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   773篇
  免费   29篇
  国内免费   3篇
电工技术   9篇
综合类   3篇
化学工业   122篇
金属工艺   17篇
机械仪表   24篇
建筑科学   41篇
矿业工程   1篇
能源动力   49篇
轻工业   29篇
水利工程   3篇
石油天然气   1篇
无线电   87篇
一般工业技术   125篇
冶金工业   141篇
原子能技术   5篇
自动化技术   148篇
  2023年   6篇
  2022年   5篇
  2021年   17篇
  2020年   16篇
  2019年   13篇
  2018年   15篇
  2017年   13篇
  2016年   15篇
  2015年   12篇
  2014年   17篇
  2013年   72篇
  2012年   29篇
  2011年   43篇
  2010年   31篇
  2009年   24篇
  2008年   29篇
  2007年   38篇
  2006年   27篇
  2005年   19篇
  2004年   25篇
  2003年   19篇
  2002年   19篇
  2001年   6篇
  2000年   15篇
  1999年   9篇
  1998年   27篇
  1997年   13篇
  1996年   15篇
  1995年   10篇
  1994年   6篇
  1993年   9篇
  1992年   20篇
  1990年   12篇
  1988年   8篇
  1987年   8篇
  1986年   10篇
  1985年   9篇
  1984年   12篇
  1983年   11篇
  1982年   5篇
  1981年   9篇
  1980年   9篇
  1979年   6篇
  1978年   6篇
  1976年   5篇
  1975年   7篇
  1974年   5篇
  1973年   4篇
  1970年   4篇
  1966年   4篇
排序方式: 共有805条查询结果,搜索用时 46 毫秒
101.
In order for applied experiential psychotherapy to progress, there are certain problems that must be solved, including the need for (a) a strategy of therapeutic procedures, (b) a library of significant live data on experiential psychotherapy, (c) a dream screen, (d) instruments to measure bodily feelings, (e) ways for therapists to disengage from their personalities and assimilate to the patient, and (f) methods by which the patient interacts with deeper personality processes. The solution of these problems would constitute breakthroughs for the development of applied experiential practice. Psychotherapeutic theoreticians and researchers are invited to use their resources, knowledge, and expertise to solve these practical problems. (55 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
102.
"46 schizophrenic patients were compared with 80 control Ss with respect to their estimation of one clock second's duration under long and short anchor conditions, where anchor represented the extreme duration in a series. In addition, the interaction of recent and more remote anchors was studied." The findings suggested that the schizophrenic is likely to overestimate the duration of a clock second and that they responded only to the pulling effect of immediate anchors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
103.
104.
One hundred and sixty patients undergoing minor surgical procedures were randomly allocated to receive either thiopentone or propofol for induction of anaesthesia. All patients were assessed in the recovery period for the development of postanaesthetic shivering. Twenty patients (25%) in the thiopentone group and 8 patients (10%) in the propofol group developed postanaesthetic shivering (p < 0.05). There was no statistically significant difference in tympanic temperature between shivering and nonshivering patients. Propofol as an induction agent is associated with a lower incidence of postanaesthetic shivering as compared to thiopentone.  相似文献   
105.
An integrated life-cycle model is presented for use in a software maintenance environment. The model represents information about the development and maintenance of software systems, emphasizing relationships between different phases of the software life cycle. It provides the basis for automated tools to assist maintenance personnel in making changes to existing software systems. The model is independent of particular specification, design, and programming languages because it represents only certain `basic' semantic properties of software systems: control flow, data flow, and data structure. The software development processes by which one phase of the software life cycle is derived from another are represented by graph rewriting rules, which indicate how various components of a software system have been implemented. This approach permits analysis of the basic properties of a software system throughout the software life cycle. Examples are given to illustrate the integrated software life-cycle model during evolution  相似文献   
106.
Count data with excess zeros relative to a Poisson distribution are common in many biomedical applications. A popular approach to the analysis of such data is to use a zero-inflated Poisson (ZIP) regression model. Often, because of the hierarchical study design or the data collection procedure, zero-inflation and lack of independence may occur simultaneously, which render the standard ZIP model inadequate. To account for the preponderance of zero counts and the inherent correlation of observations, a class of multi-level ZIP regression model with random effects is presented. Model fitting is facilitated using an expectation-maximization algorithm, whereas variance components are estimated via residual maximum likelihood estimating equations. A score test for zero-inflation is also presented. The multi-level ZIP model is then generalized to cope with a more complex correlation structure. Application to the analysis of correlated count data from a longitudinal infant feeding study illustrates the usefulness of the approach.  相似文献   
107.
108.
Tolerance evaluation is critical to quality assurance in modern manufacturing. In contrast to traditional measurement which relies on specific hard gauges, coordinate measuring machines provide more flexibility for dimensional measurement and tolerance evaluations. To fully automate CMM inspection and tolerance evaluation, CAD/CMM integration is an important key. Although the subject of CAD-directed inspection has been widely researched, CAD model-based tolerance evaluation has received less attention. This paper presents a CAD model-based approach for evaluating general form tolerances using non-uniform rational B-splines. Unlike classical methods which construct substitute geometric features from the measurement data, this method evaluates form tolerances by comparing the measurement data with a nominal CAD model. Non-uniform rational B-spline (NURBS) is used to represent general form features since NURBS offers a common format for modeling different form features. With this unified database, a general best-fit algorithm is developed that can be applied to the evaluation of various form tolerances. Computer simulations have been performed on different form features to study the robustness and efficiency of the algorithm. Application to the profile analysis of turbo charger housing and turbine blade die segments are also presented.  相似文献   
109.
Yat Yau  Hong Poh 《传热工程》2019,40(7):574-587
The present research is to develop a homogenous mathematical model to simulate capillary tube-suction line heat exchanger (CT-SL HX) based on the fundamentals of conservations of mass, momentum and energy with comprehensive experimental result validations. The computer model is fully validated by 72 experimental data with error bands of ±15%, ±2°C and ±35% on the mass flow rate prediction, the suction pipe outlet temperature, and the heat exchange estimation respectively. The results suggest that the internal diameter of the capillary tube, and the heat-transfer length of the CT-SL HX have demonstrated an apparent impact on the capillary tube outlet conditions and heat transfer across the segment.  相似文献   
110.
We fulfill a comprehensive study based on density functional theory (DFT) computations to cast insight into the dissociation mechanism of hydrogen molecule on pristine, B‐, and N‐doped penta‐graphene. The doping effect has been also illustrated by varying the concentration of dopant from 4.2 at% (one doping atom in 24 host atoms) to 8.3 at% (two doping atoms in 24 host atoms) and by contemplating different doping sites. Our theoretical investigation shows that the adsorption energy of H2 molecule and H atom on the substrate can be substantially enhanced by incorporating boron or nitrogen into penta‐graphene sheet. The B‐ and N‐doped penta‐graphene can effectively decompose H2 molecule into two H atoms. Our results demonstrate that activation energies for H2 dissociation and H diffusion on the B‐ and N‐doped penta‐graphene are much smaller than the pristine penta‐graphene. Further investigation of increasing concentration dopants of the penta‐graphene sheet gives sufficiently low activation barrier for H2 dissociation process. This investigation reveals that the boron and nitrogen dopants can act as effective active site for H2 dissociation and storage.  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