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991.
Howard Huang Harish Viswanathan Andrew Blanksby Mohamed A. Haleem 《The Journal of VLSI Signal Processing》2002,30(1-3):55-69
A High Data Rate (HDR) system has been proposed for providing downlink wireless packet service by using a channel-aware scheduling algorithm to transmit to users in a time-division multiplexed manner. In this paper, we propose using multiple antennas at the transmitter and/or at the receiver to improve performance of an HDR system. We consider the design tradeoffs between scheduling and multi-antenna transmission/detection strategies and investigate the average Shannon capacity throughput as a function of the number of antennas assuming ideal channel estimates and rate feedback. The highest capacities are achieved using multiple antennas at both the transmitter and receiver. For such systems, the best performance is achieved using a multi-input multi-output capacity-achieving transmission scheme such as BLAST (Bell Labs Layered Space-Time) in which the transmitted signal is coded in space and time, and the receive antennas are used to resolve the spatial interference. In the second part of the paper, we discuss practical transmitter and receiver architectures using BLAST for approaching the theoretical gains promised by the capacity analysis. Because the terminal receivers will be portable devices with limited computational and battery power, we perform a computational complexity analysis of the receiver and make high-level assessments on its feasibility. We conclude that the overall computational requirements are within the reach of current hardware technology. 相似文献
992.
Silvin Paul Knight Jacinta Elizabeth Browne James Frances Mary Meaney Andrew John Fagan 《Magma (New York, N.Y.)》2017,30(5):461-471
Objectives
The aim of this study was to investigate the effect of the temporal resolution (T res) and acquisition duration (AD) on the measurement accuracy of contrast concentration–time curves (CTCs), and derived phenomenological and pharmacokinetic parameter values, in a dynamic contrast-enhanced MRI experiment using a novel phantom test device.Materials and methods
‘Ground truth’ CTCs were established using a highly precise optical imaging system. These precisely known CTCs were produced in an anthropomorphic environment, which mimicked the male pelvic region, and presented to the MRI scanner for measurement. The T res was varied in the range [2–24.4 s] and the AD in the range [30–600 s], and the effects on the measurement accuracy were quantified.Results
For wash-in parameter measurements, large underestimation errors (up to 40%) were found using T res values ≥16.3 s; however, the measured wash-out rate did not vary greatly across all T res values tested. Errors in derived K trans and v e values were below 14 and 12% for acquisitions with {T res ≤ 8.1 s, AD ≥ 360 s} and {T res ≤ 16.3 s, AD ≥ 360 s}, respectively, but increased dramatically outside these ranges.Conclusions
Errors in measured wash-in, wash-out, K trans, and v e parameters were minimised using T res ≤ 8.1 s and AD ≥ 360 s, with large errors recorded outside of this range.993.
Dr. Andrew M. Riley Dr. Sabine Windhorst Dr. Hong‐Yin Lin Prof. Barry V. L. Potter 《Chembiochem : a European journal of chemical biology》2014,15(1):57-67
When applied extracellularly, myo‐inositol hexakisphosphate (InsP6) and myo‐inositol pentakisphosphate (InsP5) can inhibit the growth and proliferation of tumour cells. There is debate about whether these effects result from interactions of InsP6 and InsP5 with intracellular or extracellular targets. We synthesised FAM‐InsP5, a fluorescent conjugate of InsP5 that allows direct visualisation of its interaction with cells. FAM‐InsP5 was internalised by H1229 tumour cells, a finding that supports earlier reports that externally applied inositol phosphates can—perhaps surprisingly—enter into cells. Close examination of the process of FAM‐InsP5 uptake suggests a mechanism of non‐receptor‐mediated endocytosis, which is blocked at 4 °C and probably involves interaction of the ligand with the glycocalyx. However, our results are difficult to reconcile with antiproliferative mechanisms that require direct interactions of externally applied InsP5 or InsP6 with cytosolic proteins, because internalised FAM‐InsP5 appears in lysosomes and apparently does not enter the cytoplasm. Studies using FAM‐InsP5 are less difficult and time‐consuming than experiments using InsP5 or InsP6, a factor that allowed us to analyse cellular uptake across a range of human cell types, identifying strong cell‐specific differences. 相似文献
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Humanoid three‐dimensional (3D) models can be easily acquired through various sources, including through online marketplaces. The use of such models within a game or simulation environment requires human input and intervention in order to associate such a model with a relevant set of motions and control mechanisms. In this paper, we demonstrate a pipeline where humanoid 3D models can be incorporated within seconds into an animation system and infused with a wide range of capabilities, such as locomotion, object manipulation, gazing, speech synthesis and lip syncing. We offer a set of heuristics that can associate arbitrary joint names with canonical ones and describe a fast retargeting algorithm that enables us to instill a set of behaviors onto an arbitrary humanoid skeleton on‐the‐fly. We believe that such a system will vastly increase the use of 3D interactive characters due to the ease that new models can be animated.Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
997.
Tooru Kitagawa Kazuyuki Yabuki Andrew C. Wright Robert. J. Young 《Journal of Materials Science》2014,49(18):6467-6474
A detailed morphological study of the microstructure of poly(p-phenylene benzobisoxazole) (PBO) fibres (HM and HM+) and a polypyridobisimidazole (PIPD) (HT) fibre has been undertaken using transmission electron microscopy. Both PBO and PIPD fibres are composed of rigid-rod polymers having p-phenylene rings in the molecular backbone and show high modulus (280–360 GPa) and high strength (4–6 GPa). It is found that the PBO HM+ fibre has the highest degree of molecular orientation of the three fibres and the longest crystal length along the fibre axis, while the PIPD fibre shows a lower degree of orientation and a shorter crystal length than the PBO fibres. To understand the effect of crystalline size and fine structure of the fibres upon mechanical properties, dark-field and high-resolution lattice images were obtained and analysed in detail. 相似文献
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999.
William G. Buttlar Brian C. Hill Y. Richard Kim M. Emin Kutay Anne Millien Antonio Montepara Glaucio H. Paulino Christophe Petit Ion Octavian Pop Elena Romeo Riccardo Roncella Seyed Amirshayan Safavizadeh Gabriele Tebaldi Andrew Wargo 《Materials and Structures》2014,47(8):1373-1390
This paper is the outcome of a specific task group of the RILEM Technical Committee 241-MCD “Mechanisms of Cracking and Debonding in Asphalt and Composite Pavements”. The group on “Advanced Measurement Techniques” was established in 2011 to investigate DIC applications for non-destructive and non-contact measurements of strain fields during laboratory testing. The paper illustrates different DIC/optical flow applications in measuring strain distribution during laboratory testing. Specific applications of DIC for evaluating crack initiation and crack propagation in asphalt materials are presented. 相似文献
1000.
Dan Chiappe Robert Conrad Rorie Corey Andrew Morgan Kim-Phuong L. Vu 《Theoretical Issues in Ergonomics Science》2014,15(1):69-87
Theories of team situation awareness (SA) differ in the information they require operators to have for effective coordination. Endsley stresses shared SA, whereas distributed SA argues that coordination involves transactive and compatible SA. We distinguish between weak and strong shared SA, and argue the latter enhances communication and increases team cohesion. Although we agree with Endsley on the importance of shared SA, we argue her account of how it is acquired exceeds the working memory capacity of individual team members. We offer an account consistent with our situated SA perspective that claims individuals off-load information to their environment whenever possible to minimise effortful internal processing. We argue that our approach, in conjunction with Pickering and Garrod's (2004, Towards a mechanistic psychology of dialogue. Behavioral and Brain Sciences, 27, pp. 169–226) interactive-alignment model, can explain how shared SA is acquired, relying on automatic processes enacted when individuals interact in conversations. This approach can be used to study team SA in many complex and distributed systems. 相似文献