全文获取类型
收费全文 | 1561篇 |
免费 | 60篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 36篇 |
综合类 | 2篇 |
化学工业 | 342篇 |
金属工艺 | 70篇 |
机械仪表 | 26篇 |
建筑科学 | 48篇 |
矿业工程 | 26篇 |
能源动力 | 44篇 |
轻工业 | 137篇 |
水利工程 | 7篇 |
石油天然气 | 2篇 |
无线电 | 151篇 |
一般工业技术 | 248篇 |
冶金工业 | 232篇 |
原子能技术 | 6篇 |
自动化技术 | 246篇 |
出版年
2023年 | 20篇 |
2022年 | 22篇 |
2021年 | 46篇 |
2020年 | 32篇 |
2019年 | 43篇 |
2018年 | 31篇 |
2017年 | 33篇 |
2016年 | 38篇 |
2015年 | 34篇 |
2014年 | 53篇 |
2013年 | 66篇 |
2012年 | 53篇 |
2011年 | 83篇 |
2010年 | 70篇 |
2009年 | 71篇 |
2008年 | 72篇 |
2007年 | 64篇 |
2006年 | 54篇 |
2005年 | 37篇 |
2004年 | 26篇 |
2003年 | 31篇 |
2002年 | 32篇 |
2001年 | 32篇 |
2000年 | 22篇 |
1999年 | 23篇 |
1998年 | 71篇 |
1997年 | 49篇 |
1996年 | 49篇 |
1995年 | 28篇 |
1994年 | 17篇 |
1993年 | 25篇 |
1992年 | 26篇 |
1991年 | 22篇 |
1990年 | 14篇 |
1989年 | 18篇 |
1988年 | 17篇 |
1987年 | 11篇 |
1986年 | 9篇 |
1985年 | 12篇 |
1983年 | 9篇 |
1982年 | 8篇 |
1980年 | 7篇 |
1978年 | 12篇 |
1977年 | 13篇 |
1976年 | 16篇 |
1975年 | 13篇 |
1974年 | 10篇 |
1973年 | 10篇 |
1971年 | 8篇 |
1970年 | 5篇 |
排序方式: 共有1623条查询结果,搜索用时 7 毫秒
131.
Back Cover: [3H]UR‐DE257: Development of a Tritium‐Labeled Squaramide‐Type Selective Histamine H2 Receptor Antagonist (ChemMedChem 1/2015) 下载免费PDF全文
132.
Fault-tolerant communication and energy efficiency are important requirements for future-generation wireless ad hoc networks,
which are increasingly being considered also for critical application domains like embedded systems in automotive and aerospace.
Topology control, which enables multi-hop communication between any two network nodes via a suitably constructed overlay network,
is the primary target for increasing connectivity and saving energy here. In this paper, we present a fault-tolerant distributed
topology control algorithm that constructs and continuously maintains a k-regular and k-node-connected overlay for energy-efficient multi-hop communication. As a by-product, it also builds a hierarchy of clusters
that reflects the node density in the network, with guaranteed and localized fault-tolerant communication between any pair
of cluster members. The construction algorithm automatically adapts to a dynamically changing environment, is guaranteed to
converge, and exhibits good performance as well. 相似文献
133.
Armin Tajalli Mohammad Chahardori Abbas Khodaverdi 《Analog Integrated Circuits and Signal Processing》2010,62(2):131-140
This article explores the main tradeoffs in design of power and area efficient bandgap voltage reference (BGR) circuits. A structural design methodology for optimizing the silicon area and power dissipation of CMOS BGRs will be introduced. For this purpose, basic equations of the bandgap circuit have been adapted such that can simply be applied in the optimization process. To improve the reliability of the designed circuit, the effect of amplifier offset has been also included in the optimization process. It is also shown that the minimum achievable power consumption and area are highly depending on the fabrication process parameters especially sheet resistivity of the available resistors in the technology and also the area of bipolar transistors. The proposed technique does not depend on a special process and can be applied for designing bandgap reference circuits with different topologies. 相似文献
134.
Davood Shishebori Iman Dayarian Armin Jabbarzadeh Farnaz Barzinpour 《The International Journal of Advanced Manufacturing Technology》2014,71(1-4):127-139
Locating certain facilities in predetermined sites is named the multiple facility location problems (MFLP). The objective of these kinds of problems is locating facilities to serve a given set of customers so that candidate sites and requirements are known. When the new facility sites have to be selected from a given set of candidate sites, the mentioned location problem becomes a discrete multiple facility location problem (DMFLP). In this paper, a special approach of DMFLP is considered where different multiple facilities have to be placed (location decision) and also customers have to be assigned to these facilities (allocation or assignment). The mathematical model of the proposed problem is developed, and with respect to the complexity of solving the mathematical model, especially in large scale, a new hybrid approach is proposed based on tabu search algorithm to solve the problem at each scale. Computational results on several randomly generated problems in comparison with a new proposed lower bound obtained from Lagrangian relaxation indicate that the proposed hybrid approach is both accurate and efficient. 相似文献
135.
136.
In many industries mixed-model assembly systems are increasingly supplied out of third-party consignment stock. This novel
trend gives rise to a new short-term sequencing problem which decides on the succession of models launched down the line and
aims at minimizing the cost of in-process inventory held by the manufacturer. In this work, we investigate the mathematical
structure of this part oriented mixed-model sequencing problem and prove that general instances of the problem are NP-hard
in the strong sense. Moreover, we develop a new Beam Search heuristic, which clearly outperforms existing solution procedures. 相似文献
137.
Plasma-enhanced chemical deposition processes have been studied by comparing the performance of flexible diffusion barrier layers on plastic films produced in the same reactor. Under similar experimental conditions, a higher deposition rate is achieved by microwave discharges than by bipolar, pulsed d.c. magnetron sputtering processes. However, with both discharge modes, dense hydrocarbon coatings were produced, exhibiting a barrier improvement factor up to 120 and a flexibility ranging from 1.1%–8.8% before formation of microcracks started to dominate permeation characteristics. The density of the coatings is 1.0–1.6 g cm–3 and their hydrogen content varies from 23%–33%. 相似文献
138.
M De Veerman C Heirman S Van Meirvenne S Devos J Corthals M Moser K Thielemans 《Canadian Metallurgical Quarterly》1999,162(1):144-151
It has been extensively documented that murine dendritic cells loaded with tumor-associated Ag (TAA)-derived peptides or protein can prime Ag-specific CD8+ cytotoxic T cells in vivo and can elicit Ag-specific immunity. Optimal presentation of TAA might be achieved by retroviral transduction of DCs allowing long term and stable expression of the TAA-peptides as well as the presentation of multiple epitopes in the context of MHC class I and/or class II molecules. Here we show that retroviral transduction of bone marrow-derived dendritic cells (DCs) with chicken OVA cDNA or the reporter gene green fluorescent protein retained their potent stimulatory capacity and that the transduced DCs could process and present the endogenously expressed OVA protein. The DCs transduced with cDNA encoding native OVA protein presented OVA-derived peptides in the context of MHC class I as well as MHC class II and induced a strong Ag-specific CTL response. DCs expressing a cytosolic form of OVA presented OVA peptides only in the context of MHC class I and failed to induce an OVA-specific CTL response in vivo when they had been cultured in the absence of exogenous protein. Immunization with retrovirally transduced DCs resulted in an Ag-specific immunity and rejection of a tumor cell challenge and a significant survival advantage in tumor-bearing mice. These results obtained in this rapidly lethal tumor model suggest that DCs transduced with TAA may be useful for tumor immunotherapy and underscore the importance of the simultaneous delivery of T cell help in the development of Ag-specific cytotoxic T-cells. 相似文献
139.
140.
Armin Herb 《Datenschutz und Datensicherheit - DuD》2011,35(4):270-274
Die Finanzierung des dualen Rundfunksystems in Deutschland und damit insbesondere der ?ffentlich-rechtlichen Rundfunkanstalten
soll ab dem 1. Januar 2013 auf eine neue Basis gestellt werden. Anstatt den bisherigen Gebühren für ein H?rfunk- oder Fernsehger?t
ist dann ein Rundfunkbeitrag für jede Wohnung und Betriebsst?tte zu leisten. Die nachfolgenden Ausführungen befassen sich
mit den datenschutzrechtlichen Vorschriften im neuen Rundfunkbeitragsstaatsvertrag der L?nder. 相似文献