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51.
A theoretical evaluation is presented of the mean time to first slip for some closed-loop synchronizer schemes to be used in a coherent serial receiver for offset binary modulations. Various modulation formats belonging to this class are considered, and the mean time to first slip is computed for each modulation type for different values of loop bandwidth and signal-to-noise ratio. Theoretical results are confirmed by extensive computer simulations  相似文献   
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The additive manufacturing of highly ordered, micrometer‐scale scaffolds is at the forefront of tissue engineering and regenerative medicine research. The fabrication of scaffolds for the regeneration of larger tissue volumes, in particular, remains a major challenge. A technology at the convergence of additive manufacturing and electrospinning–melt electrospinning writing (MEW)–is also limited in thickness/volume due to the accumulation of excess charge from the deposited material repelling and hence, distorting scaffold architectures. The underlying physical principles are studied that constrain MEW of thick, large volume scaffolds. Through computational modeling, numerical values variable working distances are established respectively, which maintain the electrostatic force at a constant level during the printing process. Based on the computational simulations, three voltage profiles are applied to determine the maximum height (exceeding 7 mm) of a highly ordered large volume scaffold. These thick MEW scaffolds have fully interconnected pores and allow cells to migrate and proliferate. To the best of the authors knowledge, this is the first study to report that z‐axis adjustment and increasing the voltage during the MEW process allows for the fabrication of high‐volume scaffolds with uniform morphologies and fiber diameters.  相似文献   
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Pheochromocytoma (PHEO), a rare catecholamine producing tumor arising from the chromaffin cells, may occurs sporadically (76%–80%) or as part of inherited syndromes (20%–24%). Angiogenesis is a fundamental step in tumor proliferation and vascular endothelial growth factor (VEGF-A) is the most well-characterized angiogenic factor. The role of angiogenic markers in PHEO is not fully understood; investigations were therefore made to evaluate the expression of VEGF-A and its receptors in PHEO and correlate to clinical parameters. Twenty-nine samples of PHEO were evaluated for VEGF-A, VEGF receptor-1 (VEGFR-1) VEGFR-2 expression and microvessel density (MVD) by immunohistochemistry. Clinical data were reviewed in medical records. The mean age of patients was 38 ± 14 years, and 69% were woman. VEGF-A, VEGFR-1 and VEGFR-2 staining were detected in nearly all PHEO samples. No significant correlation was observed between VEGF-A, VEGFR-1, VEGFR-2 expression or MVD and age at diagnosis, tumor size or sporadic and hereditary PHEO. However, the levels of expression of these molecules were significantly higher in malignant PHEO samples (p = 0.027, p = 0.003 and p = 0.026, respectively).VEGF-A and its receptors were shown to be up-regulated in malignant PHEO, suggesting that these molecules might be considered as therapeutic targets for unresectable or metastatic tumors.  相似文献   
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64Cu is a cyclotron‐produced radionuclide which offers, thanks to its characteristic decay scheme, the possibility of combining positron emission tomography (PET) investigations with radiotherapy. We evaluated the Alceo system from Comecer SpA to automatically produce 64Cu for radiolabelling purposes. We established a 64Cu production routine with high yields and radionuclide purity in combination with excellent operator radiation protection. The carbonic anhydrase XII targeting 6A10 antibody Fab fragment was successfully radiolabelled with the produced 64Cu, and proof‐of‐principle small‐animal PET experiments on mice bearing glioma xenografts were performed. We obtained a high tumor‐to‐contralateral muscle ratio, which encourages further in vivo investigations of the radioconjugate regarding a possible application in diagnostic tumor imaging.  相似文献   
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Zusammenfassung Gefrieren (-20° C) and Auftauen der Brust- and Schenkelmuskulatur verschiedener Geflügelarten (Huhn, Pute, Gans, Ente) führte zu keiner nennenswerten Änderung der gesamten Aktivität der Aspartat-Aminotransferase (Glutamat-Oxalacetat-Transaminase; GOT) im Gewebe. Längere Gefrierlagerung (3 Monate) bei -20° C brachte beim Brustmuskel des Huhns keine Änderung, beim Schenkelmuskel jedoch eine Abnahme der gesamten GOT-Aktivität mit sich. Der Muskelpreßsaft von gefrorenem and aufgetautem Gewebe enthielt bei beiden Muskeln aller untersuchten Geflügelarten eine höhere GOT-Aktivität als der Preßsaft des frischen, nicht gefrorenen Gewebes. Diese Erhöhung der GOT-Aktivität beruht auf einer durch Gefrieren and Auftauen hervorgerufenen partiellen Freisetzung des Mitochondrien-Isozyms GOTM in das Sarkoplasma. Offensichtlich werden die Membranen der Muskelmitochondrien durch Gefrieren des Gewebes geschädigt. Es wird eine auf diesen Resultaten beruhende Routinemethode zur Unterscheidung zwischen Frischgeflügel and aufgetautem Gefriergeflügel beschrieben.
Influence of freezing and thawing on the subcellular distribution of aspartate aminotransferase in poultry muscle
Summary Freezing (—20° C) and thawing of the breast and thigh muscles of poultry (chicken, turkey, goose, duck) did not result in a remarkable change of the total activity of aspartate amino transferase (glutamate-oxaloacetic transaminase; GOT) in the tissue. Freeze-storage for three months (-20° C) did not cause changes in the total GOT activity in chicken breast muscle but did lower the GOT activity in the thigh muscle of chicken. For both types of muscle of all species investigated, freezing and thawing of tissue caused an increase in the GOT activity of the muscle press-juice. This increase of GOT activity is due to a partial release of the mitochondria) isozyme GOTM into the sarcoplasma. Apparently the membranes of the muscle mitochondria are damaged by the process of freezing. A routine method basing on these results is decsribed which allows a differentiation between nonfrozen poultry and frozen and thawed poultry.


Fräulein Herta Sauer danken wir fur ihre fleißige and geschickte Mitarbeit.  相似文献   
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Additive manufacturing by laser-based powder bed fusion of metals (PBF-LB/M) enables the production of complex shaped components. High-carbon tool steels tend to cracking during PBF-LB/M due to internal stresses caused by the rapid solidification. Expensive atomization and long lead times for powder generate high costs in this processing route. In situ alloying during PBF-LB/M of powder blends from conventionally available powders enables a more flexible approach of alloy design. For industrial use, the mechanical properties of in situ alloyed parts must be comparable to those of conventionally manufactured parts. In some cutting and forming applications, high wear resistance and corrosion resistance are required simultaneously. High alloyed cold work tool steels with sufficient chromium solved in the metal matrix fulfill these demands. Herein, AISI H13 is modified by Cr3C2 and elemental Cr to suit these requirements. Two novel alloys are modeled thermodynamically and processed by PBF-LB/M. In-depth microstructural investigations by backscatter electron imaging and diffraction in combination with abrasive wear tests and potentiodynamic polarization curves allow microstructure property correlations for different heat-treated conditions. Partial crack-free processing, hardenability, formation of Cr-rich carbides, and residual Cr-rich inclusions are observed and their influence on the wear and corrosion resistance is discussed.  相似文献   
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