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91.
Isolation and Genetic Characterization of Toxoplasma gondii from Black Bears (Ursus americanus), Bobcats (Lynx rufus), and Feral Cats (Felis catus) from Pennsylvania
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Jitender P. Dubey Shiv K. Verma Rafael Calero‐Bernal Ana B. Cassinelli Oliver C. H. Kwok Kyle Van Why Chunlei Su Jan G. Humphreys 《The Journal of eukaryotic microbiology》2015,62(3):410-415
Toxoplasma gondii infects virtually all warm‐blooded hosts worldwide. Recently, attention has been focused on the genetic diversity of the parasite to explain its pathogenicity in different hosts. It has been hypothesized that interaction between feral and domestic cycles of T. gondii may increase unusual genotypes in domestic cats and facilitate transmission of potentially more pathogenic genotypes to humans, domestic animals, and wildlife. In the present study, we tested black bear (Ursus americanus), bobcat (Lynx rufus), and feral cat (Felis catus) from the state of Pennsylvania for T. gondii infection. Antibodies to T. gondii were found in 32 (84.2%) of 38 bears, both bobcats, and 2 of 3 feral cats tested by the modified agglutination test (cut off titer 1:25). Hearts from seropositive animals were bioassayed in mice, and viable T. gondii was isolated from 3 of 32 bears, 2 of 2 bobcats, and 2 of 3 feral cats. DNA isolated from culture‐derived tachyzoites of these isolates was characterized using multilocus PCR‐RFLP markers. Three genotypes were revealed, including ToxoDB PCR‐RFLP genotype #1 or #3 (Type II, 1 isolate), #5 (Type 12, 3 isolates), and #216 (3 isolates), adding to the evidence of genetic diversity of T. gondii in wildlife in Pennsylvania. Pathogenicity of 3 T. gondii isolates (all #216, 1 from bear, and 2 from feral cat) was determined in outbred Swiss Webster mice; all three were virulent causing 100% mortality. Results indicated that highly mouse pathogenic strains of T. gondii are circulating in wildlife, and these strains may pose risk to infect human through consuming of game meat. 相似文献
92.
An Yun Guo Kwok Sui Leung Parco Ming Fai Siu Jiang Hui Qin Simon Kwoon Ho Chow Ling Qin Chi Yu Li Wing Hoi Cheung 《Experimental Animals》2015,64(4):425-433
Sarcopenia is an age-related systemic syndrome with progressive deterioration in skeletal
muscle functions and loss in mass. Although the senescence-accelerated mouse P8 (SAMP8)
was reported valid for muscular ageing research, there was no report on the details such
as sarcopenia onset time. Therefore, this study was to investigate the change of muscle
mass, structure and functions during the development of sarcopenia. Besides the average
life span, muscle mass, structural and functional measurements were also studied. Male
SAMP8 animals were examined at month 6, 7, 8, 9, and 10, in which the right gastrocnemius
was isolated and tested for ex vivo contractile properties and fatigability while the
contralateral one was harvested for muscle fiber cross-sectional area (FCSA) and typing
assessments. Results showed that the peak of muscle mass appeared at month 7 and the onset
of contractility decline was observed from month 8. Compared with month 8, most of the
functional parameters at month 10 decreased significantly. Structurally, muscle fiber type
IIA made up the largest proportion of the gastrocnemius, and the fiber size was found to
peak at month 8. Based on the altered muscle mass, structural and functional outcomes, it
was concluded that the onset of sarcopenia in SAMP8 animals was at month 8. SAMP8 animals
at month 8 should be at pre-sarcopenia stage while month 10 at sarcopenia stage. It is
confirmed that SAMP8 mouse can be used in sarcopenia research with established time line
in this study. 相似文献
93.
Simplified method for the collection, storage, and comet assay analysis of DNA damage in whole blood
Al-Salmani K Abbas HH Schulpen S Karbaschi M Abdalla I Bowman KJ So KK Evans MD Jones GD Godschalk RW Cooke MS 《Free radical biology & medicine》2011,51(3):719-725
Single-cell gel electrophoresis (comet assay) is one of the most common methods used to measure oxidatively damaged DNA in peripheral blood mononuclear cells (PBMC), as a biomarker of oxidative stress in vivo. However, storage, extraction, and assay workup of blood samples are associated with a risk of artifactual formation of damage. Previous reports using this approach to study DNA damage in PBMC have, for the most part, required the isolation of PBMC before immediate analysis or freezing in cryopreservative. This is very time-consuming and a significant drain on human resources. Here, we report the successful storage of whole blood in ~ 250 μl volumes, at − 80 °C, without cryopreservative, for up to 1 month without artifactual formation of DNA damage. Furthermore, this blood is amenable for direct use in both the alkaline and the enzyme-modified comet assay, without the need for prior isolation of PBMC. In contrast, storage of larger volumes (e.g., 5 ml) of whole blood leads to an increase in damage with longer term storage even at − 80 °C, unless a cryopreservative is present. Our “small volume” approach may be suitable for archived blood samples, facilitating analysis of biobanks when prior isolation of PBMC has not been performed. 相似文献
94.
Significant cell damage occurs during cryopreservation resulting in a decreased number of viable and functional cells post-thawing. Recent studies have correlated the unsuccessful outcome of regenerative therapies with poor cell viability after cryopreservation. Cell damage from ice recrystallization during freeze-thawing is one cause of decreased viability after cryopreservation. We have assessed the ability of two C-AFGPs that are potent inhibitors of ice recrystallization to increase cell viability after cryopreservation. Our results indicate that a 1-1.5 mg/mL (0.5-0.8 mM) solution of C-AFGP 1 is an excellent alternative to a 2.5% DMSO solution for the cryopreservation of human embryonic liver cells. 相似文献
95.
Mi-Youn K Brusniak Sung-Tat Kwok Mark Christiansen David Campbell Lukas Reiter Paola Picotti Ulrike Kusebauch Hector Ramos Eric W Deutsch Jingchun Chen Robert L Moritz Ruedi Aebersold 《BMC bioinformatics》2011,12(1):1-15
Background
Copy number variants (CNVs), including deletions, amplifications, and other rearrangements, are common in human and cancer genomes. Copy number data from array comparative genome hybridization (aCGH) and next-generation DNA sequencing is widely used to measure copy number variants. Comparison of copy number data from multiple individuals reveals recurrent variants. Typically, the interior of a recurrent CNV is examined for genes or other loci associated with a phenotype. However, in some cases, such as gene truncations and fusion genes, the target of variant lies at the boundary of the variant.Results
We introduce Neighborhood Breakpoint Conservation (NBC), an algorithm for identifying rearrangement breakpoints that are highly conserved at the same locus in multiple individuals. NBC detects recurrent breakpoints at varying levels of resolution, including breakpoints whose location is exactly conserved and breakpoints whose location varies within a gene. NBC also identifies pairs of recurrent breakpoints such as those that result from fusion genes. We apply NBC to aCGH data from 36 primary prostate tumors and identify 12 novel rearrangements, one of which is the well-known TMPRSS2-ERG fusion gene. We also apply NBC to 227 glioblastoma tumors and predict 93 novel rearrangements which we further classify as gene truncations, germline structural variants, and fusion genes. A number of these variants involve the protein phosphatase PTPN12 suggesting that deregulation of PTPN12, via a variety of rearrangements, is common in glioblastoma.Conclusions
We demonstrate that NBC is useful for detection of recurrent breakpoints resulting from copy number variants or other structural variants, and in particular identifies recurrent breakpoints that result in gene truncations or fusion genes. Software is available at http://http.//cs.brown.edu/people/braphael/software.html. 相似文献96.
97.
Background
The key epidemiological difference between pandemic and seasonal influenza is that the population is largely susceptible during a pandemic, whereas, during non-pandemic seasons a level of immunity exists. The population-level efficacy of household-based mitigation strategies depends on the proportion of infections that occur within households. In general, mitigation measures such as isolation and quarantine are more effective at the population level if the proportion of household transmission is low.Methods/Results
We calculated the proportion of infections within households during pandemic years compared with non-pandemic years using a deterministic model of household transmission in which all combinations of household size and individual infection states were enumerated explicitly. We found that the proportion of infections that occur within households was only partially influenced by the hazard h of infection within household relative to the hazard of infection outside the household, especially for small basic reproductive numbers. During pandemics, the number of within-household infections was lower than one might expect for a given because many of the susceptible individuals were infected from the community and the number of susceptible individuals within household was thus depleted rapidly. In addition, we found that for the value of at which 30% of infections occur within households during non-pandemic years, a similar 31% of infections occur within households during pandemic years.Interpretation
We suggest that a trade off between the community force of infection and the number of susceptible individuals in a household explains an apparent invariance in the proportion of infections that occur in households in our model. During a pandemic, although there are more susceptible individuals in a household, the community force of infection is very high. However, during non-pandemic years, the force of infection is much lower but there are fewer susceptible individuals within the household. 相似文献98.
Endothelin‐1 (ET‐1) has been demonstrated to induce insulin resistance (IR) and lipolysis, raising the possibility that ET‐1 may also contribute to the elevated fatty acid levels in IR‐associated comorbidities. We attempted to evaluate whether ET‐1 also affects the long‐chain fatty acid (LCFA) utilization in 3T3‐L1 adipocytes. The effects of chronic ET‐1 exposure on basal and insulin‐stimulated LCFA uptake, and LCFA uptake kinetics were examined in 3T3‐L1 adipocytes. Chronic exposure to ET‐1 induced IR and suppressed basal and insulin‐stimulated LCFA uptake. Given that insulin acutely stimulates LCFA uptake, there was dramatically similar trend of dose‐response curves for ET‐1‐suppressed LCFA uptake, and also similar corresponding IC50 values, between basal and insulin‐stimulated states, reflecting that ET‐1 predominantly suppresses basal LCFA uptake. Results of LCFA kinetics, western blots, and CD36 inhibition using sulfosuccinimidyl oleate (SSO) revealed that suppression of LCFA uptake by ET‐1 is associated with downregulation of CD36. ET type A receptor (ETAR) antagonist BQ‐610 reversed the IR induction and the ET‐1‐suppressed LCFA uptake. Exogenous replenishment of phosphatidylinositol (PI) 4, 5‐bisphosphate (PIP2) prevented IR induction, but not the suppression of LCFA uptake by ET‐1. Pharmacological inhibition of the activation of mitogen‐activated protein kinase (MAPK)/extracellular signal‐regulated kinase (ERK) completely blocked the ET‐1‐suppressed LCFA uptake. Serving as an inducer of IR, ET‐1 also chronically suppresses LCFA uptake via PIP2‐independent and ERK‐dependent pathway. The interplay between impaired glucose disposal and diminished LCFA utilization, induced by ET‐1, could worsen the dysregulation of adipose metabolism and energy homeostasis in insulin‐resistant states. 相似文献
99.
100.
Srikhanta YN Gorrell RJ Steen JA Gawthorne JA Kwok T Grimmond SM Robins-Browne RM Jennings MP 《PloS one》2011,6(12):e27569
Many host-adapted bacterial pathogens contain DNA methyltransferases (mod genes) that are subject to phase-variable expression (high-frequency reversible ON/OFF switching of gene expression). In Haemophilus influenzae and pathogenic Neisseria, the random switching of the modA gene, associated with a phase-variable type III restriction modification (R-M) system, controls expression of a phase-variable regulon of genes (a "phasevarion"), via differential methylation of the genome in the modA ON and OFF states. Phase-variable type III R-M systems are also found in Helicobacter pylori, suggesting that phasevarions may also exist in this key human pathogen. Phylogenetic studies on the phase-variable type III modH gene revealed that there are 17 distinct alleles in H. pylori, which differ only in their DNA recognition domain. One of the most commonly found alleles was modH5 (16% of isolates). Microarray analysis comparing the wild-type P12modH5 ON strain to a P12ΔmodH5 mutant revealed that six genes were either up- or down-regulated, and some were virulence-associated. These included flaA, which encodes a flagella protein important in motility and hopG, an outer membrane protein essential for colonization and associated with gastric cancer. This study provides the first evidence of this epigenetic mechanism of gene expression in H. pylori. Characterisation of H. pylori modH phasevarions to define stable immunological targets will be essential for vaccine development and may also contribute to understanding H. pylori pathogenesis. 相似文献