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731.
Fabia Barbosa Silva Alan Carlos Costa Clarice Aparecida Megguer Júlien Silva Lima Priscila Ferreira Batista Deborah Amorim Martins Gabriel Martins Almeida Marisa Domingos Caroline Müller 《环境质量管理》2021,30(3):17-25
The economic basis of the Brazilian midwest is agriculture, concentrating most of the grain production in the country. With the purpose of increasing yield, farmers have intensified land use and the use of atrazine among other pesticides, which can supposedly compromise human health and photosynthetic metabolism of plant species from Cerrado, such as Handroanthus heptaphyllus. The aim of this study was to determine experimentally the sensitivity level of H. heptaphyllus to atrazine, by measuring gas exchange, chlorophyll a fluorescence, chloroplastidic pigments, and membrane permeability. The experiment was conducted in a factorial scheme. Nine‐month‐old H. heptaphyllus plants were treated with six realistic doses of atrazine: 0, 25, 50, 100, 200, and 400 g a.i. ha–1 (corresponding to 10, 20, 40, 80, and 100% of the commercial dose recommended for corn crops, respectively), with five replications. Evaluations were performed at 12, 36, 84, 180, and 276 h after treatment application. Photosynthesis, the effective quantum yield of photosystem II, and electron transport rate were gradually reduced by the action of atrazine. On the other hand, the nonphotochemical quenching increased gradually, which indicates that this mechanism was not sufficient to avoid oxidative stress and cellular damage in H. heptaphyllus treated plants. Based on these results, we concluded that the action of the herbicide in the photosynthetic reduction occurs by the electron transport rate limitation. Therefore, H. heptaphyllus trees are at risk in Cerrado areas next to agricultural lands. 相似文献
732.
一种最理想的杀虫剂税将按照毒性程度对市场销售的物质加以区分.在墨西哥采取这一税收是准备将来扩展按照国际协议逐步淘汰并最终消除的杀虫剂名单的最有效的方法.本文分析了三种不同的环境征税方案的内涵;对所有的杀虫剂普遍征税15%(弥补目前免征增值税的状况);根据毒性分别征税15%、10%、5%或者0%;对现在经审定的毒性最大的物质征税10%.税收必须用于恢复人类和生态系统健康以及赔付其他类型的损害. 相似文献
733.
Due to their position of interface between the sea and land, the flora and vegetation of coastal beaches and dunes, occupy ecologically extreme, sensitive, unique and valuable habitats. The occurrence of a large number of endemic taxa and specific plant associations endowed with key ecological services and adapted to a stressful and harsh environmental gradient, gives them a high interest for nature conservation and an important role in sustainable territorial planning. However, such ecosystems are vulnerable to the disruption caused by several anthropogenic sources. Among other global threat factors, the inevitable sea rise caused by climate change and, at a local scale, the non-negligible implications of trampling caused by disorderly coastal touristic exploitation, growing construction pressure in the littoral, and a seasonal population boom in late spring and in summer, plus all derivate forms of pollution, are threat factors to their integrity. Therefore, a correct planning of the touristic economic activities requires the understanding of the vegetation composition and spatial distribution patterns, intrinsically determined by their biogeographic context in the Euro-Siberian or Mediterranean Regions. This comprehensive work, based on a broad phytogeographic study, brings together disperse information on plant communities of the Portuguese sandy coasts (beaches and dunes), by analysing floristic compositions, chorology and ecological characteristics, and matching them with the “Nature 2000” network habitats. Resilience and vulnerability are also studied. In a nature conservation perspective, a positive balance (and a sustainable co-existence) between the preservation of natural values and human development in the Portuguese coast, will benefit with the integration of this knowledge in coastal planning and management activities. 相似文献
734.
The ability to achieve urban sustainability has become an indication of the competence of a municipal government aiming to gain world class status for the city. While both Guangzhou and Hong Kong are Chinese cities having their own formulation of urban sustainability, the implementation details and the actual sustainability blueprints are very different. As a result, the outcomes and prospects for urban sustainability are also different. Hong Kong has adopted a less integrative and more institutionally-oriented approach for urban sustainability. Guangzhou has used the conventional approach to formulate an integrated sustainability programme for its local Agenda 21. Hong Kong's action plan emphasizes improving coordination, making objective assessments and achieving consistency in policy-making. Guangzhou, on the other hand, emphasizes the meeting of concrete environmental targets. Unfortunately, the new institutional arrangement and monitoring tools adopted by Hong Kong have not been able to achieve the original intent and neither is there the intention to go too far beyond the weak sustainability approach. On the contrary, Guangzhou has planned and attempted to incorporate industrial ecology in its development regime while heavily investing into pollution control programmes and pushing forward a green community programme at the grass-roots level. 相似文献
735.
736.
737.
Yin-Quan Liu Carlos Bernstein Andra Thiel 《Behavioral ecology and sociobiology》2009,63(10):1459-1469
Foraging animals usually keep track of how costly it is to reach new resource patches and adjust patch residence time and
exploitation rate accordingly. There are at least two potential factors, which are not necessarily closely linked, that animals
could measure to estimate costs of traveling: the time the forager needs to reach the next patch and the amount of energy
it has to invest until arrival. In the parasitoid wasp Venturia canescens, females forage for hosts from which their offspring can develop. Two different types of this parasitoid exist. The thelytokous
type lives in anthropogenic habitats where flight is not necessarily linked with foraging. The arrhenotokous type lives under
field conditions and shows frequent flight activity. We tested whether the wasps would use time or energy needed to assess
patch availability, by either confining them into vials or letting them travel actively in a flight mill between patch visits.
Our results show that in thelytokous lines, time is a sufficient cue influencing patch exploitation and an additional effect
of the energy needed was not visible. In the arrhenotokous wasps, however, only the number of rounds flown in the mill influenced
subsequent behavior, while mere time spent traveling did not.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
738.
Isabelle Amat Emmanuel Desouhant Carlos Bernstein 《Behavioral ecology and sociobiology》2009,63(4):563-572
When foraging partially depleted patches (i.e., a fraction of hosts are already parasitized), female parasitoids must decide:
1—whether to superparasitize, and 2—whether to stay in their current patch (thus missing the opportunity of finding a better
patch elsewhere). To make these decisions, parasitoids may rely on different cues, produced both by the environment and by
conspecifics. Animals thriving in different environments may differ in cues they use. In the solitary parasitoid Venturia canescens, thelytokous (asexual) and arrhenotokous (sexual) individuals are found in two contrasting environments. Thelytokous females,
from anthropogenic conditions, are known to cope with superparasitism in an adaptive way. On the other hand, little is known
about superparasitism by arrhenotokous females. We compared the host exploitation strategies of thelytokous and arrhenotokous
females in partially depleted patches. Hosts parasitized by thelytokous females were more frequently avoided than those parasitized
by arrhenotokous females, suggesting a stronger chemical marking of the former. Only thelytokous females used information
from conspecifics for patch-leaving decisions. The conformity of the differences in the behavior of thelytokous and arrhenotokous
females with the environmental conditions they experience in their habitat is discussed. 相似文献
739.
Pablo E. Penchaszadeh Carlos Sánchez Antelo Soledad Zabala Gregorio Bigatti 《Marine Biology》2009,156(9):1929-1939
The edible volutid snail Adelomelon ancilla occurs on the Argentine coast and may have the capacity to serve as source of support for local fisheries. However, knowledge
of its reproduction is lacking. Over 3 years (from September 2000 to July 2004) we studied the oviposition at Golfo Nuevo,
Patagonia by diving. Monthly collections were performed to examine gonadal stages histologically during 2002–2003. Gamete
development stages corresponded with the expected period for oviposition occurring from July to November, a time of increasing
day length. Oviposition also took place in March when water temperature attained a maximum of 18°C. Following the spawning
period, remaining gametes were resorpted in both sexes. Males contained sperm throughout the year, parasperm and eusperm forms
were found within the same acinus. Oogonia/oocytes ranged from 20 to 240 μm in diameter during oogenesis. Females commenced
laying egg capsules from a shell length of 114 mm. Reproduction is compared with other fishable volutid snails from the Argentine
shelf, and suggests the need to apply certain fishing restrictions if the resource begins to be utilized commercially. The
imposex condition was found in snails from some shipping areas. The frequency of this condition declined with distance from
the port. 相似文献
740.
Bárbara Marinho Carlos Coelho Magnus Larson Hans Hanson 《Journal of Coastal Conservation》2018,22(3):475-489
Dredged material resulting from deepening and maintenance activities of the Aveiro Harbor inlet channel, northwestern coast of Portugal, has been used to mitigate the erosion trend recorded on nearby beaches (from Barra to Costa Nova Beach) through direct placement of sand by using standard dredge equipment. The disposal activities of dredged material have been undertaken at two main sites: between the south breakwater and the 1st groin of Costa Nova (dumping area 1, DA1) and between the 3rd and the 5th groin of Costa Nova (dumping area 2, DA2).The sand was placed in the nearshore, between the ?2 and ?7 m Chart Datum, CD, contours.In this study, short- and long-term coastal morphologic changes in the sea bottom, in response to several nourishment operations and to the incoming waves, within the dumping area boundaries are investigated based on a data set of hydrographic surveys collected annually, just before and after the nourishments, between 2009 and 2015. Preliminary results describing the main morphologic changes, evolution trends, sediment budget variations, and nourishments performance are discussed using mainly Geographic Information System techniques. Overall, the analysis demonstrates that the short-term losses in the dumping areas (one month of interval) can reach 50% of the nourished volume, revealing a significant movement of the fill material towards offshore. Seasonal variations promoting cross-shore material exchange can also prevail and misrepresent the sediment balances, if the monitoring area is not comprehensive. Furthermore, some bathymetric analysis suggested that longshore transport gradients have moved the fill material from Barra beach to downdrift areas. All the obtained results contribute to the ongoing discussion about the effectiveness of nearshore sand placements especially in context of an energetic environment. 相似文献