全文获取类型
收费全文 | 7679篇 |
免费 | 216篇 |
国内免费 | 32篇 |
专业分类
安全科学 | 208篇 |
废物处理 | 503篇 |
环保管理 | 779篇 |
综合类 | 957篇 |
基础理论 | 1785篇 |
环境理论 | 9篇 |
污染及防治 | 2510篇 |
评价与监测 | 652篇 |
社会与环境 | 451篇 |
灾害及防治 | 73篇 |
出版年
2023年 | 77篇 |
2022年 | 198篇 |
2021年 | 238篇 |
2020年 | 106篇 |
2019年 | 130篇 |
2018年 | 288篇 |
2017年 | 242篇 |
2016年 | 380篇 |
2015年 | 236篇 |
2014年 | 431篇 |
2013年 | 841篇 |
2012年 | 469篇 |
2011年 | 505篇 |
2010年 | 395篇 |
2009年 | 310篇 |
2008年 | 430篇 |
2007年 | 440篇 |
2006年 | 363篇 |
2005年 | 267篇 |
2004年 | 229篇 |
2003年 | 205篇 |
2002年 | 201篇 |
2001年 | 138篇 |
2000年 | 110篇 |
1999年 | 72篇 |
1998年 | 34篇 |
1997年 | 29篇 |
1996年 | 17篇 |
1995年 | 46篇 |
1994年 | 39篇 |
1993年 | 19篇 |
1992年 | 22篇 |
1991年 | 18篇 |
1990年 | 16篇 |
1989年 | 12篇 |
1988年 | 13篇 |
1985年 | 9篇 |
1967年 | 9篇 |
1966年 | 15篇 |
1965年 | 16篇 |
1964年 | 32篇 |
1963年 | 12篇 |
1962年 | 18篇 |
1961年 | 13篇 |
1960年 | 10篇 |
1959年 | 27篇 |
1958年 | 37篇 |
1957年 | 22篇 |
1956年 | 14篇 |
1955年 | 19篇 |
排序方式: 共有7927条查询结果,搜索用时 15 毫秒
1.
Merçon Julia Silva Cabral Dandara Chisté Teixeira Bárbara Miura Pereira Tatiana Magalhães Bona Alliny Valadares Locateli Armini Catharina do Nascimento Agostinho Silvia Gabriela Carvalho Gomes Levy 《Environmental science and pollution research international》2021,28(47):66643-66655
Environmental Science and Pollution Research - The Fundão Dam collapsed, on November 5th, 2015, dumping more than 50 million/m3 of iron ore tailings, enriched with metals, into the Doce River... 相似文献
2.
Carvalho Laíse M. Soares-Filho Antônio F. Lima Maciel S. Cruz-Filho João F. Dantas Taisa C. M. Luz Geraldo E. 《Environmental science and pollution research international》2021,28(7):7774-7785
Environmental Science and Pollution Research - A current environmental problem is the uncontrolled use of various pesticides that are harmful to the environment and public health. The herbicide... 相似文献
3.
Understanding implications of consumer behavior for wildlife farming and sustainable wildlife trade
下载免费PDF全文
![点击此处可从《Conservation biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A. Nuno J. M. Blumenthal T. J. Austin J. Bothwell G. Ebanks‐Petrie B. J. Godley A. C. Broderick 《Conservation biology》2018,32(2):390-400
Unsustainable wildlife trade affects biodiversity and the livelihoods of communities dependent upon those resources. Wildlife farming has been proposed to promote sustainable trade, but characterizing markets and understanding consumer behavior remain neglected but essential steps in the design and evaluation of such operations. We used sea turtle trade in the Cayman Islands, where turtles have been farm raised for human consumption for almost 50 years, as a case study to explore consumer preferences toward wild‐sourced (illegal) and farmed (legal) products and potential conservation implications. Combining methods innovatively (including indirect questioning and choice experiments), we conducted a nationwide trade assessment through in‐person interviews from September to December 2014. Households were randomly selected using disproportionate stratified sampling, and responses were weighted based on district population size. We approached 597 individuals, of which 37 (6.2%) refused to participate. Although 30% of households had consumed turtle in the previous 12 months, the purchase and consumption of wild products was rare (e.g., 64–742 resident households consumed wild turtle meat [i.e., 0.3–3.5% of households] but represented a large threat to wild turtles in the area due to their reduced populations). Differences among groups of consumers were marked, as identified through choice experiments, and price and source of product played important roles in their decisions. Despite the long‐term practice of farming turtles, 13.5% of consumers showed a strong preference for wild products, which demonstrates the limitations of wildlife farming as a single tool for sustainable wildlife trade. By using a combination of indirect questioning, choice experiments, and sales data to investigate demand for wildlife products, we obtained insights about consumer behavior that can be used to develop conservation‐demand‐focused initiatives. Lack of data from long‐term social–ecological assessments hinders the evaluation of and learning from wildlife farming. This information is key to understanding under which conditions different interventions (e.g., bans, wildlife farming, social marketing) are likely to succeed. 相似文献
4.
Fishing‐gear restrictions and biomass gains for coral reef fishes in marine protected areas
下载免费PDF全文
![点击此处可从《Conservation biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Stuart J. Campbell Graham J. Edgar Rick D. Stuart‐Smith German Soler Amanda E. Bates 《Conservation biology》2018,32(2):401-410
Considerable empirical evidence supports recovery of reef fish populations with fishery closures. In countries where full exclusion of people from fishing may be perceived as inequitable, fishing‐gear restrictions on nonselective and destructive gears may offer socially relevant management alternatives to build recovery of fish biomass. Even so, few researchers have statistically compared the responses of tropical reef fisheries to alternative management strategies. We tested for the effects of fishery closures and fishing gear restrictions on tropical reef fish biomass at the community and family level. We conducted 1,396 underwater surveys at 617 unique sites across a spatial hierarchy within 22 global marine ecoregions that represented 5 realms. We compared total biomass across local fish assemblages and among 20 families of reef fishes inside marine protected areas (MPAs) with different fishing restrictions: no‐take, hook‐and‐line fishing only, several fishing gears allowed, and sites open to all fishing gears. We included a further category representing remote sites, where fishing pressure is low. As expected, full fishery closures, (i.e., no‐take zones) most benefited community‐ and family‐level fish biomass in comparison with restrictions on fishing gears and openly fished sites. Although biomass responses to fishery closures were highly variable across families, some fishery targets (e.g., Carcharhinidae and Lutjanidae) responded positively to multiple restrictions on fishing gears (i.e., where gears other than hook and line were not permitted). Remoteness also positively affected the response of community‐level fish biomass and many fish families. Our findings provide strong support for the role of fishing restrictions in building recovery of fish biomass and indicate important interactions among fishing‐gear types that affect biomass of a diverse set of reef fish families. 相似文献
5.
Francisco M. Baena-Moreno Mónica Rodríguez-Galán Fernando Vega Luis F. Vilches Benito Navarrete 《International Journal of Green Energy》2019,16(5):401-412
Biomethane production through biogas upgrading is a promising renewable energy for some industries which could be part of the equilibrium needed with fossil fuels consumption to achieve a sustainable society. This paper presents a comprehensive list of biogas upgrading technologies focused on carbon dioxide removal as well as recent advances reported by researcher with wide expertise in this topic. Additionally, an extensive costs–performance comparison among the technologies studied is discussed. Among the different alternatives, chemical scrubbing stood out to achieve high biomethane purities while cryogenic technologies proved to be effective against methane losses. Regarding the different costs, water scrubbing and membrane separation seem to be the most affordable techniques. 相似文献
6.
Rocío Mariano-Jelicich Florencia Botto Paulina Martinetto Oscar Iribarne Marco Favero 《Marine Biology》2008,155(4):443-450
The degree of individual or gender variation when exploiting food resources is an important aspect in the study of foraging
ecology within a population. Previous information on non-breeding skimmers obtained through conventional methodologies suggested
sex-related differences in prey species. In this study, stable isotope techniques were used to investigate the intraspecific
segregation in diet and foraging habits of the Black Skimmer (Rynchops niger intercedens) at Mar Chiquita Coastal Lagoon (37°40′S, 57°22′W), Argentina. These results were compared with contemporary data on the
trophic composition obtained by conventional methodologies. Blood samples were taken from birds captured with mist-nets during
their non-breeding season. The isotopic signatures of skimmers showed a diet mainly composed of marine prey with some degree
of estuarine fish intake. When comparing diet between sexes, males showed enrichment in 15N compared to females, while no differences were observed in 13C. The use of mixing models revealed differences in the relative composition of prey in the diet of male and female skimmers.
This study highlights stable isotope analysis as a valuable tool to test inter-individual differences and sexual segregation
in trophic ecology of Black Skimmers as compared to conventional methodologies. The results show a trophic segregation in
the Black Skimmer during the non-breeding season that can be explained by differences in prey species and larger prey sizes
of male skimmers. Our findings have significant implications for conservation since any environmental change occurring at
wintering areas might have profound effects on several avian life-history traits, and could be different for males and females
due to trophic segregation. 相似文献
7.
8.
F. Rincón-León G. Zurera-Cosano R. Moreno-Rojas M. Amaro-López 《Environmental monitoring and assessment》1993,27(3):193-200
The importance of eating habits and the number of fish sampled in the estimation of mercury environmental contamination through biological indicators was studied. The species used were one with piscivorous habits (Anguilla anguilla) and another with omnivorous habits (Ciprinus carpio). From one original sample for each species, randomized samples were generated using the subroutine GGSRS from the mathematics library IMSL, and later the statistical significance of Pearson's correlation coefficient for the relationship between fish weight and mercury concentrations in muscle was obtained for each random sample. The results show that the use of omnivorous species such as Ciprinus carpio as a biological indicator of contamination enables us to carry out estimations with a greater degree of confidence than when piscivorous species such as Anguilla anguilla are used. 相似文献
9.
The structure of the choroid plexus was studied in five normal human embryos, three normal fetuses and three fetuses with choroid plexus cysts. These were detected by ultrasound and the fetuses were karyotypically normal. The choroid plexus appears in the lateral cerebral ventricles at the seventh developmental week. The early structure is lobulated with vessels running in the mesenchymal stroma and forming capillary nets under the single-layered ependymal epithelium. This embryonal structure is converted into the fetal type during the ninth developmental week as the embryonal capillary net is replaced by elongated loops of wavy capillaries that lie under regular longitudinal epithelial folds. The choroid plexus cysts exhibited accumulation of fluid within distended mesenchymal stroma and did not show the wavy folds on this surface, which was smooth. Within this connective tissue of the cyst wall were distended angiomatous interconnecting thin-walled capillaries. Therefore, filled cavities were not lined by any epithelium. We suggest that fetal choroid plexuses cysts (at least in many cases) are in fact pseudocysts exhibiting angiomatous patterns of capillaries in their walls. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
10.