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281.
The membrane CO(2) flux into Arabidopsis mesophyll cells was studied using a scanning pH microelectrode. Arabidopsis thaliana mesophyll cells were exposed to photosynthesis-triggering light intensities, which induced cellular CO(2) uptake. Data obtained on a AtPIP1;2 T-DNA insertion line indicated that under these conditions, cellular CO(2) transport was not limited by unstirred layer effects but was dependent on the expression of the aquaporin AtPIP1;2. Complementation of the AtPIP1;2 knockout restored membrane CO(2) transport levels to that of controls. The results provide new arguments for the ongoing debate about the validity of the lipid bilayer model system and the Meyer - Overton rule for cellular gas transport. In conclusion, we suggest a modified model of molecular gas transport mechanisms in living cells. 相似文献
282.
Citrullination is a posttranslational modification of arginine. It plays both a physiological role, for instance during apoptosis and epigenetics, and a pathological role in cancer or diseases of the central nervous system. Most research on citrullination to date focuses on its role in auto-immune diseases such as multiple sclerosis and rheumatoid arthritis. In this context, the exact knowledge of citrullination sites in a protein can provide invaluable information about the etiological importance of these citrullinated proteins. However, few techniques exist that can accurately detect citrullination on the peptide level. This review aims to give an overview of the different methods available to date for the detection of citrullinated proteins and peptides. These include 2D-SDS-PAGE and immunodetection, as well as specific mass spectrometry (MS) approaches, both labeled and unlabeled. These MS approaches have been developed to pinpoint the exact location of citrullination on the peptide level. Improving the currently existing detection strategies while focusing on the role of citrullinated proteins will be invaluable to elucidate the importance of this posttranslational modification in vivo. 相似文献
283.
284.
Telomere length and cardiovascular risk factors in a middle-aged population free of overt cardiovascular disease 总被引:2,自引:0,他引:2
Bekaert S De Meyer T Rietzschel ER De Buyzere ML De Bacquer D Langlois M Segers P Cooman L Van Damme P Cassiman P Van Criekinge W Verdonck P De Backer GG Gillebert TC Van Oostveldt P;Asklepios investigators 《Aging cell》2007,6(5):639-647
Evidence assembled over the last decade shows that average telomere length (TL) acts as a biomarker for biological aging and cardiovascular disease (CVD) in particular. Although essential for a more profound understanding of the underlying mechanisms, little reference information is available on TL. We therefore sought to provide baseline TL information and assess the association of prevalent CVD risk factors with TL in subjects free of overt CVD within a small age range. We measured mean telomere restriction fragment length of peripheral blood leukocytes in a large, representative Asklepios study cohort of 2509 community-dwelling, Caucasian female and male volunteers aged approximately 35-55 years and free of overt CVD. We found a manifest age-dependent telomere attrition, at a significantly faster rate in men as compared to women. No significant associations were established with classical CVD risk factors such as cholesterol status and blood pressure, yet shorter TL was associated with increased levels of several inflammation and oxidative stress markers. Importantly, shorter telomere length was associated with an increasingly unhealthy lifestyle, particularly in men. All findings were age and gender adjusted where appropriate. With these cross-sectional results we show that TL of peripheral blood leukocytes primarily reflects the burden of increased oxidative stress and inflammation, whether or not determined by an increasingly unhealthy lifestyle, while the association with classical CVD risk factors is limited. This further clarifies the added value of TL as a biomarker for biological aging and might improve our understanding of how TL is associated with CVD. 相似文献
285.
Autosomal dominant optic atrophy (adOA) is the most common form of hereditary optic neuropathy. The majority of cases are
associated with mutations in the OPA1 gene. A few cases of adOA are known to be associated with moderate progressive hearing loss. To gain insight into the pathogenesis
of this hearing loss, we performed expression analyses of OPA1 in the rat auditory and vestibular organ. In cochlear tissue,
several splice variants of OPA1 were detected, which are also expressed in retinal tissue. OPA1 mRNA and protein was found in the hair cells and ganglion
cells of the cochlea and vestibular organ. In ganglion cells, OPA1 mRNA and protein was already detectable at birth, whereas
in the organ of Corti OPA1 mRNA and protein was up-regulated after birth and reached mature-like expression level during the
onset of hearing. Comparison of an antibody directed to the mitochondrial marker protein HSP60 with antibodies directed to
different amino acid stretches of OPA1 revealed a sub-cellular distribution of OPA1 in areas of significant density of mitochondria.
The data suggest that defects in OPA1 cause hearing disorders due to a progressing metabolic disturbance of hair and ganglion
cells in the inner ear.
Stefanie Bette and Ulrike Zimmermann contributed equally to this work. 相似文献
286.
Abstract Activated sludge samples from pilot plants using different processes for enhanced biological phosphorus removal were investigated for the occurrence of polyphosphate-accumulating bacteria. All samples showed a direct correlation between the relative number of phosphate-accumulating bacteria and phosphate uptake. Various species of bacteria with polyphosphate granules were found in sludge flocs, but in every case Acinetobacter -like cells formed part or the main part of the polyphosphate-accumulating bacterial population. The spectrum of the bacteria with stored polyphosphates varied, depending on the sewage composition on the one hand and on the processes used for phosphorus removal on the other hand. 相似文献
287.
Karolien Verheyden Herlinde Noppe Lynn Vanhaecke Klaas Wille Julie Vanden Bussche Karen Bekaert Olivier Thas Colin R. Janssen Hubert F. De Brabander 《The Journal of steroid biochemistry and molecular biology》2009,117(1-3):8-14
Boldenone (17-hydroxy-androsta-1,4-diene-3-one, Bol) and boldione (androst-1,4-diene-3,17-dione, ADD), are currently listed as exogenous anabolic steroids by the World Anti-Doping Agency. However, it has been reported that these analytes can be produced endogenously. Interestingly, only for Bol a comment is included in the list on its potential endogenous origin. In this study, the endogenous origin of ADD in human urine was investigated, and the potential influence of phytosterol consumption was evaluated.We carried out a 5-week in vivo trial with both men (n = 6) and women (n = 6) and measured α-boldenone, β-boldenone, boldione, androstenedione, β-testosterone and α-testosterone in their urine using gas chromatography coupled to multiple mass spectrometry (GC–MS–MS). The results demonstrate that endogenous ADD is sporadically produced at concentrations ranging from 0.751 ng mL−1 to 1.73 ng mL−1, whereas endogenous Bol could not be proven. We also tested the effect of the daily consumption of a commercially available phytosterol-enriched yogurt drink on the presence of these analytes in human urine. Results from this study could not indicate a relation of ADD-excretion with the consumption of phytosterols at the recommended dose. The correlations between ADD and other steroids were consistently stronger for volunteers consuming phytosterols (test) than for those refraining from phytosterol consumption (control). Excretion of AED, bT and aT did not appear to be dependent on the consumption of phytosterols.This preliminary in vivo trial indicates the endogenous origin of boldione or ADD in human urine, independent on the presence of any structural related analytes such as phytosterols. 相似文献
288.
Kennedy J Baker P Piper C Cotter PD Walsh M Mooij MJ Bourke MB Rea MC O'Connor PM Ross RP Hill C O'Gara F Marchesi JR Dobson AD 《Marine biotechnology (New York, N.Y.)》2009,11(3):384-396
Samples of the marine sponge Haliclona simulans were collected from Irish coastal waters, and bacteria were isolated from these samples. Phylogenetic analyses of the cultured
isolates showed that four different bacterial phyla were represented; Bacteriodetes, Actinobacteria, Proteobacteria, and Firmicutes. The sponge bacterial isolates were assayed for the production of antimicrobial substances, and biological activities against
Gram-positive and Gram-negative bacteria and fungi were demonstrated, with 50% of isolates showing antimicrobial activity
against at least one of the test strains. Further testing showed that the antimicrobial activities extended to the important
pathogens Pseudomonas aeruginosa, Clostridium difficile, multi-drug-resistant Staphylococcus aureus, and pathogenic yeast strains. The Actinomycetes were numerically the most abundant producers of antimicrobial activities, although activities were also noted from Bacilli and Pseudovibrio isolates. Surveys for the presence of potential antibiotic encoding polyketide synthase and nonribosomal peptide synthetase
genes also revealed that genes for the biosynthesis of these secondary metabolites were present in most bacterial phyla but
were particularly prevalent among the Actinobacteria and Proteobacteria. This study demonstrates that the culturable fraction of bacteria from the sponge H. simulans is diverse and appears to possess much potential as a source for the discovery of new medically relevant biological active
agents. 相似文献
289.
Genevieve Paulissen Natacha Rocks Maud M Gueders Celine Crahay Florence Quesada-Calvo Sandrine Bekaert Jonathan Hacha Mehdi El Hour Jean-Michel Foidart Agnes Noel Didier D Cataldo 《Respiratory research》2009,10(1):127
Lungs are exposed to the outside environment and therefore to toxic and infectious agents or allergens. This may lead to permanent activation of innate immune response elements. A Disintegrin And Metalloproteinases (ADAMs) and ADAMs with Thrombospondin motifs (ADAMTS) are proteinases closely related to Matrix Metalloproteinases (MMPs). These multifaceted molecules bear metalloproteinase and disintegrin domains endowing them with features of both proteinases and adhesion molecules. Proteinases of the ADAM family are associated to various physiological and pathological processes and display a wide spectrum of biological effects encompassing cell fusion, cell adhesion, "shedding process", cleavage of various substrates from the extracellular matrix, growth factors or cytokines... This review will focus on the putative roles of ADAM/ADAMTS proteinases in airway diseases such as asthma and COPD. 相似文献