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141.
目的 采用超高压液相色谱-电喷雾串连四极杆质谱分析食品基质中的可乐定, 为可乐定中毒事件的
样本分析提供依据。方法 食物样本粉碎后经甲醇水溶液超声提取, 低温离心后, 上清液用 Waters ACQUITY
UPLCTM BEH C18 色谱柱分离, 以 0.1%甲酸和甲醇溶液为流动相梯度洗脱, 最后用串联四极杆质谱在正离子
MRM 模式下进行测定。结果 以淀粉和炸鸡为加标基质, 三个加标水平下可乐定的平均回收率为
91.5%~127.8%, 相对标准偏差小于 16%, 定量限为 0.02 mg/kg。结论 该方法操作快速简单、重现性好, 成功
用于 2010 年 4 月怀柔水岸山吧可乐定中毒事件的食品检测。 相似文献
142.
我国食源性蜡样芽孢杆菌毒力基因和药物敏感性研究 总被引:3,自引:0,他引:3
目的 了解我国不同地区食源性蜡样芽孢杆菌的毒力基因携带特点及其对抗生素的敏感性,为食源性食物中毒的防治提供参考依据.方法 采用PCR方法对2011年我国不同地区收集的238株食源性蜡样芽孢杆菌10种毒力基因进行检测;采用微量肉汤稀释法测定其抗生素敏感性.结果 溶血素BL基因、肠毒素T基因和细孢毒素K基因是我国食源性蜡样芽孢杆菌的主要毒力基因,至少携带一个毒力基因的菌株达到检出菌总数的87.4%;蜡样芽孢杆菌对庆大霉素、万古霉素、环丙沙星、复方新诺明的敏感率为100%,对红霉素、四环素、氯霉素、克林霉素的敏感率分别为88.8%、90.2%、99.6%、87.1%,对氨苄西林和头孢噻肟的敏感率仅为0.4%和5.4%.结论 我国食源性蜡样芽孢杆菌毒力基因携带率较高,对食品安全和公共健康构成潜在的威胁;蜡样芽孢杆菌对氨苄西林、头孢噻肟的敏感性差,不应作为经验用药和预防用药. 相似文献
143.
144.
145.
A conventional NO
x
-trap catalyst containing platinum, rhodium, barium and lanthanum was conditioned with oxygen at 500°C, preloaded with NO under standard oxidising conditions and then subjected to regeneration with the reductants H2, CO and C3H6, either alone or as a mixture. Hydrogen is the most efficient reductant in terms of NO
x
conversion efficiency and reductant usage efficiency. There is a temperature optimum for CO between 300 and 400°C and a catalyst loading optimum (mols reductant added)/(mols NO
x
adsorbed) between 1.5 and 3.0. The behaviour of the catalyst towards sulphur poisoning was examined in supplementary trials with the adsorption of SO2 in the presence or absence of water vapour. When water is not present in both adsorption and reduction steps, very stable sulphates are formed, unattacked by reductants even at 1000°C. Sulfates are more easily reduced when water is present in the reductant mixture. 相似文献
146.
Ismagilov Z.R. Shkrabina R.A. Tsykoza L.T. Sazonov V.A. Yashnik S.A. Kuznetsov V.V. Shikina N.V. Veringa H.J. 《Topics in Catalysis》2001,16(1-4):307-310
The method of preparation of modified Cu-substituted zeolite DeNOx catalysts washcoated on monolith ceramics has been developed. Non-modified and modified monolith catalysts were tested in DeNOx reaction with propane. It was shown that the catalyst modified by cerium and containing titania together with H-ZSM-5 and Al2O3 in the washcoating layer demonstrates high level of activity, and its resistance during multiple cycles of poisoning by sulfur compounds and water at 400 and 500°C is also high. 相似文献
147.
目的 研究大鼠内皮素(ET) 、血清TNF-α等指标对急性中毒性胃黏膜损伤的监测作用, 同时检测胃黏膜局部组织中环氧化酶2(COX-2) 的表达强度。方法 36 只SD 大鼠随机分成急性中毒对照组、常规剂量奥美拉唑治疗组和大剂量奥美拉唑治疗组。测定血清ET 、TNF-α及胆碱酯酶活力, 计算溃疡指数(UI), 进行胃黏膜HE 染色及COX-2 的免疫组织化学检查, 观察胃黏膜病理改变以及COX-2 的表达强度变化, 并进行相关性分析。结果 大鼠血清中ET 及TNF-α含量与中毒性胃黏膜损伤程度存在显著相关;大鼠胃黏膜COX-2 表达强度与胃黏膜损伤相关不明显。结论 ET 、TNF-α可以成为急性中毒性胃黏膜损伤时血液早期检测指标, 而且可作为中毒性胃黏膜损伤临床治疗效果的监测指标。 相似文献
148.
Ahamed S Kumar Sengupta M Mukherjee A Amir Hossain M Das B Nayak B Pal A Chandra Mukherjee S Pati S Nath Dutta R Chatterjee G Mukherjee A Srivastava R Chakraborti D 《The Science of the total environment》2006,370(2-3):310-322
This communication presents results of our 2-year survey on groundwater arsenic contamination in three districts Ballia, Varanasi and Gazipur of Uttar Pradesh (UP) in the upper and middle Ganga plain, India. Analyses of 4,780 tubewell water samples revealed that arsenic concentrations in 46.5% exceeded 10 microg/L, in 26.7%, 50 microg/L and in 10% 300 microg/L limits. Arsenic concentrations up to 3,192 microg//L were observed. The age of tubewells (n=1,881) ranged from less than a year to 32 years, with an average of 6.5 years. Our study shows that older tubewells had a greater chance of contamination. Depth of tubewells (n=3,810) varied from 6 to 60.5 m with a mean of 25.75 m. A detailed study in three administrative units within Ballia district, i.e. block, Gram Panchayet, and village was carried out to assess the magnitude of the contamination. Before our survey the affected villagers were not aware that they were suffering from arsenical toxicity through contaminated drinking water. A preliminary clinical examination in 11 affected villages (10 from Ballia and 1 from Gazipur district) revealed typical arsenical skin lesions ranging from melanosis, keratosis to Bowens (suspected). Out of 989 villagers (691 adults, and 298 children) screened, 137 (19.8%) of the adults and 17 (5.7%) of the children were diagnosed to have typical arsenical skin lesions. Arsenical neuropathy and adverse obstetric outcome were also observed, indicating severity of exposure. The range of arsenic concentrations in hair, nail and urine was 137-10,900, 764-19,700 microg/kg, and 23-4,030 microg/L, respectively. The urine, hair and nail concentrations of arsenic correlated significantly (r=0.76, 0.61, and 0.55, respectively) with drinking water arsenic concentrations. The similarity to previous studies on arsenic contamination in West Bengal, Bihar and Bangladesh indicates that people from a significant part of the surveyed areas in UP are suffering and this will spread unless drives to raise awareness of arsenic toxicity are undertaken and an arsenic safe water supply is immediately introduced. 相似文献
149.
Michael A.K. Vogel Christian B.W. Stark IlyaM. Lyapkalo 《Advanced Synthesis \u0026amp; Catalysis》2007,349(7):1019-1024
A mechanistic study on the ligand‐free room‐temperature Heck reaction of alkenyl nonafluorobutanesulfonates (nonaflates) is described. Kinetic data obtained from poisoning experiments, centrifugation and variation of catalyst loading consistently provide evidence for a homogeneous palladium catalysis unprecedented in Heck chemistry. The Heck reaction of alkenyl perfluorobutanesulfonates represents a remarkably robust, active and efficient catalytic system generally applicable to the coupling with a broad range of terminal olefins including non‐activated ones under ambient conditions. It features insensitivity towards atmospheric oxygen and moisture, furnishing uniformly high yields of the anticipated coupling products without the necessity to purify commercial reagents and solvents. 相似文献
150.