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121.
Jui Chakraborty Mithlesh K. Sinha Debabrata Basu 《Journal of the American Ceramic Society》2007,90(4):1258-1261
Bone, a natural composite, comprises non-stoichiometric calcium hydroxyapatite (HAp) precipitated in a controlled reaction environment of a highly aligned, anisotropic organic template (type I collagen) that leads to its exotic tensile and compressive strength. It differs from stoichiometric hydroxyapatite in composition, crystallinity, and other physical and mechanical properties. In the present study, functionalized biomolecular template-induced precipitation of HAp on an SS 316 L substrate following biomimetic route exhibits distinct alterations in crystal growth and geometry, which in turn indicates the potential of the process to develop a non-stoichiometric HAp coating on metal implants. 相似文献
122.
Ashis Kumar Manda Prasanta Kumar Sinha Santanu Sen Sitendu Mondal Chandan Guha Ranjan Sen 《化学与化工:英文版》2014,(4):349-357
This study reports preparation of glass composition (54.50 wt.%) SiO2, (10.80 wt.%) B2O3, (14.20 wt.%) Na2O, (1.20 wt.%) K2O, (6.00 wt.%) CaO, (4.00 wt.%) Fe2O3 and (9.30 wt.%) TiO2 by melt quenching method using direct microwave heating and conventional resistive heating. Study of dielectric loss factor of the glass as function of temperature illustrated increasing loss factor above 370 ℃, 550 ℃, 650 ℃ and 900 ℃, indicating enhanced microwave absorption by the glass at above these temperatures. Chemical analysis results of both the glasses depicted more volatilization loss of volatile ingredients in conventional heating. The study of chemical durability was performed from leachate analysis describing less leaching of Na2O, K2O and other constituents from glass melted in microwave furnace. Glass transition temperatures (Tg) were found to be 576.3 ℃ and 569.5 ℃ for glass melted in conventional and microwave heating route, respectively. Laboratory experiment of glass melting utilizing microwave energy as an alternate heating source demonstrated 70%-75% electrical power saving. 相似文献
123.
The double perovskite oxide strontium gadolinium tantalate, Sr2GdTaO6 (SGT) is synthesized by solid-state reaction technique. The Rietveld refinement of the X-ray diffraction pattern of the sample shows monoclinic phase at room temperature. FTIR spectrum shows two primary phonon modes of the sample at around 373 cm−1 and 562 cm−1. The electronic structure of SGT has been investigated by Vienna ab-initio simulation package. The eigen frequencies of different phonon modes have been calculated and compared with the experimental data observed by Raman spectroscopy. Dielectric properties of the sample are investigated in a temperature range from 303 K to 673 K and in a frequency range of 42 Hz–1 MHz. The relaxation peaks are observed in the frequency dependent spectra for imaginary part of the dielectric constant. The modified Cole–Cole equation is used to describe the relaxation mechanism in SGT. The frequency dependent conductivity spectra follow the Jonscher power law. 相似文献
124.
Yogesh S. Kashyap Ashish Agrawal P.S. Sarkar Mayank Shukla Tushar Roy Amar Sinha 《NDT & E International》2011,44(1):41-46
We have used the contrast transfer function based X-ray phase retrieval technique for phase retrieval studies on a two-component system. Pyro-carbon coated alumina matrix was chosen as a two-component system for these studies. Simulations as well as experimental results are presented. This paper shows that X-ray phase contrast along with phase retrieval can become an alternative tool for non-destructive characterization of these materials. We have also attempted to retrieve the spatial distribution of the projected thickness map of the two different elements. 相似文献
125.
Raj Kumar Singh Sunil Kumar Sinha A. Rama Rao 《Nuclear Engineering and Design》2009,239(10):1760-1767
The primary function of the shut down system in a nuclear reactor is to terminate any reactivity transient occurring in the core during its entire design life. Normally there is more than one system, which are independent and diverse in its mode of operation. They consist of quick acting mechanisms like dropping of safety rods by gravity, poison injection, etc. Typically in liquid poison injection system wherein high flow velocities are involved, there is significant fluid structure interaction associated with cyclic shock transients in the system. One such phenomenon has been captured and analyzed to understand the dynamics involved in the loop. The trends of loop pressure and vibration indicated presence of more than two pressure transients after complete injection of poison. The first transient arrived after 1.44 s and the second after 0.75 s. The reverse pressure pulses that manifested in the loop as a result of fast injection of fluid has been mathematically characterized by solving basic fluid balance equations. Possibility of ball lifting due to momentum pulse is also discussed. 相似文献
126.
V. N. Sekhar T. C. Chai S. Balakumar Lu Shen S. K. Sinha A. A. O. Tay Seung Wook Yoon 《Journal of Materials Science: Materials in Electronics》2009,20(1):74-86
In the present study, we have investigated the thickness dependence of mechanical properties of the Black Diamond? (SiOC:H, BD, Low-k) films, which are of great interest in current Cu/low-k Back End of the Line (BEOL) interconnect/packaging technologies. For this investigation the BD thin films of six different thicknesses 100, 300, 500, 700, 1,000 and 1,200 nm were deposited on the 8″ Si wafer by using plasma enhanced chemical vapor deposition (PECVD) technique. Nanoindentation and nanoscratch tests of the BD films were performed by using the Nano Indenter® XP (MTS Corp. USA). In nanoindentation testing of the BD films, significant differences in the elastic modulus of the BD films were observed. In nanoscratch testing, it is found that the critical load (Lc) and scratch width increases as the thickness of the film increases. Cross-sectional analysis of residual nanoindentation impressions was carried out using atomic force microscopy (AFM) to study the deformation behavior. The nanoindentation and nanoscratch responses of the BD thin films of six different thicknesses are different and they are expected mainly due to the molecular reorganization in thin/ultra thin films. 相似文献
127.
We present in this paper a new energy-efficient communication scheme called CNS (Compression with Null Symbol) that combines the power of data compression and communication through silent symbol. The concept of communication through silent symbol is borrowed from the energy efficient schemes proposed in Sinha (Proceedings
of 6th IEEE consumer communications and networking conference (CCNC), Las Vegas, pp. 1–5, 2009), Ghosh et al. (Proceedings
of 27th IEEE international performance computing and communications conference (IPCCC), USA, pp. 85–92, 2008), and Sinha and
Sinha (Proceedings of international conference on distributed computing and internet technologies (ICDCIT), LNCS, pp. 139–144,
2008). We show that the average theoretical energy saving at the transmitter by CNS is 62.5%, assuming an ideal channel and
for equal likelihood of all possible binary strings of a given length. Next, we propose a transceiver design that uses a hybrid
modulation scheme utilizing FSK and ASK so as to keep the cost/complexity of the radio devices low. Considering an additive
white gaussian noise (AWGN) channel and a non-coherent detection based receiver, CNS shows a saving in transmitter energy
by 30% when compared to binary FSK, for equal likelihood of all possible binary strings of a given length. Simultaneously,
there is a saving of 50% at the receiver for all types of data modulation due to halving of the transmitted data duration,
compared to binary encoding. In contrast, RBNSiZeComm proposed in Sinha (Proceedings of 6th IEEE consumer communications and
networking conference (CCNC), Las Vegas, pp. 1–5, 2009), TSS proposed in Ghosh et al. (Proceedings of 27th IEEE international
performance computing and communications conference (IPCCC), USA, pp. 85–92, 2008) and RZE proposed in Sinha and Sinha (Proceedings
of international conference on distributed computing and internet technologies (ICDCIT), LNCS, pp. 139–144, 2008) generate
average transmitter energy savings of about 41, 20, and 35.2%, respectively. Also, at the receiver side, while RBNSiZeComm
does not generate any saving, TSS and RZE produce about 36.9 and 12.5% savings on an average, respectively. Considering certain
data types that may occur in the context of some wireless sensor networks (WSN) based applications (e.g., remote healthcare, agricultural WSNs, etc.), our simulation results demonstrate that for
AWGN noisy channels, the transmitter side savings vary from about 33–50% on an average, while for RBNSiZeComm, this saving
is about 33–61% on the same data set (Sinha in Proceedings of 6th IEEE consumer communications and networking conference (CCNC),
Las Vegas, pp. 1–5, 2009). Thus, taking into account the low cost/complexity of the proposed transceiver, these results clearly
establish that CNS can be a suitable candidate for communication in low power wireless sensor networks, such as in remote
healthcare applications, body area networks, home automation, WSNs for agriculture and many others. 相似文献
128.
Jaein Lim Brajalal Sinha Torati Sri Ramulu KunWoo Kim Dong-Young Kim CheolGi Kim 《Metals and Materials International》2013,19(4):875-878
NiCo alloy materials have been investigaged as a potential sensing layer for planar Hall effect (PHE) sensors in magnetic multilayer structures. In this study, the magnetoresistive performance of the NiCo alloy is compared with that of the NiFe alloy. With an optimum thickness of 10 nm, the increment of the PHE voltage (V max ) for the NiCo-based sensor was approximately 1.5 times larger than that of the NiFe-based sensor. The field sensitivity of both sensor types appeared to be nearly equal. However, the dynamic field range for the NiCo sensor was increased by approximately 40% compared with that of the NiFe sensor. The measuring configuration was optimized in order to obtain higher field sensitivity in the sensor. The field sensitivity was measured to be at a maximum at a 20° angle between the easy axis of the sensor and the applied external field, which was approximately three times higher than that in the perpendicular direction. 相似文献
129.
Here we have investigated theoretically the average integrated ground level concentration of sulphur dioxide in wet and dry regions due to the emission from an elevated point source. The profiles of concentration distribution have been obtained in wet and dry regions on various rates of rainfall. 相似文献
130.
In accordance with the FAA certification requirements, all modern commercial turbofan engines must successfully demonstrate its ability to withstand a fan blade-out (FBO) event through actual test. Possibility of losing a rotating fan blade from a running engine is a flight safety consideration, which must be addressed during the design phase of the engine. A typical fan blade-out event involves very complex nonlinear transient dynamics with large deflection of the release blade and rigid body rotation of the trailing blade as well as progressive failure and fragmentation of various components. Due to the nature of the impact type loading, the solution to the problem should also address dependence of the material behavior such as yield strength as a function of strain rates. In short, the transient dynamic analysis of a fan blade-out event highlights the complexity of the numerical technique, which includes all the nonlinearities of structural dynamics: plastic behavior of the materials, large displacements, and contact interaction between structural elements. In this paper, we present the results of a LS-DYNA simulation of a FBO event on a full-engine analytical model, which covers both the primary as well as secondary damages. 相似文献