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81.
Effects of carbonization and solvent-extraction on change in fuel characteristics of sewage sludge 总被引:1,自引:0,他引:1
Urban sewage sludge was carbonized at 300-500 °C for 1 h, and combustible components were extracted through the solvent-extraction process. N-methyl-2-pyrrolidinone (NMP) was used as the solvent for extraction, and the extraction temperature was fixed at 360 °C. The atomic ratios of the solvent-extracted sludge of CS300 (ECS300) were shown to be 1.04 for H/C and 0.11 for O/C, which represented the characteristics of its coal band. Thus, its coal band was similar to that of a high-rank fuel such as bituminous coal. FT-IR analysis showed that the absorbance band of ECS300 was considerably different from that of dried sludge (RS) or the carbonized sludge at 300 °C (CS300) but similar to that of coal, although the ash content absorbance band of 800-1200 cm−1 was of very low intensity. The combustion profile showed that combustion of ESC300 occurred at a temperature higher than the ignition temperature (Ti) or maximum weight loss rate (DTGmax) of coal. 相似文献
82.
83.
Graham P. Bailey Dirk Mariën 《Birth defects research. Part B, Developmental and reproductive toxicology》2011,92(4):273-291
Recent changes in the regulations from the FDA and EMA have shifted the focus of juvenile toxicity studies more to the safe use of all pharmaceuticals and the absence of label or safety information for the pediatric population. Unlike other regulatory guidance, the need or design of these animal studies is not specified. Ideally these should be decided “case‐by‐case” based on the patient population, pharmacology, existing toxicological and clinical data, dosing regimen, and developing system impact. Following the publishing of a small intercompany survey (Bailey and Mariën, 2009), a more extensive survey was commissioned by the ILSI/HESI DART Technical Committee to clarify what has been learned for the safety assessment for pediatrics. Contributions from 24 companies totaling 241 studies (84% rat and 14% dog) were received. In 12 of 82 programs (15%) were the existing adult preclinical or clinical data considered a sufficient safety prediction for pediatric trials. Clinical/preclinical correlates were observed in 17.2% (rat) and 42.9% (dog) of the studies and a lack of predictability from the pharmacology or the adult toxicity data was seen in 25% of rat and 14.3% of dog studies. Many of the studies were large, lengthy, complex, included parameters that mirrored the adult studies and yielded no new or useful information. We should avoid conducting complex or inappropriate studies and Contract Research Organisations and regulatory agencies have a role in encouraging more targeted designs. Only with appropriate designs can we adequately identify safety or pharmacokinetic issues, suggest clinical endpoints, and contribute to the product label. Birth Defects Res (Part B) 92:273–291, 2011. © 2011 Wiley‐Liss, Inc. 相似文献
84.
E. Chavoshi M. Afyuni M. A. Hajabbasi A. H. Khoshgoftarmanesh K. C. Abbaspour H. Shariatmadari 《人类与生态风险评估》2011,17(2):414-430
Fluoride is a potentially toxic element, with a narrow range of tolerable amounts taken up via food or drinking water. To evaluate F content in surface soils, 255 topsoil samples (0–20 cm) in an area of 6800 km2 in Isfahan province of central Iran were collected. Crop plants and randomly sampled water samples from wells were evaluated during the spring and summer seasons. Total F concentration in 96% of soil samples was lower than the global suggested average of 200 mg kg?1. The mean F concentration of water samples in the study area was 0.05 and 0.3 mg L?1 in summer and spring, respectively. Fluoride concentrations in different plant species were in the range of normal values. The total hazard quotient (HQ) for both population groups via consumption of cereals, vegetables, and water; incidental ingestion of soil; inhalation of soil particulates; and dermal contact with water and soil was less than 1.0, resembling no obvious risk. It is suggested that neither age group in Isfahan province will experience a significant potential health risk through their dietary intake of cereals, vegetables, and water; ingestion of soil; inhalation of particulates; and dermal contact. 相似文献
85.
86.
Larabee JL Hocker JR Lerner MR Lightfoot SA Cheung JY Brackett DJ Gallucci RM Hanas JS 《Cell biology and toxicology》2005,21(5-6):233-246
Limited information is available regarding the development of systemic organ stress by dermal exposure to JP-8 fuel. In this
study, the systemic stress potential of this fuel is evaluated in a rat model subjected to dermal applications of JP-8 for
7 days at 300 μl per day. Tissue histology indicated that JP-8 induces morphological alterations that suggest that tissue
stress in the heart is more substantial than stress in the kidney and liver. Immunoblot analysis of tissues revealed increased
levels of the inducible heat shock protein 70 (HSP70) in the heart, kidney, and liver after this dermal JP-8 exposure. This
exposure also leads to increased levels of heme oxygenase-1 (HO-1/HSP3) in the liver. Additionally during this exposure, a
negative regulator of inflammation, IκBα (inhibitor of NF-κB), was increased in the liver, slightly increased in the kidney,
and not increased in the heart. Two regions of the rat brain were also examined and HSP70 and IκBα were increased in the cerebellum
but not significantly increased in the cortex. This study indicates dermal JP-8 exposure causes systemic alterations that
are associated with cytoprotective activities (e.g., in the liver) as well as potentially toxic mechanisms (heart and kidney). 相似文献
87.
Kim GT Hyun MS Chang IS Kim HJ Park HS Kim BH Kim SD Wimpenny JW Weightman AJ 《Journal of applied microbiology》2005,99(4):978-987
AIMS: The isolation and identification of a glucose-oxidizing Fe(III)-reducing bacteria (FRB) with electrochemical activity from an anoxic environment, and characterization of the role of Fe(III) in its metabolism. METHODS AND RESULTS: A Gram-positive (Firmicutes), nonmotile, coccoid and facultative anaerobic FRB was isolated based on its ability to reduce Fe(III). Using the Vitek Gram-positive identification card kit and 16S rRNA gene sequence analysis, the isolate was identified as Enterococcus gallinarum, designated strain MG25. On glucose this isolate produced lactate plus small amounts of acetate, formate and CO2 and its growth rates were similar in the presence and absence of Fe(O)OH. These results suggest that MG25 can couple glucose oxidation to Fe(III) reduction, but without conservation of energy to support growth. Cyclic voltammetry showed that strain MG25 was electrochemically active. CONCLUSIONS: An electrochemically active and FRB, E. gallinarum MG25, was isolated from submerged soil. Fe(III) is used in the bacterial metabolism as an electron sink. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report concerning the electrochemical activity of glucose-oxidizing FRB, E. gallinarum. This organism and others like it could be used as new biocatalysts to improve the performance of a mediator-less microbial fuel cell. 相似文献
88.
Saccharomyces cerevisiae-based ethanol fermentations were conducted in batch culture, in a single stage continuous stirred tank reactor (CSTR), a multistage CSTR, and in a fermentor contaminated with Lactobacillus that corresponded to the first fermentor of the multistage CSTR system. Using a glucose concentration of 260 g l–1 in the medium, the highest ethanol concentration reached was in batch (116gl–1), followed by the multistage CSTR (106gl–1), and the single stage CSTR continuous production system (60gl–1). The highest ethanol productivity at this sugar concentration was achieved in the multistage CSTR system where a productivity of 12.7gl–1h–1 was seen. The other fermentation systems in comparison did not exceed an ethanol productivity of 3gl–1h–1. By performing a continuous ethanol fermentation in multiple stages (having a total equivalent working volume of the tested single stage), a 4-fold higher ethanol productivity was achieved as compared to either the single stage CSTR, or the batch fermentation. 相似文献
89.
森林火灾带来了严重后果,但许多人对黑色防火感到一些困惑,计划烧除是"防火"、"用火"还是"放火".随着数据分析技术的进步,运用数据库、多元统计分析等方法可以分析森林火灾调查和统计的数据,探索森林防火的最佳措施.针对黑色防火的深入理解,对试验数据进行了相关分析.该相关分析是利用了云南松林里进行计划烧除后得到的各种数据,然后通过SPSS软件来分析数据.试验结果可以表明:计划烧除时火强度、火蔓延速度与火焰高度属于正相关;火强度与森林可燃物的生物量也属于正相关,通过小强度的计划烧除能有效的减少森林可燃物的生物量,从而提高森林的自防能力. 相似文献
90.
Wildfire is the major natural agent of disturbance in interior Alaska. We examined the magnitude of human impact on fire by
comparing fire regime between individual 1-km2 grid cells designated for fire suppression with lands where fires are allowed to burn naturally. Two-thirds of interior Alaska
has an essentially natural fire regime, with few human ignitions, negligible suppression activity, and many large lightning-caused
fires. In the 17% of land that is designated for fire suppression due to its proximity to communities and roads, there was
a 50% reduction in the proportion of area burned from 1992–2001, relative to areas without suppression. The remaining 16%
of land serves as a buffer, receives some suppression, and has an intermediate fire regime. Even though there were 50 times
more fires and the fire season began two months earlier in lands designated for suppression, most of these fires were lit
by people and remained small because fires tended to occur at times and places less favorable for fire spread and were more
accessible to fire fighters compared to lands not designated for suppression. Even in the absence of fire suppression, human-caused
fires were less likely to exceed 400 ha compared to lightning-caused fires. Fire suppression reduced area burned in all fuel
types but was somewhat more effective in less flammable (non-forest) vegetation. Alaska’s fire policy of focusing suppression
efforts on a small proportion of the fire-prone region maximizes the ecological and social benefits associated with fire-dependent
ecosystem services, while minimizing the social and ecological costs of suppression. Application of this policy to other areas
would require well-informed managers and stakeholders to make difficult decisions about the relative costs and benefits of
fire across ecologically and culturally variable landscapes. 相似文献