全文获取类型
收费全文 | 2408篇 |
免费 | 101篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 22篇 |
综合类 | 3篇 |
化学工业 | 519篇 |
金属工艺 | 51篇 |
机械仪表 | 51篇 |
建筑科学 | 94篇 |
矿业工程 | 2篇 |
能源动力 | 31篇 |
轻工业 | 301篇 |
水利工程 | 19篇 |
石油天然气 | 5篇 |
无线电 | 173篇 |
一般工业技术 | 333篇 |
冶金工业 | 617篇 |
原子能技术 | 20篇 |
自动化技术 | 273篇 |
出版年
2023年 | 25篇 |
2022年 | 50篇 |
2021年 | 97篇 |
2020年 | 57篇 |
2019年 | 37篇 |
2018年 | 51篇 |
2017年 | 44篇 |
2016年 | 61篇 |
2015年 | 55篇 |
2014年 | 61篇 |
2013年 | 119篇 |
2012年 | 126篇 |
2011年 | 121篇 |
2010年 | 104篇 |
2009年 | 101篇 |
2008年 | 143篇 |
2007年 | 100篇 |
2006年 | 75篇 |
2005年 | 64篇 |
2004年 | 72篇 |
2003年 | 64篇 |
2002年 | 46篇 |
2001年 | 56篇 |
2000年 | 31篇 |
1999年 | 54篇 |
1998年 | 104篇 |
1997年 | 76篇 |
1996年 | 63篇 |
1995年 | 42篇 |
1994年 | 29篇 |
1993年 | 40篇 |
1992年 | 37篇 |
1991年 | 18篇 |
1990年 | 17篇 |
1989年 | 25篇 |
1988年 | 13篇 |
1987年 | 30篇 |
1986年 | 21篇 |
1985年 | 15篇 |
1984年 | 12篇 |
1983年 | 9篇 |
1982年 | 16篇 |
1981年 | 6篇 |
1980年 | 14篇 |
1979年 | 12篇 |
1978年 | 11篇 |
1977年 | 12篇 |
1976年 | 22篇 |
1975年 | 8篇 |
1974年 | 7篇 |
排序方式: 共有2514条查询结果,搜索用时 31 毫秒
1.
2.
Pierre Santucci Christina Dedaki Alexandros Athanasoulis Laura Gallorini Anaïs Munoz Dr. Stéphane Canaan Dr. Jean-François Cavalier Dr. Victoria Magrioti 《ChemMedChem》2019,14(3):349-358
In the quest for new antibacterial agents, a series of novel long- and medium-chain mono- and disubstituted β-lactones was developed. Their activity against three pathogenic mycobacteria—M. abscessus, M. marinum, and M. tuberculosis—was assessed by the resazurin microtiter assay (REMA). Among the 16 β-lactones synthesized, only 3-hexadecyloxetan-2-one (VM005) exhibited promising activity against M. abscessus, whereas most of the β-lactones showed interesting activities against M. marinum, similar to that of the classical antibiotic, isoniazid. Regarding M. tuberculosis, six compounds were found to be active against this mycobacterium, with β-lactone VM008 [trans-(Z)-3-(hexadec-7-en-1-yl)-4-propyloxetan-2-one] being the best growth inhibitor. The promising antibacterial activities of the best compounds in this series suggest that these molecules may serve as leads for the development of much more efficient antimycobacterial agents. 相似文献
3.
4.
5.
Thomas S. Lowry John C. Bright Murray E. Close Christina A. Robb Paul A. White Stewart G. Cameron 《国际水资源开发杂志》2003,19(4):579-592
The primary objective of this project is to identify gaps, whether real or perceived, that hinder effective groundwater management in New Zealand. These gaps show as gaps in information, gaps in implementation, gaps in technological and management tools, and gaps in understanding of fundamental processes. The secondary objective is to propose a management strategy to close the identified gaps. Several methods are used to meet these objectives: surveys distributed to selected staff in each regional council; the review of various written reports; the analysis of land-use databases; and private consultation within each regional council. Results show that groundwater management in New Zealand is generally reactionary with the main gaps being in strategic planning and national guidelines. Most gaps appear to be predominantly information and implementation issues. In some cases there are gaps in the understanding of fundamental processes within an aquifer system, including the long-term effects of land-use on groundwater quality. An adaptive management approach is suggested as a means of closing these gaps. 相似文献
6.
P. J. C. Skitt M. A. Javed S. A. Sanders A. M. Higginson 《Journal of Intelligent Manufacturing》1993,4(1):79-94
The potential of using artificially simulated neural networks as intelligent, adaptive process-monitoring devices is discussed. The investigation is considered as a method for automatic, intelligent exception reporting for quality control applications. The technique is also compared with the conventional statistical approaches of principal component analysis and Kohonen's feature map. The applications of the technique in aerospace and manufacturing environments are presented and a possible extension of the method to incorporate a diagnostic function is discussed.Seconded from Cheltenham and Gloucester College of Higher Education as a Royal Society/SERC Research Fellow at Smith's Industries Aerospace and Defence Systems, Bishop's Cleeve, Cheltenham, UK. 相似文献
7.
Stochastic extensions to Petri nets have gained widespread acceptance as a method for describing the dynamic behavior of discrete-event
systems. Both simulation and analytic methods have been proposed to solve such models. This paper describes a set of efficient
procedures for simulating models that are represented as stochastic activity networks (SANs, a variant of stochastic Petri
nets) and composed SAN-based reward models (SBRMs). Composed SBRMs are a hierarchical representation for SANs, in which individual
SAN models can be replicated and joined together with other models, in an iterative fashion. The procedures exploit the hierarchical
structure and symmetries introduced by the replicate operation in a composed SBRM to reduce the cost of future event list
management. The procedures have been implemented as part of a larger performance-dependability modeling package known asUltraSAN, and have been applied to real, large-scale applications.
This work was supported in part by the Digital Equipment Corporation Faculty Program: Incentives for Excellence. 相似文献
8.
9.
SIMULATION STUDIES OF THE REMOVAL OF WATER FROM ETHANOL BY A CATALYTIC DISTILLATION PROCESS 总被引:1,自引:0,他引:1
Christina B. Dirk-Faitakis Karl T. Chuang 《Chemical Engineering Communications》2005,192(11):1541-1557
A new approach based on catalytic distillation (CD) technology was proposed to remove water from ethanol. Isobutylene was introduced to react with water in the CD column. The commercial software simulation tool Aspen Plus was used to investigate the effects of key design factors such as operating pressure and temperature, reactant ratios, reflux and distillate to feed ratios, number of separation and reaction stages, and feed and reaction zone location. It was found that the CD technology offers potential advantages of reduced energy consumption and reduced capital cost over traditional approaches for the removal of water from ethanol. 相似文献
10.