全文获取类型
收费全文 | 20249篇 |
免费 | 108篇 |
国内免费 | 106篇 |
专业分类
安全科学 | 325篇 |
废物处理 | 914篇 |
环保管理 | 2278篇 |
综合类 | 4637篇 |
基础理论 | 5120篇 |
环境理论 | 11篇 |
污染及防治 | 4275篇 |
评价与监测 | 1284篇 |
社会与环境 | 1549篇 |
灾害及防治 | 70篇 |
出版年
2022年 | 140篇 |
2021年 | 134篇 |
2018年 | 747篇 |
2017年 | 697篇 |
2016年 | 705篇 |
2015年 | 283篇 |
2014年 | 341篇 |
2013年 | 998篇 |
2012年 | 630篇 |
2011年 | 1236篇 |
2010年 | 852篇 |
2009年 | 953篇 |
2008年 | 1158篇 |
2007年 | 1444篇 |
2006年 | 532篇 |
2005年 | 530篇 |
2004年 | 478篇 |
2003年 | 565篇 |
2002年 | 534篇 |
2001年 | 510篇 |
2000年 | 396篇 |
1999年 | 284篇 |
1998年 | 193篇 |
1997年 | 174篇 |
1996年 | 141篇 |
1995年 | 202篇 |
1994年 | 195篇 |
1993年 | 153篇 |
1992年 | 154篇 |
1991年 | 183篇 |
1990年 | 155篇 |
1989年 | 157篇 |
1988年 | 158篇 |
1987年 | 128篇 |
1985年 | 129篇 |
1984年 | 152篇 |
1983年 | 140篇 |
1982年 | 146篇 |
1981年 | 113篇 |
1980年 | 116篇 |
1979年 | 133篇 |
1978年 | 117篇 |
1977年 | 108篇 |
1974年 | 110篇 |
1967年 | 112篇 |
1965年 | 118篇 |
1964年 | 109篇 |
1963年 | 109篇 |
1961年 | 114篇 |
1957年 | 112篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
E. A. Kleshcheva 《Russian Journal of Ecology》2007,38(2):94-100
A method for estimating the current state of plant communities based on the ecological amplitudes of constituent species is proposed. An original program, Fitoindikatsiya, has been developed to compute the indices of disturbance and homogeneity of plant communities from species ecological scale values. The current state of pine forests in the part of Novosibirsk oblast east of the Ob River has been analyzed; slightly, moderately, and severely disturbed zones have been distinguished. 相似文献
62.
63.
T. Stoichev L. Makedonski T. Trifonova M. Stancheva F. Ribarova 《Chemistry and Ecology》2007,23(3):191-200
In spite of a worldwide reduction in the utilization of organochlorine pesticides (OCPs), they are still a problem for the aquatic environment and human health. The Black Sea is still being polluted with persistent chemicals, including OCPs. Aquatic organisms (sprat, scad, bluefish, shad, belted bonito, goby, and black mussel) with different feeding behaviours were sampled on a seasonal basis from the Bulgarian region of the Black Sea, and the concentrations of 13 OCP residues were determined. Although many of the OCPs were not detected in the samples, in all samples 1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane (DDT) was present mainly in the form of its metabolites 1,1-dichloro-2,2-bis(4-chlorophenyl) ethane (DDD) and 1,1-dichloro-2,2-bis(4-chlorophenyl) ethylene (DDE). Only about 12% of the total DDT was present as the parent compound pp-DDT, which suggests that it was not being used recently in the region. The total DDT concentrations were generally below 150 μg kg-1 fresh weight, but higher levels—up to 354 μg kg-1 fresh weight—were also measured for fish species with a high fat content. Between-species differences were observed, even when the concentrations were presented on a fat-level basis. DDT concentrations did not show any significant changes over the 2-yr sampling period. Fish sampled in the northern areas of the Bulgarian Black Sea coast seemed to contain higher DDT levels than those from the southern areas, suggesting a major (historical) influence of the Danube River. For permanent monitoring purposes, the utility of Black Sea gobies and scad should be considered. 相似文献
64.
Community evacuation following a chlorine release, Mississippi 总被引:1,自引:0,他引:1
On 7th September 1986, four miles north of Collins, Mississippi, a train transporting chlorine derailed. Two cars ruptured and gas escaped. As a result, 100 families were evacuated. To study the evacuation process, we conducted person-to-person interviews with sixty-two families staying in the evacuation center. Only 52.5% of the families received their first directive to evacuate directly from police or other officials. Delays in evacuating tended to be shorter when people were warned by the police and were told the reason for evacuating. Lack of personal transportation and preexisting health problems resulted in delays in evacuation. Concerns about evacuation included fear of looting, lack of a place to go, lack of transportation, difficulty in moving with children and elderly persons, and the need to take care of pets. One third of the interviewees reported feeling panic. Community evacuation procedures would be improved if: (1) officials contact all households directly; (2) the warning message addresses people's concerns; and (3) transportation is provided. 相似文献
65.
Living veligers of the Cassoidea have been observed to use a mantle appendage to form and resorb periostracum. Anatomical and histological examinations of a ranellid (Cymatium sp.) larva collected from the Red Sea in 1987 revealed the structure and location of the pallial appendage. The mantle edges of juvenile or adult species of the Cassoidea do not show a comparable specialization. It is demonstrated that cassoid larval conch characters are sufficient to prove the existence of a pallial appendage without anatomical confirmation. A mantle appendage is not known from teleplanic (long-living planktic) veligers of other gastropod superfamilies. In cases where the larval strategies of the latter are known they are totally different. Therefore it is suggested that the adaptation of cassoid larvae to pelagic life is unique among gastropods representing an autapomorphic character of the superfamily. 相似文献
66.
67.
Indices of abundance and reproduction rate are considered in some groups of aquatic and terrestrial vertebrates from the zones of technogenic disasters. Upon a critical population decline caused by external destructive factors, such as emissions of acute ecotoxicants, the ecophysiological and behavioral compensatory mechanisms are activated, which provide for restoration of the total population size to the optimum within a short period of time. Environmental pollution with substances disturbing the reproductive function has the gravest consequences for animals. In this case, population size may remain fairly high, and, therefore, the effect of enhanced reproduction as a response to population decline does not take place, which eventually leads to a gradual but irreversible destruction of the population. Pathologies of reproduction should be used as a criterion for assessing the state of animals in the zones of technogenic disasters.Translated from Ekologiya, No. 1, 2005, pp. 32–38.Original Russian Text Copyright © 2005 by Shilova, Shatunovskii. 相似文献
68.
5p deletion syndrome commonly known as cri du chat is well described in affected neonates with catlike cry and hypotonia. Karyotyping will usually show a deletion of the short arm of one chromosome 5 with variable breakpoints. Only a few cases have been reported prenatally, and the fetal form of the syndrome has not been clearly individualised. We report a new case of 5p deletion syndrome diagnosed prenatally in association with Dandy–Walker syndrome and agenesis of the corpus callosum. Other brain anomalies have been reported previously, but this unusual association suggests the use of a specific probe in the investigation of these malformations. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
69.
New data on the composition of surface assemblages of plant macroremains from soil and swamp samples have been obtained in the study of geomorphologically different localities in the middle reaches of the Nizhnyaya Tunguska River. The results of paleocarpological analysis of forest soil sections supported by relevant palynological and geochronological data are presented. Natural changes of the forest cover over the past 2400 years and quantitative characteristics of the paleoclimate during each stage are described.Translated from Ekologiya, No. 1, 2005, pp. 3–10.Original Russian Text Copyright © 2005 by Koshkarova, Koshkarov. 相似文献
70.
Linden F Vincent 《Natural resources forum》2003,27(2):108-116
Situations of water scarcity challenge sustainability and threaten small users' access to water. In response to this problem, there has been a search for a method of hydrological analysis that can better represent the needs of small water users. While this search is rooted in the debate favouring a more participatory and inclusive allocation of the resource, it also requires a new focus on smallholder hydrology that can confront the gaps and biases found in current hydrological practices in many countries. This article looks at past hydrological practices and also at results of recent studies, highlighting the perspective of smallholder irrigators in surface water planning in Zimbabwe, and groundwater planning in India. These case studies show that wider social forces, not always best science, drive hydrological practices. However, new frameworks focusing on the water user can emerge for more equitable and sustainable water management. 相似文献