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31.
The selective antagonism of the excitatory responses of oxytocin by alpha-thioglycerol and its potentiation by Mg++ indicate the presence of specific oxytocin receptors in fowl rectum. In addition, the sensitivity of the rectum to very small doses of oxytocin suggests a possible facilitatory role of neurohypophyseal hormones in oviposition. 相似文献
32.
R. R. Mishra 《Cellular and molecular life sciences : CMLS》1969,25(6):657-657
Zusammenfassung Nach UV-Bestrahlung von gesunden und mit Viren infizierten Chenopodium-Pflanzen (Chenopodium, amaranticolor, Coste und Reyn) konnte eine Zunahme der Pilzflora in der Rhizosphäre, besonders der infizierten Pflanzen, beobachtet werden. 相似文献
33.
Sr^2+ modified polycrystalline PZT-PMN ceramics were synthesized by a semi-wet route. Impedance spectroscopy studies indicate the bulk and grain boundary effects of PZT-PMN material along with the negative temperature coefficient of resistance. The bulk conductiv-ity exhibits an Arrhenius-type thermally activated hopping process which is supported by the AC conductivity behavior as a function of fre-quency and temperature. It is observed that the remnant polarization increases with an increase in the Sr2+content in PZT-PMN. 相似文献
34.
35.
Continuous-drive rotary friction welding was performed to join cylindrical specimens of carbon steel (EN24) and nickel-based superalloy (IN718), and the microstructures of three distinct weld zones—the weld interface (WI)/thermo-mechanically affected zone (TMAZ), the heat-affected zone (HAZ), and the base metal—were examined. The joint was observed to be free of defects but featured uneven flash formation. Electron backscatter diffraction (EBSD) analysis showed substantial changes in high-angle grain boundaries, low-angle grain boundaries, and twin boundaries in the TMAZ and HAZ. Moreover, significant refinement in grain size (2–5 μm) was observed at the WI/TMAZ with reference to the base metal. The possible causes of these are discussed. The microhardness profile across the welded joint shows variation in hardness. The changes in hardness are ascribed to grain refinement, phase transformation, and the dissolution of strengthening precipitates. The tensile test results reveal that a joint efficiency of 100% can be achieved using this method. 相似文献
36.
Kinetics of thermal decomposition of hydrated minerals associated with hematite ore in a fluidized bed reactor 下载免费PDF全文
The kinetics of removal of loss on ignition (LOI) by thermal decomposition of hydrated minerals present in natural iron ores (i.e., kaolinite, gibbsite, and goethite) was investigated in a laboratory-scale vertical fluidized bed reactor (FBR) using isothermal methods of kinetic analysis. Experiments in the FBR in batch processes were carried out at different temperatures (300 to 1200℃) and residence time (1 to 30 min) for four different iron ore samples with various LOIs (2.34wt% to 9.83wt%). The operating velocity was maintained in the range from 1.2 to 1.4 times the minimum fluidization velocity (Umf). We observed that, below a certain critical temperature, the FBR did not effectively reduce the LOI to a desired level even with increased residence time. The results of this study indicate that the LOI level could be reduced by 90% within 1 min of residence time at 1100℃. The kinetics for low-LOI samples (<6wt%) indicates two different reaction mechanisms in two temperature regimes. At lower temperatures (300 to 700℃), the kinetics is characterized by a lower activation energy (diffusion-controlled physical moisture removal), followed by a higher activation energy (chemically controlled removal of LOI). In the case of high-LOI samples, three different kinetics mechanisms prevail at different temperature regimes. At temperature up to 450℃, diffusion kinetics prevails (removal of physical moisture); at temperature from 450 to 650℃, chemical kinetics dominates during removal of matrix moisture. At temperatures greater than 650℃, nucleation and growth begins to influence the rate of removal of LOI. 相似文献
37.
Mishra SK Ammon T Popowicz GM Krajewski M Nagel RJ Ares M Holak TA Jentsch S 《Nature》2011,474(7350):173-178
Alternative splicing of pre-messenger RNAs diversifies gene products in eukaryotes and is guided by factors that enable spliceosomes to recognize particular splice sites. Here we report that alternative splicing of Saccharomyces cerevisiae SRC1 pre-mRNA is promoted by the conserved ubiquitin-like protein Hub1. Structural and biochemical data show that Hub1 binds non-covalently to a conserved element termed HIND, which is present in the spliceosomal protein Snu66 in yeast and mammals, and Prp38 in plants. Hub1 binding mildly alters spliceosomal protein interactions and barely affects general splicing in S. cerevisiae. However, spliceosomes that lack Hub1, or are defective in Hub1-HIND interaction, cannot use certain non-canonical 5' splice sites and are defective in alternative SRC1 splicing. Hub1 confers alternative splicing not only when bound to HIND, but also when experimentally fused to Snu66, Prp38, or even the core splicing factor Prp8. Our study indicates a novel mechanism for splice site utilization that is guided by non-covalent modification of the spliceosome by an unconventional ubiquitin-like modifier. 相似文献
38.
J. Mihaly I. Hogga S. Barges M. Galloni R. K. Mishra K. Hagstrom M. Müller P. Schedl L. Sipos J. Gausz H. Gyurkovics F. Karch 《Cellular and molecular life sciences : CMLS》1998,54(1):60-70
Eukaryotic chromosomes are thought to be organized into a series of discrete higher-order chromatin domains. This organization
is believed to be important not only in the compaction of the chromatin fibre, but also in the utilization of genetic information.
Critical to this model are the domain boundaries that delimit and segregate the chromosomes into units of independent gene
activity. In Drosophila, such domain boundaries have been identified through two different approaches. On the one hand, elements like scs/scs′ and
the reiterated binding site for the SU(HW) protein have been characterized through their activity of impeding enhancer-promoter
interactions when intercalated between them. Their role of chromatin insulators can protect transgenes from genomic position
effects, thereby establishing in dependent functional domains within the chromosome. On the other hand, domain boundaries
of the Bithorax complex (BX-C) like Fab-7 and Mcp have been identified through mutational analysis. Mcp and Fab-7, however, may represent a specific class of boundary elements; instead of separating adjacent domains that contain separate
structural genes, Mcp and Fab-7 delimit adjacent cis-regulatory domains, each of which interacts independently with their target promoters. In this article, we review the genetic
and molecular characteristics of the domain boundaries of the BX-C. We describe how Fab-7 functions to confine activating as well as repressive signals to the flanking regulatory domains. Although the mechanisms
by which Fab-7 works as a domain boundary remain an open issue, we provide preliminary evidence that Fab-7 is not a mere insulator like scs or the reiterated binding site for the SU(HW) protein. 相似文献
39.
INTRODUCTION
The Indian Pulp & Paper Industry is more than a
century old industry . The first paper mill was
established in the year 1832 and today the number
has grown to more than 400 in the organised sector
which are located through out the country . In
addition there are another 500 pulp & paper mills in
the unorganized sector. The Indian pulp & paper
industry can be categorised into large, medium and
small depending on the scale of operation as
indicated in Table -I
Most of the large mills established initially were
based on woody raw materials. 相似文献
40.
R. R. Mishra G. D. Sharma I. B. Kharsyntiew 《Cellular and molecular life sciences : CMLS》1981,37(6):568-569
Summary The effect of the inoculum density of vesicular arbuscular mycorrhizal endophytes on growth and development in maize was investigated in sterilized soil under glass-house conditions. Mycorrhizal plants grew robust and produced three times more dry weight than non-mycorrhizal plants. 40 or more endophytes per plant produced the highest mycorrhizal association and the maximum growth in maize. The uninoculated plants exhibited the symptoms of chlorosis. 相似文献