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71.
72.
Chauhan SV Chaurasia B Rana A 《Journal of environmental biology / Academy of Environmental Biology, India》2004,25(3):291-297
Cassia siamea plants growing at two different sites (polluted and non-polluted) on two important roads of Agra city exhibited significant differences in their flowering phenology and floral morphology. The flowering in plants growing at polluted site is delayed and there was a marked reduction in flowering density, flowering period, size of floral parts, pollen fertility, fruit and seed-set. SEM observations revealed the presence of well developed glandular structures and reduction in the number and size of large stomata on the anther surface at polluted site. These changes were found to be closely associated with the extent of air pollution caused mainly by significant in the number of automobiles. 相似文献
73.
von Helversen O Heller KG Mayer F Nemeth A Volleth M Gombkötö P 《Die Naturwissenschaften》2001,88(5):217-223
The analysis of morphological, behavioural and genetic characters of whiskered bats revealed a new European bat species within the family Vespertilionidae. We describe the morphology, karyology, genetic similarity, ecology and distribution of Myotis alcathoe n. sp. It closely resembles Myotis mystacinus, Myotis brandtii and Myotis ikonnikovi in morphology, but all four species show clear genetic differences in two mitochondrial genes (ND1 and 12S rRNA). Myotis alcathoe n. sp. is the smallest species among the European whiskered bats and uses the highest-frequency echolocation calls of all the European Myotis species. It prefers to hunt in small valleys with deciduous trees and flowing water, which is an endangered habitat. Records from Greece and Hungary indicate a distribution range in south-eastern Europe. 相似文献
74.
Virginia E. Villafañe Paul J. Janknegt Marco de Graaff Ronald J. W. Visser Willem H. van de Poll Anita G. J. Buma E. Walter Helbling 《Marine Biology》2008,154(6):1021-1029
During austral summer 2006, experiments were carried out to evaluate the effects of ultraviolet radiation (UVR, 280–400 nm)
on carbon fixation of natural phytoplankton assemblages from Patagonia (Argentina). Surface water samples were collected (ca.
100 m offshore) at mid morning using an acid-cleaned (1 N HCl) dark container. The short-term impact of UVR (measured as radiocarbon
incorporation) was immediately assessed by exposing samples to three artificial illumination treatments: PAR (400–700 nm),
PAR + UV-A (320–700 nm), and PAR + UV-A + UV-B (280–700 nm). Pico-nanoplankton characterized the assemblages, and taxon-specific
pigment fingerprinting combined with CHEMTAX and supplemented with microscopic observations showed varied proportions of diatoms,
chlorophytes, and cyanobacteria throughout January–February 2006. Photosynthetic efficiency, as assessed through assimilation
numbers, was high [between 4.4 and 10.4 μg C (μg chl-a)−1 h−1], and it was probably favored by the supply of inorganic nutrients from the Chubut River. UVR-induced photoinhibition appeared
to be related to the taxonomic composition: in general, higher photoinhibition was observed when diatoms dominated, whereas
this was lower when samples were dominated by chlorophytes. Our data suggest that xanthophyll pigments might have provided
only limited protection in these already highlighted acclimated assemblages. 相似文献
75.
The theory behind,and the challenges of,conserving nature's stage in a time of rapid change
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Joshua J. Lawler David D. Ackerly Christine M. Albano Mark G. Anderson Solomon Z. Dobrowski Jacquelyn L. Gill Nicole E. Heller Robert L. Pressey Eric W. Sanderson Stuart B. Weiss 《Conservation biology》2015,29(3):618-629
Most conservation planning to date has focused on protecting today's biodiversity with the assumption that it will be tomorrow's biodiversity. However, modern climate change has already resulted in distributional shifts of some species and is projected to result in many more shifts in the coming decades. As species redistribute and biotic communities reorganize, conservation plans based on current patterns of biodiversity may fail to adequately protect species in the future. One approach for addressing this issue is to focus on conserving a range of abiotic conditions in the conservation‐planning process. By doing so, it may be possible to conserve an abiotically diverse “stage” upon which evolution will play out and support many actors (biodiversity). We reviewed the fundamental underpinnings of the concept of conserving the abiotic stage, starting with the early observations of von Humboldt, who mapped the concordance of abiotic conditions and vegetation, and progressing to the concept of the ecological niche. We discuss challenges posed by issues of spatial and temporal scale, the role of biotic drivers of species distributions, and latitudinal and topographic variation in relationships between climate and landform. For example, abiotic conditions are not static, but change through time—albeit at different and often relatively slow rates. In some places, biotic interactions play a substantial role in structuring patterns of biodiversity, meaning that patterns of biodiversity may be less tightly linked to the abiotic stage. Furthermore, abiotic drivers of biodiversity can change with latitude and topographic position, meaning that the abiotic stage may need to be defined differently in different places. We conclude that protecting a diversity of abiotic conditions will likely best conserve biodiversity into the future in places where abiotic drivers of species distributions are strong relative to biotic drivers, where the diversity of abiotic settings will be conserved through time, and where connectivity allows for movement among areas providing different abiotic conditions. 相似文献
76.
Singh Anita Chaudhary Sudesh Dehiya Brijnandan S. 《Environmental science and pollution research international》2021,28(4):3942-3952
Environmental Science and Pollution Research - Heavy metal discharge from anthropogenic sources on open soil surfaces and in natural water bodies poses serious environmental and health concerns. In... 相似文献
77.
Quality assessment of water is essential to ensure sustainable safe use of it for drinking, agricultural, and industrial purposes. For the same purpose the study was conducted for the samples of water of Sambhar lake city and its adjoining areas. The standard methods of APHA were used to analysis 15 samples collected from hand pumps and tube wells of the specified area. The analytical results show higher concentration of total dissolved solids, electrical conductivity sodium, nitrate, sulfate, and fluoride, which indicate signs of deterioration but values of pH, calcium, magnesium, total hardness, and carbonate are within permissible limits as per WHO standards. From the Hill-piper trilinear diagram, it is observed that the majority of groundwater from sampling stations are sodium?Cpotassium?Cchloride?Csulfate type water. The values of sodium absorption ratio and electrical conductivity of the groundwater were plotted in the US salinity laboratory diagram for irrigation water. Only the one sample fall in C3S1 quality with high salinity hazard and low sodium hazard. Other samples fall in high salinity hazard and high sodium hazard. Chemical analysis of groundwater shows that mean concentration of cation is in order sodium > magnesium > calcium > potassium while for the anion it is chloride > bicarbonate > nitrate > sulfate. 相似文献
78.
Impact and adaptation opportunities for European agriculture in response to climatic change and variability 总被引:2,自引:0,他引:2
Marco Moriondo Marco Bindi Zbigniew W. Kundzewicz M. Szwed A. Chorynski P. Matczak M. Radziejewski D. McEvoy Anita Wreford 《Mitigation and Adaptation Strategies for Global Change》2010,15(7):657-679
Climate change, involving changes in mean climate and climatic variability, is expected to severely affect agriculture and
there is a need to assess its impact in order to define the appropriate adaptation strategies to cope with. In this paper,
we projected a scenario of European agriculture in a +2°C (above pre-industrial levels) world in order to assess the potential
effect of climatic change and variability and to test the effectiveness of different adaptation options. For this purpose,
the outputs of HadCM3 General Circulation Model (GCM) were empirically downscaled for current climate (1975–2005) and a future
period (2030–2060), to feed a process-based crop simulation model, in order to quantify the impact of a changing climate on
agriculture emphasising the impact due to changes in the frequency of extreme events (heat waves and drought). The same climatic
dataset was used to compare the effectiveness of different adaptations to a warmer climate strategies including advanced or
delayed sowing time, shorter or longer cycle cultivar and irrigation. The results indicated that both changes in mean climate
and climate variability affected crop growth resulting in different crop fitting capacity to cope with climate change. This
capacity mainly depended on the crop type and the geographical area across Europe. A +2°C scenario had a higher impact on
crops cultivated over the Mediterranean basin than on those cultivated in central and northern Europe as a consequence of
drier and hotter conditions. In contrast, crops cultivated in Northern Europe generally exhibited higher than current yields,
as a consequence of wetter conditions, and temperatures closer to the optimum growing conditions. Simple, no-cost adaptation
options such as advancement of sowing dates or the use of longer cycle varieties may be implemented to tackle the expected
yield loss in southern Europe as well as to exploit possible advantages in northern regions. 相似文献
79.
Unpublished field observations in Leucauge argyra, a tropical orb weaver spider, suggest the occurrence of conspicuous mating plugs that could reduce or prevent remating attempts.
Otherwise, the sexual behavior of this species remains unknown. The aims of this study were to describe the courtship behavior
and copulation in L. argyra and investigate mating plug formation in this species. Fourteen virgin females and 12 plugged females were exposed to up
to three males and checked for mating plug formation. Of the 12 virgins that copulated, nine produced plugs (five immediately
after copulation), and the five plugged females that copulated produced another mating plug immediately after copulation.
We did not detect the transfer of any male substance during copulation but observed a whitish liquid emerging from female
genital ducts. Plug formation was positively associated with male twanging during courtship. One virgin and four plugged females
cannibalized males. In seven trials with virgins and in three trials with plugged females, the male’s palp adhered to a substance
that emerged from female genital ducts and spread on her genital plate. The male had to struggle energetically to free his
glued palp; two of these males were cannibalized while trying to release their palps. Females seem to determine copulation
duration by altering the timing of mating plug formation and through sexual cannibalism. This is the first case reported of
a mating plug as a sticky trap for males. 相似文献
80.
Amy Hinsley Anita Kar Yan Wan David Garshelis Michael Hoffmann Sifan Hu Tien Ming Lee Keila Meginnis Brendan Moyle Yingjie Qiu Xiangdong Ruan E. J. Milner-Gulland 《Conservation biology》2022,36(3):e13895
An important rationale for legally farmed and synthetic wildlife products is that they reduce illegal, wild-sourced trade by supplying markets with sustainable alternatives. For this to work, more established illegal-product consumers must switch to legal alternatives than new legal-product consumers switch to illegal wild products. Despite the widespread debate on the magnitude and direction of switching, studies among actual consumers are lacking. We used an anonymous online survey of 1421 traditional Chinese medicine consumers in China to investigate switching among legal farmed, synthetic, and illegal wild bear bile. We examined the past consumption behavior, applied a discrete choice experiment framed within worsening hypothetical disease scenarios, and used latent class models to investigate groups with shared preferences. Bear bile consumers (86% respondents) were wealthier, more likely to have family who consumed bile, and less knowledgeable about bile treatments than nonconsumers. Consumer preferences were heterogenous, but most consumer preferences switched between bile types as disease worsened. We identified five distinct latent classes within our sample: law-abiding consumers (34% respondents), who prefer legal products and were unlikely to switch; two all-natural consumer groups (53%), who dislike synthetics but may switch between farmed and wild; and two nonconsumer groups (12%), who prefer not to buy bile. People with past experience of bile consumption had different preferences than those without. Willingness to switch to wild products was related to believing they were legal, although the likelihood of switching was mediated by preferences for cheaper products sold in legal, familiar places. We found that consumers of wild bile may switch to legal alternatives, given the availability of a range of products, whereas legal-product consumers may switch to illegal products if the barriers to doing so are small. Understanding preferences that promote or impede switching should be a key consideration when attempting to predict consumer behavior in complex wildlife markets. 相似文献