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61.
We show that the electrode/molecule chemical bond does not change the tunneling barrier for charge transport through alkyl chain monolayers sandwiched between Si and Hg electrodes. This observation can be understood if the interfacial bond mainly governs the monolayer's structure, while the electronic states due to molecule-electrode bonding do not contribute significantly to tunneling. Yet, the nature of the bond affects the Schottky barrier inside the semiconductor due to changes in the interface dipole. 相似文献
62.
The paper analyzes the mechanism of partitioning and rejection of organic solutes by polyamide membranes for reverse osmosis and nanofiltration. The partitioning of homologous series of alcohols and polyols, in which polarity changes with size in opposite ways, was measured using attenuated total reflection IR spectroscopy. The results show that the partitioning of polyols monotonously decreases with size, whereas for alcohols it is not monotonous and slightly decreases for small C1-C3 alcohols followed by a sharp increase for larger alcohols. These results may be explained by assuming a heterogeneous structure of polyamide comprising a hydrophobic polyamide matrix and a polar internal aqueous phase. The partitioning data could consistently explain the results of rejection in standard filtration experiments. They clearly demonstrate that high/low partitioning may play a significant role in achieving a low/high rejection of organics. In particular, this points to the need to account for the partitioning effect while using molecular probes such as polyols or sugars for estimating the effective "pore" size or molecular weight cutoff of a membrane and for choosing/developing organic-rejecting membranes. 相似文献
63.
We describe several software side-channel attacks based on inter-process leakage through the state of the CPU’s memory cache.
This leakage reveals memory access patterns, which can be used for cryptanalysis of cryptographic primitives that employ data-dependent
table lookups. The attacks allow an unprivileged process to attack other processes running in parallel on the same processor,
despite partitioning methods such as memory protection, sandboxing, and virtualization. Some of our methods require only the
ability to trigger services that perform encryption or MAC using the unknown key, such as encrypted disk partitions or secure
network links. Moreover, we demonstrate an extremely strong type of attack, which requires knowledge of neither the specific
plaintexts nor ciphertexts and works by merely monitoring the effect of the cryptographic process on the cache. We discuss
in detail several attacks on AES and experimentally demonstrate their applicability to real systems, such as OpenSSL and Linux’s
dm-crypt encrypted partitions (in the latter case, the full key was recovered after just 800 writes to the partition, taking 65 milliseconds).
Finally, we discuss a variety of countermeasures which can be used to mitigate such attacks. 相似文献
64.
Federica Fiorini Eko Adi Prasetyanto Francesca Taraballi Laura Pandolfi Francisco Monroy Iván López‐Montero Ennio Tasciotti Luisa De Cola 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(35):4881-4893
The challenge of mimicking the extracellular matrix with artificial scaffolds that are able to reduce immunoresponse is still unmet. Recent findings have shown that mesenchymal stem cells (MSC) infiltrating into the implanted scaffold have effects on the implant integration by improving the healing process. Toward this aim, a novel polyamidoamine‐based nanocomposite hydrogel is synthesized, cross‐linked with porous nanomaterials (i.e., mesoporous silica nanoparticles), able to release chemokine proteins. A comprehensive viscoelasticity study confirms that the hydrogel provides optimal structural support for MSC infiltration and proliferation. The efficiency of this hydrogel, containing the chemoattractant stromal cell‐derived factor 1α (SDF‐1α), in promoting MSC migration in vitro is demonstrated. Finally, subcutaneous implantation of SDF‐1α‐releasing hydrogels in mice results in a modulation of the inflammatory reaction. Overall, the proposed SDF‐1α‐nanocomposite hydrogel proves to have potential for applications in tissue engineering. 相似文献
65.
66.
Lorina Dascal Adi Ditkowski Nir A. Sochen 《Journal of Mathematical Imaging and Vision》2007,29(1):63-77
We analyze the discrete maximum principle for the Beltrami color flow. The Beltrami flow can display linear as well as nonlinear
behavior according to the values of a parameter β, which represents the ratio between spatial and color distances. In general, the standard schemes fail to satisfy the discrete
maximum principle. In this work we show that a nonnegative second order difference scheme can be built for this flow only
for small β, i.e. linear-like diffusion. Since this limitation is too severe, we construct a novel finite difference scheme, which is
not nonnegative and satisfies the discrete maximum principle for all values of β. Numerical results support the analysis.
相似文献
Nir A. Sochen (Corresponding author)Email: |
67.
68.
Mohd?Norihan?IbrahimEmail author Waluyo?Adi?Siswanto Ahmad?Mujahid?Ahmad?Zaidi 《Journal of Mechanical Science and Technology》2014,28(11):4475-4482
The paper describes a work focused on the process of perforation of aluminum sheet. A numerical investigation has been carried out to analyze in details the perforation process subjected to normal impact by different nose shapes of projectiles. The perforation process has been simulated by the application of 3D analysis using IMPACT dynamic FE program suite. The comparison on failure modes depending on the projectile nose shape have been studied and evaluated. An appropriate constitutive relation was applied to describe the material behavior of the aluminum sheet. The study covered different failure modes including petalling, plug ejection and circumference necking of perforated aluminum sheet according to different level of impact velocity ranging from 100 m/s to 600 m/s. In this investigation, a special attention will be given on the deformation and failure. 相似文献
69.
Adi Eindor-Abarbanel Genelle R. Healey Kevan Jacobson 《International journal of molecular sciences》2021,22(22)
There is mounting evidence that the gut microbiota plays an important role in the pathogenesis of inflammatory bowel disease (IBD). For the past decade, high throughput sequencing-based gut microbiome research has identified characteristic shifts in the composition of the intestinal microbiota in patients with IBD, suggesting that IBD results from alterations in the interactions between intestinal microbes and the host’s mucosal immune system. These studies have been the impetus for the development of new therapeutic approaches targeting the gut microbiome, such as nutritional therapies, probiotics, fecal microbiota transplant and beneficial metabolic derivatives. Innovative technologies can further our understanding of the role the microbiome plays as well as help to evaluate how the different approaches in microbiome modulation impact clinical responses in adult and pediatric patients. In this review, we highlight important microbiome studies in patients with IBD and their response to different microbiome modulation therapies, and describe the differences in therapeutic response between pediatric and adult patient cohorts. 相似文献
70.
Sixteen degradable, tyrosine-derived polyarylates with well-defined chemical structures were used to study the effect of polymer structure on the glass transition temperature and enthalpy relaxation kinetics (physical aging). These polyarylates compose a model system where the number of methylene groups present in either the pendent chain or the polymer backbone can be altered independently and in a systematic fashion. Quantitative differential scanning calorimetry was employed to measure the glass transition temperature and the enthalpy relaxation kinetics. Correlations between these material properties and the polymer structure were established. The glass transition temperature of this family of polymers ranged from 13 to 78°C. The addition of methylene groups to either the pendent chain or the polymer backbone made a fairly constant contribution to lowering the glass transition temperature. The rate of enthalpy relaxation increased with an increasing number of methylene groups in the polymer backbone, but was independent of the number of methylene groups in the pendent chain. This observation indicated that the rate of enthalpy relaxation in these polymers was limited by the mobility of the polymer backbone. The enthalpy relaxation data was fitted to the Cowie-Ferguson model and the relaxation times obtained ranged from 44 min to about 100 min. Although these structure-property correlations facilitate the design of new materials with predictable thermal properties, they are rarely investigated for biomedical polymers. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1441–1448, 1997 相似文献