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   12328篇
  免费   687篇
  国内免费   858篇
工业技术   13873篇
  2024年   23篇
  2023年   103篇
  2022年   157篇
  2021年   243篇
  2020年   205篇
  2019年   219篇
  2018年   219篇
  2017年   273篇
  2016年   367篇
  2015年   395篇
  2014年   713篇
  2013年   678篇
  2012年   670篇
  2011年   1025篇
  2010年   666篇
  2009年   693篇
  2008年   752篇
  2007年   887篇
  2006年   833篇
  2005年   715篇
  2004年   655篇
  2003年   673篇
  2002年   485篇
  2001年   400篇
  2000年   282篇
  1999年   286篇
  1998年   256篇
  1997年   208篇
  1996年   154篇
  1995年   147篇
  1994年   102篇
  1993年   67篇
  1992年   74篇
  1991年   46篇
  1990年   38篇
  1989年   43篇
  1988年   30篇
  1987年   8篇
  1986年   16篇
  1985年   19篇
  1984年   12篇
  1983年   10篇
  1982年   9篇
  1981年   6篇
  1980年   4篇
  1979年   2篇
  1978年   1篇
  1976年   3篇
  1973年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
《Planning》2015,(3)
为了培养青年医师运用医学科普语言传播医学知识的能力,向社会提供更优质、可及的健康知识,改善医患关系,促进社会和谐;同时出于向社区、媒体推送一批优秀青年医学科普人才的考虑,本文在总结北京协和医院培养青年医务人员医学科普能力经验的基础上,尝试构建一套适合大型公立医院(尤其是教学医院)培养青年医务人员医学科普能力的新模式——“科普训练营”。本文旨在系统介绍该模式的产生背景、实践经验及初期效果,阐释实施后的重要意义,及实施过程中的挑战与应对策略。  相似文献   
3.
孙暐  吴镇扬 《信号处理》2006,22(4):559-563
根据Flether等人的研究,基于感知独立性假设的子带识别方法被用于抗噪声鲁棒语音识别。本文拓展子带方法,采用基于噪声污染假定的多带框架来减少噪声影响。论文不仅从理论上分析了噪声污染假定多带框架在识别性能上的潜在优势,而且提出了多带环境下的鲁棒语音识别算法。研究表明:多带框架不仅回避了独立感知假设要求,而且与子带方法相比,多带方法能更好的减少噪声影响,提高系统识别性能。  相似文献   
4.
This article, the first of three articles on the synthesis of rice processing plants, focuses on the development of simplified mathematical models necessary for use in optimizing rice processing plants. The second concentrates on the optimal synthesis of a rice plant and the third on the sensitivity of the optimization to uncertainty in model parameters. Existing models for rice processing unit operations are not suitable for flowsheet optimization and new models need to be developed to overcome numerical difficulties that occur in optimization applications, specifically in mixed integer nonlinear programming (MINLP) applications. Simplified models of the drying, cooling, and tempering units are developed. In addition head rice yield models, used as a quality indicator, energy consumption, and economic models were also developed. Naturally, the new models exhibit some mismatch with respect to the existing models from which they were developed. However, a sensitivity analysis, presented in Part III, has shown that the optimal flowsheet structure was not sensitive to a lack of fit between the simplified and complex models. The simplified models were found adequate to be appropriate for use at the synthesis stage.  相似文献   
5.
6.
本文讨论了一个具有通用性的测试评估软件生成系统的设计思想和实现方法,给出了该生成器的系统组成、数据组织结构、查询搜索方式以及用户界面的设计。该系统具广泛的应用领域和实用意义。  相似文献   
7.
This paper gives a tutorial overview of basic approaches for model validation and model structure determination.Work partially supported by the Swedish Research Council for Engineering Sciences under contract 98-654.  相似文献   
8.
In polyolefin processes the melt index (MI) is the most important control variable indicating product quality. Because of the difficulty in the on-line measurement of MI, a lot of MI estimation and correlation methods have been proposed. In this work a new dynamic MI estimation scheme is developed based on system identification techniques. The empirical MI estimation equation proposed in the present study is derived from the 1 st -order dynamic models. Effectiveness of the present estimation scheme was illustrated by numerical simulations based on plant operation data including grade change operations in high density polyethylene (HDPE) processes. From the comparisons with other estimation methods it was found that the proposed estimation scheme showed better performance in MI predictions. The virtual sensor model developed based on the estimation scheme was combined with the virtual on-line analyzer (VOA) to give a quality control system to be implemented in the actual HDPE plant. From the application of the present control system, significant reduction of transition time and the amount of off-spec during grade changes was achieved  相似文献   
9.
This article specifies a virtual structural dynamic subsystem and some systems, as well as mathematical models that approximately simulate them. The purpose is to define a setting for model validations conceived by participants in the Sandia National Laboratories Validation Workshop. Some broad guidelines for the model validations are set, as well as a regulatory requirement to be satisfied by the target system. Participants are directed to present techniques for subsystem model validation, to analytically predict whether or not the regulatory requirement will be met, and to estimate the likelihood of accuracy of the prediction.  相似文献   
10.
Modelling the FEBEX THM experiment using a state surface approach   总被引:1,自引:0,他引:1  
Buffer materials being considered as engineered barriers in nuclear fuel waste (NFW) disposal systems possess a pronounced nonlinear behaviour in the unsaturated state. In order to simulate such non-linear responses,the authors adopted an incrementally nonlinear poro-elastic approach where the coefficients of the governing equations are assumed to be functions of suction and the void ratio. These functions are in turn developed from a state-surface equation obtained from suction-controlled oedometric tests. In this paper we show the derivation of the governing equations of the poro-elastic model. A finite element computer code, FRACON, was developed by the authors to numerically solve the above equations. We first use the code to simulate laboratory tests to characterize the swelling properties of a typical bentonite. That same bentonite was used in the FEBEX in-situ heater experiment, conducted at the Grimsel site, Switzerland. The FRACON code was also used to perform blind predictions of the FEBEX heater experiment. It is shown that the model correctly predicts drying of the bentonite near the heaters and re-saturation near the rock interface. The evolution of temperature and the heater thermal output were also reasonably well predicted by the model. The trends in the total stresses developed in the bentonite were correctly predicted; the absolute values however were underestimated probably due to the omission of pore pressure build-up in the rock mass.  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