全文获取类型
收费全文 | 179篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 7篇 |
废物处理 | 2篇 |
环保管理 | 27篇 |
综合类 | 46篇 |
基础理论 | 67篇 |
污染及防治 | 23篇 |
评价与监测 | 6篇 |
社会与环境 | 2篇 |
出版年
2022年 | 4篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 7篇 |
2016年 | 5篇 |
2015年 | 9篇 |
2014年 | 2篇 |
2013年 | 10篇 |
2012年 | 3篇 |
2011年 | 6篇 |
2010年 | 2篇 |
2009年 | 5篇 |
2008年 | 8篇 |
2007年 | 14篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1990年 | 5篇 |
1987年 | 3篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1978年 | 3篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1965年 | 1篇 |
1964年 | 2篇 |
1963年 | 3篇 |
1961年 | 1篇 |
1960年 | 3篇 |
1959年 | 1篇 |
1958年 | 4篇 |
1957年 | 2篇 |
1956年 | 2篇 |
1955年 | 3篇 |
1954年 | 2篇 |
1953年 | 2篇 |
1950年 | 1篇 |
1930年 | 1篇 |
排序方式: 共有180条查询结果,搜索用时 15 毫秒
121.
122.
A hydraulic jump is characterized by strong energy dissipation and mixing, large-scale turbulence, air entrainment, waves,
and spray. Despite recent pertinent studies, the interaction between air bubbles diffusion and momentum transfer is not completely
understood. The objective of this paper is to present experimental results from new measurements performed in a rectangular
horizontal flume with partially developed inflow conditions. The vertical distributions of the void fraction and the air bubbles
count rate were recorded for inflow Froude number Fr
1 in the range from 5.2 to 14.3. Rapid detrainment process was observed near the jump toe, whereas the structure of the air
diffusion layer was clearly observed over longer distances. These new data were compared with previous data generally collected
at lower Froude numbers. The comparison demonstrated that, at a fixed distance from the jump toe, the maximum void fraction
C
max increases with the increasing Fr
1. The vertical locations of the maximum void fraction and bubble count rate were consistent with previous studies. Finally,
an empirical correlation between the upper boundary of the air diffusion layer and the distance from the impingement point
was derived. 相似文献
123.
The interest in air–water flows has not diminished in recent years, but it is accompanied by frequent citations of early,
sometimes outdated articles. A basic issue is the inadequate, incomplete interpretation of air–water flow instrumentation
by hydraulic engineers and researchers. This article comments on high-velocity air–water flow measurements by means of intrusive
phase detection probes. This article focus on the bubbly flow structure of high-velocity air–water flow based upon measurements
by means of intrusive phase detection probes. It is shown that some advanced post-processing techniques may yield expanded
information on the air–water turbulent flow properties and bubbly flow structures. The outcomes demonstrate simple techniques
in high-velocity air–water flow analysis. 相似文献
124.
125.
Blank LW Payer HD Pfirrmann T Rehfuess KE 《Environmental pollution (Barking, Essex : 1987)》1990,64(3-4):385-395
This paper summarizes and evaluates the main findings of 14 preceding papers related to the joint 14-month tree-exposure experiment carried out by the 'Munich Working Party on Air Pollution' at the GSF, Munich, FRG, from July 1986 to September 1987. The experiment tested the hypothesis that an interaction of ozone/acid mist/soil/extreme climatic conditions is the cause of decline of Norway spruce (Picea abies (L.) Karst.) at higher altitudes of the Inner Bavarian Forest. The main findings of the individual studies are presented and their implications for the hypothesis are discussed. Clear effects of soil and genetic factors (differences between clones), for example on growth and frost resistance were found. Treatment with O(3)/acid mist was shown to have effects on plant biochemistry, physiology, histology/ cytology, and growth. The wide scattering of these effects, and the lack of a consistent pattern of response across all clones does not permits a firm conclusion on the validity of the experimental hypothesis. These effects were not confounded by the nutrient stresses imposed during the initial exposure period and were not found to be cumulative during repeated treatments, as was proposed by the hypothesis. It is concluded that the experimental evidence does not indicate that ozone/acid mist are major factors to explain the Norway spruce decline on acidic sites at higher altitudes of the Inner Bavarian Forest and probably similar forest areas. 相似文献
126.
127.
128.
129.
130.
Rebecca J. Safran Kevin M. Pilz Kevin J. McGraw Stephanie M. Correa Hubert Schwabl 《Behavioral ecology and sociobiology》2008,62(3):427-438
Recently, evidence is mounting that females can adaptively engineer the quality of their offspring via the deposition of yolk
compounds, including carotenoids and androgens. In this study, we simultaneously consider how both carotenoids and androgens
in egg yolk relate to parental quality in barn swallows (Hirundo rustica erythrogaster). First, we found no relationship between concentrations or amounts of yolk androgens and carotenoids. Yolk carotenoids decreased
with laying order, whereas we found no relationship between yolk androgens and laying order. Second, we tested the Investment
Hypothesis, which predicts that high-quality females or females paired to high quality mates, allocate differentially more
of these yolk compounds to their offspring. For carotenoids, we mostly found evidence to counter predictions of the Investment
hypothesis: (1) Carotenoid concentrations varied among females, (2) heavier eggs contained lower carotenoid concentrations,
although heavier yolks contained greater amounts of carotenoids, (3) eggs of earlier-laying females had lower concentrations
in their eggs, and (4) yolk carotenoids were not correlated with clutch size or male plumage ornamentation. For androgens,
we found weak support for the Investment Hypothesis: (1) Yolk androgens varied among females, (2) heavier eggs and yolks contained
greater amounts, although not concentrations of androgens, (3) females paired to more colorful males laid eggs with greater
concentrations of androgens, and (4) no effects of laying date or morphological correlates of female quality on androgen concentrations
in egg yolks. Overall, these findings suggest that each yolk compound may have different functions and therefore may be regulated
by different mechanisms. 相似文献