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651.
Geographic variation in polyphenolic levels of Northeastern Pacific kelps and rockweeds 总被引:1,自引:0,他引:1
K. L. Van Alstyne J. J. McCarthy III C. L. Hustead D. O. Duggins 《Marine Biology》1999,133(2):371-379
Brown algal polyphenolic compounds are secondary metabolites whose functions may include protecting plants from pathogens
or damage by UV radiation, and deterring feeding by herbivores. We present here the first analysis of spatial variation (at
scales from tens of meters to hundreds of kilometers) in concentration of these compounds in two orders of brown algae from
the northeastern Pacific Ocean. In kelps (order Laminariales), variation among sites was significant in only 25% of species
examined and was consistent within families (high in the Alariaceae and low in the Laminariaceae and Lessoniaceae). In rockweeds
(order Fucales, family Fucaceae), site variation was high in three of four species examined. Both the proportion of high polyphenolic
kelp species and the magnitude of spatial variation within species from both kelps and rockweeds were much higher than would
have been predicted from previous studies in other regions. In one kelp (Laminaria groenlandica), significant differences between sites occurred at scales of only tens of meters. No latitudinal clines were observed. Differences
in phenolic concentrations of kelps spanned nearly an order of magnitude in one species, Hedophyllum sessile. Phenolic levels were significantly higher in members of the Fucales than the Laminariales, but showed no significant differences
between intertidal and subtidal species.
Received: 22 July 1996 / Accepted: 26 October 1998 相似文献
652.
Twenty-Six Years of Green Turtle Nesting at Tortuguero, Costa Rica: An Encouraging Trend 总被引:4,自引:0,他引:4
Karen A. Bjorndal Jerry A. Wetherall Alan B. Bolten & Jeanne A. Mortimer 《Conservation biology》1999,13(1):126-134
The green turtle ( Chelonia mydas ) population that nests at Tortuguero, Costa Rica, is the largest in the Atlantic by at least an order of magnitude. Surveys to monitor the nesting activity on the northern 18 km of the 36-km beach were initiated in 1971 and extended to the entire beach in 1986. From the survey data, we estimated the total number of nesting emergences on the northern 18 km for each year from 1971 through 1996. Evaluation of the trend in nesting emergences indicated a relatively consistent increase from 1971 to the mid-1980s, constant or perhaps decreasing nesting during the late 1980s, and then resumption of an upward trend in the 1990s. Evaluation of trends in sea turtle nesting populations requires many years of data because of the large degree of annual variation in nesting numbers. The trends reported in this study must be evaluated with caution for several reasons. First, if the mean number of nests deposited by each female each year (clutch frequency) varies significantly among years, changes in the number of nesting emergences among years could reflect changes in the number of nesting females, clutch frequency, or both. Second, we only assessed the trend in one segment of the population (mature females), which may or may not represent the trend of the entire green turtle population and which, because of late maturity, may not reflect changes in juvenile mortality for many years. Third, survey frequency, and thus confidence in annual estimates, varied among years. The upward population trend must be assessed from the perspective of the catastrophic decline that the Caribbean green turtle populations have experienced since the arrival of Europeans. If careful management is continued in Costa Rica and adopted throughout the region, the collapse of the Caribbean green turtle populations—which seemed imminent in the 1950s—can be avoided. 相似文献
653.
Current Normative Concepts in Conservation 总被引:5,自引:0,他引:5
A plethora of normative conservation concepts have recently emerged, most of which are ill-defined: biological diversity, biological integrity, ecological restoration, ecological services, ecological rehabilitation, ecological sustainability, sustainable development, ecosystem health, ecosystem management, adaptive management, and keystone species are salient among them. These normative concepts can be organized and interpreted by reference to two new schools of conservation philosophy, compositionalism and functionalism. The former comprehends nature primarily by means of evolutionary ecology and considers Homo sapiens separate from nature. The latter comprehends nature primarily by means of ecosystem ecology and considers Homo sapiens a part of nature. Biological diversity, biological integrity, and ecological restoration belong primarily in the compositionalist glossary; the rest belong primarily in the functionalist glossary. The former set are more appropriate norms for reserves, the latter for areas that are humanly inhabited and exploited. In contrast to the older schools of conservation philosophy, preservationism and resourcism, compositionalism and functionalism are complementary, not competitive and mutually exclusive. As the historically divergent ecological sciences—evolutionary ecology and ecosystem ecology—are increasingly synthesized, a more unified philosophy of conservation can be envisioned. 相似文献
654.
Wu Jiayu Chen Tianyue Ge Shengbo Fan Wei Wang Hui Zhang Zhongfeng Lichtfouse Eric Van Tran Thuan Liew Rock Keey Rezakazemi Mashallah Huang Runzhou 《Environmental Chemistry Letters》2023,21(6):3393-3424
Environmental Chemistry Letters - In the context of the circular economy and decreasing earth resources, waste should be converted into value-added materials such as carbon quantum dots, which are... 相似文献
655.
The freedom employees feel to communicate safety concerns with their supervisors, termed upward safety communication, has been shown to be related to adverse safety events (Hofmann and Morgeson, 1999). Research to date has demonstrated that good supervisor–employee relationships (leader–member exchange), a sense that the organization values an employee (perceived organizational support) and safety climate (including perceived management attitudes toward safety, job demands interfering with safety, and pressure from coworkers to behave safely) all contribute to employees’ comfort in bringing up safety issues with their supervisors. However, little is known about which specific dimensions of safety climate are most predictive of upward safety communication. Using a sample of 548 railway workers, we found that when all factors were considered simultaneously using dominance analysis, the dominant factor predicting upward safety communication was perceived management attitudes toward safety, followed by job demands interfering with safety and then leader–member exchange. Implications for research and practice are discussed. 相似文献
656.
Magnoli Karen Carranza Cecilia Soledad Aluffi Melisa Eglé Magnoli Carina Elizabeth Barberis Carla Lorena 《Environmental science and pollution research international》2020,27(31):38501-38512
Environmental Science and Pollution Research - One of the main herbicides used in the agricultural environments is 2,4-dichlorophenoxyacetic acid (2,4-D). It is a synthetic plant hormone auxin... 相似文献
657.
Methneni Nosra Anthonissen Roel Van de Maele Jolien Trifa Fatma Verschaeve Luc Mansour Hedi Ben Mertens Birgit 《Environmental science and pollution research international》2020,27(32):40088-40100
Environmental Science and Pollution Research - Due to the complexity and variability of textile wastewater composition, a constant search for new treatment strategies that are efficient,... 相似文献
658.
Sustainability principles are at the forefront of regional planning. In Hawaii, the movement toward “sustainability” gave way to revisiting the State Plan. This paper uses a case study of the Hawaii 2050 Sustainability Plan (Hawaii 2050) to illustrate how adopting popular notions of sustainability, without critical examination of how the respective policy frames diverge or interrelate, can lead to “tautological traps.” In the case of Hawaii 2050, the “triple-bottom-line” (embedded within sustainable development) became the dominant sustainability frame during the solicitation of public input and was thus used to guide the planning discourse. The application of triple-bottom-line concepts at the level of policy and planning led to a process that polarized economic and environmental interests. While the goals of sustainable development and the use of triple-bottom-line concepts are useful for planners, we argue that they should be applied within the parameters of ecological sustainability in a US regional context, lest resulting plans continue to allow the momentum of development to override ecological concerns. 相似文献
659.
Jorge M. Plaza David Van Wagener Gary T. Rochelle 《International Journal of Greenhouse Gas Control》2010,4(2):161-166
Hilliard completed several thermodynamic models in Aspen Plus® for modeling CO2 removal with amine solvents, including MEA–H2O–CO2. This solvent was selected to make a system model for CO2 removal by absorption/stripping. Both the absorber and the stripper used RateSep? to rigorously calculate mass transfer rates. The accuracy of the new model was assessed using a recent pilot plant run with 35 wt.% (9 m) MEA. Absorber loading and removal were predicted within 6%, and the temperature profile was approached within 5 °C. An average 3.8% difference between measured and calculated values was achieved in the stripper. A three-stage flash configuration which efficiently utilizes solar energy was developed. It reduces energy use by 6% relative to a simple stripper. Intercooling was used to reach 90% removal in the absorber at these optimized conditions. 相似文献
660.
Stephanie A. Freeman Ross Dugas David H. Van Wagener Thu Nguyen Gary T. Rochelle 《International Journal of Greenhouse Gas Control》2010,4(2):119-124
Concentrated, aqueous piperazine (PZ) has been investigated as a novel amine solvent for carbon dioxide (CO2) absorption. The CO2 absorption rate of aqueous PZ is more than double that of 7 m MEA and the amine volatility at 40 °C ranges from 11 to 21 ppm. Thermal degradation is negligible in concentrated, aqueous PZ up to a temperature of 150 °C, a significant advantage over MEA systems. Oxidation of concentrated, aqueous PZ is appreciable in the presence of copper (4 mM), but negligible in the presence of chromium (0.6 mM), nickel (0.25 mM), iron (0.25 mM), and vanadium (0.1 mM). Initial system modeling suggests that 8 m PZ will use 10–20% less energy than 7 m MEA. The fast mass transfer and low degradation rates suggest that concentrated, aqueous PZ has the potential to be a preferred solvent for CO2 capture. 相似文献