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71.
Takenori Miyamoto Diego Restrepo Edward J. Cragoe Jr. John H. Teeter 《The Journal of membrane biology》1992,127(3):173-183
Summary Olfactory receptor neurons enzymatically dissociated from channel catfish olfactory epithelium were depolarized transiently following dialysis of IP3 or cAMP (added to the patch pipette) into the cytoplasm. Voltage and current responses to IP3 were blocked by ruthenium red, a blocker of an IP3-gated Ca2+-release channel in sarcoplasmic reticulum. In contrast, the responses to cAMP were not blocked by extracellularly applied ruthenium red, nor by l-cis-diltiazem or amiloride and two of its derivatives. The current elicited by cytoplasmic IP3 in neurons under voltage clamp displayed a voltage dependence different from that of the cAMP response which showed marked outward rectification. A sustained depolarization was caused by increased cytoplasmic IP3 or cAMP when the buffering capacity for Ca2+ of the pipette solution was increased, when extracellular Ca2+ was removed or after addition of 20–200 nm charibdotoxin to the bathing solution, indicating that the repolarization was caused by an increase in [Ca
i
] that opened Ca2+-activated K+ channels. The results suggest that different conductances modulated by either IP3 or cAMP are involved in mediating olfactory transduction in catfish olfactory receptor neurons and that Ca2+-activated K+ channels contribute to the termination of the IP3 and cAMP responses.Abbreviations ATP
adenosine 5-triphosphate
- BAPTA
(bis-(o-aminophenoxy)-ethane-N-N-N-N)-tetraacetic acid
- cAMP
adenosine cyclic 3,5-monophosphate
- cGMP
guanosine cyclic 3,5-monophosphate
- CTX
charybdotoxin
- DCB
3,4-dichlorobenzamil
- EDTA
ethylenediaminetetraacetic acid
- EGTA
ethylenglycol-bis-(b-aminoethyl)-N-N-N-N-tetraacetic acid
- HEPES
N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid
- IP3
inositol-1,4,5-triphosphate
- NMDG
N-methyl-d-glucamine
We would like to thank the Tanabe Seiyaku Co., Ltd., for their gift of l-cis-diltiazem. This work was supported by National Institutes of Health grants DC00566 and BRSG S07RR05825. 相似文献
72.
A Rojas-Martinez D Garcia-Cruz C Medina M Moller C M Restrepo H Rivera 《Annales de génétique》1990,33(4):228-230
A 3.5-year-old boy with a de novo tandem duplication 5q11.1----5q15 is reported. Since the physical stigmata of seven liveborn cases with 5q proximal duplications are variable and inconspicuous, a recognizable syndrome could not be delineated. On the contrary, the associated developmental delay seems to be severe in duplications extending into 5q22 and mild in duplications 5q11----q13. 相似文献
73.
Cassava bacterial blight (CBB) is caused by Xanthomonas axonopodis pv. manihotis (Xam). Resistance is found in Manihot esculenta and, in addition, has been introgressed from a wild relative, M. glaziovii. The resistance is thought to be polygenic and additively inherited. Ninety-three varieties of M. esculenta (Crantz) were assessed by AFLPs for genetic diversity and for resistance to CBB. AFLP analysis was performed using two primer combinations and a 79.2% level of polymorphism was found. The phenogram obtained showed between 74% and 96% genetic similarity among all cassava accessions analysed. The analysis permitted the unique identification of each individual. Two Xam strains were used for resistance screening. Variation in the reaction of cassava varieties to Xam strains was observed for all plant accessions. The correlation of resistance to both strains, had a coefficient of 0.53, suggesting the independence of resistance to each strain. Multiple correspondence analysis showed a random distribution of the resistance/susceptibility response with respect to overall genetic diversity as measured by AFLP analysis. A total heterozygosity index was calculated to determine the diversity within clusters as well as among them. Our results demonstrate that resistance to CBB is broadly distributed in cassava germplasm and that AFLP analysis is an effective and efficient means of providing quantitative estimates of genetic similarities among cassava accessions. 相似文献
74.
Olfactory receptor neurons respond to odorants with G-protein mediated increases in the concentration of cyclic adenosine 3′,5′-monophosphate (cAMP) and/or inositol 1,4,5-triphosphate (InsP3). These two second messengers directly regulate opening of cAMP- and InsP3-regulated conductances localized to the apical transduction compartments of the cell (cilia and olfactory knob). In the presence of physiological concentrations of extracellular Ca2+, these second messenger regulated conductances mediate influx of Ca2+ into the olfactory neuron resulting in large, localized increases in intracellular Ca2+ ([Ca2+]i). A significant advance in our understanding of the molecular mechanisms of olfaction is the recent realization that this increase in [Ca2+]i plays an important role as a “third messenger” in olfactory transduction. Second messenger dependent increases in [Ca2+]i cause opening of ciliary Ca2+-activated Cl−, cation and/or K+ channels that can carry a large percentage of the generator current, thus amplifying the signal substantially. As a result of this sequence of events, the generator potential in olfactory neurons can be depolarizing, leading to excitation of the neuron, or hyperpolarizing, leading to suppression of basal action potential firing rate. This dual effect of odorants on olfactory neurons may play an important role in quality coding and in the ability to detect low concentrations of odorants, particularly in complex mixtures. © 1996 John Wiley & Sons, Inc. 相似文献
75.
76.
Bravo R Caltabiano LM Fernandez C Smith KD Gallegos M Whitehead RD Weerasekera G Restrepo P Bishop AM Perez JJ Needham LL Barr DB 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2005,820(2):229-236
We have developed a method to measure 12 urinary phenolic metabolites of pesticides or related chemicals. The target chemicals for our method are 2-isopropoxyphenol; 2,4-dichlorophenol; 2,5-dichlorophenol; carbofuranphenol; 2,4,5-trichlorophenol; 2,4,6-trichlorophenol; 3,5,6-trichloro-2-pyridinol; para-nitrophenol, ortho-phenylphenol, pentachlorophenol, 1-naphthol and 2-naphthol. The sample preparation involves enzyme hydrolysis, isolation of the target chemicals using solid phase extraction cartridges, a phase-transfer catalyzed derivatization, cleanup using sorbent-immobilized liquid/liquid extraction cartridges, and concentration of the sample. Derivatized samples are analyzed by capillary gas chromatography-tandem mass spectroscopy using isotope dilution calibration for quantification. The limits of detection are in the mid ng/L range and the average coefficient of variation was below 15% for most of the analytes. Using our method, we measured concentrations of the target chemicals in urine samples from the general population. 相似文献
77.
Szabó CA Leland MM Sztonák L Restrepo S Haines R Mahaney MA Williams JT 《American journal of primatology》2004,62(2):95-106
Spontaneous seizures have been observed in several baboon species housed at the Southwest National Primate Research Center (SNPRC), including Papio hamadryas anubis and cynocephalus/anubis, hamadryas/anubis, and papio/anubis hybrids. The goal of this study was to establish a noninvasive, reliable electroencephalographic technique to characterize epilepsy phenotypes and assess photosensitivity in these subspecies. Thirty baboons with witnessed seizures, and 15 asymptomatic baboons underwent scalp electroencephalograms (EEGs) with photic stimulation (PS). The sensitivity and specificity of surface EEG for identifying interictal epileptic discharges (IEDs) in baboons with witnessed seizures were examined. The morphology of IEDs, electroclinical features of seizures and responses to PS, reproducibility of EEG findings, and intrarater reliability were also evaluated. Twenty-three seizure baboons (77%) demonstrated IEDs, predominantly with frequencies of 4-6 Hz in 18 baboons and 2-3 Hz in six baboons. Two seizure animals had a mixture of 2-3-Hz and 4-6-Hz IEDs. All animals with 2-3-Hz IEDs were 3 years old or younger. Myoclonic seizures (MS) and generalized tonic-clonic seizures (GTCS) were recorded in 13 baboons (43%). PS activated IEDs in 15 baboons (50%) and seizures in nine baboons. The presence of IEDs or seizures was not associated with a particular gender or species (Fisher exact test, alpha=0.05). Seizures were more common in animals >3 years old, while PS-induced IEDs and seizures were more prevalent in P.h. anubis/cynocephalus crosses compared to P.h. anubis. In the asymptomatic controls, IEDs were recorded in five baboons (33%), and photoparoxysmal responses were observed in two (13%). Surface EEG is a sensitive and reliable instrument for characterizing the epilepsy encountered in Papio species. Electroclinically, the seizure animals had generalized epilepsy with photosensitivity. The variation in IED morphology may be age-related or it may reflect different epileptic phenotypes. Ketamine provoked IEDs and seizures in most seizure animals and only in a few asymptomatic baboons; therefore, it may enhance the sensitivity of surface EEG for detecting a predisposition to epilepsy. 相似文献
78.
Rawson NE Eberwine J Dotson R Jackson J Ulrich P Restrepo D 《Journal of neurochemistry》2000,75(1):185-195
Evidence has accumulated to support a model for odorant detection in which individual olfactory receptor neurons (ORNs) express one of a large family of G protein-coupled receptor proteins that are activated by a small number of closely related volatile chemicals. However, the issue of whether an individual ORN expresses one or multiple types of receptor proteins has yet to be definitively addressed. Physiological data indicate that some individual ORNs can be activated by odorants differing substantially in structure and/or perceived quality, suggesting multiple receptors or one nonspecific receptor per cell. In contrast, molecular biological studies favor a scheme with a single, fairly selective receptor per cell. The present studies directly assessed whether individual rat ORNs can express multiple receptors using single-cell PCR techniques with degenerate primers designed to amplify a wide variety of receptor sequences. We found that whereas only a single OR sequence was obtained from most ORNs examined, one ORN produced two distinct receptor sequences that represented different receptor gene families. Double-label in situ hybridization studies indicated that a subset of ORNs co-express two distinct receptor mRNAs. A laminar segregation analysis of the cell nuclei of ORNs labeled with the two OR mRNA probes showed that for one probe, the histogram of the distribution of the cell nuclei along the depth of the epithelium was bimodal, with one peak overlapping the (unimodal) histogram for the other probe. These results are consistent with co-expression of two OR mRNAs in a population of single ORNs. 相似文献
79.
Gonzalez A Lenzi HL Motta EM Caputo L Sahaza JH Cock AM Ruiz AC Restrepo A Cano LE 《Microbes and infection / Institut Pasteur》2005,7(4):666-673
In infected tissues, leukocyte recruitment is mediated by interactions between adhesion molecules, expressed on activated vascular endothelial cells, and ligands present on circulating cells. We evaluated the inflammatory response and the expression of cellular adhesion molecules (ICAM-1, VCAM-1, CD18, LFA-1 and Mac-1) in lungs of BALB/c mice infected with Paracoccidioides brasiliensis conidia. When compared with uninfected animals, infected mice had a significant increase in the inflammatory response during the first 4 days, peaking 2-3 days post-challenge, 40.3% vs. 0.0% and 41.8% vs. 0.7%, respectively. This inflammatory infiltrate was composed mainly of neutrophils and macrophages with a few eosinophils and lymphocytes. An increase in the intensity of immunofluorescence (IF) for ICAM-1 was also observed during days 1-4. ICAM-1 was present in bronchiolar epithelium, type II pneumocytes, and macrophages, as well as on vascular endothelium. The control animals presented ICAM-1 constitutively. In infected mice, VCAM-1 was only observed on vascular endothelium during the first 2 days, with some macrophages expressing this molecule throughout the study periods. CD18 and Mac-1 but not LFA-1 were expressed with a high intensity on neutrophils and macrophages present in the inflammatory infiltrate. In addition, we observed a significant decrease in Colony forming units (CFUs) after the first 2 days post-challenge. These findings suggest that during these early stages, up-regulation of ICAM-1, VCAM-1, CD18 and Mac-1 expression occurs, participating in the inflammatory process and as such, in the pathogenesis of paracoccidioidomycosis (PCM). 相似文献
80.
Restrepo D 《Neuron》2005,45(4):481-482
Stimulation of olfactory receptor neurons with odors culminates in opening of a ciliary Ca2+-activated Cl- channel. Because intracellular Cl- ([Cl-]i) is above electrochemical equilibrium in these cells, the result is cell depolarization that triggers action potentials that carry information to the olfactory bulb. In this issue of Neuron, Reisert and coworkers use combined pharmacological and mouse genetic approaches to show that the transporter responsible for maintaining Cl- above electrochemical equilibrium is NKCC1, a (Na+)(2Cl-)(K+) cotransporter found in other tissues, including neurons. 相似文献