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71.
Rainesalo S Keränen T Palmio J Peltola J Oja SS Saransaari P 《Neurochemical research》2004,29(1):319-324
Altered plasma and cerebrospinal fluid amino acid levels may be associated with human epilepsy. We studied three groups of patients, those with a generalized epileptic syndrome, juvenile myoclonic epilepsy, patients with refractory localization-related epilepsies, and patients with acute seizures (within 24 h). Plasma levels of amino acids were studied in all patient groups, as were those in the cerebrospinal fluid (CSF) of patients with acute seizures. After acute seizures, the amino acid changes in the CSF were limited to a reduction in the level of taurine, whereas the levels of most amino acids in plasma were decreased. On the other hand, levels of the excitatory amino acids glutamate and aspartate were increased. The most notable finding in the juvenile myoclonic epilepsy patients was an increase in glutamate level in the plasma. Our study supports the conception of an altered metabolism of glutamate in generalized epilepsies. 相似文献
72.
The novel neurotransmitter/neuromodulator nitric oxide (NO), which is linked to the activation of the N-methyl-D-aspartate class of glutamate receptors, has been shown to modify transmitter release in brain tissue. Release of the inhibitory amino acid taurine is also markedly enhanced by N-methyl-D-aspartate and NO-producing agents under normal conditions in the mouse hippocampus. The release of preloaded [3H]taurine from hippocampal slices from adult (3-month-old) and developing (7-day-old) mice was characterized under ischemic conditions in the presence of different NO-generating compounds, hydroxylamine, sodium nitroprusside, and S-nitroso-N-acetylpenicillamine (SNAP), using a superfusion system. The ischemia-induced taurine release at both ages was markedly enhanced by 1.0 mM nitroprusside and 1.0 mM SNAP, whereas 5.0 mM hydroxylamine was effective only in adults. The nitroprusside- and SNAP-induced releases were reduced by the inhibitors of NO synthase (nitroarginine and 7-nitroindazole) and NO-sensitive soluble guanylyl cyclase [1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one], suggesting involvement of the NO/cGMP pathway. The release in ischemia in the absence of Na+ was modified by NO compounds only in adults; the 0.1 mM N-methyl-D-aspartate stimulated taurine release at both ages. The enhanced release of taurine associated with NO production could be beneficial to brain tissue under cell-damaging conditions and corroborates the neuroprotective role of this amino acid, particularly in the immature brain. 相似文献
73.
Pirjo Kainulainen† Anne Nissinen† Anne Piirainen‡ Kari Tiilikkala† Jarmo K. Holopainen† 《Agricultural and Forest Entomology》2002,4(3):211-216
- 1 The carrot psyllid Trioza apicalis and Lygus rugulipennis can cause serious damage to cultivated carrots, especially at the seedling stage. The essential oil composition in leaves of several carrot varieties was studied in relation to oviposition acceptance by sucking insect herbivores that have different feeding strategies. Of the insect species studied, T. apicalis is a carrot specialist, T. anthrisci is an Apiaceae specialist, and L. rugulipennis is a generalist.
- 2 The oil composition differed significantly between leaves from different carrot varieties (Flakkeer 2, Nantura, Parano, Napoli, Panther, Splendid, Nantes 3 Express).
- 3 There were no differences in the mean numbers of eggs laid by T. apicalis or T. anthrisci on different varieties, but L. rugulipennis laid fewer eggs on the Panther variety than on Nantes 3 Express.
- 4 There was a negative linear correlation between limonene concentration and number of eggs laid by T. apicalis, confirming that limonene is a repellent to the carrot psyllid. Results suggest that only particular compounds influence the preference of the carrot psyllid, and these compounds may not be the main components in the essential oil of carrots.
- 5 A positive correlation was found between myrcene concentration and number of eggs laid by T. anthrisci. Essential oil composition did not explain egg‐laying preference of L. rugulipennis.
- 6 The results indicate that essential oil composition of carrot varieties affects host preference of Apiaceae specialists more than that of generalists.
74.
V. Varga R. Janáky K-M Marnela Pirjo Saransaari S. S. Oja 《Neurochemical research》1994,19(3):243-248
The in vitro effects of -L-glutamyltaurine on different stages of excitatory aminoacidergic neurotransmission were tested with -D-glutamyltaurine as reference. -L-Glutamyltaurine enhanced the K+-stimulated release of [3H]glutamate from cerebral cortical slices (25% at 0.1 mM) and slightly inhibited the uptake by crude brain synaptosomal preparations (about 10% at 1 mM). -L-Glutamyltaurine was also a weak displacer of glutamate and its agonists from their binding sites in brain synaptic membrane preparations, being, however, less selective to quisqualate (QA) sites than -D-glutamyltaurine. The basal influx of Ca2+ into cultured cerebellar granular cells was not affected by 1 mM -L-glutamyltaurine, but the glutamate- and its agonist-activated influx was significantly inhibited in low-Mg2+ (0.1 mM) and Mg2+-free media. The glutamate-evoked increase in free intracellular Ca2+ and the kainate-activated formation of cGMP in cerebellar slices were both markedly inhibited by 0.1 mM -L-giutamyltaurine. We propose that -L-glutamyltaurine may act as endogenous modulator in excitatory aminoacidergic neurotransmission. 相似文献
75.
The horizontal distribution of bacteria (BACT), bacterial production(FDC), picoplanktonic cyanobacteria (CYANO), and photosynthetic(PNF) as well as heterotrophic (HNF) nanoflagellates was studiedat the end of June on the SW coast of Finland, the Baltic Sea.Samples were taken at 0 and 10 m depths from three transects500 and 800 m apart. The distance between sampling points was20 m. Cell counts of BACT, CYANO, PNF, HNF and the FDC showed3- to 5-fold deviations in the whole data set. Differences betweenthe duplicate counts within the subsamples were 1020%.Within the transects, the maximum values were 1.23.0times higher than the minimum values. Differences between thetransects were statistically significant for all variables exceptFDC. Deviations in cell numbers between the surface and 10 mwere quite irregular. but often statistically significant. Inmost cases, the organism groups did not correlate significantlywith each other. The horizontal distribution of pelagic microbeswas sufficiently uniform, on a meter scale. for one samplingpoint to give a reliable estimate of microbial densities inthe area under investigation. The differences between the surfaceand the lower stratum of the mixed layer (10 m) were in mostcases statistically significant. 相似文献
76.
Lipid metabolism of the subarctic moss Dicranum elongatum was studied by feeding the moss with 2-14C-acetate and, after extraction of the lipids, counting the 14C-content of different lipid fractions immediately after feeding or after chase periods. Translocation of 14C after 14C-feeding was studied with autoradiography. Both low temperature (+6°C) and drought (at +23°C) resulted in increased incorporation of 14C into the neutral lipid (NL) fraction and decreased incorporation of 14C into the glycolipid (GL) fraction of the green shoot part of the moss. The distribution of radioactivity between the NL classes suggests that diacylglycerols (1, 2-DAG) and common triacylglycerols (cTAG) are turned into acetylenic triacylglycerols (aTAG), which are accumulated preferentially. The decrease in the radioactivity of the GL fraction was due to two unknown fractions, whereas 14C incorporation into the chloroplast membrane lipids, monogalactosyl diacylglycerol (MGDG) and digalactosyl diacylglycerol (DGDG), was very low throughout the experiments. The phospho-lipid (PL) fraction accounted for 48–63% of total lipid radioactivity at both low and high temperatures. 2-14C-acetate feeding to the senescent moss part resulted in vigorous 14C incorporation into the lipids, especially into the reserve TAGs. Electron microscopic examination showed the presence of plastids, which explains the capability of the senescent part of the moss for lipid synthesis. The fact that transport of 14C from 2-14C-acetate took place upwards and downwards in the moss shoot, together with the capability for lipid synthesis of the senescent moss part, supports the suggestion that the senescent moss part plays a role as an energy store. 相似文献
77.
Marjut?Kreivi Pirjo?Rautiainen Jouni?AspiEmail author Marko?Hyv?rinen 《Conservation Genetics》2005,6(5):683-696
Arctophila fulva var. pendulina is a rare endemic perennial grass confined to seashore and riverbank meadows around the Bothnian Bay, the northernmost part
of the Baltic Sea. The number of A. fulva populations has decreased during the last few decades in Finland and Sweden, and nowadays there are only eight populations
left in the drainage area of the Bothnian Bay. We investigated the distribution of genetic variation within and between six
subpopulations in the largest remaining population at Liminka Bay, Finland, using amplified fragment length polymorphism (AFLP)
markers. Relatively high amounts of variation were found in the subpopulations, the mean Nei’s expected heterozygosity being
typical (0.267) for an outcrossing species. Despite the fact that no seedlings or viable seeds of A. fulva have been found in the previous field studies, the observed high genotypic diversity suggested that sexual reproduction has
played an important role at some time during the history of the studied A. fulva population. Analysis of population structure revealed a low level of genotypic differentiation (ΦST=0.046) between subpopulations, and also significant sub-structuring within subpopulations. Isolation-by-distance between
subpopulations was present on scales larger than 1 km. The overall pattern of genetic variation within and between subpopulations
suggest that the population has characters of both stepping-stone and metapopulation models. Because our results suggested
that subpopulations are more or less ephemeral, the conservation and management effort in this species should be targeted
to conservation of the required habitat of the species instead of extant subpopulations. 相似文献
78.
Tahvanainen K Niño J Halonen P Kuusela T Laitinen T Länsimies E Hartikainen J Hietanen M Lindholm H 《Bioelectromagnetics》2004,25(2):73-83
A recent study raised concern about increase of resting blood pressure after a 35 min exposure to the radiofrequency (RF) field emitted by a 900 MHz cellular phone. In this randomized, double blind, placebo controlled crossover trial, 32 healthy subjects were submitted to 900 MHz (2 W), 1800 MHz (1 W) cellular phone exposure, and to sham exposure in separate sessions. Arterial blood pressure (arm cuff method) and heart rate were measured during and after the 35 min RF and sham exposure sessions. We evaluated cardiovascular responses in terms of blood pressure and heart rate during controlled breathing, spontaneous breathing, head-up tilt table test, Valsalva manoeuvre and deep breathing test. Arterial blood pressure and heart rate did not change significantly during or after the 35 min RF exposures at 900 MHz or 1800 MHz, compared to sham exposure. The results of this study indicate that exposure to a cellular phone, using 900 MHz or 1800 MHz with maximal allowed antenna powers, does not acutely change arterial blood pressure and heart rate. 相似文献
79.
Robust parameters confirm predominance of heterotrophic processes in the plankton of a highly humic pond 总被引:1,自引:0,他引:1
Kalevi?SalonenEmail author Taina?Hammar Pirjo?Kuuppo Ulla?Smolander Anne?Ojala 《Hydrobiologia》2005,543(1):181-189
The conclusions about the role of allochthonous organic matter in the food chains of inland waters are still often conflicting. Here we studied whether the results of specific experiments made in a small pond with very high concentration of allochthonous organic matter could be verified by simple, but robust, basic environmental parameters measured in the field. In summer primary production of phytoplankton could explain only ca. 20% of epilimnetic respiration and <10% of the nutritional requirements of zooplankton. These results agree with those of earlier experimental approaches and unequivocally suggest the major role played by allochthonous nutrition for the plankton in this pond. The roles played by photochemical degradation and anaerobic processes in the transformation of humic compounds available to epilimnetic food web in particular deserve further elucidation. 相似文献
80.
Eremin KO Kudrin VS Saransaari P Oja SS Grivennikov IA Myasoedov NF Rayevsky KS 《Neurochemical research》2005,30(12):1493-1500
Corticotrophin (ACTH) and its analogues, particularly Semax (Met-Glu-His-Phe-Pro-Gly-Pro), demonstrate nootropic activity.
Close functional and anatomical links have been established between melanocortinergic and monoaminergic brain systems. The
aim of present work was to investigate the effects of Semax on neurochemical parameters of dopaminergic- and serotonergic
systems in rodents. The tissue content of 5-hydroxyindoleacetic acid (5-HIAA) in the striatum was significantly increased
(+25%) 2 h after Semax administration. The extracellular striatal level of 5-HIAA gradually increased up to 180% within 1–4 h
after Semax (0.15 mg/kg, ip) administration. This peptide alone failed to alter the tissue and extracellular concentrations
of dopamine and its metabolites. Semax injected 20 min prior d-amphetamine dramatically enhanced the effects of the latter on the extracellular level of dopamine and on the locomotor activity
of animals. Our results reveal the positive modulatory effect of Semax on the striatal serotonergic system and the ability
of Semax to enhance both the striatal release of dopamine and locomotor behavior elicited by d-amphetamine.
Special issue dedicated to Dr. Simo S. Oja. 相似文献