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101.
Charles W. Francis Elizabeth M. Keele Victor J. Marder 《Biochimica et Biophysica Acta (BBA)/General Subjects》1984,797(3):328-335
Three forms of the normal human plasma fibrinogen γ-chain which differ in molecular weight have been purified. Plasma fibrinogen was separated by ion exchange chromatography on DEAE-Sephacel into three populations of molecules, each with a unique γ-chain composition. Following reduction and S-carboxymethylation, the fibrinogen polypeptide chains in each chromatographic peak were separated by ion exchange chromatography on DEAE-Sephacel and identified following sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The Aα, Bβ and smallest γ-chain (γ50) eluted at progressively higher ionic strengths, but the elution positions of Aα, Bβ and γ50 chains were identifcal for fibrinogen from each of the three different chromatographic fractions. The unique γ chain of fibrinogen in the second chromatographic peak (γ55) eluted at an ionic strength higher than that of the γ50 chain, while the largest γ-chain (γ57.5), which was contained only in the third chromatographic peak of fibrinogen, eluted at the highest ionic strength. The higher ionic strengths needed to elute fibrinogen in the second and third peaks was paralleled by the higher ionic strengths needed to elute the γ-chains unique to them, suggesting that the γ-chain composition of the three fibrinogen fractions accounted for their differential binding to the ion exchange resin. Following desialation with neuraminidase, the differences in electrophoretic mobilities between the three γ-chain forms was maintained, indicating that differential migration on SDS-polyacrylamide gel electrophoresis was not due to variation in sialic acid content. 相似文献
102.
Sensory neurons provide important feedback to pattern-generating motor systems. In the crustacean stomatogastric nervous system (STNS), feedback from the anterior gastric receptor (AGR), a muscle receptor neuron, shapes the activity of motor circuits in the stomatogastric ganglion (STG) via polysynaptic pathways involving anterior ganglia. The AGR soma is located in the dorsal ventricular nerve posterior to the STG and it has been thought that its axon passes through the STG without making contacts. Using high-resolution confocal microscopy with dye-filled neurons, we show here that AGR from the crab Cancer borealis also has local projections within the STG and that these projections form candidate contact sites with STG motor neurons or with descending input fibers from other ganglia. We develop and exploit a new masking method that allows us to potentially separate presynaptic and postsynaptic staining of synaptic markers. The AGR processes in the STG show diversity in shape, number of branches and branching structure. The number of AGR projections in the STG ranges from one to three simple to multiply branched processes. The projections come in close contact with gastric motor neurons and descending neurons and may also be electrically coupled to other neurons of the STNS. Thus, in addition to well described long-loop pathways, it is possible that AGR is involved in integration and pattern regulation directly in the STG. 相似文献
103.
A Universal Vector for High-Efficiency Multi-Fragment Recombineering of BACs and Knock-In Constructs
Karamjit Singh Dolt Melanie L. Lawrence Eve Miller-Hodges Joan Slight Anna Thornburn Paul S. Devenney Peter Hohenstein 《PloS one》2013,8(4)
There is an increasing need for more efficient generation of transgenic constructs. Here we present a universal multi-site Gateway vector for use in recombineering reactions. Using transgenic mouse models, we show its use for the generation of BAC transgenics and targeting vectors. The modular nature of the vector allows for rapid modification of constructs to generate different versions of the same construct. As such it will help streamline the generation of series of related transgenic models. 相似文献
104.
105.
Isaac Brito-Morales Jorge García Molinos David S. Schoeman Michael T. Burrows Elvira S. Poloczanska Christopher J. Brown Simon Ferrier Tom D. Harwood Carissa J. Klein Eve McDonald-Madden Pippa J. Moore John M. Pandolfi James E.M. Watson Amelia S. Wenger Anthony J. Richardson 《Trends in ecology & evolution》2018,33(6):441-457
106.
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108.
Yumi Kono Suyun Yang Eve A. Roberts 《In vitro cellular & developmental biology. Animal》1997,33(6):467-472
Summary To develop a strategy for extended primary culture of human hepatocytes, we placed human hepatocytes between two layers of
collagen gel, called a “collagen gel sandwich.” Maintenance of hepatocellular functions in this system was compared with that
of identical hepatocyte preparations cultured on dry-collagen coated dishes or co-cultured with rat liver epithelial cells.
Human hepatocytes in a collagen gel sandwich (five separate cultures) survived for more than 4 wk, with the longest period
of culture being 78 d. They maintained polygonal morphology with bile canaliculuslike structures and high levels of albumin
secretion throughout the period of culture. In contrast, hepatocytes on dry-collagen became feature-less, and albumin secretion
could not be detected after 14 d of culture. This loss of albumin secretion was partially recovered by overlaying one layer
of collagen gel. Ethoxyresorufin O-deethylase activity, associated with cytochrome P450 1A2, was detected basally up to 29 d in collagen gel sandwich culture.
These activities were induced four- to eightfold after induction with dibenz(a,h)anthracene. Cocultures also maintained basal activity up to 29 d. However, their inducibility was lower than that of hepatocytes
in collagen gel sandwich. No ethoxyresorufin O-deethylase activity was detected in hepatocytes cultured on dry-collagen at 7 d. Thus, the collagen gel sandwich system preserves
differentiated morphology and functions of human hepatocytes in primary culture for a prolonged period of time. This system
is a promising model for studying human hepatocellular function, including protein synthesis and drug metabolism in vitro. 相似文献
109.
Chan Alvin C. Wagner Michelle Kennedy Chris Chen Eve Lanuville Odette Mezl Vasek A. Tran Khai Choy Patrick C. 《Molecular and cellular biochemistry》1998,185(1-2):153-159
The alteration in calcium transport in the liver nuclei of rats orally administered carbon tetrachloride (CCl4) was investigated. Rats received a single oral administration of CCl4(5, 10, and 25%, 1.0ml/100 g body weight), and 5, 24 and 48 h later the animals were sacrificed. The administration of CCl4 (25%) caused a remarkable elevetion of calcium content in the liver tissues and the nuclei of rats. Liver nuclear Ca2+-ATPase activity was markedly decreased by CCl4 (25%) administration. The presence of dibutyryl cyclic AMP(10-4 and 10-3 M) or inositol 1,4,5-trisphosphate (10-6 and 10-5 M) in the enzyme reaction mixture caused a significant decrease in Ca2+-ATPase activity in the liver nuclei obtained from normal rat, while the enzyme activity was significantly increased by calmodulin (1.0 and 2.0 g/ml). These signaling factor's effects were completely impaired in the liver nuclei obtained from CCl4 (25%)-administered rats. DNA fragmentation in the liver nuclei obtained from CCl4 -administered rats was significantly decreased by the presence of EGTA (2 mM) in the reaction mixture, suggesting that the endogenous calcium activates nuclear DNA fragmentation. The present study demonstrates that calcium transport system in the liver nuclei is impaired by liver injury with CCl4 administration in rats. 相似文献
110.
SUBPLASMALEMMAL MICROFILAMENTS AND MICROTUBULES IN RESTING AND PHAGOCYTIZING CULTIVATED MACROPHAGES 总被引:53,自引:34,他引:19 下载免费PDF全文
The subplasmalemmal organization of the free and glass-attached surfaces of resting and phagocytizing cultivated macrophages were examined in an attempt to define specific membrane-associated structures related to phagocytosis. From analysis of serial thin sections of oriented cells it was found that the subplasmalemmal region of the attached cell surface has a complex microfilament and microtubule organization relative to the subplasmalemmal area of the free surface. A filamentous network composed of 40–50-Å microfilaments extended for a depth of 400–600 Å from the attached plasma membrane. Immediately subjacent to the filamentous network was a zone of oriented bundles of 40–50-Å microfilaments and a zone of microtubules. Additional microtubules were found to extend from the plasma membrane to the interior of the cell in close association with electron-dense, channellike structures. In contrast, the free aspect of the cultivated macrophage contained only the subplasmalemmal filamentous network. However, after a phagocytic pulse with polystyrene particles (14 µm diam) microtubules and oriented filaments similar to those found on the attached surface were observed surrounding the ingested particles. The observations reported in this paper provide support for the hypothesis that microfilaments and/or microtubules play a role in the translocation of plasma membrane required for the functionally similar processes of phagocytosis and cell attachment to glass. 相似文献