全文获取类型
收费全文 | 2036篇 |
免费 | 86篇 |
国内免费 | 10篇 |
学科分类
工业技术 | 2132篇 |
出版年
2024年 | 3篇 |
2023年 | 14篇 |
2022年 | 68篇 |
2021年 | 101篇 |
2020年 | 72篇 |
2019年 | 56篇 |
2018年 | 98篇 |
2017年 | 71篇 |
2016年 | 84篇 |
2015年 | 61篇 |
2014年 | 92篇 |
2013年 | 170篇 |
2012年 | 108篇 |
2011年 | 135篇 |
2010年 | 103篇 |
2009年 | 97篇 |
2008年 | 107篇 |
2007年 | 90篇 |
2006年 | 57篇 |
2005年 | 62篇 |
2004年 | 39篇 |
2003年 | 35篇 |
2002年 | 36篇 |
2001年 | 24篇 |
2000年 | 16篇 |
1999年 | 37篇 |
1998年 | 26篇 |
1997年 | 19篇 |
1996年 | 24篇 |
1995年 | 20篇 |
1994年 | 29篇 |
1993年 | 22篇 |
1992年 | 21篇 |
1991年 | 11篇 |
1990年 | 14篇 |
1989年 | 10篇 |
1988年 | 7篇 |
1987年 | 12篇 |
1986年 | 5篇 |
1985年 | 10篇 |
1984年 | 5篇 |
1983年 | 9篇 |
1982年 | 10篇 |
1981年 | 10篇 |
1980年 | 8篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1975年 | 2篇 |
1974年 | 2篇 |
排序方式: 共有2132条查询结果,搜索用时 15 毫秒
991.
An exploratory study into factors of service quality for application service providers 总被引:3,自引:1,他引:2
An examination of the services offered by application service providers (ASPs) indicates that their current service quality needs to be improved to satisfy current and future clients. This study attempted to fulfill this need by identifying the dimensions of service quality for the ASP industry through both qualitative and quantitative approaches. As a result, seven dimensions were identified (features, availability, reliability, assurance, empathy, conformance, and security). In addition, an initial checklist was developed to help ASPs assess and diagnose their service quality performance. Some insights and implications to the ASP practitioners were also discussed. 相似文献
992.
Suresh Baskaran Lin Song Jun Liu Yuan L. Chen Gordon L. Graff 《Journal of the American Ceramic Society》1998,81(2):401-408
Titanium oxide (TiO2 ) thin films have been deposited on silicon, glass, and plastic substrates by destabilization of an aqueous titanium lactate solution at low temperatures (<100°C). The process uses a commercially available, low-cost precursor and is simple to perform; it involves only control of pH in aqueous, chelated titanium solutions. With this solution technique, high deposition rates (>50 nm/min), film thickness (>100 nm), and excellent film uniformity have been obtained. Uniform coatings can be applied on complex-shaped polymeric substrates and porous membranes. Films can be formed on both sulfonated and untreated polymeric surfaces. As-deposited films on plastic substrates consist of amorphous, hydrated TiO2 . On sulfonated self-assembled monolayers on silicon substrates, nanocrystalline TiO2 films have been formed. The deposited films exhibit strong ultraviolet (UV) absorption with excellent transmission in the visible wavelength range, which indicates that the coatings may be useful as protective UV blockers for polymeric materials. 相似文献
993.
Curve Matching,Time Warping,and Light Fields: New Algorithms for Computing Similarity between Curves
Alon Efrat Quanfu Fan Suresh Venkatasubramanian 《Journal of Mathematical Imaging and Vision》2007,27(3):203-216
The problem of curve matching appears in many application domains, like time series analysis, shape matching, speech recognition,
and signature verification, among others. Curve matching has been studied extensively by computational geometers, and many
measures of similarity have been examined, among them being the Fréchet distance (sometimes referred in folklore as the “dog-man”
distance).
A measure that is very closely related to the Fréchet distance but has never been studied in a geometric context is the Dynamic Time Warping measure (DTW), first used in the context of speech recognition. This measure is ubiquitous across different domains, a surprising
fact because notions of similarity usually vary significantly depending on the application. However, this measure suffers
from some drawbacks, most importantly the fact that it is defined between sequences of points rather than curves. Thus, the
way in which a curve is sampled to yield such a sequence can dramatically affect the quality of the result. Some attempts
have been made to generalize the DTW to continuous domains, but the resulting algorithms have exponential complexity.
In this paper we propose similarity measures that attempt to capture the “spirit” of dynamic time warping while being defined
over continuous domains, and present efficient algorithms for computing them. Our formulation leads to a very interesting
connection with finding short paths in a combinatorial manifold defined on the input chains, and in a deeper sense relates to the way light travels in a medium of variable refractivity.
Alon Efrat earned his Bachelor in Applied Mathematics from the Technion, Israel’s Institute of Technology in 1991, earned his Master
in Computer Science from the Technion in 1993, and his Ph.D. in Computer Science from Tel-Aviv University in 1998. During
the years 1998–2000 he was a Post Doctorate Research Assistant at the Computer Science Department at Stanford University,
and at IBM Almaden Research Center. Since 2000, he is an assistant Professor at the Computer Science Department at the University
of Arizona. His main research areas are Computational Geometry, and its applications.
Quanfu Fan is a Ph.D. student in the department of Computer Science at the University of Arizona. His research interests include object
recognition and image understanding, information retrieval, and geometric algorithms. 相似文献
994.
995.
PD Rye NV Bovin EV Vlasova AA Molodyk A Baryshnikov FT Kreutz WI Garinther BC Schultes AA Noujaim R Madiyalakan J Magnani O Nilsson K Nilsson K Nustad L Norum H Bell Y Cao MR Suresh DL Very JV Freeman KK Yeung J Hilgers 《Canadian Metallurgical Quarterly》1998,19(5):390-420
The ISOBM TD-6 Workshop is the first international workshop on monoclonal antibodies against the Sialyl Lewisa (SLea) antigen. Eight research groups participated in a blind study to characterize the epitope binding, relative affinity and performance in immunoradiometric assays, of a panel of 20 monoclonal antibodies. The antibodies were tested against a diverse panel of neoglycoconjugates, purified antigens and human serum pools from gastrointestinal malignancies. Epitope specificities were determined for the majority of antibodies in the panel. Cross-reactivity with related saccharide structures was noted in several antibodies. Overall, the results of the TD-6 Workshop show further development of SLea immunoassays may yield yet more specific assays for the detection and management of gastrointestinal and other malignancies. 相似文献
996.
Rahman K.M. Fahimi B. Suresh G. Rajarathnam A.V. Ehsani M. 《Industry Applications, IEEE Transactions on》2000,36(1):111-121
Land vehicles need their drivetrain to operate entirely in constant power in order to meet their operational constraints, such as initial acceleration and gradability, with minimum power rating. The internal combustion engine (ICE) is inappropriate for producing this torque-speed profile. Therefore, multiple gear transmission is necessary with the ICE in a vehicle. Some electric machines, if designed and controlled appropriately, are capable of producing an extended constant power range. The purpose of this paper is to investigate the capabilities of the switched reluctance motor (SRM) for electric vehicle and hybrid electric vehicle applications. This investigation is carried out in two steps. The first step involves the machine design and the finite-element analysis to obtain the static characteristic of the motor. In the second step, the finite-element field solutions are used in the development of a nonlinear model to investigate the dynamic performance of the designed motor 相似文献
997.
This paper proposes a cut-based technique to compute bounds on the full access probability of an extra stage shuffle exchange network (ESEN) and a wrap-around inverse banyan network (WIBN). Note that the problem of finding an exact full access probability is known to be NP-hard. Our results obtain tighter bounds as compared to those using existing techniques. For a small size multistage interconnection network, it deviates less from the exact value. We also notice that our proposed lower bound is conservative. Further, the lower bound is important as it suggests that a network is at least this much reliable 相似文献
998.
Viral immune evasion due to persistence of activated T cells without effector function 总被引:1,自引:0,他引:1
AJ Zajac JN Blattman K Murali-Krishna DJ Sourdive M Suresh JD Altman R Ahmed 《Canadian Metallurgical Quarterly》1998,188(12):2205-2213
We examined the regulation of virus-specific CD8 T cell responses during chronic lymphocytic choriomeningitis virus (LCMV) infection of mice. Our study shows that within the same persistently infected host, different mechanisms can operate to silence antiviral T cell responses; CD8 T cells specific to one dominant viral epitope were deleted, whereas CD8 T cells responding to another dominant epitope persisted indefinitely. These virus-specific CD8 T cells expressed activation markers (CD69(hi), CD44(hi), CD62Llo) and proliferated in vivo but were unable to elaborate any antiviral effector functions. This unresponsive phenotype was more pronounced under conditions of CD4 T cell deficiency, highlighting the importance of CD8- CD4 T cell collaboration in controlling persistent infections. Importantly, in the presence of CD4 T cell help, adequate CD8 effector activity was maintained and the chronic viral infection eventually resolved. The persistence of activated virus-specific CD8 T cells without effector function reveals a novel mechanism for silencing antiviral immune responses and also offers new possibilities for enhancing CD8 T cell immunity in chronically infected hosts. 相似文献
999.
Analytical Models for Single-Hop and Multi-Hop Ad Hoc Networks 总被引:1,自引:1,他引:0
There is considerable interest in modeling the performance of ad hoc networks analytically. This paper presents approximate
analytical models for the throughput performance of single-hop and multi-hop ad hoc networks. The inherent complexity of analysis
of a multi-hop ad hoc network together with the fact that the behavior of a node is dependent not only on its neighbors' behavior,
but also on the behavior of other unseen nodes makes multi-hop network analysis extremely difficult. However, our approach
in this paper to analyze multi-hop networks offers an accurate approximation with moderate complexity. Our approach is based
on characterizing the behavior of a node by its state and the state of the channel it sees. This approach is used to carry
out an analysis of single-hop and multi-hop ad hoc networks in which different nodes may have different traffic loads. In
order to validate the model, it is applied to IEEE 802.11-based networks, and it is shown through extensive simulations that
the model is very accurate.
Farshid Alizadeh-Shabdiz received his B.Sc. in 1989 at University of Science and Technology, M.Sc. in 1991 at Tehran University, Iran, and D.Sc. in
2004 at the George Washington University. He is a senior research engineer in Advanced Solution Group, part of Cross Country
Automotive Services, and he is also a part time faculty member at Boston University.
Dr. Alizadeh-Shabdiz was part of the design and implementation team of the three first satellite-based mobile networks: ICO
global medium orbit satellite network voice and data services, Thuraya GEO satellite network, and the first phase of Inmarsat
high speed data network. His research interests include MAC layer, physical layer and network layer of wireless and satellite
networks.
Suresh Subramaniam received the Ph.D. degree in electrical engineering from the University of Washington, Seattle, in 1997. He is an Associate
Professor in the Department of Electrical and Computer Engineering at the George Washington University, Washington, DC. His
research interests are in the architectural, algorithmic, and performance aspects of communication networks, with particular
emphasis on optical and wireless ad hoc networks.
Dr. Subramaniam is a co-editor of the books “Optical WDM Networks – Principles and Practice” and “Emerging Optical Network
Technologies: Architectures, Protocols, and Performance”. He has been on the program committees of several conferences including
Infocom, ICC, Globecom, and Broadnets, and served as TPC Co-Chair for the 2004 Broadband Optical Networking Symposium. He
currently serves on the editorial boards of Journal of Communications and Networks and IEEE Communications Surveys and Tutorials.
He is a co-recipient of the Best Paper Award at the 1997 SPIE Conference on All-Optical Communication Systems. 相似文献
1000.
K. Byrappa M. K. Devaraju P. Madhusudan A. S. Dayananda B. V. Suresh Kumar H. N. Girish S. Ananda K. M. Lokanatha Rai P. Javeri 《Journal of Materials Science》2006,41(5):1395-1398
The synthesis of calcium aluminum silicate hydroxide (CASH) has been carried out under mild hydrothermal and solvothermal
conditions. Different mineralizers such as HCOOH, HNO3, CH3COOH, HCl, mixed acids, NaOH and non-aqueous solvents like C2H5OH, n-butanol, glycol, methanol, etc., were employed in the synthesis of CASH. The crystals obtained were characterized by X-ray
powder diffraction and FTIR spectroscopic techniques. 相似文献