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331.
Ionic fluids are liquid salts that have been investigated for a number of applications, including catalysis, their use as solvents and electrically conducting fluids. Chemically, they consist of ionically bonded species, and depending on the cation and anion, can be extremely valuable in the chemical processing industry. Another characteristic that makes them useful is a high viscosity and good lubrication properties. This paper examines a number of ionic fluids, and determines their suitability as lubricants. This involves determining rheological properties, including viscosity and high-pressure viscosity, generally using a Barus law. In addition, their traction behavior is measured to evaluate their lubricating properties. Since metalworking fluids (and lubricants in general) are used in non-isothermal situations, the thermal conductivity of these fluids have also been measured. 相似文献
332.
Spatial resource subsidies can greatly affect the composition and dynamics of recipient communities. Caves are especially tractable for studying spatial subsidies because primary productivity is absent. Here, we performed an ecosystem-level manipulation experiment to test the direct influence of detrital subsidies on community structure in terrestrial cave ecosystems. After performing baseline censuses of invertebrates, we removed all organic material from 12 caves and constructed exclusion boxes to prevent natural resource inputs. Next, we stocked each cave with standardized quantities of two major natural subsidies to caves: leaves (leaf packs) and carcasses (commercially supplied rodents), and measured the invertebrate colonization and utilization of these resources for 23 months. Over the course of the experiment, 102 morphospecies were observed. Diplopods and collembolans were most abundant on leaf packs, and dipteran larvae and collembolans were most abundant on the rats. On average, caves receiving either treatment did not differ in species richness, but abundance was significantly higher in rat caves over both the duration of the experiment and the temporal "life" of the individual resources, which were restocked upon exhaustion. Post-manipulation invertebrate communities differed predictably depending on the type of subsidy introduced. Over the course of the experiment, caves that received the same subsidy clustered together based on community composition. In addition, the invertebrate community utilizing the resource changed over the duration of the two-year experiment, and evidence of succession (i.e., directional change) was observed. Results from this study demonstrate how allochthonous resources can drive the community dynamics of terrestrial invertebrates in cave ecosystems and highlight the need for consideration of the surface environment when managing and protecting these unique habitats. 相似文献
333.
Sigr��n H. J��nasd��ttir J?rg Dutz Marja Koski Lidia Yebra Hans Henrik Jakobsen Charles Vidoudez Georg Pohnert Jens C. Nejstgaard 《Marine Biology》2011,158(9):1943-1963
Egg and faecal pellet production and egg hatching success of the calanoid copepod Calanus finmarchicus were monitored over a period of 14?days (14?C28 April, 2008) while fed water from 4 differently treated mesocosms and ambient water. Two of the mesocosms used were inoculated with the polyunsaturated aldehyde (PUA)-producing diatom Skeletonema marinoi, while 2 received only nutrient additions with or without silica. The mesocosms developed blooms of S. marinoi, mixed diatoms or the haptophyte Phaeocystis pouchetii, respectively. Faecal pellet production of C. finmarchicus increased with increasing food availability. Egg production increased with time in all mesocosms to a maximum single female production of 232 eggs female?1?day?1 (average of 90 eggs female?1?day?1) and followed the development of ciliates and P. pouchetii, but was not affected by the observed high (up to 15?nmol?L?1) PUA production potential of the phytoplankton. The hatching success of the eggs produced on the mesocosm diets was high (78?C96%) and was not affected by either aldehydes in the maternal diet or exposure to the dissolved aldehydes in the water. 相似文献
334.
Georg Grüll 《Journal of Environmental Economics and Management》2011,61(1):107-118
This paper examines the key design mechanisms of existing and proposed cap-and-trade markets. First, it is shown that the hybrid systems under investigation (price floor using a minimum price guarantee, price collar, allowance reserve, options offered by the regulator, and offset relaxation) can be decomposed into a combination of an ordinary cap-and-trade scheme with European- or American-style call and put options. Then, we quantify and discuss the advantages and disadvantages of the proposed hybrid schemes by investigating whether pre-set objectives (enforcement of permit price bounds and reduction of the compliance costs for relevant companies) can be accomplished while maintaining the original environmental targets. Plain vanilla options are proposed as an alternative that reconciles the otherwise conflicting policy objectives. 相似文献
335.
Joseph S. Wroblewski Trevor J. Bell Alison I. Copeland Evan N. Edinger Charles Yu Feng James D. Saxby David C. Schneider Jason M. Simms 《Journal of Cleaner Production》2009,17(3):424-430
Iceland scallop (Chlamys islandica) stocks in the North Atlantic are usually pulse harvested, resulting in boom and bust local landings. We describe an adaptive management strategy for a sustainable harvest of Iceland scallops in Gilbert Bay, a Marine Protected Area (MPA) of coastal Labrador. The current management plan for the MPA closes pristine scallop habitat, a practice that under favourable ocean conditions may lead to local reseeding. The community-based co-management structure for the MPA utilizes the local ecological knowledge of fishermen. Scallop harvesters are participating in research on the present state of the resource. Currently scallops are smaller near the mouth of the bay where fishing effort has been concentrated historically. The cooperation of fishers in enforcing area closures and in monitoring the scallop harvest may lead to a sustainable scallop fishery. 相似文献
336.
In soft water 5mg/l of a synthetic dissolved humic substance (HS) reduced the toxicity of zinc against zebrafish embryo and larvae. The appliation of this HS as an antidot against fish hazardous zinc concentrations particulary in soft water is possible. In hard water the HS is able to change the detoxification effect of high water hardness because of the interaction between the calcium and magnesium ions and the HS. In this case the protective effect of high water hardness against trace metals is reduced because of the adhesion of hardness producing ions (Ca2+, Mg2+) with the HS. 相似文献
337.
338.
339.
Götz Schneider 《Die Naturwissenschaften》1994,81(4):145-155
Catastrophic effects of earthquakes are mainly caused by human stupidity, ignorance, or carelessness. Seismic prevention consists of a number of measures to prevent or at least mitigate earthquake damage. Earthquake prediction is a long-term goal which could complement earthquake safety measures in an ideal manner. 相似文献
340.
Jordi Honey-Rosés Daniel W. Schneider Nicholas Brozović 《Environmental management》2014,53(6):1146-1157
Research on ecosystem services has focused mostly on natural areas or remote places, with less attention given to urban ecosystem services and their relationship with technological change. However, recent work by urban ecologists and urban designers has more closely examined and appreciated the opportunities associated with integrating natural and built infrastructures. Nevertheless, a perception remains in the literature on ecosystem services that technology may easily and irreversibly substitute for services previously obtained from ecosystems, especially when the superiority of the engineered system motivated replacement in the first place. We emphasize that the expected tradeoff between natural and manufactured capital is false. Rather, as argued in other contexts, the adoption of new technologies is complementary to ecosystem management. The complementarity of ecosystem services and technology is illustrated with a case study in Barcelona, Spain where the installation of sophisticated water treatment technology increased the value of the ecosystem services found there. Interestingly, the complementarity between natural and built infrastructures may remain even for the very ecosystems that are affected by the technological change. This finding suggests that we can expect the value of ecosystem services to co-evolve with new technologies. Technological innovation can generate new opportunities to harness value from ecosystems, and the engineered structures found in cities may generate more reliance on ecosystem processes, not less. 相似文献