首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   141篇
  免费   6篇
化学工业   26篇
金属工艺   1篇
机械仪表   25篇
建筑科学   10篇
矿业工程   1篇
能源动力   1篇
轻工业   21篇
无线电   2篇
一般工业技术   16篇
冶金工业   17篇
自动化技术   27篇
  2023年   1篇
  2021年   1篇
  2020年   3篇
  2018年   1篇
  2017年   3篇
  2016年   3篇
  2015年   2篇
  2014年   4篇
  2013年   5篇
  2012年   5篇
  2011年   4篇
  2010年   6篇
  2009年   8篇
  2008年   9篇
  2007年   3篇
  2006年   11篇
  2005年   4篇
  2004年   2篇
  2003年   8篇
  2002年   2篇
  2001年   3篇
  2000年   1篇
  1999年   3篇
  1998年   7篇
  1997年   6篇
  1995年   3篇
  1994年   1篇
  1993年   2篇
  1992年   1篇
  1991年   3篇
  1989年   1篇
  1988年   1篇
  1986年   2篇
  1985年   1篇
  1982年   2篇
  1981年   1篇
  1980年   2篇
  1979年   4篇
  1978年   4篇
  1977年   3篇
  1976年   3篇
  1975年   3篇
  1972年   1篇
  1970年   2篇
  1968年   1篇
  1957年   1篇
排序方式: 共有147条查询结果,搜索用时 375 毫秒
41.
Common practice in brain research and brain surgery involves the multi‐modal acquisition of brain anatomy and brain activation data. These highly complex three‐dimensional data have to be displayed simultaneously in order to convey spatial relationships. Unique challenges in information and interaction design have to be solved in order to keep the visualization sufficiently complete and uncluttered at the same time. The visualization method presented in this paper addresses these issues by using a hybrid combination of polygonal rendering of brain structures and direct volume rendering of activation data. Advanced rendering techniques including illustrative display styles and ambient occlusion calculations enhance the clarity of the visual output. The presented rendering pipeline produces real‐time frame rates and offers a high degree of configurability. Newly designed interaction and measurement tools are provided, which enable the user to explore the data at large, but also to inspect specific features closely. We demonstrate the system in the context of a cognitive neurosciences dataset. An initial informal evaluation shows that our visualization method is deemed useful for clinical research.  相似文献   
42.
43.
The rheological behaviour of four blends of multigrade oils containing different commercial viscosity index improvers has been studied for increasing shear rate and temperature. Polyalkylmethacrylate has been found to demonstrate different behaviour to styrene-isoprene, styrene-butadiene and ethylene-propylene copolymers. Oil blends for all these hydrocarbon copolymers have shown non-Newtonian behaviour with increasing shear rate (0 to 35,000 s−1) at low and moderate temperatures (−15 to 40°C), i.e. their viscosities were subject to a significant decrease, while the viscosity of the polyalkyl-methacrylate blend showed a limited decrease. With increasing shear rate at high temperature (100°C), all the formulated blends behaved as Newtonian fluids, i.e. with nearly constant viscosities. Increasing shear rate can also change the behaviour of some hydrocarbon copolymers from thickeners to viscosity index improvers.  相似文献   
44.
45.
The volatile flavor compounds of roasted Italian chestnuts, which have not been studied prior to this report, were determined by capillary gas-chromatography with a mass selective detector. Samples were obtained by SPME directly from the headspace of freshly roasted and ground chestnuts as well as by previous extraction with dichloromethane. Monoterpenes and derivatives of butane, pentane, hexane, and heptane were identified as important aroma impact compounds. -Butyrolactone (12.8%), -terpinene (9.2%), furfural (6.3%), benzaldehyde (7.2%) and 4-methyl-2-pentanone (5.3%) were found in concentrations higher than 5.0% (calculated as % peak area of GC-MS analysis using a nonpolar column).  相似文献   
46.
ABSTRACT: Four different postharvest treatments for removal of Salmonella from bell pepper and cucumber were examined, including washes with chlorinated water (HOCl; 200 ppm), acidified sodium chlorite (ASC; 1200 ppm), and peroxyacetic acid (PAA; 75 ppm), and treatment with gaseous chlorine dioxide (ClO2; total 100 mg). Only ClO2 gas was evaluated for decontamination of strawberries. Each produce was inoculated with approximately 1.0 × 107 colony-forming units (CFU) of a 5-serovar cocktail of Salmonella on artificially created wounds, smooth surfaces, and stem scar tissue. For tests involving smooth surface inoculation, ASC and PAA treatments decreased contamination to undetectable levels on bell pepper and cucumber, while the chlorine treatment of bell pepper reduced contamination by approximately 2-logs. For stem scar contamination on bell pepper, ASC and PAA treatments both showed >2-log unit reductions, and chlorine treatment showed a <1-log unit reduction. For puncture wounds on bell pepper, HOCl, ASC, and PAA treatments reduced bacterial levels approximately 2-, 3-, and 1-log units, respectively, indicating that HOCl and ASC were more effective than PAA. These aqueous treatments of cucumber with puncture wounds reduced bacterial levels approximately 1-, 2-, and 2-log units, respectively. ClO2 treatment decreased counts to undetectable levels on all inoculation sites on cucumber and on strawberry smooth surfaces, but failed to completely eliminate Salmonella from bell pepper and from the stem scar and the puncture wounds of strawberry. ASC treatment of bell pepper and ClO2 gas treatments of cucumber showed the best efficiency for inactivation of Salmonella. ClO2 treatments effectively reduced Salmonella cells inoculated on the smooth surface and stem scar of strawberries compared with unsanitized control.  相似文献   
47.
One of the main objectives of the EC water framework directive is to ensure good chemical status for all groundwater bodies. For this reason the geological surveys of Germany have produced a nationwide map of the background values of groundwater. Only naturally occurring inorganic parameters were taken into account, including the relevant major and trace elements. Based on the hydrogeological map of Germany at the scale of 1:200,000 (HüK 200), and its delimited hydrogeological regions, a total of 186 hydrogeochemical units were defined and mapped geochemically. This involved collection of more than 52,000 groundwater samples in a database and allocation to their appropriate hydrogeochemical units. In order to separate anomalies within the data-sets from the underlying normal population, probability nets were used as a statistical tool. The procedure allowed to determine the normal populations of the investigated parameters within the hydrogeochemical units and to quantify them in the form of percentiles. The resulting hydrogeochemical background values are accessible through an internet web map service that includes an online map application. The main intention of this technical note is to inform the reader about the existing internet service, which necessitates some web-site content duplication.  相似文献   
48.
49.
A modification of the Roux-en-Y anastomosis procedure was used to bypass a pyloroduodenal mass in a 12-year-old Arabian stallion. Clinical signs had consisted of a 4-week progression of ventral and hind limb edema, hypoproteinemia, fecal occult blood, intermittent abdominal pain, weight loss, and gastric reflux. On exploratory celiotomy, an obstructive mass was found in the pylorus and proximal portion of the duodenum. Gastrojejunostomy and duodenojejunostomy were performed by use of stapled side-to-side anastomosis techniques. Inaccessibility of the obstructed pyloric region prevented resection of the affected area.  相似文献   
50.
The so‐called plug & play reactor is a novel reaction device with exchangeable reaction segments as well as modules for heating/cooling and mixing. Its performance is demonstrated for two model processes: the production of acetylsalicylic acid with a fixed bed of commercial ion‐exchange particles and a Suzuki‐Miyaura cross‐coupling with a solid Pd‐catalyst developed by us. The reaction progress was monitored by inline UV‐vis spectroscopy and compared with offline HPLC. The novel set‐up leads to quantitative yields and selectivity as well as to an improved practicability of the processes.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号