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71.
Cystic fibrosis (CF) is a fatal disease affecting the lungs and digestive system by impairment of the Cystic Fibrosis Transmembrane
Conductance Regulator (CFTR). While over 1000 mutations in CFTR have been associated with CF, the majority of cases are linked
to the deletion of phenylalanine 508 (ΔF508). F508 is located in the first nucleotide binding domain (NBD1) of CFTR. This
mutation is sufficient to impair the trafficking of CFTR to the plasma membrane and, thus, its function. As an ABC transporter,
recent structural data from the family provide a framework on which to consider the effect of the ΔF508 mutation on CFTR.
There are fifty-seven known structures of ABC transporters and domains thereof. Only six of these structures are of the intact
transporters. In addition, modern bioinformatic tools provide a wealth of sequence and structural information on the family.
We will review the structural information from the RCSB structure repository and sequence databases of the ABC transporters.
The available structural information was used to construct a model for CFTR based on the ABC transporter homologue, Sav1866,
and provide a context for understanding the molecular pathology of Cystic Fibrosis. 相似文献
72.
Seed-size variation determines interspecific differential predation by mammals in a neotropical rain forest 总被引:2,自引:0,他引:2
It has been suggested that the anthropogenically driven loss of herbivorous mammals might lead to changes in the recruitment patterns of tropical rain forest plants, but few studies have examined the explicit mechanisms that might account for this effect. Here we propose a conceptual model linking differential mammalian defaunation and differential plant recruitment. We posit that in the absence of medium/large herbivores but with small rodent granivores still present (i.e. differential defaunation), predation pressure will be greater on small-seeded species than on large-seeded species. We tested such differential predation hypothesis (DPH) by means of a series of experiments directed to assess: 1) seed consumption by small rodents in laboratory cages; 2) seed-removal rates in small rodent enclosures in the field and 3) removal of seeds placed on the forest floor and exposed to either the full complement of mammals or only small rodents. Seeds used in the experiments were arranged in pairs consisting of species from the same taxonomic family but with a contrasting size (large, small). We found: 1) a significantly greater consumption of smaller seeds (a 2.3- to 20.5-fold difference) in cages and 2) a significantly greater removal of small-seeded species (a 3.7- to 65-fold difference) in field enclosures. Results of seed removal experiments in free-access plots and selective exclosures were more complex, with a general absence of significant differences among treatments but we found that predation was in general concentrated on small-seeded species and small rodents were the predominant visitors to the plots. This, together with the overall short distance of dispersal among large seeds suggest that in differentially defaunated forests large-seeded species are more likely to escape predation. We posit that such size related differential predation may lead to the floristic impoverishment observed in some defaunated forests. 相似文献
73.
Three-dimensional pore space quantification of apple tissue using X-ray computed microtomography 总被引:1,自引:0,他引:1
The microstructure and the connectivity of the pore space are important variables for better understanding of the complex
gas transport phenomena that occur in plant tissues. In this study, we present an experimental procedure for image acquisition
and image processing to quantitatively characterize in 3D the pore space of apple tissues (Malus domestica Borkh.) for two cultivars (Jonagold and Braeburn) taken from the fleshy part of the cortex using X-ray computer microtomography.
Preliminary sensitivity analyses were performed to determine the effect of the resolution and the volume size (REV, representative
elementary volume analysis) on the computed porosity of apple samples. For comparison among cultivars, geometrical properties
such as porosity, specific surface area, number of disconnected pore volumes and their distribution parameters were extracted
and analyzed in triplicate based on the 3D skeletonization of the pore space (medial axis analysis). The results showed that
microtomography provides a resolution at the micrometer level to quantitatively analyze and characterize the 3D topology of
the pore space in apple tissue. The computed porosity was confirmed to be highly dependent of the resolution used, and the
minimum REV of the cortical flesh of apple fruit was estimated to be 1.3 mm3. Comparisons among the two cultivars using a resolution of 8.5 μm with a minimum REV cube showed that in spite of the complexity
and variability of the pore space network observed in Jonagold and Braeburn apples, the extracted parameters from the medial
axis were significantly different (P-value < 0.05). Medial axis parameters showed potential to differentiate the microstructure between the two evaluated apple
cultivars. 相似文献
74.
Identification of a soluble diacylglycerol kinase required for lipoteichoic acid production in Bacillus subtilis 总被引:1,自引:0,他引:1
Jerga A Lu YJ Schujman GE de Mendoza D Rock CO 《The Journal of biological chemistry》2007,282(30):21738-21745
Diacylglycerol kinases (DagKs) are key enzymes in lipid metabolism that function to reintroduce diacylglycerol formed from the hydrolysis of phospholipids into the biosynthetic pathway. Bacillus subtilis is a prototypical Gram-positive bacterium with a lipoteichoic acid structure containing repeating units of sn-glycerol-1-P groups derived from phosphatidylglycerol head groups. The B. subtilis homolog of the prokaryotic DagK gene family (dgkA; Pfam01219) was not a DagK but rather was an undecaprenol kinase. The three members of the soluble DagK protein family (Pfam00781) in B. subtilis were tested by complementation of an E. coli dgkA mutant, and only the essential yerQ gene possessed DagK activity. This gene was dubbed dgkB, and the soluble protein product was purified, and its DagK activity was verified in vitro. Conditional inactivation of dgkB led to the accumulation of diacylglycerol and the cessation of lipoteichoic acid formation in B. subtilis. This study identifies a soluble protein encoded by the dgkB (yerQ) gene as an essential kinase in the diacylglycerol cycle that drives lipoteichoic acid production. 相似文献
75.
Mendoza L Begany P Dyrhonova M Emritte N Svobodova X 《Biomedical papers of the Medical Faculty of the University Palacky, Olomouc, Czechoslovakia》2007,151(1):65-67
AIM: A randomized, two-way, crossover, bioequivalence study was conducted in 25 fasting, healthy, male volunteers to compare two brands of fexofenadine 180 mg tablets, FEXOFENADINE 180 mg Film Tablet (Drogsan A.S., Ankara, Turkey) as test and Telfast 180 mg Tablet (Aventis Pharma, Frankfurt am Main, Germany) as a reference product. METHOD: One tablet of either formulation was administered after 10 h of overnight fasting. After dosing, serial blood samples were collected during a period of 48 hours. Plasma samples were analysed for fexofenadine by a validated HPLC method. The pharmacokinetic parameters AUC(0-48), AUC(0-alpha), C(max), T(max), K(el), T(1/2), and CL were determined from plasma concentration-time profiles for both formulations and were compared statistically. RESULTS AND CONCLUSIONS: The analysis of variance (ANOVA) did not show any significant difference between the two formulations and 90% confidence intervals (CI) fell within the acceptable range, satisfying the bioequivalence criteria of the FDA. Based on these statistical inferences it was concluded that the two brands exhibited comparable pharmacokinetics profiles and that Drogsan's Fexofenadine is equivalent to Telfast of Aventis Pharma, Frankfurt am Main, Germany. 相似文献
76.
Vilela R Souza GF Fernandes Cota G Mendoza L 《Revista iberoamericana de micología》2007,24(2):161-163
A male patient with HIV and past history of tuberculosis and suspected neurotoxoplasmosis was admitted to the hospital with vomiting and small nodules through all his body. Few of the nodules were found forming chains of enlarged lymphatic vessels, especially on lesions located on the limbs. Some of the nodules were ulcerated with a serosanguineous discharge. Collected samples from ulcerated and the nodular lesions showed the presence of Sporothrix schenckii in culture. Although all hemocultures were negative, a spinal fluid collected from this patient and cultures from the cutaneous lesions were both positive for S. schenckii. The patient showed improvement after treatment with Amphotericin B. Sadly, he later died of complications not related to the S. schenckii infection. This case of disseminated sporotrichosis is a remainder that in patients with immunological disorders exotic forms of this fungal clinical entity could be expected. 相似文献
77.
Sensitive detection and discrimination method for studying multiple infections of five major plant viruses infecting ornamental plants in nursery environments 下载免费PDF全文
78.
79.
The c‐di‐GMP phosphodiesterase BifA is involved in the virulence of bacteria from the Pseudomonas syringae complex 下载免费PDF全文
Isabel M. Aragón Daniel Pérez‐Mendoza María‐Trinidad Gallegos Cayo Ramos 《Molecular Plant Pathology》2015,16(6):604-615
In a recent screen for novel virulence factors involved in the interaction between Pseudomonas savastanoi pv. savastanoi and the olive tree, a mutant was selected that contained a transposon insertion in a putative cyclic diguanylate (c‐di‐GMP) phosphodiesterase‐encoding gene. This gene displayed high similarity to bifA of Pseudomonas aeruginosa and Pseudomonas putida. Here, we examined the role of BifA in free‐living and virulence‐related phenotypes of two bacterial plant pathogens in the Pseudomonas syringae complex, the tumour‐inducing pathogen of woody hosts, P. savastanoi pv. savastanoi NCPPB 3335, and the pathogen of tomato and Arabidopsis, P. syringae pv. tomato DC3000. We showed that deletion of the bifA gene resulted in decreased swimming motility of both bacteria and inhibited swarming motility of DC3000. In contrast, overexpression of BifA in P. savastanoi pv. savastanoi had a positive impact on swimming motility and negatively affected biofilm formation. Deletion of bifA in NCPPB 3335 and DC3000 resulted in reduced fitness and virulence of the microbes in olive (NCPPB 3335) and tomato (DC3000) plants. In addition, real‐time monitoring of olive plants infected with green fluorescent protein (GFP)‐tagged P. savastanoi cells displayed an altered spatial distribution of mutant ΔbifA cells inside olive knots compared with the wild‐type strain. All free‐living phenotypes that were altered in both ΔbifA mutants, as well as the virulence of the NCPPB 3335 ΔbifA mutant in olive plants, were fully rescued by complementation with P. aeruginosa BifA, whose phosphodiesterase activity has been demonstrated. Thus, these results suggest that P. syringae and P. savastanoi BifA are also active phosphodiesterases. This first demonstration of the involvement of a putative phosphodiesterase in the virulence of the P. syringae complex provides confirmation of the role of c‐di‐GMP signalling in the virulence of this group of plant pathogens. 相似文献
80.
Deanna M Church Valerie A Schneider Karyn Meltz Steinberg Michael C Schatz Aaron R Quinlan Chen-Shan Chin Paul A Kitts Bronwen Aken Gabor T Marth Michael M Hoffman Javier Herrero M Lisandra Zepeda Mendoza Richard Durbin Paul Flicek 《Genome biology》2015,16(1)
The human genome reference assembly is crucial for aligning and analyzing sequence data, and for genome annotation, among other roles. However, the models and analysis assumptions that underlie the current assembly need revising to fully represent human sequence diversity. Improved analysis tools and updated data reporting formats are also required. 相似文献