全文获取类型
收费全文 | 6535篇 |
免费 | 195篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 114篇 |
综合类 | 6篇 |
化学工业 | 1723篇 |
金属工艺 | 167篇 |
机械仪表 | 95篇 |
建筑科学 | 360篇 |
矿业工程 | 56篇 |
能源动力 | 84篇 |
轻工业 | 690篇 |
水利工程 | 32篇 |
石油天然气 | 9篇 |
无线电 | 444篇 |
一般工业技术 | 907篇 |
冶金工业 | 1234篇 |
原子能技术 | 66篇 |
自动化技术 | 746篇 |
出版年
2022年 | 62篇 |
2021年 | 81篇 |
2020年 | 80篇 |
2019年 | 73篇 |
2018年 | 100篇 |
2017年 | 82篇 |
2016年 | 134篇 |
2015年 | 141篇 |
2014年 | 150篇 |
2013年 | 200篇 |
2012年 | 228篇 |
2011年 | 284篇 |
2010年 | 219篇 |
2009年 | 213篇 |
2008年 | 223篇 |
2007年 | 244篇 |
2006年 | 212篇 |
2005年 | 229篇 |
2004年 | 176篇 |
2003年 | 147篇 |
2002年 | 147篇 |
2001年 | 136篇 |
2000年 | 131篇 |
1999年 | 128篇 |
1998年 | 368篇 |
1997年 | 232篇 |
1996年 | 183篇 |
1995年 | 166篇 |
1994年 | 147篇 |
1993年 | 128篇 |
1992年 | 98篇 |
1991年 | 94篇 |
1990年 | 78篇 |
1989年 | 84篇 |
1988年 | 58篇 |
1987年 | 62篇 |
1986年 | 65篇 |
1985年 | 77篇 |
1984年 | 66篇 |
1983年 | 62篇 |
1982年 | 68篇 |
1981年 | 63篇 |
1980年 | 57篇 |
1979年 | 67篇 |
1978年 | 45篇 |
1977年 | 72篇 |
1976年 | 116篇 |
1975年 | 59篇 |
1974年 | 36篇 |
1973年 | 37篇 |
排序方式: 共有6733条查询结果,搜索用时 0 毫秒
101.
Im Bereich des Sozialdatenschutzes besteht im Zusammenhang mit dem Besch?ftigtendatenschutz ein gesetzgeberischer Handlungsbedarf.
Die Regierungsparteien haben sich im Koalitionsvertrag darauf geeinigt, dass nach Jahren der Diskussion der Besch?ftigtendatenschutz
in einem Kapitel des BDSG geregelt werden soll. Hier kann die Frage dahingestellt bleiben, ob nicht eine bereichsspezifische
Regelung effektiver w?re. Eine Verbindung zwischen Besch?ftigtendatenschutz und Sozialdatenschutz wurde jedenfalls bisher
nicht ins Visier genommen. Eine solche Verknüpfung ist jedoch notwendig, wie die nachfolgend aufgezeigten Konfliktfelder und
der nachfolgend geschilderte Fall beispielhaft zeigen. Sie deuten die datenschutzrechtlichen Schwierigkeiten an, die durch
das Fehlen eines Besch?ftigtendatenschutzgesetzes für Besch?ftigte im Bereich der Jugendhilfe entstehen k?nnen. Anschlie?end
sollen sachgerechte Antworten ausgelotet werden. Sie führen gleichzeitig zu der kritischen Frage nach der Zust?ndigkeit von
Aufsichtsbeh?rden und Landesdatenschutzbeauftragten in F?llen, in denen die T?tigkeit ?ffentlicher (hier Jugendamt und Heimaufsicht)
und nicht-?ffentlicher Stellen (hier freie Tr?ger der Jugendhilfe) eng aufeinander abgestimmt werden muss. 相似文献
102.
A model, a heuristic and a decision support system to solve the scheduling problem of an earth observing satellite constellation 总被引:1,自引:0,他引:1
China plans to launch four small optical satellites and four small SAR satellites to form a natural disaster monitoring constellation. Data can be obtained by the constellation in all weather conditions for disaster alert and environmental damage analysis. The scheduling problem for the constellation consists of selecting and timetabling the observation activities to acquire the requested images of the earth surface and scheduling the download activities to transmit the image files to a set of ground stations. The scheduling problem is required to be solved every day in a typical 1-day horizon and it must respect complex satellite operational constraints as well as request preferences, such as visibility time windows, transition time between consecutive observations or downloads, memory capacity, energy capacity, polygon target requests and priorities. The objective is to maximize the rewards of the images taken and transmitted. We present a nonlinear model of the scheduling problem, develop a priority-based heuristic with conflict-avoided, limited backtracking and download-as-needed features, which produces satisfactory feasible plans in a very short time. A decision support system based on the model and the heuristic is also provided. The system performance shows a significant improvement with respect to faster and better scheduling of an earth observing satellite constellation. 相似文献
103.
Xiaoxu Guan C.J. Noble O. Zatsarinny K. Bartschat B.I. Schneider 《Computer Physics Communications》2009,180(12):2401-2409
We describe a general ab initio and non-perturbative method to solve the time-dependent Schrödinger equation (TDSE) for the interaction of a strong attosecond laser pulse with a general atom. While the field-free Hamiltonian and the dipole matrices may be generated using an arbitrary primitive basis, they are assumed to have been transformed to the eigenbasis of the problem before the solution of the TDSE is propagated in time using the Arnoldi–Lanczos method. Probabilities for survival of the ground state, excitation, and single ionization can be extracted from the propagated wavefunction.
Program summary
Program title: ALTDSECatalogue identifier: AEDM_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEDM_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 2154No. of bytes in distributed program, including test data, etc.: 30 827Distribution format: tar.gzProgramming language: Fortran 95. [A Fortran 2003 call to “flush” is used to simplify monitoring the output file during execution. If this function is not available, these statements should be commented out.].Computer: Shared-memory machinesOperating system: Linux, OpenMPHas the code been vectorized or parallelized?: YesRAM: Several Gb, depending on matrix size and number of processorsSupplementary material: To facilitate the execution of the program, Hamiltonian field-free and dipole matrix files are provided.Classification: 2.5External routines: LAPACK, BLASNature of problem: We describe a computer program for a general ab initio and non-perturbative method to solve the time-dependent Schrödinger equation (TDSE) for the interaction of a strong attosecond laser pulse with a general atom [1,2]. The probabilities for survival of the initial state, excitation of discrete states, and single ionization due to multi-photon processes can be obtained.Solution method: The solution of the TDSE is propagated in time using the Arnoldi–Lanczos method. The field-free Hamiltonian and the dipole matrices, originally generated in an arbitrary basis (e.g., the flexible B-spline R-matrix (BSR) method with non-orthogonal orbitals [3]), must be provided in the eigenbasis of the problem as input.Restrictions: The present program is restricted to a 1Se initial state and linearly polarized light. This is the most common situation experimentally, but a generalization is straightforward.Running time: Several hours, depending on the number of threads used.References: [1] X. Guan, O. Zatsarinny, K. Bartschat, B.I. Schneider, J. Feist, C.J. Noble, Phys. Rev. A 76 (2007) 053411. [2] X. Guan, C.J. Noble, O. Zatsarinny, K. Bartschat, B.I. Schneider, Phys. Rev. A 78 (2008) 053402. [3] O. Zatsarinny, Comput. Phys. Comm. 174 (2006) 273. 相似文献104.
This paper examines and classifies the computational complexity of model checking and satisfiability for hybrid logics over
frames with equivalence relations. The considered languages contain all possible combinations of the downarrow binder, the
existential binder, the satisfaction operator, and the global modality, ranging from the minimal hybrid language to very expressive
languages. For model checking, we separate polynomial-time solvable from PSPACE-complete cases, and for satisfiability, we
exhibit cases complete for NP, PSpace, NExpTime, and even N2ExpTime. Our analysis includes the versions of all these languages without atomic propositions, and also complete frames. 相似文献
105.
Thomas Neumann Matthias Bender Sebastian Michel Ralf Schenkel Peter Triantafillou Gerhard Weikum 《Distributed and Parallel Databases》2009,26(1):3-27
Top-k query processing is a fundamental building block for efficient ranking in a large number of applications. Efficiency is a
central issue, especially for distributed settings, when the data is spread across different nodes in a network. This paper
introduces novel optimization methods for top-k aggregation queries in such distributed environments. The optimizations can be applied to all algorithms that fall into the
frameworks of the prior TPUT and KLEE methods. The optimizations address three degrees of freedom: 1) hierarchically grouping
input lists into top-k operator trees and optimizing the tree structure, 2) computing data-adaptive scan depths for different input sources, and
3) data-adaptive sampling of a small subset of input sources in scenarios with hundreds or thousands of query-relevant network
nodes. All optimizations are based on a statistical cost model that utilizes local synopses, e.g., in the form of histograms,
efficiently computed convolutions, and estimators based on order statistics. The paper presents comprehensive experiments,
with three different real-life datasets and using the ns-2 network simulator for a packet-level simulation of a large Internet-style
network. 相似文献
106.
107.
108.
Vasileios Belagiannis Xinchao Wang Horesh Beny Ben Shitrit Kiyoshi Hashimoto Ralf Stauder Yoshimitsu Aoki Michael Kranzfelder Armin Schneider Pascal Fua Slobodan Ilic Hubertus Feussner Nassir Navab 《Machine Vision and Applications》2016,27(7):1035-1046
Multiple human pose estimation is an important yet challenging problem. In an operating room (OR) environment, the 3D body poses of surgeons and medical staff can provide important clues for surgical workflow analysis. For that purpose, we propose an algorithm for localizing and recovering body poses of multiple human in an OR environment under a multi-camera setup. Our model builds on 3D Pictorial Structures and 2D body part localization across all camera views, using convolutional neural networks (ConvNets). To evaluate our algorithm, we introduce a dataset captured in a real OR environment. Our dataset is unique, challenging and publicly available with annotated ground truths. Our proposed algorithm yields to promising pose estimation results on this dataset. 相似文献
109.
Universal Access in the Information Society - Helping blind people to build cognitive maps of an environment is one of the aims of several assistive systems. In order to evaluate such assistive... 相似文献
110.