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961.
The purpose of this study was to examine whether monoamine oxidase type B (MAO-B) has a role in striatal dopamine metabolism in animals with a unilateral lesion of the medial forebrain bundle, and whether 2-phenylethylamine (PE) could have a role in amplification of dopamine (DA) responses in DA depleted striatum. Inhibition of MAO-B did not alter DA metabolism in lesioned striata. PE accumulation decreased with loss of DA as long as there was no DA dysfunction. In lesioned striata with dysfunction of DA transmission at the synaptic level, PE accumulation increased,suggesting a compensatory increase in PE synthesis. This increase in PE levels does not appear to be mediated by an increase in the total striatal aromaticl-amino acid decarboxylase (AADC) activity. We conclude that inhibition of MAO-B has no effect on DA metabolism in the hemi-parkinsonian rat striatum and that PE could be involved in the antiparkinsonian action of MAO-B inhibitors. 相似文献
962.
G. E. Khachatrian N. I. Mkrtchian T. V. Khachatrian A. L. Simonian 《World journal of microbiology & biotechnology》1994,10(6):711-712
Twelve strains of Pseudomonas fluorescens and P. putida were grown in a synthetic medium that contained l-lysine as the only source of carbon and nitrogen, and screened for l-lysine-2-monooxygenase production. Best production was by P. putida BKM B-1458 at 30 IU/g wet wt biomass when grown in a shake-flask but 25 IU/g in a 250-l fermenter. 相似文献
963.
Comparison of selective agents for use with the selectable marker gene bar in maize transformation 总被引:6,自引:0,他引:6
Briana K. Dennehey William L. Retersen Colleen Ford-Santino Mark Pajeau Charles L. Armstrong 《Plant Cell, Tissue and Organ Culture》1994,36(1):1-7
The effectiveness of four phosphinothricin (PPT)-based selective agents were evaluated for use in maize transformation: glufosinate, bialaphos, Basta® and Herbiace®. Glufosinate and its commercial formulation, Basta®, were less effective in controlling growth of non-transgenic corn callus than the tripeptide, bialaphos, or its commercial formulation, Herbiace®. Addition of 25 mM l-proline had no significant effect on selection when using bialaphos. However, when l-proline was included with the selective agent glufosinate, selection was inhibited and callus growth was enhanced. At four weeks, callus growth on 0.3, 1.0 and 3.0 mg l-1 glufosinate in the presence of proline was 76, 43, and 21% of control growth, respectively, and in the absence of proline was only 32, 9, and 6% of control growth. Optimized selection protocols for Basta® and bialaphos yielded comparable numbers of transformants. Using these protocols, fertile transgenic plants were regenerated from transformed callus cultures.Abbreviations AA
amino acid
- GS
glutamine synthetase
- PAT
phosphinothricin acetyl transferase
- PPT
2-amino-(methylphosphinyl)-butanoic acid (phosphinothricin)
- 2,4-d
2,4-dichlorophenoxyacetic acid 相似文献
964.
Frances Yee Hans Ericson Donald J. Reis Claes Wahlestedt 《Cellular and molecular neurobiology》1994,14(5):475-486
Summary 1. Antisense oligodeoxynucleotides (ODNs) internally labeled with biotin or digoxigenin were injected into the lateral ventricle of rats and the distribution of the labeled ODNs was examined at several timepoints following the intracerebroventricular (icv) injections. The stability of these injected antisense ODNs, which had no backbone modifications, was also studied by performing recovery experiments.2. The most intense labeling was observed near the injection site, in periventricular areas, and in perivascular regions. Many of the labeled cells appeared to be neurons, and both the cytoplasm and the nuclei were stained. The labeled cells were detected 15 min after icv injection, demonstrating that the antisense ODNs were taken up rapidly by cells in the parenchyma. The digoxigeninated antisense ODNs were presented in both the cytoplasmic and the nuclear fractions of rat brain extracts, however, the levels appeared to be much lower in the nuclear fractions.3. Antisense ODNs injected into the lateral ventricle seemed to follow the bulk flow of cerebrospinal fluid (CSF), i.e., from the injection site in the lateral ventricle, through the ventricular system, to the subarachnoid spaces and the perivascular spaces. From the ventricular and perivascular spaces, the antisense ODNs diffused into the extracellular space and were taken up by cells. The full-length digoxigeninated antisense ODNs were detectable within cells after only 15 min, indicating their rapid uptake. In addition, the antisense ODNs appeared to be relatively stable in the brain since the full-length digoxigeninated ODNs were still detectable after 4 hr. 相似文献
965.
Ricardo Titze-de-Almeida Cilene Lino de Oliveira Hilda W. Shida Francisco Silveira Guimarães Elaine Aparecida Del Bel 《Cellular and molecular neurobiology》1994,14(4):373-380
Summary 1. The effects of restraint stress on c-fos mRNA expression in the dentate gyrus were investigated byin situ hybridization.2. Confirming previous findings, c-fos mRNA expression increased after 30 min of forced restraint.3. This effect was attenuated by a previous i.c.v. injection of the anxiolytic benzodiazepine midazolam (20 nmol/2 µl) or theN-methyl-d-aspartate (NMDA) receptor antagonist 2-amino-7-phosphonoheptanoic acid (AP-7; 5 nmol/2 µl).4. These results suggest that the dentate gyrus is activated during restraint stress and that this activation may be modulated by benzodiazepine -aminobutyric acidA (GABAA) or NMDA receptors. 相似文献
966.
The hyperthermophilic archaeon Pyrococcus furiosus was found to form substantial amounts of l-alanine during batch growth on either cellobiose, maltose or pyruvate. Acetate, CO2 and H2 were produced next to alanine. The carbon- and electron balances were complete for all three substrates. Under standard growth conditions (N2/CO2 atmosphere) an alanine/acetate ratio of about 0.3 was found for either substrate. The alanine /acetate ratio was influenced, however, by the hydrogen partial pressure. In the presence of S0 or in coculture with Methanococcus jannaschii this ratio was only 0.07, whereas under a H2/CO2 atmosphere this ratio could amount up to 0.8. Alanine formation was also aflected by the NH
inf4
sup+
concentration, i.e. below 4 mM, NH
inf4
sup+
becomes limiting to alanine formation. Alanine formation was shown to occur via an alanine aminotransferase, which exhibited a specific activity in cell-free extract of up to 6.0 U/mg (90°C; direction of pyruvate formation). The alanine aminotransferase probably cooperates with glutamate dehydrogenase (up to 23 U/mg; 90°C) and ferredoxin: NADP+ oxidoreductase (up to 0.7 U/mg, using methyl viologen; 90°C) to recycle the electron acceptors involved in catabolism. Thus, the existence of this unusual alanine-forming branch enables P. furiosus to adjust its fermentation, depending on the redox potential of the terminal electron acceptor.Abbreviations DTT
dithiothreitol
- MV
methyl viologen
- AAT
alanine aminotransferase
- GDH
glutamate dehydrogenase
- MV: NADP+ OR
methyl viologen: NADP+ oxidoreductase 相似文献
967.
Kazuhiro Imai Ph. D. T. Fukushima T. Santa H. Homma Y. Huang M. Shirao K. Miura 《Amino acids》1998,15(4):351-361
Summary The distribution of radioactivities in rats following intravenous administration of14C-d- or -l-serine was investigated by whole body autoradiography. The radioactivities were distributed throughout the whole body in both cases with the greatest amount being found in the pancreas. D- andl- Serine levels in the pancreas were determined by high-performance liquid chromatography with a chiral column which revealed, for the first time, the existence ofd-serine in the rat pancreas (12.6 ± 7.90 nmol/g wet tissue) together with a much higher concentration (924 ± 116 nmol/g) ofl-serine. The results suggested that exogenous D-serine of dietary origin contributed at least in part to the D-serine levels found in mammalian tissues.The accumulation of radioactivity in the kidney, especially in the corticomedullary area, even at 24 hr after administration of14C-l-serine suggested a possible link between acute necrosis of the renal proximal tubules and the administration of a large dose of D-serine [Am J Pathol 77: 269–282 (1974)]. 相似文献
968.
Valérie S Fénelon Béatrice Casasnovas John Simmers Pierre Meyrand 《Current opinion in neurobiology》1998,8(6):705-709
In contrast to the wealth of knowledge about the organizational rules of adult central pattern generators, far less is known about how these networks are assembled during development. The basic architecture for adult central pattern generators appears early in development but different generators may follow completely different developmental pathways to reach maturity. Recent evidence suggests that neuromodulatory inputs, in addition to their short-term adaptive control of central pattern generator activity, play a crucial role in both the final developmental tuning and the long-term maintenance of adult network function. 相似文献
969.
James P Lund Arlette Kolta Karl-Gunnar Westberg George Scot 《Current opinion in neurobiology》1998,8(6):718-724
The essential elements controlling trigeminal motoneurons during feeding lie between the trigeminal and facial motor nuclei. These include populations of neurons in the medial reticular formation and pre-motoneurons in the lateral brainstem that reorganize to generate various patterns. Orofacial sensory feedback, antidromic firing in spindle afferents and intrinsic properties of motoneurons also contribute to the final masticatory motor output. 相似文献
970.
The expression of plateau potentials in spinal motor neurons is regulated by neuromodulatory substances. Recent experiments have shed new light on this regulation at the cellular level. It is now possible to evaluate the existence of plateau potentials in intact organisms, including humans, and to address the functional role of plateau potentials in motor control, as well as in information transfer in the brain. 相似文献