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971.
Ana Carolina C. Asbahr Luzia Franco Andersson Barison Caroline W.P. Silva Humberto G. Ferraz Letícia N.C. Rodrigues 《Bioorganic & medicinal chemistry》2009,17(7):2718-2723
The aim of this study was to determine whether inclusion complexes between 2-hydroxypropyl-β-cyclodextrin (HPβCD) and finasteride (FIN) are formed, and to characterize these. Equimolar FIN/HPβCD solid systems in the presence or absence of 0.1% (w/v) of polyvinylpyrrolidone K30 (PVP K30) or 0.3% of chitosan were prepared by coevaporation and freeze-drying methods. The systems were characterized by phase solubility, NMR, DSC, and XRD analysis. The results suggest that true binary and ternary inclusion complexes were formed. 相似文献
972.
Sebastián Rodríguez Adriana Alvizu Alejandro Tagliafico Carolina Bastidas 《Hydrobiologia》2009,624(1):1-11
The study of coral repopulation in marginal communities may provide a useful analog for understanding the dynamics of coral
reefs subjected to deleterious environmental changes. Repopulation of scleractinian reef corals may strongly impact the community
structure on tropical reefs; however, the extent of this process on coral communities influenced by upwelling is unknown,
especially in the Caribbean. In this study, the potential for natural repopulation of coral communities subjected to wind-driven
upwelling was evaluated at three sites on the island of Cubagua, Venezuela. Coral spawning behavior was recorded and both
larval settlement and juvenile abundance were estimated. Upwelling did not appear to affect coral spawning behavior, since
at this locality spawning occurred at dates and times similar to those reported for well-developed reefs in the Caribbean.
Also, juveniles produced by brooding corals were six times more abundant than those of broadcasting species, similar to patterns
on other Caribbean reefs that are not under the influence of upwelling. By contrast, mean larval settlement (4 settlers m−2) and juvenile abundance (0.1 juveniles m−2) in Cubagua were both lower than those elsewhere in the Caribbean and on Pacific reefs. Thus, the potential for repopulation
of these marginal communities seems lower than for well-developed coral reefs in other regions. These results suggest that
more fully developed coral reefs also may have reduced repopulation potential, as they become influenced by suboptimal environmental
conditions.
Handling editor: I. Nagelkerken 相似文献
973.
Fermín Echarri Claudia Tambussi Carolina Acosta Hospitaleche 《Journal of Ornithology》2009,150(1):75-84
A bioclimatic analysis of the crested tinamous was conducted to explore climatic factors underpinning the distribution of
both Eudromia elegans and E. formosa and to evaluate its potential application in paleontological studies. The study utilized records throughout the entire known
range of Eudromia spp. in southern South America. Relationships between 20 environmental parameters and the presence of Eudromia species were established, mapping and characterizing their spatial distribution in a geographic information system using
BIOCLIM and MAXENT algorithms. The MAXENT prediction map shows a more homogeneous pattern while BIOCLIM showed a patchier
pattern. The models applied here generated maps that adjust to the well-known previous distributions of both species. Nevertheless,
for Eudromia elegans, the distribution predicted by MAXENT includes areas where it is actually considered absent, and the BIOCLIM prediction does
not include some areas where it is presumed present. Eudromia formosa were found in warmer and wetter sites than E. elegans. Low precipitation areas were identified as suitable for Eudromia elegans. Strong differences between the climatic profiles for both Eudromia spp distributions occurred, with the precipitation the most important influence. E. formosa tolerates the highest maximum temperatures, whereas E. elegans supports the lowest temperatures. 相似文献
974.
Paola Searovic Marcelo Alonso Carolina Oses Karla Pereira‐Flores Victoria Velarde Claudia G. Saez 《Journal of cellular biochemistry》2009,106(3):473-481
Chemopreventive approaches for the treatment of breast cancer have been validated clinically and with in vitro studies. The combined action of tamoxifen/all‐trans retinoic acid was advantageous in MCF‐7 cells, reducing cell proliferation, Bcl‐2 and c‐Myc protein levels and increasing E‐Cadherin protein levels and Gap junctional Intercellular Communication. We further investigated their combined effect in the presence of bradykinin, a pro‐inflammatory agent, previously reported to contribute to the proliferation of breast cancer cells. Bradykinin increased MCF‐7 cell proliferation, c‐Myc levels and ERK1/2 activity. The co‐incubation of bradykinin‐MCF‐7 cells with tamoxifen/all‐trans retinoic acid reduced cell proliferation, ERK1/2 activity, as well as Bcl‐2, c‐Myc, and bradykinin receptor‐2 levels, without altering the enhanced E‐cadherin levels induced by tamoxifen/all‐trans retinoic acid. We showed that the anti‐tumoral effect of tamoxifen/all‐trans retinoic acid is beneficial in MCF‐7 breast cancer cells grown in a bradykinin‐pro‐mitogenic environment, an effect that might be, at least in part, through the MAPK pathway and B2‐bradykinin receptor inhibition. J. Cell. Biochem. 106: 473–481, 2009. © 2008 Wiley‐Liss, Inc. 相似文献
975.
Marcus Franz Karin Spiegel Claudia Umbreit Petra Richter Carolina Codina-Canet Angela Berndt Annelore Altendorf-Hofmann Sven Koscielny Peter Hyckel Hartwig Kosmehl Ismo Virtanen Alexander Berndt 《Histochemistry and cell biology》2009,131(5):651-660
Snail is a regulator of epithelial–mesenchymal transition (EMT) and considered crucial to carcinoma metastasis, myofibroblast
transdifferentiation, and fibroblast activation. To investigate the role of Snail in oral squamous cell carcinoma (OSCC),
its immunohistochemical expression was analysed in 129 OSCC samples and correlated to nodal metastasis, histological grade,
E-cadherin, and alpha smooth-muscle-actin (αSMA). The results were compared to findings in 23 basal cell carcinomas (BCC).
Additionally, the influence of TGFβ1 and EGF on Snail, E-cadherin, vimentin, and αSMA expression was analysed in two OSCC
cell lines. As a result, Snail-positive cells were mainly found in the stroma of the OSCC invasive front without statistically
significant correlation to histological grade or nodal metastasis. Snail was co-localised to αSMA but not to E-cadherin or
cytokeratin and showed a significant correlation to the loss of membranous E-cadherin. All BCCs were Snail negative. In OSCC
culture, the growth-factor-mediated EMT-like phenomenon was accompanied by αSMA down-regulation. In summary, Snail expression
in OSCC is a stromal phenomenon associated with the myofibroblast phenotype and not related to growth-factor-mediated transdifferentiation
of the carcinoma cells themselves. Consequently, Snail immunohistochemistry cannot contribute to the prediction of the metastatic
potential. Furthermore, stromal Snail expression is suggested to be the result of mutual paracrine interaction of fibro-/myofibroblasts
and dedifferentiated carcinoma cells leading to the generation of a special type of carcinoma-associated fibroblasts.
M. Franz and K. Spiegel have contributed equally to the study. 相似文献
976.
Mondillo C Pagotto RM Piotrkowski B Reche CG Patrignani ZJ Cymeryng CB Pignataro OP 《Biology of reproduction》2009,80(1):144-152
This study was conducted to shed light on the so far unexplored intracellular mechanisms underlying negative modulation of Leydig cell steroidogenesis by histamine (HA). Using the MA-10 cell line and highly purified rat Leydig cells as experimental models, we examined the effect of the amine on biochemical steps known to be modulated by HA or involved in LH/hCG action. In agreement with previous findings, HA at 10 microM showed a potent inhibitory effect on hCG-stimulated steroid synthesis, regardless of the gonadotropin concentration used. Moreover, HA decreased not only LH/hCG-induced cAMP production but also steroid synthesis stimulated by the permeable cAMP analog dibutyryl cAMP (db-cAMP). Considering the post-cAMP sites of HA action, it is shown herein that HA markedly inhibited db-cAMP-stimulated steroidogenic acute regulatory (STAR) protein expression, as well as steps catalyzed by P450-dependent enzymes, mainly the conversion of cholesterol to pregnenolone by cholesterol side-chain cleavage enzyme (CYP11A). The antisteroidogenic action of HA was blocked by addition of the phospholipase C (PLC) inhibitor U73122, and HA significantly augmented inositol triphosphate (IP3) production, suggesting a major role for the PLC/IP3 pathway in HA-induced inhibition of Leydig cell function. Finally, HA increased nitric oxide synthase (NOS) activity, and the NOS inhibitor NG-nitro-L-arginine methyl ester (L-NAME) markedly attenuated the effect of the amine on steroid synthesis. On the basis of our findings, HA antagonizes the gonadotropin action in Leydig cells at steps before and after cAMP formation. NOS activation is the main intracellular mechanism by which HA exerts its antisteroidogenic effects. 相似文献
977.
978.
979.
Irmgard Paris Carolina Perez-Pastene Eduardo Couve Pablo Caviedes Susan LeDoux Juan Segura-Aguilar 《The Journal of biological chemistry》2009,284(20):13306-13315
Parkinsonism is one of the major neurological symptoms in Wilson disease,
and young workers who worked in the copper smelting industry also developed
Parkinsonism. We have reported the specific neurotoxic action of
copper·dopamine complex in neurons with dopamine uptake.
Copper·dopamine complex (100 μm) induces cell death in
RCSN-3 cells by disrupting the cellular redox state, as demonstrated by a
1.9-fold increase in oxidized glutathione levels and a 56% cell death
inhibition in the presence of 500 μm ascorbic acid; disruption
of mitochondrial membrane potential with a spherical shape and well preserved
morphology determined by transmission electron microscopy; inhibition (72%,
p < 0.001) of phosphatidylserine externalization with 5
μm cyclosporine A; lack of caspase-3 activation; formation of
autophagic vacuoles containing mitochondria after 2 h; transfection of cells
with green fluorescent protein-light chain 3 plasmid showing that 68% of cells
presented autophagosome vacuoles; colocalization of positive staining for
green fluorescent protein-light chain 3 and Rhod-2AM, a selective indicator of
mitochondrial calcium; and DNA laddering after 12-h incubation. These results
suggest that the copper·dopamine complex induces mitochondrial
autophagy followed by caspase-3-independent apoptotic cell death. However, a
different cell death mechanism was observed when 100 μm
copper·dopamine complex was incubated in the presence of 100
μm dicoumarol, an inhibitor of NAD(P)H quinone:oxidoreductase
(EC 1.6.99.2, also known as DT-diaphorase and NQ01), because a more extensive
and rapid cell death was observed. In addition, cyclosporine A had no effect
on phosphatidylserine externalization, significant portions of compact
chromatin were observed within a vacuolated nuclear membrane, DNA laddering
was less pronounced, the mitochondria morphology was more affected, and the
number of cells with autophagic vacuoles was a near 4-fold less.A possible role of copper in the neurodegeneration of dopaminergic neurons
is supported by the fact that patients with neurological Wilson disease, a
copper deposition disorder, display a number of extrapyramidal motor symptoms,
including Parkinsonism. The cerebral manifestations in neurological Wilson
disease are expressed as bradykinesia, rigidity, tremor, dyskinesia, and
dysarthria (1). It has been
proposed that neurological Wilson disease can be assigned to the group of
secondary Parkinsonian syndromes
(2). Interestingly, young
workers who worked in the copper smelting industry also developed Parkinsonism
(3).Studies performed in rats showed copper (Cu2+)-induced
degeneration of dopaminergic neurons in the nigrostriatal system. Likewise, it
was described that copper neurotoxicity in rat substantia nigra and striatum
is dependent on NAD(P)H dehydrogenase inhibition
(4,
5). All of these results
support a possible role for copper in the neurodegeneration of dopaminergic
neurons.The general mechanism of toxicity, induced by the reduced form of copper
(Cu+) catalyzing the formation of hydroxyl radicals in the presence
of hydrogen peroxide through the Fenton reaction, cannot explain the specific
degeneration of dopaminergic neurons in Parkinsonism induced in neurological
Wilson disease, or in miners working in the copper smelting industry. The
selective action of copper can be explained by the ability of copper to form a
complex with dopamine, allowing this metal to be transported by cells that
have the ability to take up dopamine
(6). This specific neurotoxic
action of copper in neurons with dopamine uptake is dependent on (i) the
ability of copper to form a complex with dopamine
(Cu·DA)2
(6,
7), (ii) uptake of Cu·DA
complex by dopamine transporters, (iii) oxidation of dopamine to aminochrome,
and (iv) one-electron reduction of aminochrome by inhibiting NAD(P)H
dehydrogenase (6). These
findings may explain the selective neurotoxic action of copper in the brain,
but they do not explain the cell death mechanism.Currently, cell death is divided into three categories: apoptosis,
autophagy, and necrosis. At the current time, only apoptosis and autophagic
cell death are generally accepted as being legitimate forms of programmed cell
death. Alternative models of cell death have therefore been proposed,
including para-apoptosis, mitotic catastrophe, oncosis, and pyroptosis
(8–12).
Necrosis is characterized mostly by the absence of caspase activation,
cytochrome c release, and DNA oligonucleosomal fragmentation.
Apoptotic cells are characterized by the formation of blebs, chromatin
condensation, DNA oligonucleosomal fragmentation, and exposure of
phosphatidylserine on the external membrane. This mode of cell death can be
dependent or independent of activation of caspases
(13). On the other hand,
autophagy can be distinguished from apoptosis by sequestration of bulk
cytoplasm and organelles in double or multimembrane autophagic vacuoles that
then fuse with the lysosomal system. Some of these described mechanisms are
related to neurological diseases such as Parkinson disease
(14,
15). Cells can use different
methods to activate their own destruction, and more than one death program may
be activated at the same time
(16,
17).The purpose of this study was to examine the Cu·DA complex-induced
cell death mechanism in RCSN-3 cells, a cell line that expresses dopamine,
norepinephrine, and serotonin transporters
(18,
19). 相似文献
980.
The phylogeography of Hymenaea courbaril var. stilbocarpa from Atlantic Forest and riverine forests of the Cerrado biome in central and southeastern Brazil was investigated. The data were compared with those of its congeneric Hymenaea stigonocarpa, a typical tree from savanna. In the Cerrado, H. courbaril var. stilbocarpa is found in sites contiguous with those of H. stigonocarpa, and they share common life-history attributes. The psbC/trnS3 region of the chloroplast DNA was sequenced in 149 individuals of H. courbaril var. stilbocarpa. High genetic variation was found in this species, with the identification of 18 haplotypes, similarly to what was found in H. stigonocarpa with 23 haplotypes in the same geographic region. Populations of H. courbaril var. stilbocarpa could be structured in 3 phylogeographic groups. Spatial analysis of molecular variation indicated that 46.4% of the genetic variation was due to differences among these groups. Three haplotypes were shared by H. courbaril var. stilbocarpa and H. stigonocarpa, and only 10.5% of the total genetic variation could be attributed to between-species difference. We surmise that during the glacial times, H. courbaril var. stilbocarpa populations must have gone extinct in most parts of the southern of its present-day occurrence area. After climate amelioration, these areas were probably recolonized from northern and eastern. The relatively similar phylogeographic structure of vicariant Hymenaea species suggests that they were subjected to the same impacts during the Quaternary climatic fluctuations. The sharing of haplotypes and the genetic similarity between the 2 Hymenaea species suggest the existence of ancestral polymorphism and/or hybridization. 相似文献