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91.
Evaluation of curing and thermal behaviors of konjac glucomannan–chitosan–polypeptide adhesive blends 下载免费PDF全文
An environmentally friendly wood adhesive has been achieved through novel blending of konjac glucomannan and chitosan with polypeptide. Tensile tests reveal an optimal curing temperature of 130°C. Both viscoelastic properties of the adhesive blends during curing process, and the structural variation of chemical components induced by curing temperature, were defined by using dynamic rheometry, X‐ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. Results show both storage and loss modulus increase markedly from 90 to 105°C because of the reactions occurred between konjac glucomannan, chitosan, and polypeptide with formation of amide. Increased polypeptide content not only strengthens intermolecular hydrogen bonds but also enhances covalent reactions occurred between the components. Thermogravimetric and differential scanning calorimetry analyses indicate good miscibility of components in the adhesive blends and improved thermal stability with added polypeptide. Hydrogen bonds between polysaccharides and polypeptide break at 125 ± 10°C. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42202. 相似文献
92.
We offer an efficient approach based on difference of convex functions (DC) optimization for self-organizing maps (SOM). We consider SOM as an optimization problem with a nonsmooth, nonconvex energy function and investigated DC programming and DC algorithm (DCA), an innovative approach in nonconvex optimization framework to effectively solve this problem. Furthermore an appropriate training version of this algorithm is proposed. The numerical results on many real-world datasets show the efficiency of the proposed DCA based algorithms on both quality of solutions and topographic maps. 相似文献
93.
Experimental Evidence of Anisotropic and Stable Charged Excitons (Trions) in Atomically Thin 2D ReS2
Xiaofan Wang Keisuke Shinokita Yuhei Miyauchi Nguyen Thanh Cuong Susumu Okada Kazunari Matsuda 《Advanced functional materials》2019,29(51)
Experimentally observed, stable trions with large binding energy (≈25 meV) in atomically thin monolayer 2D transition metal dichalcogenides MX2 (M = Mo, W, X = S, Se, and Te) with an isotropic crystal structure have been extensively studied. In contrast, the characteristics of trions in atomically thin 2D materials with an anisotropic crystal structure are not completely understood. Low‐temperature photoluminescence (PL) spectroscopy in few‐layer ReS2 with an anisotropic crystal structure by applying a gate voltage is described. A new PL peak that emerges below the lower‐energy side of neutral excitons obtained by tuning the gate voltages is attributed to emission from negative trions. Furthermore, the trion binding energy that is strongly dependent on the layer thickness reaches a large value of ≈60 meV in 1L–ReS2, which is ≈2 times larger than that in other isotropic 2D materials (MX2). The enhancement of the binding energy reflects the quasi‐1D nature of the trions in anisotropic atomically thin ReS2. These experimental observations will promote a better understanding of the optical response and applications in new categories of the anisotropic atomically thin 2D materials with a quasi‐1D nature. 相似文献
94.
Bui Hai Dang Son Vo Quang Mai Dang Xuan Du Nguyen Hai Phong Nguyen Duc Cuong Dinh Quang Khieu 《Journal of Porous Materials》2017,24(3):601-611
Mn–Fe binary oxides incorporated into diatomite (denoted as FM-diatomite) was prepared by the redox reaction of KMnO4 and FeSO4 with pH ranging from 3 to 9. The catalytic activities of FM-diatomite were studied for phenol oxidation and were compared with iron oxide modified diatomite (F-diatomite) and manganese oxide modified diatomite (M-diatomite). The obtained catalysts were characterized by scanning electron microscope, powder X-ray diffraction, energy dispersive spectroscopy, transmission electron microscope, X-ray photoelectron spectroscopy, and nitrogen adsorption/desorption isotherms. The results show that Fe–Mn binary oxides were highly dispersed on the diatomite surface in which manganese oxide and iron oxide displayed multiple oxidation states including Mn4+, Mn3+, Fe2+ and Fe3+. The phenol oxidation by H2O2 through the use of Mn–Fe-diatomite as a catalyst was conducted. FM-diatomite exhibited as an excellent catalyst for the total oxidation of phenol and main intermediates (catechol and hydroquinone). The conversion of phenol and main intermediates by means of FM-diatomite was 100 % under 50 min while that by F-diatomite also was 100 % after 110 min but other intermediates still remained. While phenol conversion by M-diatomite was close to zero due to speedy hydroperoxide decomposition over the manganese oxide catalyst. These results show that there was a synergized effect of iron and manganese oxide present in FM-diatomite. 相似文献
95.
Cao C Gontard LC Thuy Tram le L Wolff A Bang DD 《Small (Weinheim an der Bergstrasse, Germany)》2011,7(12):1701-1708
A mechanism of dual enlargement of gold nanoparticles (AuNPs) comprising two steps is described. In the first step, the AuNPs are enlarged by depositing Au atoms on their crystalline faces. In this process, the particles are not only enlarged but they are also observed to multiply: new Au nuclei are formed by the budding and division of the enlarged particles. In the second step, a silver enhancement is subsequently performed by the deposition of silver atoms on the enlarged and newly formed AuNPs to generate bimetallic Au@Ag core-shell structures. The dual nanocatalysis greatly enhances the electron density of the nanostructures, leading to a stronger intensity for colorimetric discrimination as well as better sensitivity for quantitative measurement. Based on this, a simple scanometric assay for the on-slide detection of the food-born pathogen Campylobacter jejuni is developed. After capturing the target bacteria, gold-tagged immunoprobes are added to create a signal on a solid substrate. The signal is then amplified by the dual enlargement process, resulting in a strong color intensity that can easily be recognized by the unaided eye, or measured by an inexpensive flatbed scanner. In this paper, dual nanocatalysis is reported for the first time. It provides a valuable mechanistic insight into the development of a simple and cost-effective detection format. 相似文献
96.
Characterization of aortic microstructure with ultrasound: implications for mechanisms of aortic function and dissection 总被引:1,自引:0,他引:1
Nguyen CT Hall CS Wickline SA 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2002,49(11):1561-1571
Specific ultrasonic tissue characterization parameters were correlated with the three-dimensional architecture and material properties (density, compressibility, size, and orientation) of aortic elastic elements at the microscopic level. The medial layer of 10 samples of normal canine aorta were insonified in vitro utilizing acoustic microscopy from 30 to 44 MHz. The following quantitative indexes exhibited substantial anisotropic elastic behavior in radial (R), circumferential (C), and longitudinal (L) directions: backscatter coefficient (R:0.9/spl plusmn/0.2; C:0.008/spl plusmn/0.0008; L:0.0077/spl plusmn/0.0008 sr/sup -1/ cm/sup -1/); frequency dependence of backscatter (R:3.3; C:1.4; L:1.5); attenuation coefficients (R:105/spl plusmn/22; L:135/spl plusmn/13; C:131/spl plusmn/14 dB/cm). Thus, the ultrasonic indexes are anisotropic: equivalent in the C and L directions, but markedly different in the R direction. These data are indicative of an aortic microstructure that interacts with ultrasonic waves as thin sheet-like elastic layers instead of independent elastin fibers. This specific sheet-like organization of elastin microfibers may function to limit shear injury to concentric aortic lamellae and prevent aortic dissection. The marked anisotropic behavior of normal aortas suggests that ultrasound may be useful for nondestructive characterization of vascular integrity. 相似文献
97.
Richard Witas Astrid Rasmussen Robert H. Scofield Lida Radfar Donald U. Stone Kiely Grundahl David Lewis Kathy L. Sivils Christopher J. Lessard A. Darise Farris Cuong Q. Nguyen 《International journal of molecular sciences》2021,22(18)
Sjögren’s syndrome (SjS) is a chronic autoimmune disease primarily involving the exocrine glands in which the involvement of the innate immune system is largely uncharacterized. Mer signaling has been found to be protective in several autoimmune diseases but remains unstudied in SjS. Here, we investigated the role of Mer signaling in SjS. Mer knockout (MerKO) mice were examined for SjS disease criteria. SjS-susceptible (SjSS) C57BL/6.NOD-Aec1Aec2 mice were assessed for defective Mer signaling outcomes, soluble Mer (sMer) levels, A disintegrin and metalloprotease 17 (ADAM17) activity, and Rac1 activation. In addition, SjS patient plasma samples were evaluated for sMer levels via ELISA, and sMer levels were correlated to disease manifestations. MerKO mice developed submandibular gland (SMG) lymphocytic infiltrates, SMG apoptotic cells, anti-nuclear autoantibodies (ANA), and reduced saliva flow. Mer signaling outcomes were observed to be diminished in SjSS mice, as evidenced by reduced Rac1 activation in SjSS mice macrophages in response to apoptotic cells and impaired efferocytosis. Increased sMer was also detected in SjSS mouse sera, coinciding with higher ADAM17 activity, the enzyme responsible for cleavage and inactivation of Mer. sMer levels were elevated in patient plasma and positively correlated with focus scores, ocular staining scores, rheumatoid factors, and anti-Ro60 levels. Our data indicate that Mer plays a protective role in SjS, similar to other autoimmune diseases. Furthermore, we suggest a series of events where enhanced ADAM17 activity increases Mer inactivation and depresses Mer signaling, thus removing protection against the loss of self-tolerance and the onset of autoimmune disease in SjSS mice. 相似文献
98.
99.
We present multifocus holographic 3-D image fusion based on independent component analysis (ICA). In this paper, the ICA technique is used to fuse multiple reconstructed holographic images at different distances from the image sensor. A hologram of two dice located at distances of 315 and 345 mm, respectively, from the sensor is recorded using phase-shifting digital holography and used in our experiments. The resulting reconstructed fused holographic image shows both dice objects clearly in focus. This is compared with a single reconstructed holographic image in which only one of the die objects is in focus at a particular reconstruction distance. 相似文献
100.
Stable and Low‐Threshold Optical Gain in CdSe/CdS Quantum Dots: An All‐Colloidal Frequency Up‐Converted Laser 下载免费PDF全文