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91.
Profiling unauthorized natural resource users for better targeting of conservation interventions
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Mariel Harrison Julia Baker Medard Twinamatsiko E.J. Milner‐Gulland 《Conservation biology》2015,29(6):1636-1646
Unauthorized use of natural resources is a key threat to many protected areas. Approaches to reducing this threat include law enforcement and integrated conservation and development (ICD) projects, but for such ICDs to be targeted effectively, it is important to understand who is illegally using which natural resources and why. The nature of unauthorized behavior makes it difficult to ascertain this information through direct questioning. Bwindi Impenetrable National Park, Uganda, has many ICD projects, including authorizing some local people to use certain nontimber forest resources from the park. However, despite over 25 years of ICD, unauthorized resource use continues. We used household surveys, indirect questioning (unmatched count technique), and focus group discussions to generate profiles of authorized and unauthorized resource users and to explore motivations for unauthorized activity. Overall, unauthorized resource use was most common among people from poor households who lived closest to the park boundary and farthest from roads and trading centers. Other motivations for unauthorized resource use included crop raiding by wild animals, inequity of revenue sharing, and lack of employment, factors that created resentment among the poorest communities. In some communities, benefits obtained from ICD were reported to be the greatest deterrents against unauthorized activity, although law enforcement ranked highest overall. Despite the sensitive nature of exploring unauthorized resource use, management‐relevant insights into the profiles and motivations of unauthorized resource users can be gained from a combination of survey techniques, as adopted here. To reduce unauthorized activity at Bwindi, we suggest ICD benefit the poorest people living in remote areas and near the park boundary by providing affordable alternative sources of forest products and addressing crop raiding. To prevent resentment from driving further unauthorized activity, ICDs should be managed transparently and equitably. 相似文献
92.
Jarvie HP Neal C Withers PJ Baker DB Richards RP Sharpley AN 《Journal of environmental quality》2011,40(2):492-504
Extended end-member mixing analysis (E-EMMA) is presented as a novel empirical method for exploring phosphorus (P) retention and release in rivers and watersheds, as an aid to water-quality management. E-EMMA offers a simple and versatile tool that relies solely on routinely measured P concentration and flow data. E-EMMA was applied to two river systems: the Thames (U.K.) and Sandusky River (U.S.), which drain similar watershed areas but have contrasting dominant P sources and hydrology. For both the Thames and Sandusky, P fluxes at the watershed outlets were strongly influenced by processes that retain and cycle P. However, patterns of P retention were markedly different for the two rivers, linked to differences in P sources and speciation, hydrology and land use. On an annual timescale, up to 48% of the P flux was retained for the Sandusky and up to 14% for the Thames. Under ecologically critical low-flow periods, up to 93% of the P flux was retained for the Sandusky and up to 42% for the Thames. In the main River Thames and the Sandusky River, in-stream processes under low flows were capable of regulating the delivery of P and modifying the timing of delivery in a way that may help to reduce ecological impacts to downstream river reaches, by reducing ambient P concentrations at times of greatest river eutrophication risk. The results also suggest that by moving toward cleaner rivers and improved ecosystem health, the efficiency of P retention may actually increase. 相似文献
93.
E. L. Carroll N. J. Patenaude S. J. Childerhouse S. D. Kraus R. M. Fewster C. S. Baker 《Marine Biology》2011,158(11):2565-2575
The abundance of New Zealand subantarctic southern right whales (Eubalaena australis) was estimated for the first time using mark-recapture methods based on photo-identification and microsatellite genotyping
(13 loci). Individual identification photographs of 383 whales and microsatellite genotypes of 235 whales were collected during
annual austral winter field surveys from 1995 to 1998. Given the 4-year survey period and lack of geographic and demographic
closure, we estimated super-population abundance using the POPAN Jolly-Seber model implemented in the software programme MARK.
Models with constant survivorship but time-varying capture probability and probability of entry into the population were the
most suitable due to the survey design. This provided estimates of abundance in 1998 of 908 non-calf whales (95% C.L. = 755,
1,123) for the photo-identification and 910 non-calf whales (95% C.L. = 641, 1,354) for the microsatellite genotype data sets.
The current estimate of 900 whales may represent less than 5% of the pre-whaling abundance in New Zealand waters. 相似文献
94.
Craig F. Aumack Charles D. Amsler James B. McClintock Bill J. Baker 《Marine Biology》2011,158(8):1879-1885
Amphipods along the western Antarctic Peninsula appear to gain refuge from predators by associating with chemically defended
macroalgae rather than palatable macroalgae. However, nothing is known about amphipod activity at night. If foraging on non-chemically
defended macroalgae regularly occurs, then nocturnal foraging seems beneficial since visual predators are disadvantaged. To
test this hypothesis, we collected three common macroalgal species and affiliated mesograzers, approximately 3 h before and
after sunset. All associated mesofauna were counted and densities recorded. Amphipod densities were significantly decreased
during the night on the chemically defended Desmarestia menziesii, while significantly increased on the palatable Iridaea cordata. Additionally, the amphipod Gondogeneia antarctica was found in significantly higher densities at night on Palmaria decipiens, a species shown to be readily eaten by G. antarctica and omnivorous fish. We believe that chemically defended macroalgae act as a refuge for mesograzers during the day, while
more widespread foraging occurs at night. 相似文献
95.
96.
Low pH markedly reduced heterotrophic microbial activity in sediment-lake water systems. A marked reduction in both the rate and the total amount of oxygen consumed occurred as pH decreased. In addition, low pH and also low temperature (0°C) resulted in longer turnover times (Tn) and also smaller Vmax values when the kinetics of 14C-glucose, 14C-glycine, and 14C-glutamic acid utilization were examined. When the response of the microorganisms to heavy metals was examined, mercury was generally more toxic than lead over the pH range of 4.5 to 7.5 but both metals were more toxic at pH 4.5 than at higher pH levels. Mercury also inhibited oxygen utilization and 14C-glucose mineralization more than lead at all pH levels. Bisulfite reduced microbial activity at all pH levels although it was always more toxic to the sediment microorganisms at pH values of 4 and 5 than at pH 7. 相似文献
97.
Myron Charles Baker Gregory L. Sherman Tad C. Theimer Dana C. Bradley 《Behavioral ecology and sociobiology》1982,11(2):133-137
Summary A field study of the ranging behavior of post-fledging White-crowned Sparrows (Zonotrichia leucophrys nuttalli) was carried out in undisturbed natural habitat in the Point Reyes National Seashore, Marin Co., California, USA. Forty-three first-brood juveniles, with tail feathers still growing, were banded at an estimated average age of 27 days and re-trapped an average of an additional 24 days for a total minimum time in residence in the immediate natal area of 51 days (Table 1).The distance from the site of first capture to subsequent recapture sites was about 60 m until age 35 days; then the distance increased to about 250 m by age 50 days (Fig. 2). These data indicate that the average juvenile White-crowned Sparrow completes at least the first 50 days of life in its natal area. Experimental work on song ontogeny has previously demonstrated that the sensitive period for song learning ends at about 50 days. Hence, young in our study population probably learn their natal dialect prior to any major dispersal movements. The correspondence between residence time and song learning would have the consequence of perpetuating song dialects as geographically structured populations. 相似文献
98.
99.
Abstract A series of mesocosms was exposed to a suite of light treatments and nutrient enrichment in order to generate algal communities of varying biomass. the influence of this biomass on the speciation of copper (II) was studied. Distribution coefficients ( Kd,Lkg?1) were relatively high (log Kd = 5 to 7), indicative of robust trace metal sequestration, and were likely controlled by the particulate organic carbon content (foc). Differences in Kd over time and among treatments were significant, as was the relationship between Kd and foc. Fluorescence quenching was used to determine binding capacities ( Lt , M) and their associated binding constants ( Kcond ,M?1) in order to model the solid phase copper speciation. the Kcond ranged between 2.1 and 5.2 × 1012M?1, indicating a very strong copper-ligand complex, and was higher in mesocosms that received more light. the light Lt increased over time, dramatically after the nutrient enrichment, but did not vary systematically among light treatments. Lt ranged from 7.2 × 10? 7 to 4.9 × 10? 5 M. the large magnitudes of Kd , Kcond and Lt ensured that greater than 97% of total copper in the mesocosms was complexed by organic matter. the total copper concentration ([Cu]T, M) needed to reach a target dissolved copper concentration of 10?12.5 M (pCu = 12.5) was determined for each mesocosm over time. [Cu]T was between 8.02 × 10?5 and 3.41 × 10?2 M, and increased over time. the [Cu]T normalized to the target pCu (Effective Dose Ratio, EDR) increased directly with increases in algal biomass, indicating a direct link between system productivity and copper exposure. Approximately 45% of the variance in EDR was explained by variance in total biomass, while the residual variance in EDR was due likely to differences in the strengths of particle associations and magnitude of binding capacities. 相似文献
100.
We developed quantitative PCR (qPCR) assays to distinguish each of the four clades (A–D) of dinoflagellate endosymbionts (genus Symbiodinium) commonly found in Caribbean corals. We applied these primer sets, which target portions of the multi-copy ribosomal DNA (rDNA) gene family, to assess the presence/absence of symbionts in clade D (as indicated by the detection of clade D DNA). We detected these symbionts in five of six Caribbean host species/genera (21% of samples analyzed, N = 10 of 47 colonies), from which clade D had rarely or never been observed. This suggests that Symbiodinium in clade D are present in a higher diversity of coral species than previously thought. This qPCR-based approach can improve our understanding of the total microbial diversity associated with corals, particularly in hosts thought to be relatively specific, and has many other potential applications for studies of coral reef ecology and conservation. 相似文献