全文获取类型
收费全文 | 6755篇 |
免费 | 38篇 |
国内免费 | 47篇 |
专业分类
安全科学 | 99篇 |
废物处理 | 397篇 |
环保管理 | 530篇 |
综合类 | 1008篇 |
基础理论 | 1862篇 |
环境理论 | 4篇 |
污染及防治 | 1966篇 |
评价与监测 | 559篇 |
社会与环境 | 407篇 |
灾害及防治 | 8篇 |
出版年
2023年 | 44篇 |
2022年 | 129篇 |
2021年 | 128篇 |
2020年 | 48篇 |
2019年 | 53篇 |
2018年 | 256篇 |
2017年 | 218篇 |
2016年 | 378篇 |
2015年 | 158篇 |
2014年 | 243篇 |
2013年 | 408篇 |
2012年 | 625篇 |
2011年 | 454篇 |
2010年 | 208篇 |
2009年 | 166篇 |
2008年 | 276篇 |
2007年 | 293篇 |
2006年 | 275篇 |
2005年 | 525篇 |
2004年 | 629篇 |
2003年 | 499篇 |
2002年 | 132篇 |
2001年 | 98篇 |
2000年 | 62篇 |
1999年 | 63篇 |
1998年 | 19篇 |
1997年 | 21篇 |
1996年 | 11篇 |
1995年 | 34篇 |
1994年 | 21篇 |
1993年 | 14篇 |
1992年 | 10篇 |
1991年 | 13篇 |
1990年 | 14篇 |
1989年 | 12篇 |
1975年 | 7篇 |
1967年 | 8篇 |
1966年 | 13篇 |
1965年 | 15篇 |
1964年 | 28篇 |
1963年 | 12篇 |
1962年 | 17篇 |
1961年 | 12篇 |
1960年 | 9篇 |
1959年 | 26篇 |
1958年 | 25篇 |
1957年 | 18篇 |
1956年 | 13篇 |
1955年 | 18篇 |
1954年 | 7篇 |
排序方式: 共有6840条查询结果,搜索用时 0 毫秒
51.
Ana M. Martín González Juan Francisco Ornelas Bo Dalsgaard Ubaldo Márquez-Luna Carlos Lara 《Die Naturwissenschaften》2018,105(9-10):54
Recent studies on ecological networks have quantified the contribution of ecological, historical, and evolutionary factors on the structure of local communities of interacting species. However, the influence of species’ biogeographical traits, such as migratory habits or phylogeographical history, on ecological networks is poorly understood. Meta-networks, i.e., networks that cover large spatial extensions and include species not co-occurring locally, enable us to investigate mechanisms that operate at larger spatial scales such as migratory patterns or phylogeographical distributions, as well as indirect relationships among species through shared partners. Using a meta-network of hummingbird-plant interaction across Mexico, we illustrate the usefulness of this approach by investigating (1) how biogeographical and morphological factors associate with observed interactions and (2) how species-specific biogeographical characteristics associate with species’ network roles. Our results show that all studied hummingbird and plant species in the meta-network were interrelated, either directly or through shared partners. The meta-network was structured into modules, resulting from hummingbirds and plants interacting preferentially with subsets of species, which differed in biogeographical, and, to a lesser extent, morphological traits. Furthermore, migrants and hummingbirds from Nearctic, Transition, and widespread regions had a higher topological importance in the meta-network. Our study illustrates how meta-networks may contribute to our current knowledge on species’ biogeographical traits and biotic interactions, providing a perspective complementary to local-scale networks. 相似文献
52.
Silva Marcio Roberto Ferreira Fernando César Maranhão Adriana Gonçalves Lanzarini Natália Maria de Carvalho Castro Karina Neboo Miagostovich Marize Pereira 《Food and environmental virology》2021,13(4):528-534
Food and Environmental Virology - Enteric viruses have been described as important contaminants in fresh and ready-to-eat foods such as sandwiches, deli meat and dairy products. This is a... 相似文献
53.
54.
Adánez-Rubio Iñaki Pérez-Astray Antón Abad Alberto Gayán Pilar De Diego Luis F. Adánez Juan 《Mitigation and Adaptation Strategies for Global Change》2019,24(7):1293-1306
Mitigation and Adaptation Strategies for Global Change - Bioenergy with carbon dioxide (CO2) capture and storage (BECCS) technologies represent an interesting option to reach negative carbon... 相似文献
55.
56.
Enrique Castelán 《Ambio-人类环境杂志》2003,32(2):124-129
引言 墨西哥城大都市区(MCMA)位于被称作"墨西哥谷(Valle deMexico)"的天然围合的盆地里,海拔2240m.它下辖联邦区和墨西哥州的34个自治市.墨西哥城是墨西哥的首都,位于联邦区(DistritoFederal,DF),四面环山,海拔高度超过5000m.墨西哥州是墨西哥人口最稠密的地区(据报道有1300万居民),人口仅次于它的是墨西哥城,大约有860万人[1]. 相似文献
57.
Tamás Marton Júlia Hajdú Csaba Papp Péter Patkós Ervin Hruby Zoltán Papp 《黑龙江环境通报》2001,21(6):452-456
The present study describes an association between adverse outcome in the twin-to-twin transfusion syndrome (TTTS) and pulmonary stenosis or reactive right ventricular hypertrophy. Six discordant monozygotic twin pregnancies with TTTS are described. Ventricular hypertrophy and atrioventricular valvular regurgitation occurred in all the recipient twins with pulmonary valvular stenosis in three cases and infundibular stenosis in one case. The recipient twin in one pair and both twins in another pregnancy died as a consequence of immaturity but the remaining twins all survived. Surgical intervention was required in one baby for valvular pulmonary stenosis. Our observations suggest that elevated blood pressure in the transfusion recipient may play an important role in pathogenesis. We hypothesise that both pulmonary stenosis and right chamber hypertrophy are secondary to hemodynamic changes. Although we have found valvular pulmonary stenosis in three recipients and infundibular stenosis in only one, this (obstruction to outflow) could be due to right chamber hypertrophy. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
58.
Wax perception in honeybees: contact is not necessary 总被引:1,自引:0,他引:1
In social insects, much progress has been made in identifying variations in the cuticular signatures of sexes, castes, kin and reproductive status. In contrast to this, we still do not know how the receivers perceive these recognition cues. This study was designed to investigate whether honeybees use contact-chemosensory or olfactory sensilla to perceive wax components. To answer this question in a behavioral assay, we combined classical conditioning of the proboscis extension reaction and a recently established method using zinc sulfate to selectively block antennal contact-chemosensory sensilla. Comparison of the responses to sucrose, wax and geraniol before and after antennal zinc sulfate treatment revealed that the sucrose response is lost after treatment but the responses to wax and geraniol are maintained. As sucrose is perceived by the contact-chemosensory sensilla, the retention of the wax response indicates that contact-chemosensory sensilla are not necessary for wax perception. 相似文献
59.
In Acromyrmex octospinosus leaf-cutting ants the metapleural glands produce an array of antibiotic compounds that serve as a general defence against unwanted microbes on the cuticle. Leaf-cutting ants also grow mutualistic Pseudonocardiaceae bacteria on their cuticle that produce antibiotics controlling a microfungal parasite of their fungus gardens. Interaction between this bacterium and gland secretion therefore seems unavoidable. We document the typical development of bacterial growth on the cuticle of young major workers, show that growth starts a few days after eclosion, and that the maximal cover is reached after 2–3 weeks and gradually declines when workers mature. Experimental closure of the metapleural glands had no effect on the initial exponential growth phase of the bacterium, but significantly reduced the cover during the decline phase. The age-dependent abundance of the bacterium and its partial dependence on metapleural gland secretion support the hypothesis that the abundance of this mutualist is actively regulated. 相似文献
60.
Discrimination between conspecific and heterospecific signals is a key element in the evolution of pheromone-mediated communication in insects. Pheromone antagonists prevent heterospecific attraction. They are typically pheromone synergists in other species and enable specific communication in closely related species, using partly the same chemicals. In codling moth, Cydia pomonella, as in other moths, upwind flights to a pheromone/antagonist blend were slower and more convoluted than to pheromone. However, this deteriorated flight behaviour did not account for the strong decrease in male attraction. The pheromone/antagonist blend blocked instead the onset of upwind flight. This was corroborated by placing a separate source of pheromone close by, which restored male attraction. Males flying upwind did not discriminate between pheromone and the adjacent pheromone/antagonist blend, and landed on either source. This indicates differences in the neural regulation for initiating and maintaining a behavioural response to pheromone. 相似文献