatures and low nutrients, reproduction by their microscopic stages is not. Specifically,
while E. arborea produced embryonic sporophytes at both 12 and 18°C, temperatures commonly observed throughout the southern portion of its
range, P. californica produced sporophytes at 12 but not at 18°C. As a result, it appears that the southern distribution of P. californica, which ends in northern Baja California, Mexico, may be limited by temperature acting on its microscopic stages. In contrast,
the ability of E. arborea’s microscopic and adult stages to tolerate elevated temperatures allows it to persist in the warmer southern waters of Baja
California, as well as to the north along the California coast where both species co-occur. 相似文献
69.
Tone River supplies most of the water requirements of the Tokyo Metropolitan Area (TMA). Lowering of Tone flow and yearly
fluctuation, however, is causing water shortage along TMA nowadays. This study investigated the future water availability
scenarios under climatic changes. A state-of-the-art approach to utilize the output of several GCM has been demonstrated to
investigate the future water availability scenarios for TMA from the Tone River. An integrated modeling approach for water
balance considering several hydrological risk indices was adopted to quantify the future changes in this case. It is observed
that the future summer precipitation along the Tone basin is going to be increased considerably, while an almost constant
or decreasing trend is observed for winter season. Natural flow availability for winter or spring seasons thus can be crucial
under future scenarios. After reservoir routing, the hydrological risk indices estimated, however, were not found to be changed
significantly due to the presence of a robust reservoir system at the upstream. 相似文献
70.
E. A. Kleshcheva 《Russian Journal of Ecology》2007,38(2):94-100
A method for estimating the current state of plant communities based on the ecological amplitudes of constituent species is proposed. An original program, Fitoindikatsiya, has been developed to compute the indices of disturbance and homogeneity of plant communities from species ecological scale values. The current state of pine forests in the part of Novosibirsk oblast east of the Ob River has been analyzed; slightly, moderately, and severely disturbed zones have been distinguished. 相似文献