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   130篇
  免费   7篇
  国内免费   4篇
电工技术   5篇
化学工业   13篇
金属工艺   13篇
机械仪表   12篇
建筑科学   4篇
能源动力   6篇
轻工业   10篇
无线电   18篇
一般工业技术   26篇
冶金工业   21篇
自动化技术   13篇
  2023年   1篇
  2022年   2篇
  2021年   3篇
  2019年   5篇
  2018年   3篇
  2017年   5篇
  2016年   7篇
  2015年   3篇
  2014年   1篇
  2013年   6篇
  2012年   4篇
  2011年   3篇
  2010年   11篇
  2009年   2篇
  2008年   2篇
  2007年   2篇
  2006年   5篇
  2005年   5篇
  2004年   3篇
  2003年   2篇
  2002年   3篇
  2001年   4篇
  2000年   5篇
  1999年   4篇
  1998年   7篇
  1997年   7篇
  1996年   5篇
  1995年   1篇
  1993年   3篇
  1992年   1篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1988年   2篇
  1985年   1篇
  1984年   2篇
  1983年   4篇
  1977年   2篇
  1976年   2篇
  1975年   1篇
  1972年   1篇
  1970年   1篇
  1968年   2篇
  1967年   1篇
  1922年   1篇
  1921年   1篇
  1913年   1篇
排序方式: 共有141条查询结果,搜索用时 0 毫秒
1.
2.
The work presented in Part 1 of this article showed that additions of magnesium chloride (MgCl2) to ammonia solutions reduced the tendency of ammonia-induced stress-corrosion cracking (SCC) initiation in a Cu-5%Ni alloy. The present work was undertaken to study the SCC behavior of the test alloy exposed to ammonia in the presence of varying concentrations of MgCl2. The exposure to MgCl2 additions reduced the severity of the ammonia-induced SCC.  相似文献   
3.
In this paper, we address a multi-product loading problem in which a vehicle (a truck or a ship) is used to transfer multiple products. The product demands are different but stationary over time. The vehicle consists of compartments of different sizes and each compartment can contain only one product type during each shipment. No shortages are permitted, and we assume that the inventory holding cost is significantly lower than the delivery cost. The objective is to minimize the setup rate, that is, the number of deliveries per time unit. A cyclic policy is shown to be optimal, and a heuristic algorithm is developed to determine the cycle length as well as the assignments of products to the compartments during each of the requisite number of shipments made during that cycle. A comparison of the solutions obtained by the proposed algorithm with the optimal solutions (or a bound) indicate that the algorithm provides solutions with optimal setup rates in most of the problem instances considered and, when not optimal, the setup rates of these solutions are close to optimal values.  相似文献   
4.
Thomas  Emil  Sarin  Vivek 《Applied Intelligence》2022,52(2):1254-1267
Applied Intelligence - This paper presents techniques to improve the prediction accuracy of approximation methods used in Gaussian process regression models. Conventional methods such as...  相似文献   
5.
6.
描渍是一种现已失传的清官式建筑彩画绘制工艺,经文献研究与实例调研发现,文渊阁大木彩画中仍留存有该工艺的使用痕迹,且现存彩画包含自始建年代至清末的多次修缮遗迹。本文以文渊阁勘察项目为依托,采用剖面显微分析和偏光显微分析等科技考古手段,结合文献研究,揭示出文渊阁彩画中描渍工艺的用料与操作特征,并通过实验的方式对此工艺进行复原。  相似文献   
7.
Conclusion The main aim of the present paper is to give a more general formulation for velocity distribution function and in consequence the advantages of the present method are discussed in detail in comparison with other methods, particularly that of Shen. The method is then applied to the problem of plane linearized couette flow and the method of analysis is outlined. Moreover, the method seems to be suitable for non-linear cases. Further work on the applicability of the present method is in progress and it will be published soon.  相似文献   
8.
Efforts toward defining a standard for workflow interoperability began in 1994 with the Workflow Reference Model from the Workflow Management Coalition (WfMC). From that model other standardization efforts have evolved: from OMG's jointflow specification to the simple Workflow Access Protocol. The WfMC's Wf-XML focuses on a simple subset of SWAP for a first version of a standard, with the aim of future extension  相似文献   
9.
In this paper we report on the fabrication and characterization of SrHfO(3):Ce ceramics. Powders were prepared by solid-state synthesis using metal oxides and carbonates. X-ray diffraction measurements showed that phase-pure SrHfO(3) is formed at 1200°C. Inductively coupled plasma spectroscopy confirmed the purity and composition of each batch. SrHfO(3) exhibits several phase changes in the solid, but this does not appear to be detrimental to the ceramics. Microprobe experiments showed uniform elemental grain composition, whereas aluminum added as charge compensation for trivalent cerium congregated at grain boundaries and triple points. Radioluminescence spectra revealed that the light yield decreases when the concentration of excess Sr increases. The decrease in the light yield may be related to the change of Ce(3+) into Ce(4+) ions. For stoichiometric SrHfO(3):Ce, the light yield is about four times that of bismuth germanate (BGO), the conventional benchmark, indicating great potential for many scintillator applications.  相似文献   
10.
PURPOSE: This retrospective study was performed to assess the treatment outcome and prognostic factors in 101 men with invasive squamous carcinoma of the penis treated at the Royal Marsden Hospital between 1960-1990. METHODS AND MATERIALS: The tumor was confined to the glans penis (T1) in 79 patients, 82 were node negative (N0), and two patients had distant metastases at presentation. The histology was Grade 1 (G1) in 36, Grade 2 (G2) in 18, Grade 3 (G3) in 28, and unknown in 19 patients. Node-positive disease was commoner in patients with G3 (p = 0.02) or T2/3/4 tumors (p = 0.007). Treatment for the primary tumor was external beam radiotherapy (EBRT) in 59, interstitial brachytherapy in 13, and partial or total penectomy in 29 patients. The median dose, dose/fraction, and treatment time for EBRT was 60 Gy, 2 Gy/fraction, and 46 days, respectively. Eighty patients received no inguinal node treatment, 13 had EBRT (4 with chemotherapy), and 8 underwent groin dissection at presentation. RESULTS: During a median follow-up of 5.2 years (2 months-22 years), 56 patients died (penile cancer 31, intercurrent illness 23 and unknown cause 2), giving 10 year overall and cause-specific survival (CSS) of 39 and 57%, respectively. Adverse prognostic factors for CSS on univariate analysis were G3, ulcerative/fungating or T2/3/ 4 tumors, node positive, Jackson's Stage 2/3/4, and surgical treatment for the primary. All but the last two were significant independent prognostic factors for CSS on multivariate analysis. Penile or perineal recurrence or residual disease after initial treatment was seen in 36 out of 98 evaluable patients, giving a 10-year local failure rate (LFR) of 45%. Local failure after initial treatment was successfully salvaged in the majority (26 out of 36) of patients with further surgery or radiotherapy, and local control was achieved ultimately in 74 out of 77 T1, 7 out of 12 T2; 3 out of 3 T3, and 3 out of 5 T4 tumors. In the 44 evaluable patients with T1 tumors treated by EBRT the only adverse RT parameter approaching prognostic significance (p = 0.052) was a BED value corrected for recovery of <60 Gy (alpha/beta 10, K = 0.5 Gy/day, mean = 21 days). CONCLUSION: Invasive squamous carcinomas of the penis carry a significant risk of loco-regional recurrence after initial radiotherapy and this can be successfully salvaged in most patients with further treatment. This mandates close follow-up to detect loco regional recurrence early.  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