全文获取类型
收费全文 | 308篇 |
免费 | 4篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 10篇 |
废物处理 | 5篇 |
环保管理 | 17篇 |
综合类 | 114篇 |
基础理论 | 82篇 |
污染及防治 | 69篇 |
评价与监测 | 12篇 |
社会与环境 | 5篇 |
出版年
2022年 | 2篇 |
2021年 | 2篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 6篇 |
2016年 | 7篇 |
2015年 | 5篇 |
2014年 | 6篇 |
2013年 | 14篇 |
2012年 | 15篇 |
2011年 | 17篇 |
2010年 | 12篇 |
2009年 | 13篇 |
2008年 | 8篇 |
2007年 | 12篇 |
2006年 | 15篇 |
2005年 | 8篇 |
2004年 | 10篇 |
2003年 | 7篇 |
2002年 | 12篇 |
2001年 | 11篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 9篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1985年 | 3篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1966年 | 7篇 |
1965年 | 3篇 |
1964年 | 4篇 |
1963年 | 4篇 |
1962年 | 5篇 |
1960年 | 2篇 |
1958年 | 3篇 |
1957年 | 3篇 |
1955年 | 4篇 |
1954年 | 2篇 |
1952年 | 2篇 |
1951年 | 3篇 |
1943年 | 2篇 |
1940年 | 2篇 |
1939年 | 2篇 |
1923年 | 1篇 |
1921年 | 1篇 |
排序方式: 共有314条查询结果,搜索用时 31 毫秒
61.
We present a new system for microscopic multicolour variable chlorophyll fluorescence imaging of aquatic phototrophs. The
system is compact and portable and enables microscopic imaging of photosynthetic performance of individual cells and chloroplasts
using different combinations of blue, green, red or white light. Automated sequential exposure of microscopic samples to the
three excitation colours enables subsequent deconvolution of the resulting fluorescence signals and colour marking of cells
with different photopigmentation, i.e., cyanobacteria, green algae, red algae and diatoms. The photosynthetic activity in
complex mixtures of phototrophs and natural samples can thus be assigned to different types of phototrophs, which can be quantified
simultaneously. Here, we describe the composition and performance of the new imaging system and present applications with
both natural phytoplankton and microalgal culture samples. 相似文献
62.
Weise Katrin Kurth Thomas Politowski Irina Winkelmann Carola Schäffer Andreas Kretschmar Susanne Berendonk Thomas Ulrich Jungmann Dirk 《Environmental science and pollution research international》2022,29(18):26706-26725
Environmental Science and Pollution Research - Although the development and application of nanomaterials is a growing industry, little data is available on the ecotoxicological effects on aquatic... 相似文献
63.
Jürgen Warrelmann Hartmut Kochler Tobias Frische Ingo Dobner Ulrich Walter Wolfgang Heyser 《Environmental Sciences Europe》2000,12(6):351-357
On the area of a former ordnance plant (‘Werk Tanne’, Clausthal-Zellerfeld, Germany), a field experiment for phytoremediation of TNT-contaminated soils has been carried out since May 1999. The concept is based on a stepwise degradation of TNT by white-rot fungi and mycorrhiza within the rhizosphere of site-specific seedlings. An appropiate site with contaminants in the surface-soil was prepared with a large-scale soil grader and subsequently divided into different experimental plots, including an uncontaminated control as well as a contaminated plot without treatment. Planting of the selected trees and shrubs (infected with mycorrhiza during nursery) and inoculation with wood chips (inoculated with white-rot fungi) is followed by a detailed monitoring of the experimental plots (chemical analyses, biotest-battery, ecological field indicators). For the evaluation of the results, multivariate methods are applied. 相似文献
64.
Athlua B. Attygalle Karla Jessen Hans-Jürgen Bestmann Alfred Buschinger Ulrich Maschwitz 《Chemoecology》1996,7(1):8-12
Summary Gas chromatographic analyses of volatizable material from gaster intersegmental complex glands ofP. tridentata revealed the presence of linoleic acid, palmitic acid, methyl oleate, and several long-chain hydrocarbons as major constituents, which form an oily fluid mixture. The nest relocation communication ofP. tridentata is tandem running. Tandem following is mediated by pheromones as demonstrated by dummy experiments with isolated gasters and thoraces and with glass balls. The secretions of all gaster complex glands, as well as hind gut contents and metapleural gland secretions, were unable to evoke tandem following. Morphology and position of the glands, lack of pheromonal function, oily properties, low volatility, and lack of antibiotic effects of these secretions strongly suggest a function as lubricants for the ants' gastral segments. 相似文献
65.
66.
Complement is a physiological constituent of bloodplasma. In its activated state complement is able to stimulate various cells for special performance, e.g., monocytes, macrophages, granulocytes, platelets, but also T- and B-lymphocytes. The biological functions of the complement system cover the following areas: induction of inflammation, defence against microbial infections, handling of immune complexes, and modulation of the immune response. 相似文献
67.
The patency of the vascular tree as well as thrombus formation are achieved by the interactions of several components of the circulating blood and the vessel wall. Circulating glycoproteins (coagulation factors), cellular elements of the blood (platelets), the fibrinolytic system, the endothelium of the vasculature and inhibitors that are present in the blood stream are involved in the maintainance of the subtle balance between anti-coagulant and pro-coagulant forces. Regulation of the activity of thrombin represents a key event in this process. 相似文献
68.
Ulrich Struck Maren Voss Bodo von Bodungen Nicolai Mumm 《Die Naturwissenschaften》1998,85(12):597-603
15 N of bulk sediment, organic carbon concentrations, and abundances of exoskeletons of Bosmina
longispina
maritima in the sediment, the data are used to evaluate significant sources of nitrogen in the food web over the past century. Nitrogen
isotopic composition of bulk sediments ranges from 2.5 to 4.5?, that of exokeletons varies between 0.4 and 6.2?. The two are
positively correlated. A marked increase in the abundance of Bosmina since 1965 (from less than 500 specimen to more than 5000 specimen cm3 of sediment) is correlated with a significant increase in sedimentary organic carbon concentrations (from 4% to more than
10%). The isotopic data do not identify increased land-derived nitrate as the dominant nitrogen source fuelling the increase.
Instead, we postulate that nitrogen fixation by diazotrophic bacteria has been one of the larger sources of nitrogen in the
Baltic Sea, as it is today.
Received: 29 April 1998 / Accepted in revised form: 13 August 1998 相似文献
69.
70.