首页 | 官方网站   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   1843篇
  免费   37篇
  国内免费   181篇
工业技术   2061篇
  2021年   31篇
  2020年   30篇
  2019年   33篇
  2018年   34篇
  2017年   28篇
  2016年   40篇
  2015年   18篇
  2014年   25篇
  2013年   216篇
  2012年   29篇
  2011年   41篇
  2010年   46篇
  2009年   51篇
  2008年   21篇
  2006年   20篇
  2005年   18篇
  2004年   33篇
  2003年   24篇
  2002年   46篇
  2000年   16篇
  1999年   24篇
  1998年   69篇
  1997年   79篇
  1996年   54篇
  1995年   36篇
  1994年   38篇
  1993年   71篇
  1992年   40篇
  1991年   48篇
  1990年   134篇
  1989年   69篇
  1988年   65篇
  1987年   36篇
  1986年   28篇
  1985年   21篇
  1984年   16篇
  1982年   15篇
  1981年   14篇
  1980年   50篇
  1979年   12篇
  1975年   29篇
  1974年   34篇
  1973年   22篇
  1972年   22篇
  1971年   14篇
  1970年   28篇
  1969年   12篇
  1968年   18篇
  1966年   12篇
  1963年   11篇
排序方式: 共有2061条查询结果,搜索用时 484 毫秒
1.
Microsystem Technologies - The original version of this article unfortunately contained a mistake. Farzad Ebrahimi was not listed among the authors.  相似文献   
2.
The association between obesity, cancer and cardiovascular disease (CVD) has been demonstrated in animal and epidemiological studies. However, the specific role of visceral obesity on cancer and CVD remains unclear. Visceral adipose tissue (VAT) is a complex and metabolically active tissue, that can produce different adipokines and hormones, responsible for endocrine-metabolic comorbidities. This review explores the potential mechanisms related to VAT that may also be involved in cancer and CVD. In addition, we discuss the shared pharmacological treatments which may reduce the risk of both diseases. This review highlights that chronic inflammation, molecular aspects, metabolic syndrome, secretion of hormones and adiponectin associated to VAT may have synergistic effects and should be further studied in relation to cancer and CVD. Reductions in abdominal and visceral adiposity improve insulin sensitivity, lipid profile and cytokines, which consequently reduce the risk of CVD and some cancers. Several medications have shown to reduce visceral and/or subcutaneous fat. Further research is needed to investigate the pathophysiological mechanisms by which visceral obesity may cause both cancer and CVD. The role of visceral fat in cancer and CVD is an important area to advance. Public health policies to increase public awareness about VAT’s role and ways to manage or prevent it are needed.  相似文献   
3.
Nodal sensitivities as error estimates in computational mechanics   总被引:2,自引:0,他引:2  
Summary This paper proposes the use of special sensitivities, called nodal sensitivities, as error indicators and estimators for numerical analysis in mechanics. Nodal sensitivities are defined as rates of change of response quantities with respect to nodal positions. Direct analytical differentiation is used to obtain the sensitivities, and the infinitesimal perturbations of the nodes are forced to lie along the elements. The idea proposed here can be used in conjunction with general purpose computational methods such as the Finite Element Method (FEM), the Boundary Element Method (BEM) or the Finite Difference Method (FDM); however, the BEM is the method of choice in this paper. The performance of the error indicators is evaluated through two numerical examples in linear elasticity.  相似文献   
4.
岳炳良 《世界电信》1995,8(5):26-27,31
本文根据我国陆海空移动用户的需求与特点,借鉴国外经验,提出了建设UHF频段卫星移动通信系统的建议;对照已建成的C波段卫星固定通信系统,分析了其优缺点;最后深入探讨了应用中的若干技术问题。  相似文献   
5.
提出了用三角函数表示的一类用于油田开发指标预测的增长曲线共6条,从而进一步完善和丰富了现有的增长曲线法。提出和推导了它们的Np-t、Qt-t、Qt-Np关系式、(Np/NRmax)Qtmax准数计算式以及参数求解式。其特片研究表明,它们特征相近;(Np/NRamx)Qtmax变化范围为0-0.36785,属于峰值产量出现在油田开发初期的情况,其Qt-Np关系为一不对称的拱形曲线。提出了求取曲线参数的过原点重复线性回归法。双河油田的实例表明该方法有一定实用价值。  相似文献   
6.
7.
Tolerances are basic to the production of every part. This is because perfect parts cannot be produced with existing processes and machines. The determination of tolerances for the individual parts of a functional assembly is critical, but not trivial. Numerous approaches are suggested in past literature for (analytical) tolerance allocation. With the advent of total automation, more attempts are being made to computerize manual design tasks. Tolerance design, assignment and allocation can also be fully automated if the assembly function can be estimated by the computer.

In the present paper, an attempt is made to computerize tolerance assignment. A simple example of a two piece assembly, viz., a fit, is used to demonstrate the developed methodology. A feature extraction is first performed from both detail and assembly drawings. Then, probable assembly interfaces are determined using a rule based procedure. Consequently, tolerances are assigned to the basic dimensions of each feature and to the assembly interfaces using a tolerance database and user interaction. More complex analysis for tolerance allocation is also under study.  相似文献   

8.
Applying the critical path method to manufacturing routing   总被引:1,自引:0,他引:1  
Traditionally the critical path method (CPM) has been used primarily as an a'priori planning and scheduling device. Its applications have typically been limited to one-shot projects, usually with a long period of completion time. This paper proposes taking these ideas to continuous production systems, and to implement the CPM not just at the outset but throughout the process. The algorithm calls for repeatedly calculating the critical path through the production process and routing parts so as to remain off this path. Before the model is presented, some basic ideas are introduced from group technology (GT) and CPM. After the presentation of the model, two potential implementations with the usage of computer are proposed.  相似文献   
9.
Image processing allows the automation of the business transaction, turning “paper factories” into “image factories.” This burgeoning new area of computerization needs new paradigms, theories, and methods to maximize its effectiveness at cutting time and costs. This paper investigates what this new area of computerization can gain from CIM technology. It examines the similarities between the processing of computer images in a paperless business environment and the processing of materials into products in the manufacturing plant. These similarities will allow us to apply mature, well-tested CIM techniques to emerging image factories.  相似文献   
10.
孟洛明 《世界电信》1996,9(4):25-27
本文叙述了智能网的业务管理系统所实现的3种功能:业务管理功能,网络管理功能和业务管理访问功能,还介绍了业务管理和网络管理之间的关系,SMS的集中式和分布式两种体系结构及业务管理功能的设计方法和进一步研究方向。  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-23

京公网安备 11010802026262号