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   60篇
  免费   1篇
化学工业   6篇
金属工艺   4篇
建筑科学   3篇
轻工业   2篇
无线电   3篇
一般工业技术   2篇
冶金工业   31篇
自动化技术   10篇
  2022年   1篇
  2021年   3篇
  2018年   1篇
  2017年   1篇
  2016年   2篇
  2014年   1篇
  2013年   2篇
  2012年   1篇
  2011年   2篇
  2010年   3篇
  2009年   1篇
  2008年   3篇
  2007年   4篇
  2004年   1篇
  1999年   3篇
  1998年   8篇
  1997年   5篇
  1996年   4篇
  1995年   1篇
  1994年   2篇
  1993年   3篇
  1990年   2篇
  1980年   1篇
  1978年   2篇
  1976年   3篇
  1957年   1篇
排序方式: 共有61条查询结果,搜索用时 15 毫秒
11.
扩大圆锭结晶器冷却水出口区   总被引:2,自引:0,他引:2  
Allen  TW Wags.  RB 《轻合金加工技术》1999,27(1):15-18,47
在过去的几年中,圆锭结晶器已有了几次改进。尽管这些改进主要限于结晶器,但却改善了整个铸造系统的效能。双排喷水孔可增大冷却水的喷射角和喷射速度,减少冲击铸锭后飞溅离开铸锭表面的水量。这些改进提高了二次水冷效果,允许在铸速相同的情况下采用更长的结晶器膛。由于这种结构的结晶器冷却效果提高,故在水温一定的条件下,可减少冷却水的用量。石墨环结构及其材质的改进使铸锭质量提高,结晶器维修工作量减少。这种双排射流  相似文献   
12.
The purpose of this study was to investigate the prognostic value of the expression of intercellular adhesion molecule 1 (ICAM-1), leukocyte function antigen 3 (LFA-3), human leukocyte differentiation antigen (HLA)-ABC, HLA-DR, and 5T4 with regard to disease-free survival in Dukes' B and C colorectal carcinoma patients. Forty-one patients (28 Dukes' B and 13 Dukes' C) were entered into this study. Immunocytochemistry was performed on cytospin preparations of enzymatically digested colorectal carcinoma cell suspensions. The frequency of metastases and the duration of disease-free survival were compared between the 25% lowest expressers and the 75% remaining patients for ICAM-1, LFA-3, HLA-ABC, and HLA-DR, and between the 25% highest expressers and the 75% remaining patients for 5T4. Low numbers of ICAM-1-expressing tumor cells were associated with a shorter disease-free survival (P < 0. 001), independent of Dukes' stage. High numbers of 5T4-expressing tumor cells were associated with shorter disease-free survival in Dukes' B patients (P = 0.04). Cox proportional hazard analysis indicated that low numbers of ICAM-1(+) and high numbers of 5T4(+) cells were independent prognostic factors with relative risks of 13. 0 (P = 0.0002) and 4.7 (P = 0.02), respectively. The combination of 5T4 and ICAM-1 marker information identified subgroups of patients with a good (high ICAM-1) or poor (low ICAM-1/high 5T4) prognosis. Neither a lack of HLA-ABC and LFA-3 expression nor the presence of HLA-DR on the tumor cells gave additional prognostic information. These findings demonstrate that low ICAM-1 and high 5T4 expression on tumor cells are prognostic markers, additional to Dukes' stage, for reduced disease-free survival in Dukes' B and C colorectal carcinoma patients.  相似文献   
13.
我曾经探讨过各种试图将乱麻一般的电线规整得井井有条的方法.然而任何解决方案都非完美,我得第一个跳出来承认我在这方面做得很糟糕.不过现在有了一种新方法:一种名为Eubiq的产品.  相似文献   
14.
Overexpression of the gene encoding the 70-kDa heat shock protein (hsp70) has previously been shown to protect neuronal cells against subsequent thermal or ischemic stress. It has no protective effect, however, against stimuli that induce apoptosis, although a mild heat shock (sufficient to induce hsp synthesis) does have a protective effect against apoptosis. We have prepared disabled herpes simplex virus-based vectors that are able to produce high level expression of individual hsps in infected neuronal cells without damaging effects. We have used these vectors to show that hsp27 and hsp56 (which have never previously been overexpressed in neuronal cells) as well as hsp70 can protect dorsal root ganglion neurons from thermal or ischemic stress. In contrast, only hsp27 can protect dorsal root ganglion neurons from apoptosis induced by nerve growth factor withdrawal, and hsp27 also protects the ND7 neuronal cell line from retinoic acid-induced apoptosis. However, hsp70 showed no protective effect against apoptosis in contrast to its anti-apoptotic effect in non-neuronal cell types. These results thus identify hsp27 as a novel neuroprotective factor and show that it can mediate this effect when delivered via a high efficiency viral vector.  相似文献   
15.
16.
17.
Sesquiterpenoids, and specifically sesquiterpene lactones from Asteraceae, may play a highly significant role in human health, both as part of a balanced diet and as pharmaceutical agents, due to their potential for the treatment of cardiovascular disease and cancer. This review highlights the role of sesquiterpene lactones endogenously in the plants that produce them, and explores mechanisms by which they interact in animal and human consumers of these plants. Several mechanisms are proposed for the reduction of inflammation and tumorigenesis at potentially achievable levels in humans. Plants can be classified by their specific array of produced sesquiterpene lactones, showing high levels of translational control. Studies of folk medicines implicate sesquiterpene lactones as the active ingredient in many treatments for other ailments such as diarrhea, burns, influenza, and neurodegradation. In addition to the anti-inflammatory response, sesquiterpene lactones have been found to sensitize tumor cells to conventional drug treatments. This review explores the varied ecological roles of sesquiterpenes in the plant producer, depending upon the plant and the compound. These include allelopathy with other plants, insects, and microbes, thereby causing behavioural or developmental modification to these secondary organisms to the benefit of the sesquiterpenoid producer. Some sesquiterpenoid lactones are antimicrobial, disrupting the cell wall of fungi and invasive bacteria, whereas others protect the plant from environmental stresses that would otherwise cause oxidative damage. Many of the compounds are effective due to their bitter flavor, which has obvious implications for human consumers. The implications of sesquiterpenoid lactone qualities for future crop production are discussed.  相似文献   
18.
Rapid extraction of photogenerated charge carriers is essential to achieve high efficiencies with perovskite solar cells (PSCs). Here, a new mesoscopic architecture as electron‐selective contact for PSCs featuring 40 nm sized TiO2 beads endowed with mesopores of a few nanometer diameters is introduced. The bimodal pore distribution inherent to these films produces a very large contact area of 200 m2 g?1 whose access by the perovskite light absorber is facilitated by the interstitial voids between the particles. Modification of the TiO2 surface by CsBr further strengthens its interaction with the perovskite. As a result, photogenerated electrons are extracted rapidly producing a very high fill factor of close to 80% a VOC of 1.14 V and a PCE up to 21% with negligible hysteresis.  相似文献   
19.
Novelis Inc. recently introduced a multi-alloy, multi-layered, aluminum ingot solidification technology that allows the production of a variety of engineered clad products on a commercial scale. The technology allows selection of the appropriate combinations of clad and core alloys to produce desired mechanical properties as well as forming and surface characteristics superior to either monolithic material alone. It has been shown that the Novelis Fusion™ interface is oxide film and porosity free. This article analyzes the interplay of the aforementioned alloy combinations giving particular attention to the cast intermetallics, the diffusion of silicon and magnesium, the population of secondary phase particles (dispersoids) at the interface, and the rate of diffusion.  相似文献   
20.
Domperidone is a selective antagonist at peripheral dopamine D2 receptors, with gastroprokinetic and antiemetic properties. It increases the frequency and duration of antral and duodenal contractions, thus decreasing/improving transit time of food through the gastrointestinal tract. Gastric emptying of liquids and solids is significantly improved with oral domperidone 40 to 120 mg/day in patients with diabetic gastropathy. Oral domperidone 40 to 80 mg/day significantly decreased the severity of symptoms of gastropathy from baseline values in 66 to 88% of patients with type 1 (insulin-dependent) or insulin-requiring diabetes mellitus. Double-blind withdrawal of domperidone from patients who had responded previously led to greater deterioration of symptoms in patients with delayed gastric emptying than in those who continued receiving the drug. Quality of life was significantly improved in patients who showed a symptomatic response to domperidone. The administration of domperidone 40 to 120 mg/day significantly reduced hospitalisation rates in patients with gastropathy. The symptomatic improvement with domperidone 80 mg/day was similar to that seen with cisapride 40 mg/day or metoclopramide 40 mg/day, and therapeutic benefits seen in symptoms of gastropathy were maintained with domperidone for up to 12 years. Domperidone 40 to 80 mg/day may be effective in patients who are refractory to metoclopramide, and a combination of domperidone 80 mg/day with cisapride 80 mg/day may improve some symptoms in patients who do not respond to either agent alone. Domperidone 40 to 120 mg/day was well tolerated for periods up to 12 years in trials in patients with diabetic gastropathy. Adverse events with domperidone 80 mg/day were similar to those seen in placebo recipients and significantly fewer than in patients receiving metoclopramide 40 mg/day. Although significant elevation of plasma prolactin levels (unrelated to dosage and duration of treatment) occurred in all domperidone recipients, prolactin-related adverse events were observed in only 10 to 20% of patients. CONCLUSIONS: The available data suggest that domperidone 40 to 80 mg/day is an effective agent for the management of symptoms of gastropathy in patients with type 1 diabetes mellitus. In addition, it may provide symptom improvement in patients with gastropathy refractory to other gastroprokinetic agents. Domperidone maintains efficacy in the long term (up to 12 years) and appears to have a better tolerability profile than metoclopramide 40 mg/day.  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