全文获取类型
收费全文 | 1108篇 |
免费 | 166篇 |
国内免费 | 125篇 |
专业分类
安全科学 | 37篇 |
废物处理 | 6篇 |
环保管理 | 265篇 |
综合类 | 579篇 |
基础理论 | 307篇 |
环境理论 | 4篇 |
污染及防治 | 29篇 |
评价与监测 | 38篇 |
社会与环境 | 107篇 |
灾害及防治 | 27篇 |
出版年
2024年 | 11篇 |
2023年 | 30篇 |
2022年 | 34篇 |
2021年 | 45篇 |
2020年 | 39篇 |
2019年 | 52篇 |
2018年 | 27篇 |
2017年 | 53篇 |
2016年 | 44篇 |
2015年 | 51篇 |
2014年 | 41篇 |
2013年 | 80篇 |
2012年 | 94篇 |
2011年 | 78篇 |
2010年 | 51篇 |
2009年 | 53篇 |
2008年 | 56篇 |
2007年 | 62篇 |
2006年 | 55篇 |
2005年 | 51篇 |
2004年 | 50篇 |
2003年 | 35篇 |
2002年 | 31篇 |
2001年 | 37篇 |
2000年 | 29篇 |
1999年 | 20篇 |
1998年 | 37篇 |
1997年 | 28篇 |
1996年 | 16篇 |
1995年 | 18篇 |
1994年 | 17篇 |
1993年 | 8篇 |
1992年 | 11篇 |
1991年 | 4篇 |
1990年 | 7篇 |
1989年 | 5篇 |
1988年 | 10篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1971年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有1399条查询结果,搜索用时 234 毫秒
71.
Stefan Gelcich Miriam Fernández Natalio Godoy Antonio Canepa Luis Prado Juan Carlos Castilla 《Conservation biology》2012,26(6):1005-1015
Territorial user rights for fisheries have been advocated as a way to achieve sustainable resource management. However, few researchers have empirically assessed their potential as ancillary marine conservation instruments by comparing them to no‐take marine protected areas. In kelp (Lessonia trabeculata) forests of central Chile, we compared species richness, density, and biomass of macroinvertebrates and reef fishes among territorial‐user‐right areas with low‐level and high‐level enforcement, no‐take marine protected areas, and open‐access areas in 42 100‐m subtidal transects. We also assessed structural complexity of the kelp forest and substratum composition. Multivariate randomized permutation tests indicated macroinvertebrate and reef fish communities associated with the different access regimes differed significantly. Substratum composition and structural complexity of kelp forest did not differ among access regimes. Univariate analyses showed species richness, biomass, and density of macroinvertebrates and reef fishes were greater in highly enforced territorial‐user‐right areas and no‐take marine protected areas than in open‐access areas. Densities of macroinvertebrates and reef fishes of economic importance were not significantly different between highly enforced territorial‐user‐right and no‐take marine protected areas. Densities of economically important macroinvertebrates in areas with low‐level enforcement were significantly lower than those in areas with high‐level enforcement and no‐take marine protected areas but were significantly higher than in areas with open access. Territorial‐user‐right areas could be important ancillary conservation instruments if they are well enforced. Derechos de Usuario Territoriales para Pesquerías como Instrumentos Accesorios para la Conservación Marina Costera en Chile 相似文献
72.
KIRSTIN K. HOLSMAN MARK D. SCHEUERELL ERIC BUHLE ROBERT EMMETT 《Conservation biology》2012,26(5):912-922
Abstract: Captive rearing and translocation are often used concurrently for species conservation, yet the effects of these practices can interact and lead to unintended outcomes that may undermine species’ recovery efforts. Controls in translocation or artificial‐propagation programs are uncommon; thus, there have been few studies on the interacting effects of these actions and environmental conditions on survival. The Columbia River basin, which drains 668,000 km2 of the western United States and Canada, has an extensive network of hydroelectric and other dams, which impede and slow migration of anadromous Pacific salmon (Oncorhynchus spp.) and can increase mortality rates. To mitigate for hydrosystem‐induced mortality during juvenile downriver migration, tens of millions of hatchery fish are released each year and a subset of wild‐ and hatchery‐origin juveniles are translocated downstream beyond the hydropower system. We considered how the results of these practices interact with marine environmental conditions to affect the marine survival of Chinook salmon (O. tshawytscha). We analyzed data from more than 1 million individually tagged fish from 1998 through 2006 to evaluate the probability of an individual fish returning as an adult relative to its rearing (hatchery vs. wild) and translocation histories (translocated vs. in‐river migrating fish that traveled downriver through the hydropower system) and a suite of environmental variables. Except during select periods of very low river flow, marine survival of wild translocated fish was approximately two‐thirds less than survival of wild in‐river migrating fish. For hatchery fish, however, survival was roughly two times higher for translocated fish than for in‐river migrants. Competition and predator aggregation negatively affected marine survival, and the magnitude of survival depended on rearing and translocation histories and biological and physical conditions encountered during their first few weeks of residence in the ocean. Our results highlight the importance of considering the interacting effects of translocation, artificial propagation, and environmental variables on the long‐term viability of species. 相似文献
73.
David Sztybel 《Journal of Agricultural and Environmental Ethics》2001,14(3):259-273
Even if animal liberation were to be adopted, would rights for animals be redundant – or even deleterious? Such an objection, most prominently voiced by L. W. Sumner and Paul W. Taylor, is misguided, risks an anthropocentric and anthropomorphic conception of autonomy and freedom, overly agent-centered rights conceptions, and an overlooking of the likely harmful consequences of positing rights for humans but not for nonhuman animals. The objection in question also stems from an overly pessimistic construal of autonomy-infringements thought to result from extending rights to animals, and also, of confusions that supposedly may ensue from ascribing animal rights. Whether or not a case for animal liberation and/or animal rights can cogently be made, the redundancy-or-worse objection to animal rights need pose no barrier. 相似文献
74.
MAYEUL DALLEAU SERGE ANDRÉFOUËT COLETTE C.C. WABNITZ CLAUDE PAYRI LAURENT WANTIEZ MICHEL PICHON KIM FRIEDMAN LAURENT VIGLIOLA FRANCESCA BENZONI 《Conservation biology》2010,24(2):541-552
Abstract: Marine protected areas (MPAs) have been highlighted as a means toward effective conservation of coral reefs. New strategies are required to more effectively select MPA locations and increase the pace of their implementation. Many criteria exist to design MPA networks, but generally, it is recommended that networks conserve a diversity of species selected for, among other attributes, their representativeness, rarity, or endemicity. Because knowledge of species’ spatial distribution remains scarce, efficient surrogates are urgently needed. We used five different levels of habitat maps and six spatial scales of analysis to identify under which circumstances habitat data used to design MPA networks for Wallis Island provided better representation of species than random choice alone. Protected‐area site selections were derived from a rarity–complementarity algorithm. Habitat surrogacy was tested for commercial fish species, all fish species, commercially harvested invertebrates, corals, and algae species. Efficiency of habitat surrogacy varied by species group, type of habitat map, and spatial scale of analysis. Maps with the highest habitat thematic complexity provided better surrogates than simpler maps and were more robust to changes in spatial scales. Surrogates were most efficient for commercial fishes, corals, and algae but not for commercial invertebrates. Conversely, other measurements of species‐habitat associations, such as richness congruence and composition similarities provided weak results. We provide, in part, a habitat‐mapping methodology for designation of MPAs for Pacific Ocean islands that are characterized by habitat zonations similar to Wallis. Given the increasing availability and affordability of space‐borne imagery to map habitats, our approach could appreciably facilitate and improve current approaches to coral reef conservation and enhance MPA implementation. 相似文献
75.
J. M. Bewers 《Chemistry and Ecology》2013,29(1-2):9-23
Abstract Differences between the scientific and environmental policy communities regarding marine environmental protection strategies are discussed in the context of the nature and extent of scientific influence on marine environmental policy. Public perceptions of the nature and severity of marine pollution frequently differ from scientific assessments. the thesis of this paper is that the increasing influence of public perception on marine environmental protection policy is leading to the adoption of simplistic and unnecessarily extreme approaches to marine pollution prevention and to a reduced reliance on science. This trend is illustrated by some recent international developments and some suggestions are made towards enhancing the influence of science on marine protection policy. 相似文献
76.
JULIO A. BAISRE 《Conservation biology》2013,27(5):927-935
The recent extnction of the Caribbean monk seal Monachus tropicalis has been considered an example of a human‐caused extinction in the marine environment, and this species was considered a driver of the changes that have occurred in the structure of Caribbean coral reef ecosystems since colonial times. I searched archaeological records, historical data, and geographic names (used as a proxy of the presence of seals) and evaluated the use and quality of these data to conclude that since prehistoric times the Caribbean monk seal was always rare and vulnerable to human predation. This finding supports the hypothesis that in AD 1500, the Caribbean monk seal persisted as a small fragmented population in which individuals were confined to small keys, banks, or isolated islands in the Gulf of Mexico and the Caribbean Sea. This hypothesis is contrary to the assumption that the species was widespread and abundant historically. The theory that the main driver of monk seal extinction was harvesting for its oil for use in the sugar cane industry of Jamaica during the 18th century is based primarily on anecdotal information and is overemphasized in the literature. An analysis of reported human encounters with this species indicates monk seal harvest was an occasional activity, rather than an ongoing enterprise. Nevertheless, given the rarity of this species and its restricted distribution, even small levels of hunting or specimen collecting must have contributed to its extinction, which was confirmed in the mid‐20th century. Some sources had been overlooked or only partially reviewed, others misinterpreted, and a considerable amount of anecdotal information had been uncritically used. Critical examination of archaeological and historical records is required to infer accurate estimations of the historical abundance of a species. In reconstructing the past to address the shifting baseline syndrome, it is important to avoid selecting evidence to confirm modern prejudices. Puntos de Referencia Cambiantes y la Extinción de la Foca Monje Caribeña 相似文献
77.
Responsibility as a dual to human rights is presented as a moral alternative to extended, complex systems of animal and ecological rights. This simple idea of responsibility is then applied to four levels of agricultural technology: animal (nature) rights, conservation, organization of agriculture, and people versus planet relationships. The stewardship argument is freed from at least some of the complications of animal rights and ecology, but leaves responsibility with humans to do the right thing.The views expressed are the author's and do not necessarily represent policies or views of the U.S. Department of Agriculture. 相似文献
78.
Evelyn Pluhar 《Journal of Agricultural and Environmental Ethics》1990,3(2):147-171
The ethical theory underlying much of our treatment of animals in agriculture and research is the moral agency view. It is assumed that only moral agents, or persons, are worthy of maximal moral significance, and that farm and laboratory animals are not moral agents. However, this view also excludes human non-persons from the moral community. Utilitarianism, which bids us maximize the amount of good (utility) in the world, is an alternative ethical theory. Although it has many merits, including impartiality and the extension of moral concern to all sentient beings, it also appears to have many morally unacceptable implications. In particular, it appears to sanction the killing of innocents when utility would be maximized, including cases in which we would deliberately kill and replace a being, as we typically do to animals on farms and in laboratories. I consider a number of ingenious recent attempts by utilitarians to defeat the killing and replaceability arguments, including the attempt to make a place for genuine moral rights within a utilitarian framework. I conclude that utilitarians cannot escape the killing and replaceability objections. Those who reject the restrictive moral agency view and find they cannot accept utilitarianism's unsavory implications must look to a different ethical theory to guide their treatment of humans and non-humans. 相似文献
79.
80.
Joseph W. Dellapenna 《Journal of the American Water Resources Association》1994,30(2):197-204
ABSTRACT: Lawyers, engineers, and hydrologists are accustomed to thinking of water law as falling into one of two incompatible models: riparian rights (under which water is allocated by courts according to the relative reasonableness of the competing uses) and appropriative rights (under which water is allocated according to the temporal priority of the competing uses, largely by the action of the water users themselves but perfected by the issuance of an administrative permit). Usually unnoticed is the existence of a third approach, which I have dubbed “regulated riparianism.” Under regulated riparianism, water is allocated by water permits issued after an administrative determination of the reasonableness of the proposed use before the use is commenced. This system, now in place in about half of the states east of Kansas City (plus Hawaii), thus is fundamentally different from either the traditional ripanan rights that it replaces or the appropriative rights found in western states. 相似文献