全文获取类型
收费全文 | 299篇 |
免费 | 6篇 |
专业分类
305篇 |
出版年
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2017年 | 2篇 |
2016年 | 9篇 |
2015年 | 8篇 |
2014年 | 9篇 |
2013年 | 19篇 |
2012年 | 20篇 |
2011年 | 21篇 |
2010年 | 15篇 |
2009年 | 11篇 |
2008年 | 13篇 |
2007年 | 21篇 |
2006年 | 25篇 |
2005年 | 18篇 |
2004年 | 22篇 |
2003年 | 20篇 |
2002年 | 23篇 |
2001年 | 1篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有305条查询结果,搜索用时 15 毫秒
101.
Poornima Parameswaran Yi Liu Krishna M. Roskin Katherine K.L. Jackson Vaishali P. Dixit Ji-Yeun Lee Karen L. Artiles Simona Zompi Maria José Vargas Birgitte B. Simen Bozena Hanczaruk Kim R. McGowan Muhammad A. Tariq Nader Pourmand Daphne Koller Angel Balmaseda Scott D. Boyd Eva Harris Andrew Z. Fire 《Cell host & microbe》2013,13(6):691-700
102.
103.
Zhernakova A Stahl EA Trynka G Raychaudhuri S Festen EA Franke L Westra HJ Fehrmann RS Kurreeman FA Thomson B Gupta N Romanos J McManus R Ryan AW Turner G Brouwer E Posthumus MD Remmers EF Tucci F Toes R Grandone E Mazzilli MC Rybak A Cukrowska B Coenen MJ Radstake TR van Riel PL Li Y de Bakker PI Gregersen PK Worthington J Siminovitch KA Klareskog L Huizinga TW Wijmenga C Plenge RM 《PLoS genetics》2011,7(2):e1002004
104.
The patients' sera had been referred to the National Salmonella Centre for routine Widal serology. Sera were predominately from patients suspected of having been infected with Salmonella Typhi, but also included one serum from patient with typhoid fever who was culture positive for Salmonella Typhi. The immunoblotting procedure using Salmonella Typhi somatic (O=9,12 LPS) and flagellar (H=d) antigens was used for preliminary testing of selected patients sera previously evaluated by Widal agglutination assay as containing different levels of antibodies against O and/or H antigens of Salmonella Typhi. Following Chart et al., immunoblotting reactions were graded between 0 and 3, with 0 indicating an absence of antibody binding, and 3 where antibody binding was readily observed. Sera giving reaction of 2 or 3 were considered to be antibody positive for this study. Positive immunoblotting reaction to O=9,12 LPS antigen was obtained only with the serum of patient with typhoid fever. Presence of specific anti-LPS antibodies was also observed in two other patients' sera diluted 1:50, and in case of one of them also in dilution 1:200, but intensity of antigen-antibody reaction was under positive result criterion. The most other sera positive to O=9,12 antigen in law dilutions (1:50, 1:100) by Widal assay, showed the traces of non-specific reaction by immunoblotting. Presence of positive antigen-antibody reaction was indicated for five sera in dilution 1:50 when tested with the >55 kDa H=d flagellar protein subunit, including the serum of patient with typhoid fever. Only in this serum the high level of specific antibodies was detected also in dilution 1:200, what was not observed in case of the other four, which appeared negative. All the other sera were shown not to contain antibodies to flagella antigen. Although the presented results are preliminary and additional study of more sera of people infected with Salmonella Typhi is needed, it can be concluded after Chart et al., that an immunoblotting procedure incorporating O=9,12 LPS and flagellar H=d antigens is a useful method for providing serological evidence of infection with Salmonella Typhi. In our opinion it can serve as a rapid test for the diagnosis of typhoid fever. 相似文献
105.
Glickstein SB Moore H Slowinska B Racchumi J Suh M Chuhma N Ross ME 《Development (Cambridge, England)》2007,134(22):4083-4093
In contrast to cyclin D1 nulls (cD1-/-), mice without cyclin D2 (cD2-/-) lack cerebellar stellate interneurons; the reason for this is unknown. In the present study in cortex, we found a disproportionate loss of parvalbumin (PV) interneurons in cD2-/- mice. This selective reduction in PV subtypes was associated with reduced frequency of GABA-mediated inhibitory postsynaptic currents in pyramidal neurons, as measured by voltage-clamp recordings, and increased cortical sharp activity in the EEGs of awake-behaving cD2-/- mice. Cell cycle regulation was examined in the medial ganglionic eminence (MGE), the major source of PV interneurons in mouse brain, and differences between cD2-/- and cD1-/- suggested that cD2 promotes subventricular zone (SVZ) divisions, exerting a stronger inhibitory influence on the p27 Cdk-inhibitor (Cdkn1b) to delay cell cycle exit of progenitors. We propose that cD2 promotes transit-amplifying divisions in the SVZ and that these ensure proper output of at least a subset of PV interneurons. 相似文献
106.
Pawlikowska-Pawlega B Gruszecki WI Misiak L Paduch R Piersiak T Zarzyka B Pawelec J Gawron A 《Biochimica et biophysica acta》2007,1768(9):2195-2204
Quercetin is a naturally occurring flavonoid that has a lot of beneficial properties to human health. In this report, using the spin label technique, the influence of quercetin on the fluidity of multilamellar DPPC liposomes was studied. The polarity of the environment preferred by quercetin was also examined by determining the dependence of the position of electronic absorption maxima on dielectric properties of different environments. Autofluorescence of quercetin was also used to examine its distribution in cells. An additional aim of the study was to find how quercetin presence affects human skin fibroblasts. The results showed that incorporation of quercetin at physiological pH into DPPC liposomes caused changes in the partition coefficient of the Tempo spin label between water and polar head group phases. By determining the electronic absorption maxima, we observed that the chromophore of quercetin is localized in the polar head region. Fluorescence microscopy of HSF cells showed quercetin presence in the membrane, cytoplasm and inside the nucleus. Ultrastructural observation revealed some changes, especially in membranous structures, after flavonol treatment. From the results we have concluded that quercetin present in the membrane and other structures can cause changes within cells crucial for its pharmacological activity. 相似文献
107.
Tomasz Boczek Malwina Lisek Bozena Ferenc Antoni Kowalski Dariusz Stepinski Magdalena Wiktorska Ludmila Zylinska 《PloS one》2014,9(7)
Plasma membrane Ca2+-ATPase (PMCA) by extruding Ca2+ outside the cell, actively participates in the regulation of intracellular Ca2+ concentration. Acting as Ca2+/H+ counter-transporter, PMCA transports large quantities of protons which may affect organellar pH homeostasis. PMCA exists in four isoforms (PMCA1-4) but only PMCA2 and PMCA3, due to their unique localization and features, perform more specialized function. Using differentiated PC12 cells we assessed the role of PMCA2 and PMCA3 in the regulation of intracellular pH in steady-state conditions and during Ca2+ overload evoked by 59 mM KCl. We observed that manipulation in PMCA expression elevated pHmito and pHcyto but only in PMCA2-downregulated cells higher mitochondrial pH gradient (ΔpH) was found in steady-state conditions. Our data also demonstrated that PMCA2 or PMCA3 knock-down delayed Ca2+ clearance and partially attenuated cellular acidification during KCl-stimulated Ca2+ influx. Because SERCA and NCX modulated cellular pH response in neglectable manner, and all conditions used to inhibit PMCA prevented KCl-induced pH drop, we considered PMCA2 and PMCA3 as mainly responsible for transport of protons to intracellular milieu. In steady-state conditions, higher TMRE uptake in PMCA2-knockdown line was driven by plasma membrane potential (Ψp). Nonetheless, mitochondrial membrane potential (Ψm) in this line was dissipated during Ca2+ overload. Cyclosporin and bongkrekic acid prevented Ψm loss suggesting the involvement of Ca2+-driven opening of mitochondrial permeability transition pore as putative underlying mechanism. The findings presented here demonstrate a crucial role of PMCA2 and PMCA3 in regulation of cellular pH and indicate PMCA membrane composition important for preservation of electrochemical gradient. 相似文献
108.
Edmond K Scott S Korczak V Ward C Sanderson C Theodoratou E Clark A Griffiths U Rudan I Campbell H 《PloS one》2012,7(2):e31239
Background
The risks of long term sequelae from childhood pneumonia have not been systematically assessed. The aims of this study were to: (i) estimate the risks of respiratory sequelae after pneumonia in children under five years; (ii) estimate the distribution of the different types of respiratory sequelae; and (iii) compare sequelae risk by hospitalisation status and pathogen.Methods
We systematically reviewed published papers from 1970 to 2011. Standard global burden of disease categories (restrictive lung disease, obstructive lung disease, bronchiectasis) were labelled as major sequelae. ‘Minor’ sequelae (chronic bronchitis, asthma, other abnormal pulmonary function, other respiratory disease), and multiple impairments were also included. Thirteen papers were selected for inclusion. Synthesis was by random effects meta-analysis and meta-regression.Results
Risk of at least one major sequelae was 5.5% (95% confidence interval [95% CI] 2.8–8.3%) in non hospitalised children and 13.6% [6.2–21.1%]) in hospitalised children. Adenovirus pneumonia was associated with the highest sequelae risk (54.8% [39.2–70.5%]) but children hospitalised with no pathogen isolated also had high risk (17.6% [10.9–24.3%]). The most common type of major sequela was restrictive lung disease (5.4% [2.5–10.2%]) . Potential confounders such as loss to follow up and median age at infection were not associated with sequelae risk in the final models.Conclusions
All children with pneumonia diagnosed by a health professional should be considered at risk of long term sequelae. Evaluation of childhood pneumonia interventions should include potential impact on long term respiratory sequelae. 相似文献109.
110.