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991.
Chiaradia LD Mascarello A Purificação M Vernal J Cordeiro MN Zenteno ME Villarino A Nunes RJ Yunes RA Terenzi H 《Bioorganic & medicinal chemistry letters》2008,18(23):6227-6230
In the search for lead compounds for new drugs for tuberculosis, the activity of 38 synthetic chalcones were assayed for their potential inhibitory action towards a protein tyrosine phosphatase from Mycobacterium tuberculosis--PtpA. The compounds were obtained by aldolic condensation between aldehydes and acetophenones, under basic conditions. Five compounds presented moderate or good activity. The structure-activity analysis reveals that the predominant factor for the activity is the molecule planarity/hydrophobicity and the nature of the substituents. 相似文献
992.
Jenkins PR Wilson J Emmerson D Garcia MD Smith MR Gray SJ Britton RG Mahale S Chaudhuri B 《Bioorganic & medicinal chemistry》2008,16(16):7728-7739
We present the design, synthesis and biological activity of a library of substituted (biphenylcarbonyl)-tryptamine and (biphenylcarbonyl)-tetrahydro-beta-carboline compounds related to the natural product fascaplysin, as novel inhibitors of CDK4/cyclin D1. We show all these molecules, prepared using the Suzuki-Miyaura reaction, being selective inhibitors of CDK4 over CDK2. The most active compounds have a CDK4 IC(50) in the range 9-11 microM, three of them containing the para-biphenyl plus para-substituents supporting the existence of a pi-stacking pocket within the active site of CDK4. 相似文献
993.
Caceres RA Saraiva Timmers LF Dias R Basso LA Santos DS de Azevedo WF 《Bioorganic & medicinal chemistry》2008,16(9):4984-4993
This work describes for the first time a structural model of purine nucleoside phosphorylase from Streptococcus agalactiae (SaPNP). PNP catalyzes the cleavage of N-ribosidic bonds of the purine ribonucleosides and 2-deoxyribonucleosides in the presence of inorganic orthophosphate as a second substrate. This enzyme is a potential target for the development of antibacterial drugs. We modeled the complexes of SaPNP with 15 different ligands in order to determine the structural basis for the specificity of these ligands against SaPNP. The application of a novel empirical scoring function to estimate the affinity of a ligand for a protein was able to identify the ligands with high affinity for PNPs. The analysis of molecular dynamics trajectory for SaPNP indicates that the functionally important motifs have a very stable structure. This new structural model together with a novel empirical scoring function opens the possibility to explorer larger library of compounds in order to identify the new inhibitors for PNPs in virtual screening projects. 相似文献
994.
995.
Arabidopsis NAD-malic enzyme functions as a homodimer and heterodimer and has a major impact on nocturnal metabolism 总被引:1,自引:1,他引:0
Tronconi MA Fahnenstich H Gerrard Weehler MC Andreo CS Flügge UI Drincovich MF Maurino VG 《Plant physiology》2008,146(4):1540-1552
Although the nonphotosynthetic NAD-malic enzyme (NAD-ME) was assumed to play a central role in the metabolite flux through the tricarboxylic acid cycle, the knowledge on this enzyme is still limited. Here, we report on the identification and characterization of two genes encoding mitochondrial NAD-MEs from Arabidopsis (Arabidopsis thaliana), AtNAD-ME1 and AtNAD-ME2. The encoded proteins can be grouped into the two clades found in the plant NAD-ME phylogenetic tree. AtNAD-ME1 belongs to the clade that includes known alpha-subunits with molecular masses of approximately 65 kD, while AtNAD-ME2 clusters with the known beta-subunits with molecular masses of approximately 58 kD. The separated recombinant proteins showed NAD-ME activity, presented comparable kinetic properties, and are dimers in their active conformation. Native electrophoresis coupled to denaturing electrophoresis revealed that in vivo AtNAD-ME forms a dimer of nonidentical subunits in Arabidopsis. Further support for this conclusion was obtained by reconstitution of the active heterodimer in vitro. The characterization of loss-of-function mutants for both AtNAD-MEs indicated that both proteins also exhibit enzymatic activity in vivo. Neither the single nor the double mutants showed a growth or developmental phenotype, suggesting that NAD-ME activity is not essential for normal autotrophic development. Nevertheless, metabolic profiling of plants completely lacking NAD-ME activity revealed differential patterns of modifications in light and dark periods and indicates a major role for NAD-MEs during nocturnal metabolism. 相似文献
996.
Pathogen derived elicitors: searching for receptors in plants 总被引:10,自引:0,他引:10
997.
Aline C. Intorne Marcos Vinicius V. de Oliveira Mariana L. Lima Juliana F. da Silva Fábio L. Olivares Gonçalo Apolinário de Souza Filho 《Archives of microbiology》2009,191(5):477-483
Gluconacetobacter diazotrophicus is a plant-growth-promoting bacterium, which is able to colonize sugarcane and other plant species of economic importance.
The potentially beneficial effects promoted by this bacterium on plants are nitrogen-fixation, production of phythormones,
action against pathogens and mineral nutrient solubilization. In this study, the molecular mechanisms associated with phosphorus
and zinc solubilization were analyzed. A transposon mutant library was constructed and screened to select for mutants defective
for phosphorous [Ca5(PO4)3OH] and zinc (ZnO) solubilization. A total of five mutants were identified in each screen. Both screenings, performed independently,
allowed to select the same mutants. The interrupted gene in each mutant was identified by sequencing and the results demonstrate
that the production of gluconic acid is a required pathway for solubilization of such nutrients in G. diazotrophicus.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
A. C. Intorne and M. V. V. de Oliveira contributed equally to this work. 相似文献
998.
Mercedes Gonzlez-Wangüemert Fernando Cnovas Concepcin Marcos ngel Prez-Ruzafa 《Biochemical Systematics and Ecology》2009,37(4):325-333
Extreme conditions of coastal lagoons could directly modify the genetic patterns of species. The aim of this work was to investigate the influence of environmental conditions and small scale dispersal patterns on the phosphoglucose isomerase (PGI*) genetic variability of Cerastoderma glaucum from the Mar Menor coastal lagoon. For this purpose, 284 cockles were collected around the perimeter of the lagoon. Vertical polyacrylamide gel electrophoresis was used to scan for PGI* polymorphisms, giving a total of seven alleles. The spatial genetic distribution of the PGI* variability, which seems to be marked by the main circulation in the lagoon, discriminates four hydrological basins. In the central basin, a gradient of allelic composition reflects the circulation forced by the dominant winds and the main channel communicated to the open sea. This result is well supported by the salinity GAM model that defines this gradient.The other three basins are defined by the distribution of fine sand in a more complex model that tries to explain the isolation of the three sites localized inside these basins. The southern, western and northern basins show the lowest degree of interconnection and are considered the most confined areas of the Mar Menor lagoon. This situation agrees with the confinement theory for benthic assemblages in the lagoon. The greater degree of differentiation seen in the Isla del Ciervo population is probably due to recent human intervention on the nearby Marchamalo channel, which has been drained in recent years thus altering the influence of the Mediterranean Sea on the southern basin. 相似文献
999.
Hélio V. Nobre-Júnior Ricardo A. Oliveira Flavio D. Maia Marcelle A. S. Nogueira Manoel Odorico de Moraes Mary Anne M. Bandeira Geanne M. Andrade Glauce S. B. Viana 《Neurochemical research》2009,34(6):1066-1075
In the present work, we showed that a chalcone-enriched fraction (CEF) isolated from the stem bark of a Brazilian medicinal
plant, Myracrodruon
urundeuva, presents neuroprotective actions on 6-hydroxydopamine (6-OHDA)-induced neuronal cell death, in rat mesencephalic cells.
In the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium] assay, which is an index of cell viability, CEF (1–100 μg/ml)
reversed in a concentration-dependent manner the 6-OHDA-induced cell death. While cells exposed to 6-OHDA (40 μM) showed an
increased concentration of thiobarbituric acid reactive substances (TBARS), the pretreatment with CEF (10–100 μg/ml) significantly
decreased the 6-OHDA-induced TBARS formation, indicative of a neuroprotection against lipoperoxidation. Furthermore, the drastic
increase of nitrite levels induced by 6-OHDA, indicative of nitric oxide formation and free radicals production, was prevented
by CEF. Double staining with acridine orange/ethidium bromide showed that cultures exposed to 6-OHDA (40 and 200 μM) presented
an increase of apoptotic and necrotic cell numbers in a concentration-dependent manner. CEF (100 μg/ml) protected cells from
apoptosis and necrosis and increased number of cells presenting a normal morphology. The immunohistochemical analysis for
tyrosine hydroxylase (TH) positive neurons indicated that 6-OHDA (40 and 200 μM) caused a concentration-dependent loss of
TH+ and TH− neurons. CEF protected both cells types from 6-OHDA-induced cell death. All together, our results demonstrated
neuroprotective effects of chalcones, which are able to reduce oxidative stress and apoptotic injury caused by 6-OHDA. Our
findings suggest that chalcones could provide benefits, along with other therapies, in neurodegenerative injuries, such as
Parkinson’s disease. 相似文献
1000.
Marcos Roberto de Oliveira Max William Soares Oliveira Guilherme Antônio Behr Matheus Augusto de Bittencourt Pasquali José Cláudio Fonseca Moreira 《Neurochemical research》2009,34(8):1410-1416
Vitamin A, beyond its biological role, is an alternative choice in treating some life threatening pathologies, for instance
leukemia and immunodeficiency. On the other hand, vitamin A therapy at moderate to high doses has caused concern among public
health researchers due to the toxicological aspect resulting from such habit. It has been described hepatotoxicity, cognitive
disturbances and increased mortality rates among subjects ingesting increased levels of vitamin A daily. Then, based on the
previously reported data, we investigated here receptor for advanced glycation endproducts (RAGE) immunocontent and oxidative
damage levels in cerebral cortex of vitamin A-treated rats at clinical doses (1,000–9,000 IU/kg day−1). RAGE immunocontent, as well as oxidative damage levels, were observed increased in cerebral cortex of vitamin A-treated
rats. Whether increased RAGE levels exert negative effects during vitamin A supplementation it remains to be investigated,
but it is very likely that deleterious consequences may arise from such alteration. 相似文献