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Arpad Horvath 《The International Journal of Life Cycle Assessment》2006,11(4):229-239
Goal, Scope and Background This study provides a life cycle inventory of air emissions (CO2, NOx, PM10, and CO) associated with the transportation of
goods by road, rail, and air in the U.S. It includes the manufacturing, use, maintenance, and end-of-life of vehicles, the
construction, operation, maintenance, and end-of-life of transportation infrastructure, as well as oil exploration, fuel refining,
and fuel distribution.
Methods The comparison is performed using hybrid life cycle assessment (LCA), a combination of process-based LCA and economic input-output
analysis-based LCA (EIO-LCA). All these components are added by means of a common functional unit of grams of air pollutant
per ton-mile of freight activity.
Results and Discussion Results show that the vehicle use phase is responsible for approximately 70% of total emissions of CO2 for all three modes.
This confirms that tailpipe emissions underestimate total emissions of freight transportation as infrastructure, pre-combustion,
as well as vehicle manufacturing and end-of-life account for a sizeable share of total emissions. Differences between tailpipe
emissions and total system wide emissions can range from only 4% for road transportation's CO emissions to an almost ten-fold
difference for air transportation's PM10 emissions.
Conclusion Rail freight has the lowest associated air emissions, followed by road and air transportation. Depending on the pollutant,
rail is 50-94% less polluting than road. Air transportation is rated the least efficient in terms of air emissions, partly
due to the fact that it carries low weight cargo. It emits 35 times more CO2 than rail and 18 times more than road transportation
on a ton-mile basis. It is important to consider infrastructure, vehicle manufacturing, and pre-combustion processes, whose
life-cycle share is likely to increase as new tailpipe emission standards are enforced.
Recommendation and Outlook Emission factors, fuel efficiency, and equipment utilization contribute the most to uncertainty in the results. Further studies
are necessary to address all variables that influence these parameters, such as road grade, vehicle speed, and vehicle weight.
A focus on regional variation, end-of-life processes, fuel refining processes, terminals, as well as more accurate infrastructure
allocation between freight and passenger transportation would strengthen the model. 相似文献
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Abstract Four control operations, each with paired pre‐feed and no‐pre‐feed treatments, and comprising two baited with carrot and two with cereal, provided strong support for the hypothesis that pre‐feeding produces higher possum kills than no pre‐feeding. In these replicates, even where high kills were achieved, the modelled two‐ to three‐fold extension of the period of population depression given by pre‐feeding was sufficient to warrant the expense of the additional bait sown. The benefits of pre‐feeding were clear‐cut, and were greatest where poorest kills were achieved, irrespective of bait type. Pre‐feeding is thus likely to reduce the probability of failure and should be considered a form of operational insurance. 相似文献
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Evidence can provide support for or against a particular biogeographical hypothesis. Treating a hypothesis as if it were evidence or an empirical observation confounds many biogeographical analyses. We focus on two recent publications that address, in part, the evolution of the biota of Sulawesi, the large Indonesian island in the centre of the Indo‐Australian Archipelago. Many biogeographical explanations are hampered by invoking simple notions of mechanism or process – dispersal and vicariance – or constraints, such as dispersal from a centre of origin, and, in so doing, dismiss more complex geological phenomena such as emergent volcanoes within island chains or composite areas as irrelevant. Moreover, they do not search for, therefore never discover, biogeographical patterns that may better explain the distribution of biota through time. 相似文献
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Culver Mvumi Elizabeth Ngadze Diana Marais Elsa S. duToit Jameson Kugara 《Archives Of Phytopathology And Plant Protection》2013,46(7-8):432-444
AbstractThe study investigates the presence and quantity of antimicrobial sinigrin glucosinolates in tomato leaves after spraying them with moringa (Moringa oleifera) leaf extract (MLAE). Moringa concentrates (0.5, 0.75, 1.00 and 1.5?kg?L?1 (w v?1)) were prepared. Distilled water was the control. Sampled tomato leaves were air-dried, freeze-dried and extracted firstly using pure methanol in a hot water bath and then pellet re-extracted using 5?mL of hot aqueous methanol (70% v v?1). An ion exchange column, and sulphatase was used to achieve glucosiodesulphonation. High performance liquid chromatography (HPLC) was employed in the identification and quantitative analysis of the sinigrin glucosinolates. Tomato (Solanum lycopersicum) leaves treated with MLAE revealed highly significant (p?<?.001) content of sinigrin glucosinolates. The sinigrin standard and the desulphated sinigrin glucosinolates had a 7?s retention time difference; 5?kg?L?1 (w v?1) resulted in a superior amount of sinigrin in tomato leaves as compared to all the other MLAE concentrations. The study reveals that spraying MLAE on putatively diseased tomato leaves donates specific quantifiable glucosinolates like sinigrin, which may be involved in defense against tomato diseases and, hence, recommends use of 5?kg?L?1 (w v?1) for the highest sinigrin defense tag. 相似文献
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Sheng-Ping Wang Erin Daniels Ying Chen Jose Castro-Perez Haihong Zhou Karen O. Akinsanya Stephen F. Previs Thomas P. Roddy Douglas G. Johns 《Journal of lipid research》2013,54(10):2858-2865
Cholesteryl ester transfer protein (CETP) transfers cholesteryl ester and triglyceride between HDL and apoB-containing lipoproteins. Anacetrapib (ANA), a reversible inhibitor of CETP, raises HDL cholesterol and lowers LDL cholesterol in dyslipidemic patients. We previously demonstrated that ANA increases macrophage-to-feces reverse cholesterol transport and fecal cholesterol excretion in hamsters, and increased preβ HDL-dependent cholesterol efflux via ABCA1 in vitro. However, the effects of ANA on in vivo preβ HDL have not been characterized. In vitro, ANA inhibited the formation of preβ, however in ANA-treated dyslipidemic hamsters, preβ HDL levels (measured by two-dimensional gel electrophoresis) were increased, in contrast to in vitro findings. Because changes in plasma preβ HDL have been proposed to potentially affect markers of cholesterol absorption with other CETP inhibitors, a dual stable isotope method was used to directly measure cholesterol absorption in hamsters. ANA treatment of hamsters (on either dyslipidemic or normal diet) had no effect on cholesterol absorption, while dalcetrapib-treated hamsters displayed an increase in cholesterol absorption. Taken together, these data support the notion that ANA promotes preβ HDL functionality in vivo, with no effects on cholesterol absorption. 相似文献