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61.
采用射频磁控溅射技术在聚酰亚胺柔性衬底上制备硅基薄膜太阳能电池用铝背电板,研究了不同溅射功率和工作气压条件对铝电极薄膜性能的影响.利用原子力显微镜分析表征了薄膜的表面形貌和粗糙度,薄膜的电学性能和光学性能分别采用四探针测量仪和紫外可见近红外分光光度计进行分析表征.测试结果表明:随着溅射功率的增加,薄膜表面均方根粗糙度迅... 相似文献
62.
Synthetic chromosome arms function in yeast and generate phenotypic diversity by design 总被引:1,自引:0,他引:1
Dymond JS Richardson SM Coombes CE Babatz T Muller H Annaluru N Blake WJ Schwerzmann JW Dai J Lindstrom DL Boeke AC Gottschling DE Chandrasegaran S Bader JS Boeke JD 《Nature》2011,477(7365):471-476
Recent advances in DNA synthesis technology have enabled the construction of novel genetic pathways and genomic elements, furthering our understanding of system-level phenomena. The ability to synthesize large segments of DNA allows the engineering of pathways and genomes according to arbitrary sets of design principles. Here we describe a synthetic yeast genome project, Sc2.0, and the first partially synthetic eukaryotic chromosomes, Saccharomyces cerevisiae chromosome synIXR, and semi-synVIL. We defined three design principles for a synthetic genome as follows: first, it should result in a (near) wild-type phenotype and fitness; second, it should lack destabilizing elements such as tRNA genes or transposons; and third, it should have genetic flexibility to facilitate future studies. The synthetic genome features several systemic modifications complying with the design principles, including an inducible evolution system, SCRaMbLE (synthetic chromosome rearrangement and modification by loxP-mediated evolution). We show the utility of SCRaMbLE as a novel method of combinatorial mutagenesis, capable of generating complex genotypes and a broad variety of phenotypes. When complete, the fully synthetic genome will allow massive restructuring of the yeast genome, and may open the door to a new type of combinatorial genetics based entirely on variations in gene content and copy number. 相似文献
63.
Gozar A Logvenov G Kourkoutis LF Bollinger AT Giannuzzi LA Muller DA Bozovic I 《Nature》2008,455(7214):782-785
The realization of high-transition-temperature (high-T(c)) superconductivity confined to nanometre-sized interfaces has been a long-standing goal because of potential applications and the opportunity to study quantum phenomena in reduced dimensions. This has been, however, a challenging target: in conventional metals, the high electron density restricts interface effects (such as carrier depletion or accumulation) to a region much narrower than the coherence length, which is the scale necessary for superconductivity to occur. By contrast, in copper oxides the carrier density is low whereas T(c) is high and the coherence length very short, which provides an opportunity-but at a price: the interface must be atomically perfect. Here we report superconductivity in bilayers consisting of an insulator (La(2)CuO(4)) and a metal (La(1.55)Sr(0.45)CuO(4)), neither of which is superconducting in isolation. In these bilayers, T(c) is either approximately 15 K or approximately 30 K, depending on the layering sequence. This highly robust phenomenon is confined within 2-3 nm of the interface. If such a bilayer is exposed to ozone, T(c) exceeds 50 K, and this enhanced superconductivity is also shown to originate from an interface layer about 1-2 unit cells thick. Enhancement of T(c) in bilayer systems was observed previously but the essential role of the interface was not recognized at the time. 相似文献
64.
Summary One of the authors has previously reported on a method which consists in the utilization of an artifical radioactive isotope (Zn63), suspended in a suitably prepared solution ofpectin, for the production oflocalized biological radiation effects.This « macromolecular occlusion » of the radioactive isotope enables one to perform intraperitoneal injections (in cases of cancer of the ovaries with severe metastatic peritoneal extension), evidently also instillations in cavernous organs, and furthermore direct intratumoral injections, without diffusion of the radioactivity outside the treated areas, as shown both by autoradiographs and controls of blood and urine specimens with a Geiger counter.The authors investigated further whether this procedure would also be suitable for obtaining, by means ofintravenous injections, alocalized radiation effect within thelungs, as presumably the radiozinc, held in the large molecules of pectin, could thus be retained in the pulmonary capillaries. Intravenous injections of such a pectin solution containing radiozinc were performed on rabbits, and autoradiographic controls gave evidence of this expected fixation within the lungs.For the purpose of preliminary clinical investigation 40 millicuries of Zn63 suspended in 6 cm3 of a 3 p. c. isotonic pectin solution were injectedintravenously in a female patient with mainly pulmonary metastases of a previously operated hypernephroma. This patient had been also submitted to X-ray therapy. In spite of a poor general condition, the injection was well tolerated. Autoradiographic controls showed quite clearly that the radioactivity remains precisely localized within the pulmonary areas. No radioactivity whatsoever was demonstrated with the counter in the urine eliminated by this patient after the injection, a fact which points to a rather amazing accuracy of the fixation of the radiozinc in the lungs. This first clinical experience seems quite interesting in view of improving the therapeutic possibilities of pathological, especially neoplastic pulmonary conditions. 相似文献
65.
F. A. Muller 《Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics》1999,30(4):444
This addendum non-trivially strengthens one of the six claims of my two-part paper ‘The Equivalence Myth of Quantum Mechanics’, published in this journal in 1997. 相似文献