全文获取类型
收费全文 | 5874篇 |
免费 | 543篇 |
国内免费 | 57篇 |
学科分类
工业技术 | 6474篇 |
出版年
2024年 | 31篇 |
2023年 | 211篇 |
2022年 | 392篇 |
2021年 | 778篇 |
2020年 | 493篇 |
2019年 | 542篇 |
2018年 | 502篇 |
2017年 | 423篇 |
2016年 | 415篇 |
2015年 | 257篇 |
2014年 | 320篇 |
2013年 | 460篇 |
2012年 | 271篇 |
2011年 | 328篇 |
2010年 | 190篇 |
2009年 | 165篇 |
2008年 | 109篇 |
2007年 | 101篇 |
2006年 | 45篇 |
2005年 | 35篇 |
2004年 | 43篇 |
2003年 | 33篇 |
2002年 | 23篇 |
2001年 | 11篇 |
2000年 | 13篇 |
1999年 | 19篇 |
1998年 | 30篇 |
1997年 | 21篇 |
1996年 | 16篇 |
1995年 | 20篇 |
1994年 | 9篇 |
1993年 | 16篇 |
1992年 | 14篇 |
1991年 | 12篇 |
1990年 | 6篇 |
1989年 | 13篇 |
1988年 | 13篇 |
1987年 | 12篇 |
1986年 | 4篇 |
1985年 | 11篇 |
1984年 | 9篇 |
1982年 | 8篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1975年 | 6篇 |
1974年 | 5篇 |
1973年 | 3篇 |
1970年 | 3篇 |
排序方式: 共有6474条查询结果,搜索用时 31 毫秒
101.
Naveed Aslam Mirza Hikmat Ullah Khan Khalid Iqbal Saqib Iqbal Muhammad Imran 《New Review of Hypermedia and Multimedia》2013,19(4):335-345
ABSTRACTThe quality of user-generated content over World Wide Web media is a matter of serious concern for both creators and users. To measure the quality of content, webometric techniques are commonly used. In recent times, bibliometric techniques have been introduced to good effect for evaluation of the quality of user-generated content, which were originally used for scholarly data. However, the application of bibliometric techniques to evaluate the quality of YouTube content is limited to h-index and g-index considering only views. This paper advocates for and demonstrates the adaptation of existing Bibliometric indices including h-index, g-index and M-index exploiting both views and comments and proposes three indices hvc, gvc and mvc for YouTube video channel ranking. The empirical results prove that the proposed indices using views along with the comments outperform the existing approaches on a real-world dataset of YouTube. 相似文献
102.
The Jackfish Bay Remedial Action Plan is the first of Lake Superior's Areas of Concern (AOCs) to consider recognition as an Area in Recovery (AiR). As a result of a high degree of complexity and uncertainty, ecosystem recovery in Jackfish Bay has been determined using a combination of regulatory policies and scientific evidence and extensive public and expert-based decision making. As a result, the conceptualization of the AiR status in Jackfish Bay has been developed with the adaptive management and the ecosystem approach, which provide the basic principles of assessing, monitoring, and managing the Area of Concern. To determine the status of beneficial use impairments caused by effluent from the Terrace Bay Pulp Inc., three public advisory committees—an academic panel of experts, a government technical review committee, and the Jackfish Bay Public Area in Recovery Review Committee (PARRC)—reviewed relevant scientific data and documents, including peer-reviewed publications, to assess changes in pollution levels in Jackfish Bay and improvements to aquatic, biotic, and benthic environments of the bay. The public decision-making process concluded with recommendations by the PARRC to develop a systematic monitoring program so that the ecosystem recovery process in the bay could be assessed on a continued basis, leading to its eventual delisting as an AOC. The entire process provides an example of blending science and public policies for remediation of a degraded ecosystem on the Great Lakes. 相似文献
103.
Muhammad Waseem Rizwan Ahmed Muhammad Irfan Shahid Qamar 《Quantum Information Processing》2013,12(12):3649-3664
We present a scheme for the implementation of three-qubit Grover’s algorithm using four-level superconducting quantum interference devices (SQUIDs) coupled to a superconducting resonator. The scheme is based on resonant, off-resonant interaction of the cavity field with SQUIDs and application of classical microwave pulses. We show that adjustment of SQUID level spacings during the gate operations, adiabatic passage, and second-order detuning are not required that leads to faster implementation. We also show that the marked state can be searched with high fidelity even in the presence of unwanted off-resonant interactions, level decay, and cavity dissipation. 相似文献
104.
Data-Intensive Cloud Computing: Requirements, Expectations, Challenges, and Solutions 总被引:1,自引:0,他引:1
Data-intensive systems encompass terabytes to petabytes of data. Such systems require massive storage and intensive computational power in order to execute complex queries and generate timely results. Further, the rate at which this data is being generated induces extensive challenges of data storage, linking, and processing. A data-intensive cloud provides an abstraction of high availability, usability, and efficiency to users. However, underlying this abstraction, there are stringent requirements and challenges to facilitate scalable and resourceful services through effective physical infrastructure, smart networking solutions, intelligent software tools, and useful software approaches. This paper analyzes the extensive requirements which exist in data-intensive clouds, describes various challenges related to the paradigm, and assess numerous solutions in meeting these requirements and challenges. It provides a detailed study of the solutions and analyzes their capabilities in meeting emerging needs of widespread applications. 相似文献
105.
Wessam M. Hassanein Layali K. Rashid Moustafa A. Hammad 《International journal of parallel programming》2008,36(2):206-225
As information processing applications take greater roles in our everyday life, database management systems (DBMSs) are growing
in importance. DBMSs have traditionally exhibited poor cache performance and large memory footprints, therefore performing
only at a fraction of their ideal execution and exhibiting low processor utilization. Previous research has studied the memory
system of DBMSs on research-based simultaneous multithreading (SMT) processors. Recently, several differences have been noted
between the real hyper-threaded architecture implemented by the Intel Pentium 4 and the earlier SMT research architectures.
This paper characterizes the performance of a prototype open-source DBMS running TPC-equivalent benchmark queries on an Intel
Pentium 4 Hyper-Threading processor. We use hardware counters provided by the Pentium 4 to evaluate the micro-architecture
and study the memory system behavior of each query running on the DBMS. Our results show a performance improvement of up to
1.16 in TPC-C-equivalent and 1.26 in TPC-H-equivalent queries due to hyperthreading. 相似文献
106.
Targeting spam control on middleboxes: Spam detection based on layer-3 e-mail content classification
This paper proposes a spam detection technique, at the packet level (layer 3), based on classification of e-mail contents. Our proposal targets spam control implementations on middleboxes. E-mails are first pre-classified (pre-detected) for spam on a per-packet basis, without the need for reassembly. This, in turn, allows fast e-mail class estimation (spam detection) at receiving e-mail servers to support more effective spam handling on both inbound and outbound (relayed) e-mails. In this paper, the naïve Bayes classification technique is adapted to support both pre-classification and fast e-mail class estimation, on a per-packet basis. We focus on evaluating the accuracy of spam detection at layer 3, considering the constraints on processing byte-streams over the network, including packet re-ordering, fragmentation, overlapped bytes, and different packet sizes. Results show that the proposed layer-3 classification technique gives less than 0.5% false positive, which approximately equals the performance attained at layer 7. This shows that classifying e-mails at the packet level could differentiate non-spam from spam with high confidence for a viable spam control implementation on middleboxes. 相似文献
107.
Mohd Saberi Mohamad Sigeru Omatu Safaai Deris Muhammad Faiz Misman Michifumi Yoshioka 《Artificial Life and Robotics》2009,13(2):410-413
A microarray machine offers the capacity to measure the expression levels of thousands of genes simultaneously. It is used
to collect information from tissue and cell samples regarding gene expression differences that could be useful for cancer
classification. However, the urgent problems in the use of gene expression data are the availability of a huge number of genes
relative to the small number of available samples, and the fact that many of the genes are not relevant to the classification.
It has been shown that selecting a small subset of genes can lead to improved accuracy in the classification. Hence, this
paper proposes a solution to the problems by using a multiobjective strategy in a genetic algorithm. This approach was tried
on two benchmark gene expression data sets. It obtained encouraging results on those data sets as compared with an approach
that used a single-objective strategy in a genetic algorithm.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
108.
Mohd Saberi Mohamad Sigeru Omatu Safaai Deris Muhammad Faiz Misman Michifumi Yoshioka 《Artificial Life and Robotics》2009,13(2):414-417
Gene expression technology, namely microarrays, offers the ability to measure the expression levels of thousands of genes
simultaneously in biological organisms. Microarray data are expected to be of significant help in the development of an efficient
cancer diagnosis and classification platform. A major problem in these data is that the number of genes greatly exceeds the
number of tissue samples. These data also have noisy genes. It has been shown in literature reviews that selecting a small
subset of informative genes can lead to improved classification accuracy. Therefore, this paper aims to select a small subset
of informative genes that are most relevant for cancer classification. To achieve this aim, an approach using two hybrid methods
has been proposed. This approach is assessed and evaluated on two well-known microarray data sets, showing competitive results.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
109.
Razzaq Saad Shah Babar Iqbal Farkhund Ilyas Muhammad Maqbool Fahad Rocha Alvaro 《Neural computing & applications》2023,35(11):8017-8026
Neural Computing and Applications - A lot of different methods are being opted for improving the educational standards through monitoring of the classrooms. The developed world uses Smart... 相似文献
110.
Shi Fang Liuan Li Danhao Wang Wei Chen Yang Kang Weiyi Wang Xin Liu Yuanmin Luo Huabin Yu Haochen Zhang Muhammad Hunain Memon Wei Hu Jr-Hau He Chen Gong Chengjie Zuo Sheng Liu Haiding Sun 《Advanced functional materials》2023,33(37):2214408
Underwater optical communication (UOC) has attracted considerable interest in the continuous expansion of human activities in marine/ocean environments. The water-durable and self-powered photoelectrodes that act as a battery-free light receiver in UOC are particularly crucial, as they may directly face complex underwater conditions. Emerging photoelectrochemical (PEC)-type photodetectors are appealing owing to their intrinsic aqueous operation characteristics with versatile tunability of photoresponses. Herein, a self-powered PEC photodetector employing n-type gallium nitride (GaN) nanowires as a photoelectrode, which is decorated with an iridium oxide (IrOx) layer to optimize charge transfer dynamics at the GaN/electrolyte interface, is reported. Strikingly, the constructed n-GaN/IrOx photoelectrode breaks the responsivity-bandwidth trade-off limit by simultaneously improving the response speed and responsivity, delivering an ultrafast response speed with response/recovery times of only 2 µs/4 µs while achieving a high responsivity of 110.1 mA W−1. Importantly, the device exhibits a large bandwidth with 3 dB cutoff frequency exceeding 100 kHz in UOC tests, which is one of the highest values among self-powered photodetectors employed in optical communication system. 相似文献