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501.
502.
Karin Stübinger Axel Brehmer Winfried L. Neuhuber Herbert Reitsamer Debora Nickla Falk Schrödl 《Histochemistry and cell biology》2010,134(2):145-157
Intrinsic choroidal neurons (ICNs) exist in some primates and bird species. They may act on both vascular and non-vascular
smooth muscle cells, potentially influencing choroidal blood flow. Here, we report on the chemical coding of ICNs and eye-related
cranial ganglia in the chicken, an important model in myopia research, and further to determine synaptic input onto ICN. Chicken
choroid, ciliary, superior cervical, pterygopalatine, and trigeminal ganglia were prepared for double or triple immunohistochemistry
of calcitonin gene-related peptide (CGRP), choline acetyltransferase (ChAT), dopamine-β-hydroxylase, galanin (GAL), neuronal
nitric oxide synthase (nNOS), somatostatin (SOM), tyrosine hydroxylase (TH), vasoactive intestinal polypeptide (VIP), vesicular
monoamine-transporter 2 (VMAT2), and α-smooth muscle actin. For documentation, light, fluorescence, and confocal laser scanning
microscopy were used. Chicken ICNs express nNOS/VIP/GAL and do not express ChAT and SOM. ICNs are approached by TH/VMAT2-,
CGRP-, and ChAT-positive nerve fibers. About 50% of the pterygopalatine ganglion neurons and about 9% of the superior cervical
ganglion neurons share the same chemical code as ICN. SOM-positive neurons in the ciliary ganglion are GAL/NOS negative. CGRP-positive
neurons in the trigeminal ganglion lack GAL/SOM. The neurochemical phenotype and synaptic input of ICNs in chicken resemble
that of other bird and primate species. Because ICNs lack cholinergic markers, they cannot be readily incorporated into current
concepts of the autonomic nervous system. The data obtained provide the basis for the interpretation of future functional
experiments to clarify the role of these cells in achieving ocular homeostasis. 相似文献
503.
504.
Mycovirus cryphonectria hypovirus 1 elements cofractionate with trans-Golgi network membranes of the fungal host Cryphonectria parasitica 下载免费PDF全文
The mycovirus cryphonectria hypovirus 1 (CHV1) causes proliferation of vesicles in its host, Cryphonectria parasitica, the causal agent of chestnut blight. These vesicles have previously been shown to contain both CHV1 genomic double-stranded RNA (dsRNA) and RNA polymerase activity. To determine the cellular origins of these virus-induced membrane structures, we compared the fractionation of several cellular and viral markers. Results showed that viral dsRNA, helicase, polymerase, and protease p29 copurify with C. parasitica trans-Golgi network (TGN) markers, suggesting that the virus utilizes the fungal TGN for replication. We also show that the CHV1 protease p29 associates with vesicle membranes and is resistant to treatments that would release peripheral membrane proteins. Thus, p29 behaves as an integral membrane protein of the vesicular fraction derived from the fungal TGN. Protease p29 was also found to be fully susceptible to proteolytic digestion in the absence of detergent and, thus, is wholly or predominantly on the cytoplasmic face of the vesicles. Fractionation analysis of p29 deletion variants showed that sequences in the C terminal of p29 mediate membrane association. In particular, the C-terminal portion of the protein (Met-135-Gly-248) is sufficient for membrane association and is enough to direct p29 to the TGN vesicles in the absence of other viral elements. 相似文献
505.
Six chemicals, known to induce lung tumors in rats, were examined for their ability to induce DNA fragmentation in primary cultures of rat and human lung cells, and in the lung of intact rats. Significant dose-dependent increases in the frequency of DNA single-strand breaks and alkali-labile sites, as measured by the single-cell gel electrophoresis (Comet) assay, were obtained in primary lung cells from male rats with the following, minimally toxic, concentrations of the six test compounds: N-nitrosodimethylamine (NDMA; 2.5-10mM), hydrazine (HZ; 0.5-4mM), cadmium sulfate (CD; 31.2 and 62.5muM), 4,4'-methylene bis (2-chloroaniline) (MOCA; 31.2-125muM), isobutyl nitrite (IBN; 7.8-31.2muM) and tetranitromethane (TNM; 1.9-15.6muM). Similar degrees of DNA fragmentation were obtained in primary human lung cells; however, due to inter-donor differences, the minimum effective concentrations were in some donors lower and in others higher than in rats, and IBN induced DNA damage only in one of three donors. The DNA-damaging potency of HZ was higher in rats than in humans, and the opposite was true for MOCA. In agreement with these findings, statistically significant increases in the average frequency of DNA breaks were obtained in the lung of rats given a single oral dose (1/2 LD50) of the six test compounds. These findings give evidence that genotoxic lung carcinogens may be identified by use of the DNA fragmentation/Comet assay on rat lung cells as targets cells, and show that the six compounds tested produce in primary cultures of lung cells from human donors DNA-damaging effects substantially similar to those observed in rats. 相似文献
506.
Augusto F. Lois Debora A. Lackey Edward J. Carroll 《Molecular reproduction and development》1986,14(4):307-321
Sperm receptor hydrolase, one of two classes of cortical granule proteoesterases (E.C.3.4.4.4) was purified approximately 30-fold with 80% yield from Strongylocentrotus purpuratus cortical granule exudate. Sperm receptor hydrolase preparations were free of vitelline delaminase activity (the other class of cortical granule proteoesterase) and had less than 1% of the starting levels of cortical granule peroxidase and β-1,3-glucanohydro-lase activities. Native polyacrylamide gel electrophoresis coupled with a protease activity stain showed that three proteases were present in the most highly purified preparations of sperm receptor hydrolase. Each of the three proteases has the same molecular weight of 60,000, but different isoelectric points of 2.4, 3.8, and 5.5. The Km value of the mixture of proteases for α-N-benzoyl-L-arginine ethyl ester as substrate was 263 μM at pH 8.4 and 30°C; the pH dependence of Vm showed a single prototrophic group with a pK of 6.7 and an enthalpy of ionization of 8.6 kcal-mol?1. The values of these kinetic parameters are consistent with an enzyme-active site containing histidine. Phenylmethyl sulfonyl fluoride, tosyl lysine chloromethyl ketone, several proteinaceous trypsin inhibitors, and p-aminobenzamidine inhibited the esterase activity of the proteases. These data suggest that sperm receptor hydrolases are serine proteases. 相似文献
507.
Calmodulin Kinase II in Pure Cultured Astrocytes 总被引:3,自引:3,他引:0
Jeff Bronstein Robert Nishimura Robert Lasher† Ruth Cole‡§ Jean de Vellis‡§ Debora Farber Claude Wasterlain 《Journal of neurochemistry》1988,50(1):45-49
Calcium- and calmodulin-dependent protein kinase activity was studied in pure neuronal and glial cultures. The addition of calcium and calmodulin stimulated 32P incorporation into several neuronal proteins including two in the 50- and 60-kilodalton (kD) region which comigrated with purified forebrain calmodulin kinase II subunits (CaM kinase II). In mature astrocytes, CaM kinase activity was also present, and was inhibited by trifluoroperazine and diazepam. Again in homogenates of these cells, two phosphoproteins of apparent molecular masses of 50 and 60 kD comigrated with purified CaM kinase. CaM kinase activity was absent in immature mixed glia and oligodendrocytes. The presence of CaM kinase in neurons and mature astrocytes was confirmed using monoclonal antibodies specific for the 50-kD subunit of the enzyme. No immunoreactivity was observed in oligodendrocytes. The presence of CaM kinase in astrocytes suggests a more ubiquitous role of this enzyme in regulating cellular processes than was previously recognized. 相似文献
508.
Cooperative interaction between Ca2+ binding sites in the hydrophilic loop of the Na+-Ca2+ exchanger
Levitsky Dmitri O. Fraysse Bodvaël Leoty Claude Nicoll Debora A. Philipson Kenneth D. 《Molecular and cellular biochemistry》1996,160(1):27-32
A high affinity Ca2+-binding domain which is located in a middle portion of the large intracellular loop of the Na+-Ca2+ exchanger contains two highly acidic sequences, each characterized by three consecutive aspartic acid residues (Levitsky DO, Nicoll DA, and Philipson KD (1994) J Biol Chem 269: 22847–22852). This portion of the protein provides secondary Ca2+ regulation of the exchanger activity. To determine number of Ca2+ binding sites participating in formation of the high affinity domain, we isolated polypeptides of different lengths encompassing the domain and measured 45Ca2+ binding. The fusion proteins containing the high affinity domain were obtained in a Ca2+-bound form and as evidenced by shifts in there mobility in SDS-polyacrylamide gels after EGTA treatment. The Ca2+ binding curves obtained after equilibrium dialysis reached saturation at 1 M free Ca2+, Kd value being approx. 0.4 M. The Ca2+ binding occured in a highly cooperative manner. Upon saturation, the amount of Ca2+ ion bound varied from 1.3–2.1 mot per mot protein. Proteins with an aspartate in each acidic sequence mutated lacked the positive cooperativity, had lower Ca2+ affinity and bound two to three times less Ca2+. Na+-Ca2+ exchangers of tissues other than heart though different from the cardiac exchanger by molecular weight most likely possess a similar Ca2+ binding site. It is concluded that, by analogy with Ca2+ binding proteins of EF-type, the high Ca2+-affinity domain of the Na+-Ca2+ exchanger is comprised of at least two binding sites interacting cooperatively. 相似文献
509.
Localization of the gene for interphotoreceptor retinoid-binding protein to mouse chromosome 14 near Np-1 总被引:2,自引:0,他引:2
Michael Danciger Christine A. Kozak John Nickerson T. Michael Redmond Debora B. Farber 《Genomics》1990,8(4)
Interphotoreceptor retinoid-binding protein (IRBP) is a large glycoprotein known to bind retinoids and found primarily in the interphotoreceptor matrix of the retina between the retinal pigment epithelium and the photoreceptor cells. It is thought to transport retinoids between the retinal pigment epithelium and the photoreceptors, a critical role in the visual process. We have used a 900-bp bovine IRBP cDNA fragment to map the corresponding gene, Rbp-3, to mouse chromosome 14 with somatic cell hybrids and have positioned the gene near Np-1 (nucleoside phosphorylase-1) by analysis of the progeny of an intersubspecific backcross. In the human genome, NP maps to human chromosome 14 and RBP3 to human chromosome 10. Thus, these two genes span the putative site of a chromosomal translocation which contributed to divergent karyotype evolution of man and mouse. 相似文献
510.
Characterization and cell type distribution of a novel, major transcript of the Duchenne Muscular Dystrophy gene 总被引:3,自引:0,他引:3