全文获取类型
收费全文 | 4828篇 |
免费 | 33篇 |
国内免费 | 29篇 |
专业分类
安全科学 | 48篇 |
废物处理 | 184篇 |
环保管理 | 172篇 |
综合类 | 2092篇 |
基础理论 | 883篇 |
环境理论 | 5篇 |
污染及防治 | 1045篇 |
评价与监测 | 270篇 |
社会与环境 | 175篇 |
灾害及防治 | 16篇 |
出版年
2022年 | 69篇 |
2021年 | 49篇 |
2020年 | 35篇 |
2019年 | 39篇 |
2018年 | 89篇 |
2017年 | 73篇 |
2016年 | 115篇 |
2015年 | 73篇 |
2014年 | 137篇 |
2013年 | 232篇 |
2012年 | 147篇 |
2011年 | 145篇 |
2010年 | 143篇 |
2009年 | 147篇 |
2008年 | 176篇 |
2007年 | 195篇 |
2006年 | 143篇 |
2005年 | 122篇 |
2004年 | 111篇 |
2003年 | 124篇 |
2002年 | 99篇 |
2001年 | 92篇 |
2000年 | 85篇 |
1999年 | 84篇 |
1998年 | 59篇 |
1997年 | 55篇 |
1996年 | 36篇 |
1995年 | 53篇 |
1994年 | 56篇 |
1993年 | 34篇 |
1991年 | 37篇 |
1990年 | 42篇 |
1989年 | 36篇 |
1985年 | 35篇 |
1979年 | 39篇 |
1969年 | 34篇 |
1967年 | 57篇 |
1966年 | 48篇 |
1965年 | 56篇 |
1964年 | 64篇 |
1963年 | 66篇 |
1962年 | 59篇 |
1961年 | 67篇 |
1960年 | 60篇 |
1959年 | 66篇 |
1958年 | 61篇 |
1957年 | 72篇 |
1956年 | 49篇 |
1955年 | 49篇 |
1954年 | 46篇 |
排序方式: 共有4890条查询结果,搜索用时 15 毫秒
991.
Şerif Hepcan Adnan Kaplan Bülent Özkan Erhan Vecdi Küçükerbaş Emine Malkoç Yiğit Hatice Sönmez Türel 《国际发展与全球生态学杂志》2013,20(5):375-389
This study examines the possibility of designating and implementing a citywide public space network, constituted of randomly dispersed and not interrelated public spaces and greenways across the city of Mu?la. Although Mu?la is a major coastal province, with worldwide tourism districts, the city centre falls behind other settlements in terms of quality of social life, physical layout, economic investment and tourism revenue. In 2001, the local government commissioned the Department of Landscape Architecture of Ege University to prepare a comprehensive master plan towards achieving a corporate public space network, as well as development strategies to ameliorate the previous failures. The master plan developed a blueprint for the citywide network and addressed each existing or potential public space and greenway as integrated components of the network. The process involved short-, medium- and long-term action from the local government to achieve the physical layout and efficiently implement phases of the network. As a guide for other small or medium urban settlements in Turkey, a model proposal was derived from the study to address formulation, implementation, and management of the network in order to create a sustainable urban development. 相似文献
992.
Julie Marmet Beno?t Pisanu Jean-Louis Chapuis Gwena?l Jacob Emmanuelle Baudry 《Behavioral ecology and sociobiology》2012,66(11):1449-1457
While sexual selection in mammals with female defense systems has historically received considerable attention, much less is known about the factors affecting reproductive success in mammalian species with scramble competition mating systems. Using mark–recapture techniques and DNA microsatellite loci to assign parentage, we examined the mating system and factors affecting the variation of the annual reproductive success in an introduced population of the Siberian chipmunk, Tamias sibiricus, a small, monomorphic, solitary squirrel. Our analyses showed that breeding females were spatially dispersed, setting the stage for a scramble competition mating system. Male reproductive success was positively associated with the size of the home range. The strength of sexual selection on this behavioral trait was very strong, equaling previous estimates for morphological traits in female defense mating systems. These findings suggest that a behavioral trait, space use, strongly influences the annual reproductive success in males, which is consistent with expectations in a scramble competition mating system. In both sexes, reproductive success was influenced by habitat, with twice as many juveniles produced in semi-open than in closed habitat, possibly due to differences in food availability between the two habitats. 相似文献
993.
Kirsten?Kreuter Elfi?Bunk Anna?Lückemeyer Robert?Twele Wittko?Francke Manfred?AyasseEmail author 《Behavioral ecology and sociobiology》2012,66(3):475-486
Social parasitism is widespread in many groups of social living hymenopteran species and has also evolved in the genus Bombus. Cuckoo bumblebees (subgenus Psithyrus) are obligate brood parasites in nests of other bumblebee species. After nest usurpation and the killing of the host queen,
the parasite female has to control worker reproduction in order to accomplish and maintain reproductive dominance and to ensure
her reproductive success. The aim of our study was to examine whether the generalist parasitic bumblebee Bombus bohemicus monopolizes and prevents worker reproduction by physical or chemical means and to identify possible odor compounds involved
therein. We performed bioassays with callow workers of the host Bombus terrestris and have shown that B. bohemicus females are able to suppress host worker ovarian development, when these host workers are under the direct influence of the
parasite female. Furthermore, by chemical analyses, we have demonstrated that the parasite females adjust to the odor profiles
of their host queens in order to maintain the level of fertility signaling inside the host colony although the host queen
is absent. We also found that host workers change their odor profile after nest usurpation by the parasite female and consequently,
we suggest that the host and parasite are caught up in a chemical arms race. 相似文献
994.
Ebensperger LA Sobrero R Quirici V Castro RA Tolhuysen LO Vargas F Burger JR Quispe R Villavicencio CP Vásquez RA Hayes LD 《Behavioral ecology and sociobiology》2012,66(2):261-274
Intraspecific variation in sociality is thought to reflect a trade-off between current fitness benefits and costs that emerge from individuals' decision to join or leave groups. Since those benefits and costs may be influenced by ecological conditions, ecological variation remains a major, ultimate cause of intraspecific variation in sociality. Intraspecific comparisons of mammalian sociality across populations facing different environmental conditions have not provided a consistent relationship between ecological variation and group-living. Thus, we studied two populations of the communally rearing rodent Octodon degus to determine how co-variation between sociality and ecology supports alternative ecological causes of group living. In particular, we examined how variables linked to predation risk, thermal conditions, burrowing costs, and food availability predicted temporal and population variation in sociality. Our study revealed population and temporal variation in total group size and group composition that covaried with population and yearly differences in ecology. In particular, predation risk and burrowing costs are supported as drivers of this social variation in degus. Thermal differences, food quantity and quality were not significant predictors of social group size. In contrast to between populations, social variation within populations was largely uncoupled from ecological differences. 相似文献
995.
Sebastian Schimmelpfennig Georgiy Kirillin Christof Engelhardt Gunnar Nützmann 《Environmental Fluid Mechanics》2012,12(4):321-339
Prediction of mixing intensity of water masses in riverine Lake Tegel (Berlin, Germany) can be used to trace the fate of pollutants that enter the lake through several inflows. Because the contributions of each inflow have not yet been quantified and because the lake features complex bathymetry and numerous islands, a hydrodynamic circulation model with high spatial resolution and dynamic wind forcing is useful. We applied the two-dimensional version of the Princeton Ocean Model to separate the influences of wind and river discharge on the currents and mass transport in Lake Tegel. For model validation, we compared the simulation results with 1?year of electrical conductivity data, which was used as a conservative tracer to distinguish between water from the River Havel and water supplied by a smaller second inflow. Calculation of currents alone is insufficient to investigate water exchanges between rivers and lakes, especially when several islands create multiple pathways for river intrusion. Therefore, mass transport simulations are applied. Our calculations based on archetypical scenarios indicate that the proportion of (polluted) water from the River Havel in the main basin of Lake Tegel fluctuates with river discharge and wind, which either amplify or neutralize each other. 相似文献
996.
Environmental variability, costs of reproduction, and heterogeneity in individual quality are three important sources of the temporal and interindividual variations in vital rates of wild populations. Based on an 18-year monitoring of an endangered, recently described, long-lived seabird, Monteiro's Storm-Petrel (Oceanodroma monteiroi), we designed multistate survival models to separate the effects of the reproductive cost (breeders vs. nonbreeders) and individual quality (successful vs. unsuccessful breeders) in relation to temporally variable demographic and oceanographic properties. The analysis revealed a gradient of individual quality from nonbreeders, to unsuccessful breeders, to successful breeders. The survival rates of unsuccessful breeders (0.90 +/- 0.023, mean +/- SE) tended to decrease in years of high average breeding success and were more sensitive to oceanographic variation than those of both (high-quality) successful breeders (0.97 +/- 0.015) and (low-quality) nonbreeders (0.83 +/- 0.028). Overall, our results indicate that reproductive costs act on individuals of intermediate quality and are mediated by environmental harshness. 相似文献
997.
Tommy Kristensen Anders Isberg Nielsen Anders Isak J?rgensen Kim N. Mouritsen Henrik Glenner Jens T. Christensen J?rgen Lützen Jens T. H?eg 《Marine Biology》2012,159(9):2015-2023
Male crabs infected by parasitic barnacles (Rhizocephala) are known to be morphologically feminized. Here, we investigate morphological chances in green crabs, Carcinus maenas, induced by the parasitic barnacle Sacculina carcini. Infected males acquire a broader, longer and segmented abdomen, fringed with marginal setae. Copulatory appendages and pereopods are reduced in length, and the chelae become smaller. The feminization show great individual variation. Males with scars from lost externae, the parasites reproductive organ situated under the abdomen, are less modified than males carrying an externa, and the feminization is more pronounced in smaller than in larger males. No super-feminization is evident in female crabs that remain morphologically unaffected by infection. The protective value of a parasitically induced enlargement of the male abdomen may constitute an adaptation that increases parasite longevity. The additional effects on male morphology are viewed as pleiotropic side effects of the main adaptive value of enlarging the abdomen. 相似文献
998.
Benoit Lebreton Pierre Richard Robert Galois Gilles Radenac Amel Brahmia Géraldine Colli Marig Grouazel Cyril André Ga?l Guillou Gérard F. Blanchard 《Marine Biology》2012,159(7):1537-1550
In an intertidal Zostera noltii Hornem seagrass bed, food sources used by sediment meiofauna were determined seasonally by comparing stable isotope signatures (δ13C, δ15N) of sources with those of nematodes and copepods. Proportions of different carbon sources used by consumers were estimated using the SIAR mixing model on δ13C values. Contrary to δ15N values, food source mean δ13C values encompassed a large range, from −22.1 ‰ (suspended particulate organic matter) to −10.0 ‰ (Z. noltii roots). δ13C values of copepods (from −22.3 to −12.3 ‰) showed that they use many food sources (benthic and phytoplanktonic microalgae, Z. noltii matter). Nematode δ13C values ranged from −14.6 to −11.4 ‰, indicating a strong role of microphytobenthos and/or Z. noltii matter as carbon sources. The difference of food source uses between copepods and nematodes is discussed in light of source accessibility and availability. 相似文献
999.
Songül Akbulut Özen Necati Celik Emrehan Dursun Halim Taskın 《Environmental geochemistry and health》2018,40(3):1111-1125
In this study, indoor and outdoor radon (222Rn) surveys were carried out in the summer and winter seasons in homes of one hundred lung cancer patients in the year 2013–2014. The aim was to investigate the relationship between radon and cancer patients. Lung cancer patients completed a questionnaire concerning their living environment, various physical parameters and living habits. Pearson correlation and t tests revealed no meaningful results between radon concentrations, on one hand, and environmental and personal living habits, on the other hand. Consequently, the BEIR VI model was adapted and 222Rn exposure was estimated to be responsible for about 12% of the lung cancer incidences in the winter season and around 5% in the summer season in the Rize Province. However, due to the limited number of data and numerous parameters that could lead to lung cancer, the estimations done with the model should be taken very lightly. The annual effective doses due to inhalation of indoor and outdoor 222Rn were estimated to be, respectively, 1.43 and 0.94 mSv y?1. The indoor and outdoor annual effective doses were, respectively, close and below the world annual effective dose (1.3 mSv y?1). At the district level, the indoor annual effective dose equivalent in the ?yidere district was 4.52 mSv y?1, which was 3.5 times greater than the world average. The number of patients in the majority of the houses in this district was more than one. 相似文献
1000.
Spherical TiO2 nanoparticles (npTiO2) were prepared by controlled hydrolysis of tetraethoxy orthotitanate under a nitrogen atmosphere. ZnO nanoparticles (npZnO) were prepared using hydrothermal methods. The crystal structure, chemical, thermal and morphological properties of npZnO and npTiO2 were characterised using Fourier Transform Infrared Spectrometer, enery-dispersive X-ray spectroscopy, X-ray diffraction, and scanning electron microscope techniques. The short- and long-term experiments were started with neonates taken from the same culture and laboratory condition. In the acute experiments, npTiO2, npZnO, and cocktail concentrations were applied. 96h-LC50 values were 1.8, 0.7, and 0.1?mg?L?1, respectively (p?<?.05). For the chronic experiments, different npTiO2 concentrations were performed. 21d-LC50 value was 1.0?mgL?1 (p?<?.05). Morphometry became progressively worse in concentrations of more than 1?mgL?1 npTiO2. Neonate and young individuals were more sensitive to death because of their low tolerance. This result was affected by population progeny and growth rates (p?<?.05). While control and 0.5?mgL?1 npTiO2 groups were determined as growing population, 1.5 and 2?mgL?1 npTiO2 groups had decreased population size as R0 values. Consequently, the relationships between nanoparticle accumulation within Daphnia magna and its population structure and body morphometry for each concentration were important indicators. Its tolerance level to nanoparticles under laboratory conditions reflected its replacement and behaviour in the ecosystem. 相似文献