全文获取类型
收费全文 | 31345篇 |
免费 | 262篇 |
国内免费 | 326篇 |
专业分类
安全科学 | 825篇 |
废物处理 | 1420篇 |
环保管理 | 3633篇 |
综合类 | 5468篇 |
基础理论 | 7888篇 |
环境理论 | 9篇 |
污染及防治 | 8187篇 |
评价与监测 | 2365篇 |
社会与环境 | 1956篇 |
灾害及防治 | 182篇 |
出版年
2022年 | 310篇 |
2021年 | 302篇 |
2020年 | 191篇 |
2019年 | 258篇 |
2018年 | 477篇 |
2017年 | 474篇 |
2016年 | 760篇 |
2015年 | 530篇 |
2014年 | 868篇 |
2013年 | 2483篇 |
2012年 | 1010篇 |
2011年 | 1299篇 |
2010年 | 1131篇 |
2009年 | 1169篇 |
2008年 | 1312篇 |
2007年 | 1390篇 |
2006年 | 1244篇 |
2005年 | 1073篇 |
2004年 | 1033篇 |
2003年 | 1018篇 |
2002年 | 965篇 |
2001年 | 1326篇 |
2000年 | 901篇 |
1999年 | 588篇 |
1998年 | 381篇 |
1997年 | 374篇 |
1996年 | 413篇 |
1995年 | 420篇 |
1994年 | 391篇 |
1993年 | 335篇 |
1992年 | 363篇 |
1991年 | 349篇 |
1990年 | 351篇 |
1989年 | 332篇 |
1988年 | 316篇 |
1987年 | 242篇 |
1986年 | 233篇 |
1985年 | 244篇 |
1984年 | 271篇 |
1983年 | 255篇 |
1982年 | 287篇 |
1981年 | 237篇 |
1980年 | 193篇 |
1979年 | 230篇 |
1978年 | 207篇 |
1977年 | 180篇 |
1976年 | 179篇 |
1975年 | 161篇 |
1974年 | 176篇 |
1972年 | 150篇 |
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
921.
922.
CARLOS CARROLL JOHN A. VUCETICH MICHAEL P. NELSON DANIEL J. ROHLF MICHAEL K. PHILLIPS 《Conservation biology》2010,24(2):395-403
Abstract: The U.S. Endangered Species Act (ESA) defines an endangered species as one “at risk of extinction throughout all or a significant portion of its range.” The prevailing interpretation of this phrase, which focuses exclusively on the overall viability of listed species without regard to their geographic distribution, has led to development of listing and recovery criteria with fundamental conceptual, legal, and practical shortcomings. The ESA's concept of endangerment is broader than the biological concept of extinction risk in that the “esthetic, ecological, educational, historical, recreational, and scientific” values provided by species are not necessarily furthered by a species mere existence, but rather by a species presence across much of its former range. The concept of “significant portion of range” thus implies an additional geographic component to recovery that may enhance viability, but also offers independent benefits that Congress intended the act to achieve. Although the ESA differs from other major endangered‐species protection laws because it acknowledges the distinct contribution of geography to recovery, it resembles the “representation, resiliency, and redundancy” conservation‐planning framework commonly referenced in recovery plans. To address representation, listing and recovery standards should consider not only what proportion of its former range a species inhabits, but the types of habitats a species occupies and the ecological role it plays there. Recovery planning for formerly widely distributed species (e.g., the gray wolf [Canis lupus]) exemplifies how the geographic component implicit in the ESA's definition of endangerment should be considered in determining recovery goals through identification of ecologically significant types or niche variation within the extent of listed species, subspecies, or “distinct population segments.” By linking listing and recovery standards to niche and ecosystem concepts, the concept of ecologically significant type offers a scientific framework that promotes more coherent dialogue concerning the societal decisions surrounding recovery of endangered species. 相似文献
923.
Leon S. Dochinger 《Journal of the Air & Waste Management Association (1995)》2013,63(12):814-816
Chlorotic dwarf is a serious disorder of eastern white pine (Pinus strobus L) in young plantations. Diseased trees are stunted and possess only current mottled foliage. Investigations into this problem were to define its symptomatology and etiology and to develop measures for control. Previous work had shown that susceptibility to chlorotic dwarf is genetically controlled and that the disease results from an aerological agent acting directly upon the foliage. By controlling the atmospheres around chlorotic dwarf field trees, evidence was obtained to prove that chlorotic dwarf is effected by the injury of gaseous dispersoids on the foliage of susceptible individuals. 相似文献
924.
Effectiveness of Scat‐Detection Dogs in Determining Species Presence in a Tropical Savanna Landscape
CARLY VYNNE JOHN R. SKALSKI RICARDO B. MACHADO MARTHA J. GROOM ANAH T. A. JÁCOMO JADER MARINHO‐FILHO MARIO B. RAMOS NETO CRISTINA POMILLA LEANDRO SILVEIRA HEATH SMITH SAMUEL K. WASSER 《Conservation biology》2011,25(1):154-162
Abstract: Most protected areas are too small to sustain populations of wide‐ranging mammals; thus, identification and conservation of high‐quality habitat for those animals outside parks is often a high priority, particularly for regions where extensive land conversion is occurring. This is the case in the vicinity of Emas National Park, a small protected area in the Brazilian Cerrado. Over the last 40 years the native vegetation surrounding the park has been converted to agriculture, but the region still supports virtually all of the animals native to the area. We determined the effectiveness of scat‐detection dogs in detecting presence of five species of mammals threatened with extinction by habitat loss: maned wolf (Chrysocyon brachyurus), puma (Puma concolor), jaguar (Panthera onca), giant anteater (Myrmecophaga tridactyla), and giant armadillo (Priodontes maximus). The probability of scat detection varied among the five species and among survey quadrats of different size, but was consistent across team, season, and year. The probability of occurrence, determined from the presence of scat, in a randomly selected site within the study area ranged from 0.14 for jaguars, which occur primarily in the forested areas of the park, to 0.91 for maned wolves, the most widely distributed species in our study area. Most occurrences of giant armadillos in the park were in open grasslands, but in the agricultural matrix they tended to occur in riparian woodlands. At least one target species occurred in every survey quadrat, and giant armadillos, jaguars, and maned wolves were more likely to be present in quadrats located inside than outside the park. The effort required for detection of scats was highest for the two felids. We were able to detect the presence for each of five wide‐ranging species inside and outside the park and to assign occurrence probabilities to specific survey sites. Thus, scat dogs provide an effective survey tool for rare species even when accurate detection likelihoods are required. We believe the way we used scat‐detection dogs to determine the presence of species can be applied to the detection of other mammalian species in other ecosystems. 相似文献
925.
Abstract: As zebra mussels (Dreissena polymorpha) continue to spread among inland lakes of the United States and Canada, there is growing interest from professionals, citizens, and other stakeholders to know which lakes are likely to be colonized by zebra mussels. Thus, we developed a classification of lake suitability for zebra mussels on the basis of measured or estimated concentrations of dissolved calcium in lake water and applied the classification to >11,500 lakes in Wisconsin and the Upper Peninsula of Michigan. The majority of lakes (58%) were classified as unsuitable (<10 mg/L Ca) for survival and reproduction of zebra mussels, 27% were identified as suitable (≥21 mg/L Ca), and 15% were classified as borderline suitable (≥10 and <21 mg/L Ca). Of the 77 inland lakes with confirmed zebra mussel records for which data on dissolved calcium were available, our method classified 74 as suitable and 3 as borderline suitable. To communicate this lake‐specific suitability information and to help prioritize regional efforts to monitor and prevent the expansion of zebra mussels and other invasive species, we developed a web‐based interface (available from http://www.aissmartprevention.wisc.edu/ ). Although we are still uncertain of how access to suitability information ultimately affects decision making, we believe this is a useful case study of building communication channels among researchers, practitioners, and the public. 相似文献
926.
Macías-Vargas José-Alberto Campos-Mañas Marina Celia Agüera Ana Sánchez Pérez José Antonio Ramírez-Zamora Rosa-María 《Environmental science and pollution research international》2021,28(19):24008-24022
Environmental Science and Pollution Research - In this work, the activated persulfate oxidation of ciprofloxacin (CIP) using a low-grade titanium ore under sunlight or simulated sunlight were... 相似文献
927.
Luo Yang Wu Yinghong Ma Shuhua Zheng Shili Zhang Yi Chu Paul K. 《Environmental science and pollution research international》2021,28(15):18727-18740
Environmental Science and Pollution Research - The rapid economic development in China places a large demand for energy, and as a result, thermal power plants in China are producing an enormous... 相似文献
928.
Suneel V. Sathish Kumar S. Balaji R. Vethamony P. 《Environmental science and pollution research international》2021,28(14):17181-17199
Environmental Science and Pollution Research - Formation of oil-suspended sediment aggregates (OSAs) is believed to be one of the natural cleaning processes in the marine environment. In this... 相似文献
929.
Novack Aline M. dos Reis Glaydson S. Hackbarth Fabíola V. Marinho Belisa A. Ðolić Maja B. Valle José A. B. Sampaio Carlos H. Lima Eder C. Dotto Guillherme L. Ulson de Souza Antônio Augusto Vilar Vítor J. P. Guelli Ulson de Souza Selene M. A. 《Environmental science and pollution research international》2021,28(19):23568-23581
Environmental Science and Pollution Research - This paper presents the synthesis of a hybrid material through the use of natural pozzolan and titanium(IV) isopropoxide using the sol-gel method and... 相似文献
930.
Sá Roberson Davis Rodríguez-Pérez Adriana Patricia Rodrigues-Silva Fernando de Paula Vinicius de Carvalho Soares Prola Liziê Daniela Tentler de Freitas Adriane Martins de Carvalho Karina Querne de Liz Marcus Vinicius 《Environmental science and pollution research international》2021,28(19):24180-24190
Environmental Science and Pollution Research - The photo-Fenton process was performed with four radiation settings to treat clinical analysis laboratory wastewater (CALWW) from a hospital, with the... 相似文献