全文获取类型
收费全文 | 237篇 |
免费 | 0篇 |
国内免费 | 6篇 |
专业分类
安全科学 | 15篇 |
废物处理 | 8篇 |
环保管理 | 25篇 |
综合类 | 77篇 |
基础理论 | 42篇 |
环境理论 | 2篇 |
污染及防治 | 61篇 |
评价与监测 | 7篇 |
社会与环境 | 5篇 |
灾害及防治 | 1篇 |
出版年
2021年 | 5篇 |
2020年 | 5篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2015年 | 2篇 |
2014年 | 3篇 |
2013年 | 12篇 |
2012年 | 10篇 |
2011年 | 6篇 |
2010年 | 5篇 |
2009年 | 15篇 |
2008年 | 11篇 |
2007年 | 15篇 |
2006年 | 9篇 |
2005年 | 3篇 |
2004年 | 26篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 5篇 |
2000年 | 6篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1987年 | 2篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1970年 | 2篇 |
1967年 | 3篇 |
1966年 | 4篇 |
1965年 | 5篇 |
1962年 | 2篇 |
1961年 | 1篇 |
1960年 | 2篇 |
1959年 | 3篇 |
1958年 | 2篇 |
1957年 | 7篇 |
1956年 | 2篇 |
1955年 | 1篇 |
1954年 | 3篇 |
1952年 | 2篇 |
1946年 | 1篇 |
1944年 | 1篇 |
1931年 | 1篇 |
1928年 | 1篇 |
1926年 | 1篇 |
排序方式: 共有243条查询结果,搜索用时 15 毫秒
141.
The application of stable hydrogen isotope (deltaD) techniques has swiftly advanced our understanding of animal movements, but this progression is dominated by studies of birds and relatively long-distance, north-south migrants. This dominance reflects the challenge of incorporating multiple sources of error into geographic assignments and the nature of spatially explicit deltaD models, which possess greater latitudinal than longitudinal resolution. However, recent progress in likelihood-based assignments that incorporate multiple sources of isotopic error and Bayesian approaches that include additional sources of information may advance finer-scale understanding of animal movements. We develop a stable-isotope method for determining probable origins of bats within hibernacula and show that this method produces spatially explicit, continuous assignments with regional resolution. We outline how these assignments can be used to infer hibernacula connectivity, an application that could inform spatial modeling of white-nose syndrome. Additionally, estimates of seasonal and annual flight distances for many cave-dwelling bat species can be derived from this approach. We also discuss how this application can be used in general to provide insights into variable migratory and foraging strategies within bat populations. 相似文献
142.
Rolf D. Schmid 《Die Naturwissenschaften》1987,74(6):267-274
By combining information about Biotechnology in Japan manually retrieved from Chemical Abstracts (Biochemical Section) with information obtained from Japanese sources, Japanese scientific meetings and from appropriate magazines such as Nikkei Biotech, a basis was formed for a better understanding of the status and perspectives of this field. Through the development of a "biotechnology abstract analyzer" program, these data were further refined and prepared for continuous up-date. Thus, assessment of changes in institute structures and trends in research goals became possible. It is evident that similar procedures can be applied to any field of science in other geographic areas. 相似文献
143.
144.
Angiogenesis factors in gliomas: a new key to tumour therapy? 总被引:16,自引:0,他引:16
Angiogenesis, the formation of new blood vessels, is required for the growth and expansion of tumours. Gliomas, the most common brain tumours, are particularly highly vascularized and, therefore, serve as a model to elucidate the process of tumour angiogenesis and to investigate new anti-angiogenic therapies. This review describes the role of angiogenic factors in glioma angiogenesis and new strategies to inhibit glioma growth by application of anti-angiogenic substances. We focus on vascular endothelial growth factor (VEGF), but also examine the role of angiopoietin and pleiotropic factors such as platelet-derived growth factor (PDGF), pleiotrophin and transforming growth factor- (TFG-). Strategies to inhibit glioma growth by reducing the action of angiogenic factors, by the application of anti-angiogenic substances such as angiostatin or endostatin, or inactivation of endothelial cells, are discussed. These new anti-angiogenic therapies appear to have a high potential not only for the treatment of gliomas, but also of other tumours. 相似文献
145.
Rolf Meissner 《Die Naturwissenschaften》1981,68(9):437-442
Geothermal energy, produced by the decay of long-lived radioactive elements in the earth's crust and inherited by the earth's formation, appears in a concentrated and exploitable form at several places in the upper 1 to 3 km of the earth's crust. The hotter the rock-water system is, the more use can be made of generation of electricity. District heating, on the other hand, can be performed by rather moderate temperatures of circulating waters in permeable sediments, a situation which is often encountered in the large sediment basins of West and Central Europe. 相似文献
146.
A mathematical model of radionuclide kinetics in a laboratory microcosm was built by systems identification techniques. Insight into the functioning of the system was obtained from analysis of the model. Methods employed have allowed movements of radioisotopes not directly observable in the experimental system to be distinguished. Results are generalized to whole ecosystems. 相似文献
147.
148.
Hans Pohl Benjamin Wipfler David Grimaldi Felix Beckmann Rolf G. Beutel 《Die Naturwissenschaften》2010,97(9):855-859
Fossilization in amber is unique in preserving specimens with microscopic fidelity; however, arthropod inclusions are rarely
examined beyond the exoskeleton as this requires destructive sampling when traditional techniques are used. We report the
first complete, digital 3D, non-destructive reconstruction of the anatomy of an insect fossil, a specimen of †Mengea tertiaria embedded in a 42-Ma Baltic amber. This was made possible using Synchrotron μ-CT. The species belongs to the stem group of
the phylogenetically enigmatic and extremely specialized Strepsiptera. Most internal structures of the fossil are preserved,
but small parts of the lumen had decayed due to incomplete infiltration of the resin. Data on internal organs provided additional
information for resolving phylogenetic relationships. A sister group relationship between †Mengea and all extant lineages of the group was confirmed with characters previously not accessible. The newly gained information
also yielded some insights in the biology of †Mengea and the early evolutionary history of Strepsiptera. The technique has a tremendous potential for a more accurate interpretation
of diverse fossil arthropods preserved in ambers from 130 Ma to the present. 相似文献
149.
Rolf Turner 《Environmental and Ecological Statistics》2009,16(2):197-223
In this paper I demonstrate some of the techniques for the analysis of spatial point patterns that have become available due
to recent developments in point process modelling software. These developments permit convenient exploratory data analysis,
model fitting, and model assessment. Efficient model fitting, in particular, makes possible the testing of statistical hypotheses
of genuine interest, even when interaction between points is present, via Monte Carlo methods. The discussion of these techniques
is conducted jointly with and in the context of some preliminary analyses of a collection of data sets which are of considerable
interest in their own right. These data sets (which were kindly provided to me by the New Brunswick Department of Natural
Resources) consist of the complete records of wildfires which occurred in New Brunswick during the years 1987 through 2003.
In treating these data sets I deal with data-cleaning problems, methods of exploratory data analysis, means of detecting interaction,
fitting of statistical models, and residual analysis and diagnostics. In addition to demonstrating modelling techniques, I
include a discussion on the nature of statistical models for point patterns. This is given with a view to providing an understanding
of why, in particular, the Strauss model fails as a model for interpoint attraction and how it has been modified to overcome
this difficulty. All actual modelling of the New Brunswick fire data is done only with the intent of illustrating techniques.
No substantive conclusions are or can be drawn at this stage. Realistic modelling of these data sets would require incorporation
of covariate information which I do not so far have available.
相似文献
Rolf TurnerEmail: |
150.
Jianyun Ruan Xun Wu Rolf Hrdter 《生态毒理学报》2001,(2):89-90
人们正加大努力以求最大限度地降低杀虫剂的使用,这些杀虫剂是控制茶树和其它作物的病虫害的基本手段.在中国,由于土壤常常缺少碳酸钾,所以适量使用这种养料有助于减少对杀虫剂的需要.已经证实,在土壤中加入钾后,茶树感染真菌病的比率下降. 相似文献