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41.
Carpospore differentiation in Faucheocolax attenuata Setch. can be separated into three developmental stages. Immediately after cleaving from the multinucleate gonimoblast cell, young carpospores are embedded within confluent mucilage produced by gonimoblast cells. These carpospores contain a large nucleus, few starch grains, concentric lamellae, as well as proplastids with a peripheral thylakoid and occasionally some internal (photosynthetic) thylakoids. Proplastids also contain concentric lamellar bodies. Mucilage with a reticulate fibrous substructure is formed within cytoplasmic concentric membranes, thus giving rise to mucilage sacs. Subsequently, these mucilage sacs release their contents, forming an initial reticulate deposition of carpospore wall material. Dictyosome vesicles with large, single dark-staining granules also contribute to wall formation and may create a separating layer between the mucilage and carpospore wall. During the latter stages of young carpospores, starch is polymerized in the perinuclear cytoplasmic area and is in close contact with endoplasmic reticulum. Intermediate-aged carpospores continue their starch polymerization. Dictyosomes deposit more wall material, in addition to forming fibrous vacuoles. Proplastids form thylakoids from concentric lamellar bodies. Mature carpospores are surrounded by a two-layered carpospore wall. Cytoplasmic constituents include large floridean starch granules, peripheral fibrous vacuoles, mature chloroplasts and curved dictyosomes that produce cored vesicles which in turn are transformed into adhesive vesicles. Pit connections remain intact between carpospores but begin to degenerate. This degeneration appears to be mediated by microtubules. 相似文献
42.
Adenosine A2A receptors are required for glutamate mGluR5‐ and dopamine D1 receptor‐evoked ERK1/2 phosphorylation in rat hippocampus: involvement of NMDA receptor
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Paraskevi Krania Eleni Dimou Maria Bantouna Stylianos Kouvaros Eirini Tsiamaki Costas Papatheodoropoulos Konstantinos Sarantis Fevronia Angelatou 《Journal of neurochemistry》2018,145(3):217-231
43.
Sharaf Al-Tardeh Thomas Sawidis Barbara -Evelin Diannelidis Stylianos Delivopoulos 《Journal of Plant Biology》2008,51(2):150-158
The morpho-anatomy and histochemistry of the hysteranthous leaf ofUrginea maritima (L.) Baker and its adaptive strategies to the Mediterranean climate were investigated. The leaf ofU. maritima is 714 μm thick and possesses moderate specific leaf mass (8.564 mg cm-2) and low tissue density (136.5 mg cm-3). The epidermal cells are compactly arranged and covered with cuticle. The average density of stomata in lower epidermis
is higher than that of the upper one. The mesophyll cells occupy 52.96% of the total volume of the leaf, while the mesophyll
intercellular spaces and the air spaces occupy 30.41%. Idioblastic cells containing raphide bundles and different phenotypes
of crystalloid inclusions, embedded in polysaccharides, occur in the lower side of the mesophyll. The presence of oil droplets
and lipids is evident. Bundle sheath cells are hardly visible with no chloroplasts which are a pronounced C3 plant character. Plastids containing protein crystalloid inclusions are abundant in the protophloem sieve elements.U. maritima, a deciduous plant, possesses leaves with mesophytic characters, in order to optimize its adaptation to the seasonal fluctuation
of environmental conditions of the Mediterranean climate. 相似文献
44.
Subjects with metabolic syndrome–a constellation of cardiovascular risk factors of which central obesity and insulin resistance
are the most characteristic–are at increased risk for developing diabetes mellitus and cardiovascular disease. In these subjects,
abdominal adipose tissue is a source of inflammatory cytokines such as tumor necrosis factor-alpha, known to promote insulin
resistance. The presence of inflammatory cytokines together with the well-documented increased risk for cardiovascular diseases
in patients with inflammatory arthritides and systemic lupus erythematosus has prompted studies to examine the prevalence
of the metabolic syndrome in an effort to identify subjects at risk in addition to that conferred by traditional cardiovascular
risk factors. These studies have documented a high prevalence of metabolic syndrome which correlates with disease activity
and markers of atherosclerosis. The correlation of inflammatory disease activity with metabolic syndrome provides additional
evidence for a link between inflammation and metabolic disturbances/vascular morbidity. 相似文献
45.
Apostolos Siapatis Marianna Giannoulaki Vasilis D. Valavanis Andreas Palialexis Eudoxia Schismenou Athanassios Machias Stylianos Somarakis 《Hydrobiologia》2008,612(1):281-295
The invasive ctenophore Mnemiopsis leidyi was accidentally introduced into the Black Sea in the early 1980s and it was first sighted in the Aegean Sea (Eastern Mediterranean)
in the early 1990s. This article presents a first attempt to develop a predictive spatial model based on M. leidyi presence data and satellite environmental data from the Aegean Sea during early summer, in order to identify those areas
in the Greek Seas and the entire Mediterranean basin that could serve as potential habitat for the species. Generalized additive models (GAM) were applied. The final GAM model indicated higher probability of finding M. leidyi present in depths of 65–135 m and sea surface temperature values of 21–25°C. Furthermore, the significant interaction between
photosynthetically active radiation (PAR) and sea level anomaly (SLA) indicated a higher probability of M. leidyi presence in low values of PAR and SLA. In the next step, the final GAM was applied in a prediction grid of mean monthly satellite
values for June 2004–2006 in order to estimate probability of M. leidyi presence in the Hellenic Seas and the whole Mediterranean basin at a GIS resolution of 4 km. In the Aegean Sea, species potential
habitat included areas influenced by the Black Sea Water (e.g. Thracian Sea, Limnos-Imvros plateau), gulfs that are affected
by river runoffs, such as the Thermaikos, Strymonikos and Patraikos gulfs, or areas with strong anthropogenic influence such
as the Saronikos gulf. Areas with the same environmental conditions as those in Aegean Sea have been indicated in certain
spots of the Levantine Sea as well as in coastal waters of Egypt and Libya, although their spatial extent varied largely among
years examined. However, the occurrence of conditions that are linked to high probability of M. leidyi presence does not necessarily mean that these areas can support successful reproduction, high population or bloom levels,
since these depend on a combination of temperature, salinity, food availability and the abundance of predators.
Guest editor: V. D. Valavanis
Essential Fish Habitat Mapping in the Mediterranean 相似文献
46.
Eudoxia Schismenou Marianna Giannoulaki Vasilis D. Valavanis Stylianos Somarakis 《Hydrobiologia》2008,612(1):201-214
Anchovy and round sardinella are two important small pelagic species in the Mediterranean that spawn during the summer period.
This is a first attempt to model and predict the two species’ potential spawning habitats in this area. Generalized additive
models (GAMs) were constructed based on satellite environmental variables and presence/absence egg data, available from ichthyoplankton
surveys conducted in the North Aegean Sea during early summer (June 2003–2006). These models were subsequently used to predict
the probability of anchovy and round sardinella spawning in the Greek Seas as well as the entire Mediterranean and Black Sea
during the same month of the year. The interaction of bottom depth and chlorophyll explained most of the deviance in the presence/absence
GAMs of both species, indicating spawning over continental shelf areas with increased surface chlorophyll values. Round sardinella
spawned closer to coast than anchovy. Predicted potential spawning areas for anchovy and round sardinella in unsampled areas
of the Greek Seas and the entire Mediterranean and Black Sea were in good agreement with existing information on the distribution
and extent of the spawning grounds, especially for anchovy. Modeling the species’ reproductive activity in relation to easily
accessible environmental information and applying the models in a predictive way could be an initial, low-cost step to designate
potential spawning fish habitats.
Guest editor: V. D. Valavanis
Essential Fish Habitat Mapping in the Mediterranean 相似文献
47.
Fatty acid composition in lipid fractions lengthwise the mycelium of Mortierella isabellina and lipid production by solid state fermentation 总被引:1,自引:0,他引:1
Stylianos Fakas Anna Makri Maria Mavromati Maria Tselepi George Aggelis 《Bioresource technology》2009,100(23):6118-6120
This paper investigates the correlation between mycelial age and fatty acid biosynthesis. The correlation was investigated by analyzing the lipid composition lengthwise the mycelium of the oleaginous fungus Mortierella isabellina, a potential producer of γ-linolenic acid (GLA). Young mycelia were rich in polar lipids (glycolipids plus sphingolipids and phospholipids), while neutral lipid content increased in aged mycelia. In young mycelia, each polar lipid fraction contained almost 40% (w/w) polyunsaturated fatty acids (PUFAs), but this content decreased to less than 30% (w/w) in aged mycelia. On the other hand, PUFA content in neutral lipids fluctuated slightly with age. These results indicate that PUFA biosynthesis is favored in young, fast growing mycelia, while it decreases significantly in aged mycelia. This trend was also observed when we grew M. isabellina on pear pomace, an agro-industrial waste. Pear pomace cultures yielded significant amounts of lipid, which reached 12% (w/w) in dry fermented mass. The produced lipid was rich in GLA and the maximum GLA content in dry fermented mass was 2.9 mg/g. 相似文献
48.
Charis Liapi Apostolos Zarros Stamatios Theocharis Hussam Al-Humadi Foteini Anifantaki Elena Gkrouzman Zois Mellios Nikolina Skandali Stylianos Tsakiris 《Biometals》2009,22(2):329-335
Lanthanum (La) is a rare earth element that is widely used for industrial, medical and agricultural purposes. Its neurotoxic
effects are linked to its physical and chemical properties and its interaction with certain trace elements and membrane-bound
enzymes. The aim of this study was to investigate the effects of short-term La-administration (as LaCl3, 53 mg/kg) on the adult rat whole brain total antioxidant status (TAS) and the activities of acetylcholinesterase (AChE),
Na+,K+-ATPase and Mg2+-ATPase, as well as the potential effect of the co-administration of the antioxidant l-cysteine (Cys, 7 mg/kg) on the above parameters. Twenty-eight male Wistar rats were divided into four groups: A (saline-treated
control), B (La), C (Cys),and D (La and Cys). All rats were treated once daily with intraperitoneal injections of the tested
compounds, for 1-week. Rats were sacrificed by decapitation and the above mentioned parameters were measured spectrophotometrically.
Rats treated with La exhibited a significant reduction in brain TAS (−36%, P < 0.001, BvsA), that was partially limited by the co-administration of Cys (−13%, P < 0.01, DvsA), while Cys (group C) had no effect on TAS. The rat brain AChE activity was found significantly increased by
both La (+23%, P < 0.001, BvsA) and Cys (+59%, P < 0.001, CvsA), while it was adjusted to control levels by the co-administration of La and Cys. The activity of rat brain
Na+,K+-ATPase was significantly decreased by La-administration (−28%, P < 0.001, BvsA), while Cys supplementation could not reverse this decrease. The activity of Mg2+-ATPase exhibited a slight but statistically significant reduction due to La (−8%, P < 0.01, BvsA), that was further reduced by Cys co-administration (−25%, P < 0.001, DvsA). The above findings suggest that La short-term in vivo administration causes a statistically significant decrease
in the rat brain TAS and an increase in AChE activity. Both effects can be, partially or totally, reversed into control levels
by Cys co-administration, which could thus be considered for future applications as a neuroprotective agent against chronic
exposure to La. The activities of Na+,K+- and Mg2+-ATPase that were inhibited by La, could not be reversed by Cys co-administration. A role for the already reported concentration-dependent
interaction of La with Ca-binding sites (such as Ca2+-ATPase) might be considered for certain of the above phenomena. 相似文献
49.
50.
Dimitris V. Politikos George Triantafyllou George Petihakis Kostas Tsiaras Stylianos Somarakis Shin-Ichi Ito Bernard A. Megrey 《Hydrobiologia》2011,670(1):141-163
A bioenergetics model is implemented for European anchovy (Engraulis encrasicolus) and applied to the north-eastern Aegean Sea (eastern Mediterranean Sea). The model reproduces the growth of anchovy in a
one-way linked configuration with a lower trophic level (LTL) ecosystem model. The LTL model provides densities for three
zooplankton functional groups (heterotrophic flagellates, microzooplankton and mesozooplankton) which serve as available energy
via consumption for the anchovy model. Our model follows the basic structure of NEMURO.FISH type models (North Pacific Ecosystem
Model for Understanding Regional Oceanography for Including Saury and Herring). Several model parameters were specific for
the Mediterranean or the Black Sea anchovy and some others were adopted from related species and NEMURO.FISH due to lack of
biological information on E. encrasicolus. Simulation results showed that the fastest growth rate occurs during spring and the slowest growth rate from August to December.
Zooplankton abundance during autumn was low implying that decreased prey density lead to a reduction in anchovy weight, especially
for the age-3 class. Feeding parameters were adjusted to adequately fit the model growth estimates to available weight-at-age
data. A detailed sensitivity analyses is conducted to evaluate the importance of the biological processes (consumption, respiration,
egestion, specific dynamic action, excretion and egg production) and their parameters to fish growth. The most sensitive parameters
were the intercept and exponent slope of the weight-dependent consumption and respiration process equations. Fish weight was
fairly sensitive to temperature-dependent parameters. 相似文献