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991.
Comparative temporal ecotoxicological study in a river basin influenced by petrochemical industries 总被引:2,自引:0,他引:2
An approach was developed to evaluate ecotoxicological effects in river basins impacted by anthropic industrial discharges. Genotoxicity was the first level of evaluation of the river water, but when cytotoxicity was associated with genotoxic effects, our research group added chronic assays allowing the assessment of the ontogenic cycle in environmental diagnosis. The genotoxicity of river water sampled during two periods was compared using the microscreen phage-induction and Salmonella/microsome assays. The study assessed the ability of these assays to diagnose environmental quality in an area where petrochemical impacts occur. The study was performed at six sampling sites using the Salmonella/microsome assay for 10 sampling periods and the microscreen phage-induction assay for 15 samplings. The percentage of mutagenic activity was higher at the sites sampled in front of the petrochemical complex in both periods, but there were more significant mutagenic responses in the first assessment. However, comparing the percentages of samples with mutagenic and cytotoxic activity observed during the two periods it becomes clear that there are more cytotoxic samples during the second period throughout the area studied. The genotoxic activity analyzed by the microscreen phage-induction assay was constant in the second period. Chronic toxicity studies with the microcrustacean Daphnia magna confirm the toxic effects observed. The mortality of individuals was higher at the site most influenced by the petrochemical complex, followed by the station located upstream from this area, while the formation of ephippial eggs was uniform at all stations. The rise in the toxic potential of the region detected by cytotoxic and chronic toxicity may interfere and probably impair the use of the Salmonella/microsome assay to determine the potential of the area, showing the importance of assay association to evaluate potentially contaminated areas. 相似文献
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995.
Toxicity of the 13 priority pollutant metals to Vibrio fisheri in the Microtox chronic toxicity test
The Microtox Acute Toxicity Test has been successfully used to measure the toxicity of metals and other pollutants at high concentrations (ppm) in selected environmental samples. However, metals and other toxicants are often found in much lower concentrations (ppb) in many municipal wastewaters and receiving waters. In order to assess the toxicity of these pollutants in these samples, a more sensitive toxicity assay is needed. The Microtox chronic toxicity test has been developed to measure the sublethal effect of toxicants over multiple generations of the test species, Vibrio fisheri. In this study, the toxicity of the 13 priority pollutant metals [i.e. As, Se, Cd, Cr (III and VI), Cu, Pb, Sb, Ag, Tl, Zn, Be, Hg and Ni] to V. fisheri was evaluated using the Microtox chronic toxicity test. In this test, the inhibitory concentration (IC), lowest observable effect concentration (LOEC), and no observable effect concentration (NOEC) were obtained after 22-h of incubation at 27+/-1 degrees C, by comparing the light output of the control to that of the test sample. Among the 13 priority pollutant metals, beryllium (Be) was found to be the most toxic in the test (LOEC=0.742-1.49 microg/l) while thallium (Tl) was the least toxic (LOEC=3840-15300 microg/l). The LOECs for copper (as Cu) and lead (Pb) in reagent (ASTM Type I) water were 6.78-13.6 microg/l and 626-1251 microg/l, respectively. The toxicity of copper sulfate (as Cu) in reagent water was shown and significantly reduced with the addition of natural organic matter (fulvic acid) or EDTA to the sample. The LOEC values for the 13 priority pollutant metals in this test were comparable to or lower than those reported for commonly used aquatic toxicity tests, such as the Ceriodaphnia dubia assay. 相似文献
996.
A 12-month bioassay was conducted to determine the effects of unchlorinated, treated, domestic wastewater on survival, growth, swimming performance, and gill tissue of brown trout (Salmo trutta). Ammonia was the toxicant of concern, because the facility's effluent periodically exceeded the U.S. Environmental Protection Agency's (EPA) recommended criterion. Juvenile brown trout (initial weight = 2 g), which were exposed to six concentrations (0–37%) of effluent, were fed a restricted ration, so that growth rates were similar to those of wild stream residents. At the highest effluent concentration, monthly mean concentrations of un-ionized ammonia ranged from 0.004 to 0.055 mg l−1 NH3---N (at. wt = 14); these concentrations exceeded the EPA criterion of 0.016 mg l−1 about 40% of the time. There were no significant effects of effluent concentration on survival, growth, or swimming performance of brown trout, but the degree of damage to gills was directly related to effluent concentration. 相似文献
997.
Acute toxicity tests were conducted in the laboratory with fathead minnows (Pimephales promelas) to determine the 96-h LC50 of cadmium under three conditions: (1) in laboratory water, (2) in water from experimental ponds, and (3) in pond water underlain by sediment. Cadmium was then applied at doses equivalent to the estimated LC50 values to 0.07-ha ponds containing caged fathead minnows. A cadmium ion selective electrode, ultrafiltration, and equilibrium calculations were used to determine cadmium speciation, and several water quality characteristics were measured to correlate differences in mortality between test systems (laboratory and field) with observed differences in water quality. The LC50 estimates (mg l−1) for the bioassays were 4.39 for the laboratory water, 3.52 for the pond water with sediment, and 2.91 for the pond water. Concentrations of Cd2+ decreased and those of cadmium in the particulate (> 1.2 μm) and 300,000 mol. wt (0.018–1.2 μm) fractions increased over the 96-h; cadmium in these fractions was believed to consist of colloidal sized CdCO3 precipitates. Concentrations of Cd2+ decreased at different rates between test systems, regulated by the degree of CdCO3(s) supersaturation which in turn depended on pH and total metal concentrations. Differences in toxicity in the laboratory tests were attributed to differences in water hardness and Cd2+ concentrations. Mortality of fathead minnows was low (0–10%) during the 96-h test period in the ponds due to the higher pH, which produced supersaturated conditions resulting in the rapid formation of nontoxic CdCO3 precipitates and a more rapid decrease in Cd2+ concentrations as compared to the laboratory bioassays. 相似文献
998.
This survey provides information on sediment toxicity and structural characteristics of the macroinvertebrates and benthic phytoplankton at 10 locations in the Cache la Poudre River after long-term exposure to coal tar residue. The application of the Australian river bioassessment system (AUSRIVAS) as well as a biotest battery was used to evaluate the river ‘health’ condition. Coal tar is a dense nonaqueous-phase liquid of significant environmental concern due to its toxicity and persistence in the subsurface. Organisms like Selenastrum capricornutum, Daphnia magna and Chironomus tentans, representing different complexities in the biosphere, were selected as test systems for ecotoxicological studies. The results obtained in this study indicate that a biotest battery, macroinvertebrate and benthic phytoplankton communities are in principle suitable biological tools for evaluation of toxic oil and coal-derived substances in long-term contaminated river sediment. 相似文献
999.
柔性聚氨酯泡沫燃烧产物毒性评估 总被引:2,自引:1,他引:2
GRAIG BEYLER 《消防科学与技术》2007,26(5):476-484
介绍了对弹性聚氨酯泡沫燃烧产物毒性的相关研究,并对其是否能用于毒性危害分析进行了评估。研究显示,暴露到聚氨酯燃烧产物中的人会导致中毒。窒息气体氮气有效剂量法能有效预测受害人因暴露于聚氨酯燃烧产物而导致的行为能力丧失情况。同时,也证明有效剂量法不能正确预测聚氨酯阴燃时情况。该方法不适用于热分解。研究发现,目前很多经验方法具有很大的局限性,对毒性危害研究造成了很多负面的影响。烟气粒子携带毒物的吸入和传播以及化学合成复杂的毒物,研究和考虑得很少。因此,很有必要对复杂毒性有机体的火灾燃烧产物进行更深入的物理和化学分析研究以及动物模型研究。 相似文献
1000.
A panel of stress-responsive luminous bacteria for the detection of selected classes of toxicants 总被引:10,自引:0,他引:10
Shimshon Belkin Dana R. Smulski Sara Dadon Amy C. Vollmer Tina K. Van Dyk Robert A. Larossa 《Water research》1997,31(12):3009-3016
A panel of bacteria, each genetically engineered to respond by increased luminescence to a different type of environmental stress, is presented. Members of the panel were shown to be sensitive to several groups of chemicals including phenols, halomethanes and several oxidants. The increase in light emission depended upon toxicant concentration and could, thus, be used to calculate a characteristic value, EC200, designating the sample concentration causing a two-fold luminescence induction. In almost all cases, EC200 values were lower than the corresponding Microtox™ EC50 values, indicating a generally higher sensitivity. One of the panel members, DPD2794, a designated DNA-damage sensor, responded within 2 h to the presence of genotoxicants, including metabolically activated nitropropane. It is suggested that these or similarly constructed strains can be used for the rapid and sensitive detection of potentially toxic and genotoxic pollutants and that the concept of genetically engineering a panel of microbial toxicity sensors can readily be implemented for environmental monitoring. 相似文献