全文获取类型
收费全文 | 423篇 |
免费 | 7篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 7篇 |
废物处理 | 16篇 |
环保管理 | 44篇 |
综合类 | 232篇 |
基础理论 | 41篇 |
污染及防治 | 71篇 |
评价与监测 | 15篇 |
社会与环境 | 5篇 |
出版年
2020年 | 4篇 |
2018年 | 5篇 |
2017年 | 6篇 |
2016年 | 7篇 |
2014年 | 5篇 |
2013年 | 19篇 |
2012年 | 10篇 |
2011年 | 16篇 |
2010年 | 12篇 |
2009年 | 4篇 |
2008年 | 14篇 |
2007年 | 10篇 |
2006年 | 10篇 |
2005年 | 6篇 |
2004年 | 6篇 |
2003年 | 8篇 |
2000年 | 7篇 |
1996年 | 4篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1983年 | 5篇 |
1981年 | 4篇 |
1977年 | 6篇 |
1965年 | 8篇 |
1963年 | 4篇 |
1962年 | 7篇 |
1961年 | 5篇 |
1960年 | 6篇 |
1959年 | 7篇 |
1958年 | 4篇 |
1957年 | 12篇 |
1956年 | 7篇 |
1955年 | 8篇 |
1954年 | 7篇 |
1952年 | 5篇 |
1941年 | 7篇 |
1940年 | 8篇 |
1939年 | 10篇 |
1938年 | 4篇 |
1937年 | 8篇 |
1936年 | 5篇 |
1935年 | 11篇 |
1934年 | 7篇 |
1933年 | 3篇 |
1931年 | 5篇 |
1929年 | 4篇 |
1928年 | 4篇 |
1927年 | 4篇 |
1926年 | 5篇 |
1924年 | 3篇 |
排序方式: 共有431条查询结果,搜索用时 31 毫秒
91.
92.
Kurt H. Meyer 《Die Naturwissenschaften》1927,15(6):129-134
93.
94.
Michael J. Lavelle Gregory E. Phillips Justin W. Fischer Patrick W. Burke Nathan W. Seward Randal S. Stahl Tracy A. Nichols Bruce A. Wunder Kurt C. VerCauteren 《Environmental geochemistry and health》2014,36(6):1049-1061
Free-ranging cervids acquire most of their essential minerals through forage consumption, though occasionally seek other sources to account for seasonal mineral deficiencies. Mineral sources occur as natural geological deposits (i.e., licks) or as anthropogenic mineral supplements. In both scenarios, these sources commonly serve as focal sites for visitation. We monitored 11 licks in Rocky Mountain National Park, north-central Colorado, using trail cameras to quantify daily visitation indices (DVI) and soil consumption indices (SCI) for Rocky Mountain elk (Cervus elaphus) and mule deer (Odocoileus hemionus) during summer 2006 and documented elk, mule deer, and moose (Alces alces) visiting licks. Additionally, soil samples were collected, and mineral concentrations were compared to discern levels that explain rates of visitation. Relationships between response variables; DVI and SCI, and explanatory variables; elevation class, moisture class, period of study, and concentrations of minerals were examined. We found that DVI and SCI were greatest at two wet, low-elevation licks exhibiting relatively high concentrations of manganese and sodium. Because cervids are known to seek Na from soils, we suggest our observed association of Mn with DVI and SCI was a likely consequence of deer and elk seeking supplemental dietary Na. Additionally, highly utilized licks such as these provide an area of concentrated cervid occupation and interaction, thus increasing risk for environmental transmission of infectious pathogens such as chronic wasting disease, which has been shown to be shed in the saliva, urine, and feces of infected cervids. 相似文献
95.
Potentiometric studies of mixed complexes of cobalt(II) and copper(II) with l‐Asparagine and adenine
Hülya Demircan Demir Mürşit Pekin Aysen Kurt Cücü Emre Dölen Hassan Y. Aboul‐Enein 《毒物与环境化学》2013,95(3-4):357-367
A potentiometric titration technique has been used to determine the stability constants for the various complexes of Co(II) and Cu(II) with L‐asparagine and from DNA base, e.g. adenine. Stability constants of ternary systems have been evaluated by the method suggested by Irwing‐Rossotti. In addition, the conditional constants were calculated as a function of pH. The maximum values of the conditional formation constants were found to be in accordance with the mixed‐ligand complex formation constants in a determined pH region. Furthermore, the molar fractions of different species from mixed complexes were calculated by means of formation constants. The values of stability constants of mixed‐ligand complexes at 25°C are as follows: log K= 5.25 for Co(II)‐L‐asparagine‐adenine; log K= 9.30 for Cu(II)‐L‐asparagine‐adenine. The ionic strength was kept constant at I = 0.20 with NaClO4. 相似文献
96.
Mie H. Sichlau Jørgen L. S. Hansen Thorbjørn J. Andersen Benni W. Hansen 《Marine Biology》2011,158(3):665-676
Distribution, abundance and age of diapause eggs from three species of calanoid copepods (in particular from Acartia spp. most likely Acartia tonsa, and Centropages hamatus and less numerous from Temora longicornis) were recorded in sediment profiles by enumerating hatched nauplii from incubated sediment samples. Phytoplankton pigments
and 210Pb and 137Cs analyses indicated that the sedimentation regimes were different between two southern and two northern stations of the
island Funen, Denmark. Significant variations in vertical distribution, abundance and mortality of diapause eggs were found
between the stations. Dating of the sediment cores suggested a ~70-year maximum age of viable eggs on the northernmost stations,
and ~28 year at the southernmost stations. The eggs exhibited a significantly higher mortality rate at the southernmost stations
compared with the northernmost, 0.35–0.53 year−1 vs. 0.07–0.08 year−1 with no systematic pattern among species. The differences in abundance, mortality and age of the diapause eggs are suggested
to be due to the sediment characteristics in which they are buried. 相似文献
97.
Food and parasites can independently play a role in destabilizing population fluctuations of animals, and yet, more than 50 years ago, David Lack proposed that these two factors should act in concert. We examined the role of these factors on the vital rates of free-living white-footed mice (Peromyscus leucopus) over the summer and autumn months. We used a replicated factorial experiment in which deer exclosures doubled acorn availability and anthelmintic application reduced gastrointestinal helminths. Specifically, we wanted to know if either factor or an interaction between the two accounted for the midsummer breeding hiatus observed in this species. We found no influence of habitat quality on mouse breeding, vital rates, or demography; however, anthelmintic treatment resulted in mice continuing to reproduce during the hiatus at the same rate as previously, and they also exhibited increased body condition, growth rate, and survival. These results provide evidence that gastrointestinal helminths reduce P. leucopus reproductive output in central Pennsylvania, and these effects on reproduction could play a role in the unstable dynamics of small mammals. 相似文献
98.
Charles J. Frost Scott E. Hygnstrom Andrew J. Tyre Kent M. Eskridge David M. Baasch Justin R. Boner Gregory M. Clements Jason M. Gilsdorf Travis C. Kinsell Kurt C. Vercauteren 《Ecological modelling》2009,220(19):2481-2490
Movements of deer can affect population dynamics, spatial redistribution, and transmission and spread of diseases. Our goal was to model the movement of deer in Nebraska in an attempt to predict the potential for spread of chronic wasting disease (CWD) into eastern Nebraska. We collared and radio-tracked >600 white-tailed deer (Odocoileus virginianus) and mule deer (Odocoileus hemionus) in Nebraska during 1990–2006. We observed large displacements (>10 km) for both species and sexes of deer, including migrations up to 100 km and dispersals up to 50 km. Average distance traveled between successive daily locations was 166 m for male and 173 for female deer in eastern Nebraska, and 427 m for male and 459 for female deer in western Nebraska. Average daily displacement from initial capture point was 10 m for male and 14 m for female deer in eastern Nebraska, and 27 m for male and 28 m for female deer in western Nebraska. We used these data on naturally occurring movements to create and test 6 individual-based models of movement for white-tailed deer and mule deer in Nebraska, including models that incorporated sampling from empirical distributions of movement lengths and turn angles (DIST), correlated random walks (CRW), home point fidelity (FOCUS), shifting home point (SHIFT), probabilistic movement acceptance (MOVE), and probabilistic movement with emigration (MOVEwEMI). We created models in sequence in an attempt to account for the shortcomings of the previous model(s). We used the Kolmogrov–Smirnov goodness-of-fit test to verify improvement of simulated annual displacement distributions to empirical displacement distributions. The best-fit model (D = 0.07 and 0.08 for eastern and western Nebraska, respectively) included a probabilistic movement chance with emigration (MOVEwEMI) and resulted in an optimal daily movement length of 350 m (maximum daily movement length of 2800 m for emigrators) for eastern Nebraska and 370 m (maximum of 2960 m) for western Nebraska. The proportion of deer that moved as emigrators was 0.10 and 0.13 for eastern and western Nebraska, respectively. We propose that the observed spread of CWD may be driven by large movements of a small proportion of deer that help to establish a low prevalence of the disease in areas east of the current endemic area. Our movement models will be used in a larger individual-based simulation of movement, survival, and transmission of CWD to help determine future surveillance and management actions. 相似文献
99.
Kazar Soydan Didem Turgut Nalan Yalçın Melis Turgut Cafer Karakuş Perihan Binnur Kurt 《Environmental science and pollution research international》2021,28(22):27511-27519
Environmental Science and Pollution Research - Pesticides may cause a potential risk to human health when applied in excess to control pests, diseases, and weeds in crop fields. In the current... 相似文献
100.
Feeding behavior in sexual and clonal strains of Poeciliopsis 总被引:1,自引:0,他引:1
Stephen C. Weeks Oscar E. Gaggiotti Russell A. Schenck Kurt P. Spindler Robert C. Vrijenhoek 《Behavioral ecology and sociobiology》1992,30(1):1-6
Summary Sexual and clonal fish of the genus Poeciliopsis occur together in desert streams of Sonora, Mexico. Their coexistence has been explained in terms of niche partitioning for food and space. We examined predatory behavior that might influence niche relationships, and found significant differences among two coexisting sperm-dependent clonal strains and their two sexual progenitors. Handling time and prey manipulation of free-swimming (Artemia) and benthic (chironomid larvae) prey differed significantly among sexual and clonal strains. Analyses of gut contents from field-collected fish revealed that the laboratory estimates of predatory efficiency were related to their feeding behavior in nature. Behavior differences, such as those described herein, contribute to our understanding of the mechanisms of unisexual/bisexual coexistence in Poeciliopsis.
Offprint requests to: R.C. Vrijenhoek 相似文献