全文获取类型
收费全文 | 7671篇 |
免费 | 247篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 124篇 |
综合类 | 13篇 |
化学工业 | 1597篇 |
金属工艺 | 191篇 |
机械仪表 | 115篇 |
建筑科学 | 349篇 |
矿业工程 | 17篇 |
能源动力 | 121篇 |
轻工业 | 826篇 |
水利工程 | 42篇 |
石油天然气 | 13篇 |
武器工业 | 1篇 |
无线电 | 571篇 |
一般工业技术 | 1251篇 |
冶金工业 | 1924篇 |
原子能技术 | 75篇 |
自动化技术 | 693篇 |
出版年
2021年 | 85篇 |
2020年 | 71篇 |
2019年 | 77篇 |
2018年 | 104篇 |
2017年 | 100篇 |
2016年 | 145篇 |
2015年 | 136篇 |
2014年 | 147篇 |
2013年 | 294篇 |
2012年 | 218篇 |
2011年 | 277篇 |
2010年 | 247篇 |
2009年 | 224篇 |
2008年 | 255篇 |
2007年 | 229篇 |
2006年 | 240篇 |
2005年 | 192篇 |
2004年 | 185篇 |
2003年 | 195篇 |
2002年 | 174篇 |
2001年 | 167篇 |
2000年 | 153篇 |
1999年 | 177篇 |
1998年 | 433篇 |
1997年 | 322篇 |
1996年 | 231篇 |
1995年 | 140篇 |
1994年 | 142篇 |
1993年 | 149篇 |
1992年 | 104篇 |
1991年 | 79篇 |
1990年 | 98篇 |
1989年 | 101篇 |
1988年 | 75篇 |
1987年 | 75篇 |
1986年 | 77篇 |
1985年 | 78篇 |
1984年 | 91篇 |
1983年 | 92篇 |
1982年 | 84篇 |
1981年 | 78篇 |
1980年 | 80篇 |
1979年 | 79篇 |
1978年 | 82篇 |
1977年 | 120篇 |
1976年 | 148篇 |
1975年 | 71篇 |
1974年 | 55篇 |
1972年 | 61篇 |
1966年 | 53篇 |
排序方式: 共有7923条查询结果,搜索用时 15 毫秒
11.
12.
CF Wippermann RG Huth FX Schmidt J Thul M Betancor D Schranz 《Canadian Metallurgical Quarterly》1996,22(5):467-471
OBJECTIVE: To compare a system that continuously monitors cardiac output by the Fick principle with measurements by the thermodilution technique in pediatric patients. DESIGN: Prospective direct comparison of the above two techniques. SETTING: Pediatric intensive care unit of a university hospital. PATIENTS: 25 infants and children, aged 1 week to 17 years (median 10 months), who had undergone open heart surgery were studied. Only patients without an endotracheal tube leak and without a residual shunt were included. METHODS: The system based on the Fick principle uses measurements of oxygen consumption taken by a metabolic monitor and of arterial and mixed venous oxygen saturation taken by pulse- and fiberoptic oximetry to calculate cardiac output every 20s. INTERVENTIONS: In every patient one pair of measurements was taken. Continuous Fick and thermodilution cardiac output measurements were performed simultaneously, with the examiners remaining ignorant of the results of the other method. RESULTS: Cardiac output measurements ranged from 0.21 to 4.55 l/min. A good correlation coefficient was found: r2 = 0.98; P < 0.001; SEE = 0.41 l/min. The bias is absolute values and in percent of average cardiac output was - 0.05 l/min or - 4.4% with a precision of 0.32 l/min or 21.3% at 2 SD, respectively. The difference was most marked in a neonate with low cardiac output. CONCLUSION: Continuous measurement of cardiac output by the Fick principle offers a convenient method for the hemodynamic monitoring of unstable infants and children. 相似文献
13.
14.
Hans-Jürgen Odenthal Herbert Pfeifer Ina Lemanowicz Rainer Gorissen 《Metallurgical and Materials Transactions B》2002,33(2):163-172
The present work describes quantitative digital particle image velocimetry measurements of a full-scale water model of a thin
slab mold. Different casting speeds and two submerged entry nozzles with one and two outlet ports have been investigated.
The flow pattern of the single-port nozzle shows a counterclockwise-rotating double vortex that is nearly steady-state but
leads to high stationary surface waves. The flow jets out of the two-port nozzle oscillate and produce a transient flow pattern
with low wave amplitudes. The amplitudes for the one-port nozzle show a linear variation with the volumetric flow rate. The
experimental results lead to a good interpretation of the flow phenomena and are used to validate steady-state numerical simulations
with the commercial program, CFX, on the basis of the Reynolds equations. To describe anisotropic turbulence effects, the
Reynolds stress model (RSM) is used for the flat single-port nozzle and the standard k-ɛ model for the mold flow. The calculated mean velocities and wave amplitudes, predicted from pressure distribution at the
water surface, are generally in the consensus of the experimental data.
An erratum to this article is available at . 相似文献
15.
16.
17.
Matthias Zobel Joachim Denzler Benno Heigl Elmar Nöth Dietrich Paulus Jochen Schmidt Georg Stemmer 《Machine Vision and Applications》2003,14(1):26-34
Abstract. This contribution introduces MOBSY, a fully integrated, autonomous mobile service robot system. It acts as an automatic dialogue-based
receptionist for visitors to our institute. MOBSY incorporates many techniques from different research areas into one working
stand-alone system. The techniques involved range from computer vision over speech understanding to classical robotics.
Along with the two main aspects of vision and speech, we also focus on the integration aspect, both on the methodological
and on the technical level. We describe the task and the techniques involved. Finally, we discuss the experiences that we
gained with MOBSY during a live performance at our institute. 相似文献
18.
在当今企业环境日益复杂而活跃的背景条件下,企业需要不断进行重组和迅速转型。这要求企业要具备更强的适应性和更高的灵活性。为了确保实现这些动态的要求,企业必须制定和实施新型的组织形式。本文介绍过程链管理——一种面向过程进行转型的工具。本文首先简要说明了过程链管理应用的工具、过程链管理的任务和构造。它的出发点是由行动、结构、资源、和指挥所组成的过程链管理。在第二步骤中,重点阐述了客户取向这个过程链管理中最重要的取向量。总体来说,整个价值创造链及与此相关的内部交换关系都具有重要意义。在对过程链管理的方法进行了说明以后,提出了一个应用实例,该实例不仅描述了垂直重构,也对水平重构进行了描述。 相似文献
19.
The vicissitudes of the Israeli-Palestinian peace process since 1967 are analyzed using attitudes and related concepts where relevant. The 1967 war returned the two peoples' zero-sum conflict around national identity to its origin as a conflict within the land both peoples claim. Gradually, new attitudes evolved regarding the necessity and possibility of negotiations toward a two-state solution based on mutual recognition, which became the building stones of the 1993 Oslo agreement. Lacking a commitment to a final outcome, the Oslo-based peace process was hampered by reserve options, which increased avoidance at the expense of approach tendencies as the parties moved toward a final agreement. The resulting breakdown of the process in 2000 produced clashing narratives, reflecting different anchors for judgment and classical mirror images. Public support for violence increased, even as public opinion continued to favor a negotiated two-state solution. Reviving the peace process requires mutual reassurance about the availability of a partner for negotiating a principled peace based on a historic compromise that meets the basic needs and validates the identities of both peoples. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
20.
Sood Johanna R.; Cisek Edward; Zimmerman Joan; Zaleski Ellen H.; Fillmore Herbert H. 《Canadian Metallurgical Quarterly》2003,48(1):44
Objective: To replicate and extend P. A. Lichtenberg and colleagues' (1996) cross-disciplinary intervention to improve physical and mental health among older adults. Participants: 14 depressed older adults (6 treatment, 8 control). Setting: The short-term rehabilitation unit of an urban nursing home. Intervention: Occupational therapists were trained to treat depression using pleasant events and cognitive-behavioral therapies. Outcome Measures: Geriatric Depression Scale, the Short Form-12, and the Multi-Level Assessment Instrument: Activities of Daily Living. Results: No significant group differences were found in physical or mental health. However, more control group members (75%) than treatment group members (33%) were depressed at study completion. Conclusions: The treatment of depressive symptoms can be integrated with a nonmental health treatment modality. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献