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91.
Abnormalities in the central cholinergic transmitter system of the genetically epilepsy-prone rat 总被引:2,自引:0,他引:2
Seizure-experienced Genetically Epilepsy-prone Rats (GEPRs) have increased acetylcholine content and choline acetyltransferase activity in the thalamus and striatum. These cholinergic differences are accompanied by a slight but statistically significant reduction in acetylcholinesterase activity in the midbrain. In addition, no abnormalities were found in the numbers of specific 3H-QNB binding sites in the striatum, hippocampus, inferior colliculi or cortex. Other work has shown no difference in muscarinic receptor function as measured by carbachol-stimulated inositol-1-phosphate formation. These data suggest a possible presynaptic defect in the striatal and thalamic cholinergic system which may play some role in the seizure-prone state of the GEPR. However, caution must be used in interpreting these cholinergic derangements since more recent findings show no differences in thalamic acetylcholine content in seizure-naive GEPRs. Thus, the original cholinergic abnormalities detected in the seizure-experienced GEPR may be an enduring response to seizure activity. 相似文献
92.
Sequence of a cDNA for mouse thymidylate synthase reveals striking similarity with the prokaryotic enzyme 总被引:11,自引:0,他引:11
Perryman SM; Rossana C; Deng TL; Vanin EF; Johnson LF 《Molecular biology and evolution》1986,3(4):313-321
We report the nucleotide sequence of a cloned cDNA, pMTS-3, that contains a
1-kb insert corresponding to mouse thymidylate synthase (E.C. 2.1.1.45).
The open reading frame of 921 nucleotides from the first AUG to the
termination codon specifies a protein with a molecular mass of 34,962
daltons. The predicted amino acid sequence is 90% identical with that of
the human enzyme. The mouse sequence also has an extremely high degree of
similarity (as much as 55% identity) with prokaryotic thymidylate synthase
sequences, indicating that thymidylate synthase is among the most highly
conserved proteins studied to date. The similarity is especially pronounced
(as much as 80% identity) in the 44-amino-acid region encompassing the
binding site for deoxyuridylic acid. The cDNA sequence also suggests that
mouse thymidylate synthase mRNA lacks a 3' untranslated region, since the
termination codon, UAA, is followed immediately by a poly(A) segment.
相似文献
93.
Dr. Edward B. Blanchard Cynthia L. Radnitz Donald D. Evans Shirley P. Schwarz Debra F. Neff Maryrose A. Gerardi 《Applied psychophysiology and biofeedback》1986,11(3):221-230
Comparisons were made among patients with IBS (n=55), tension headache (n=69), or migraine headache (n=68) and nonpatient controls (n=64) on the MMPI and several other psychological tests, including BDI, STAI, Life Events, and Psychosomatic Symptom Checklist. With two nonsignificant exceptions (MMPI scale F and Life Events) the groups were consistently ordered, in terms of increasing psychological distress: Normals < Migraine Headache < Tension Headache < IBS. The IBS patients were more like the tension headache patients than any other group. Subgroups of IBS patients, on the basis of presence or absence of diarrhea or constipation in addition to abdominal pain, were generally not significantly different on the psychological tests. 相似文献
94.
—The half-life of tryptophan 5-hydroxylase (EC 1.14.3) in rats was estimated from the return of enzyme activity after administration of p-chlorophenylalanine and from the decline of enzyme activity in spinal cord after transection or an intraspinal injection of colchicine. The half-life was 2–3 days. Axonal transport of enzyme, estimated from the reappearance of activity in consecutive portions of spinal cord after treatment with p-chlorophenylalanine, was of the order of 5–7 mm/day. This rate is characteristic of 'slow’axonal flow. Our results suggest that changes in the synthesis of new enzyme are probably not responsible for acute changes in the turnover of serotonin. 相似文献
95.
BIOGENIC AMINES AND THEIR METABOLITES AS SUBSTRATES FOR PHENOL SULPHOTRANSFERASE (EC 2.8.2.1) OF BRAIN AND LIVER 总被引:6,自引:5,他引:1
Phenol sulphotransferase activity in homogenates of rat liver and brain was determined spectrophotometrically. Rat liver had about 100-fold more phenol sulphotransferase activity than brain; however, both tissues showed about the same spectrum of activity towards the phenolic compounds tested. Dopamine and its acidic and neutral metabolites and the neutral metabolites of norepinephrine were the compounds most readily sulphury-lated in vitro. They were also the compounds most readily sulphurylated in vivo when they were injected intraventricularly together with labelled Na2SO4. When labelled Na2SO4 was injected alone, we detected conjugation of endogenous phenols. One of the compounds formed was identified by its chromatographic characteristics as 3-methoxy-4-hydroxy-phenylethyleneglycol sulphate. We detected other conjugates which appeared to be the sulphate esters of 3,4-dihydroxyphenylethyleneglycol; 3,4-dihydroxyphenylacetic acid; and homovanillic acid. In brain, sulphate conjugation may be a major route of metabolism for many of the phenolic compounds related to the biogenic amines and possibly for phenolic drugs which enter the brain. 相似文献
96.
97.
M. Hadjiconstantinou S. E. Moroi-Fetters S. -Z. Qu N. H. Neff 《Cellular and molecular neurobiology》1991,11(5):455-462
1. Agonist activation of rat retina muscarinic receptors results in suppression of cyclic AMP (cAMP) generation and enhanced phosphoinositide hydrolysis. 2. Pharmacological manipulations that elevate cAMP or stable analogues of cAMP attenuate the acetylcholine (ACh)-induced enhancement of phosphoinositide hydrolysis. We postulate that cross-talk between adenylate cyclase and phospholipase C signal transducing systems probably exists in rat retina, as has been described for other systems. 3. Intraocular administration of pertussis toxin attenuated the response of both adenylate cyclase and phospholipase C to muscarinic stimulation, suggesting that some retinal muscarinic receptors are apparently coupled to their effector systems via pertussis toxin sensitive G proteins. 相似文献
98.
A dominant trifluoperazine resistance gene from Saccharomyces cerevisiae has homology with F0F1 ATP synthase and confers calcium-sensitive growth. 总被引:11,自引:2,他引:9
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C K Shih R Wagner S Feinstein C Kanik-Ennulat N Neff 《Molecular and cellular biology》1988,8(8):3094-3103
The antipsychotic drug trifluoperazine has been long considered a calmodulin inhibitor from in vitro studies but may function in vivo as a more general inhibitor by disturbing ion fluxes and altering the membrane potential. Resistance to trifluoperazine can arise in Saccharomyces cerevisiae cells by alterations in at least three distinct genetic loci. One locus, defined by a spontaneous dominant trifluoperazine resistance mutation (TFP1-408), was isolated and sequenced. The sequence of the TFP1-408 gene revealed a large open reading frame coding for a large protein of 1,031 amino acids with predicted hydrophobic transmembrane domains. A search of existing amino acid sequences revealed a significant homology with F0F1 ATP synthase. Mutant TFP1-408 cells did not grow efficiently in the presence of 50 mM CaCl2, whereas wild-type cells did. Wild-type cells became resistant to trifluoperazine in the presence of 50 mM CaCl2 or 50 mM MgCl2. Mutant cells showed a higher rate of calcium transport relative to wild-type cells. These data suggest that the TFP1 gene product codes for a transmembrane ATPase-like enzyme possibly involved in Ca2+ transport or in generating a transmembrane ion gradient between two cellular compartments. 相似文献
99.
100.
Measurement of Acetylcholine Turnover Rate in Brain: An Adjunct to a Simple HPLC Method for Choline and Acetylcholine 总被引:2,自引:1,他引:1
P. E. Potter M. Hadjiconstantinou J. L. Meek N. H. Neff 《Journal of neurochemistry》1984,43(1):288-290
Abstract: An existing method for measuring acetylcholine (ACh) and choline (Ch) is shown to be useful formeasuring the turnover rate of ACh in mouse brain. Methl-[3H]Ch is injected into mice. They are killed atdifferent times by microwave irradiation and Ch and AChextracted and separated by reverse-phase HPLC. Ch andACh are converted to hydrogen peroxide by a post-column enzyme reaction. Hydrogen peroxide, which isdirectly related to the tissue content of Ch or ACh, isdetermined electrochemically. The fractions that corre-spond to the detector response for Ch and ACh are col-lected for the measurement of radioactivity. In this wayspecific radioactivities of endogenous Ch and ACh areestimated in the same sample. We used the specific ra-dioactivity values determined by this procedure to esti-mate the turnover of ACh for striatum, cerebral cortex, and hippocampus of the mouse. 相似文献