全文获取类型
收费全文 | 570篇 |
免费 | 2篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 8篇 |
废物处理 | 18篇 |
环保管理 | 42篇 |
综合类 | 232篇 |
基础理论 | 108篇 |
环境理论 | 1篇 |
污染及防治 | 132篇 |
评价与监测 | 12篇 |
社会与环境 | 20篇 |
灾害及防治 | 1篇 |
出版年
2021年 | 7篇 |
2020年 | 7篇 |
2018年 | 6篇 |
2017年 | 17篇 |
2016年 | 6篇 |
2015年 | 5篇 |
2014年 | 13篇 |
2013年 | 25篇 |
2012年 | 21篇 |
2011年 | 32篇 |
2010年 | 16篇 |
2009年 | 27篇 |
2008年 | 32篇 |
2007年 | 23篇 |
2006年 | 18篇 |
2005年 | 18篇 |
2004年 | 15篇 |
2003年 | 7篇 |
2002年 | 17篇 |
2001年 | 10篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1993年 | 8篇 |
1990年 | 5篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1977年 | 5篇 |
1974年 | 4篇 |
1973年 | 6篇 |
1972年 | 6篇 |
1971年 | 4篇 |
1970年 | 4篇 |
1967年 | 6篇 |
1966年 | 5篇 |
1965年 | 5篇 |
1963年 | 6篇 |
1961年 | 4篇 |
1960年 | 6篇 |
1959年 | 8篇 |
1958年 | 5篇 |
1957年 | 6篇 |
1956年 | 9篇 |
1955年 | 10篇 |
1939年 | 4篇 |
1934年 | 4篇 |
1924年 | 3篇 |
1913年 | 3篇 |
排序方式: 共有574条查询结果,搜索用时 420 毫秒
91.
Multi-year, seasonal genotypic surveys of coral-algal symbioses reveal prevalent stability or post-bleaching reversion 总被引:10,自引:0,他引:10
Daniel J. Thornhill Todd C. LaJeunesse Dustin W. Kemp William K. Fitt Gregory W. Schmidt 《Marine Biology》2006,148(4):711-722
This report documents the extent to which coral colonies show fluctuations in their associations with different endosymbiotic dinoflagellates. The genetic identity of Symbiodinium from six coral species [Acropora palmata (Lamarck), A. cervicornis (Lamarck), Siderastrea siderea (Ellis and Solander), Montastrea faveolata (Ellis and Solander), M. annularis (Ellis and Solander), and M. franksi (Gregory)] was examined seasonally over five years (1998 and 2000–2004) in the Bahamas and Florida Keys at shallow (1 to 4 m) fore-reef/patch reef sites and at deeper fore-reef (12–15 m) locations. Symbionts were identified genetically using denaturing gradient gel electrophoresis (DGGE) fingerprinting of the internal transcribed spacer region 2 (ITS2) of ribosomal RNA gene loci. Repetitive sampling from most labeled colonies from the Bahamas and the Florida Keys showed little to no change in their dominant symbiont. In contrast, certain colonies of M. annularis and M. franksi from the Florida Keys exhibited shifts in their associations attributed to recovery from the stresses of the 1997–1998 El Niño southern oscillation (ENSO) event. Over several years, a putatively stress-tolerant clade D type of Symbiodinium was progressively replaced in these colonies by symbionts typically found in M. annularis and M. franksi in Florida and at other Caribbean locations. Greater environmental fluctuations in Florida may explain the observed changes among some of the symbioses. Furthermore, symbiotic associations were more heterogeneous at shallow sites, relative to deep sites. The exposure to greater environmental variability near the surface may explain the higher symbiont diversity found within and between host colonies. 相似文献
92.
93.
Harry?L.?S.?RobertsEmail author Oliver?True Otto?Schmidt 《Behavioral ecology and sociobiology》2004,57(2):132-138
In a laboratory colony of the asexual solitary endoparasitoid Venturia canescens Grav. (Hymenoptera: Ichneumonidae), two genetically and phenotypically distinct lines (RP and RM) appear to coexist sympatrically, with the reproductive success of the RM-line being greater under con-specific superparasitism but lower under self superparasitism. To investigate the basis of the RM-lines advantage under con-specific superparasitism, we examined the outcome of inter-larval physical combat under in-vitro conditions. The results showed that the outcome depended on both the relative and absolute ages of the contestants, and that the competitive abilities of the two lines were not symmetric. In contests involving a larva and an egg, the unhatched wasp lost. In contests involving two larvae, at least one of which was newly hatched, the RP-larva tended to lose. Finally, if both larvae were at least 8–10 h post-hatching when the contest occurred, then the larger larva tended to lose, with the probability increasing with the difference in length between the two larvae. Thus, the higher reproductive success of the RM-line under competing superparasitism with the RP-line is due to a physiological difference between the newly hatched larvae of the two lines, which results in an advantage to the RM-larva independent of the order or time interval between ovipositions.Communicated by P. Heeb 相似文献
94.
95.
Distribution coefficients for the sorption of Pb2+, Cu2+, Cd2+ and Zn2+ by peat were determined as a function of the Ca2+-content of peat as well as of the Ca2+-concentration in the solution. The amount of heavy metal ions taken up was measured for Cu2+, Cd2+ and Zn2+ by atomic absorption spectrometry and for Pb2+ by using Pb-212 as a radioactive tracer.The results show that the distribution coefficients of the heavy metal ions increase, if one increases the initial ratio of the in the peat phase. The distribution coefficients for the heavy metal ions decrease, however, if - at constant initial Ca2+-content of the peat - the Ca2+-concentration of the solution is increased. 相似文献
96.
97.
Nimmermark SA Jacobson LD Schmidt DR Gay SW 《Journal of the Air & Waste Management Association (1995)》2005,55(9):1306-1314
A comparison between predicted and observed odor intensities at 20 neighborhood residences in the vicinity of seven various livestock farms in five different Minnesota counties was made to evaluate the Odor From Feedlots, Setback Estimation Tool (OFFSET) developed by the University of Minnesota. Observations by neighborhood monitors suggest that the OFFSET-predicted separation distances for annoyance-free frequencies of 99, 98, and 97% are large enough. The observations additionally indicate that predicted distances to obtain 94 and 91% annoyance-free frequencies may be large enough for some farms, but for other farms, greater distances may be needed. For two farms in the study, no significant difference between all of the observed and predicted intensities could be found. At four sites, a significant difference was found, and at three of these the difference was considerable. Odor emission rates used in the OFFSET model seem to describe the average emission fairly well for many odor sources, but improvement may be needed for some types of sources. Possible reasons for observations of annoying odor when not predicted include fluctuations in the odor emissions, wind speed fluctuations, topographic variation between sites, sensitivity differences by neighborhood monitors, and background emissions from other sources. 相似文献
98.
99.
Mohr S Feibicke M Ottenströer T Meinecke S Berghahn R Schmidt R 《Environmental science and pollution research international》2005,12(1):5-7
Scope The German Federal Environmental Agency has put into operation a new modular mesocosm system consisting of eight outdoor and eight indoor ponds and streams in order to investigate fate and effects of chemicals and municipal wastewater in aquatic ecosystems. General design and special characteristics are given to demonstrate the wide range of possibilities for experimental research. - General design. Each of the 16 streams with riffle and pool sections can be varied in length up to 106 m. The streams can be run as circular or flow-through systems at a flow velocity of 0.02 to 0.6 m/s. Physico-chemical standard parameters are measured on-line. The 16 ponds, which can be connected to the stream systems, are equipped with drainage and pore water-sampling devices for simulating processes in the littoral zone including influent and effluent ground water flow. Perspectives Since the highly flexible and controllable construction also allows treating a wide range of hydrological and ecological experiments external institutions are invited to submit proposals. 相似文献
100.
Schmidt B Patti H Hommes G Schuphan I 《Journal of environmental science and health. Part. B》2004,39(4):533-549
The biotransformation of the nonylphenol isomer [ring-U-14C]-4-(3',5'-dimethyl-3'-heptyl)-phenol (4-353-NP, consisting of two diastereomers) was studied in soybean and Agrostemma githago cell suspension cultures. With the A. githago cells, a batch two-liquid-phase system (medium/n-hexadecane 200:1, v/v) was used, in order to produce higher concentrations and amounts of 4-353-NP metabolites for their identification; 4-353-NP was applied via the n-hexadecane phase. Initial concentrations of [14C]-4-353-NP were 1 mg L(-1) (soybean), and 5 and 10 mg L(-1) (A. githago). After 2 (soybean) and 7 days (A. githago) of incubation, the applied 4-353-NP was transformed almost completely by both plant species to four types of products: glycosides of parent 4-353-NP, glycosides of primary 4-353-NP metabolites, nonextractable residues and unknown, possibly polymeric materials detected in the media. The latter two products emerged especially in soybean cultures. Portions of primary metabolites amounted to 19-22% (soybean) and 21-42% of applied 14C (A. githago). After liberation from their glycosides, the primary 4-353-NP metabolites formed by A. githago were isolated by HPLC and examined by GC-EIMS as trimethylsilyl derivatives. In the chromatograms, eight peaks were detected which due to their mass spectra, could be traced back to 4-353-NP. Seven of the compounds were side-chain monohydroxylated 4-353-NP metabolites, while the remaining was a (side-chain) carboxylic acid derivative. Unequivocal identification of the sites of hydroxylation/oxidation of all transformation products was not possible. The main primary metabolites produced by A. githago were supposed to be four diastereomers of 6'-hydroxy-4-353-NP (about 80% of all products identified). It was concluded that plants contribute to the environmental degradation of the xenoestrogen nonylphenol; the toxicological properties of side-chain hydroxylated nonylphenols remain to be examined. 相似文献