全文获取类型
收费全文 | 1518篇 |
免费 | 116篇 |
出版年
2023年 | 6篇 |
2022年 | 13篇 |
2021年 | 29篇 |
2020年 | 11篇 |
2019年 | 25篇 |
2018年 | 37篇 |
2017年 | 25篇 |
2016年 | 55篇 |
2015年 | 102篇 |
2014年 | 64篇 |
2013年 | 118篇 |
2012年 | 136篇 |
2011年 | 103篇 |
2010年 | 91篇 |
2009年 | 68篇 |
2008年 | 84篇 |
2007年 | 76篇 |
2006年 | 105篇 |
2005年 | 67篇 |
2004年 | 82篇 |
2003年 | 57篇 |
2002年 | 56篇 |
2001年 | 27篇 |
2000年 | 25篇 |
1999年 | 9篇 |
1998年 | 16篇 |
1997年 | 16篇 |
1996年 | 8篇 |
1995年 | 16篇 |
1994年 | 16篇 |
1993年 | 10篇 |
1992年 | 13篇 |
1991年 | 18篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 7篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1981年 | 2篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1952年 | 1篇 |
排序方式: 共有1634条查询结果,搜索用时 15 毫秒
131.
Ashley Chin Jeffrey S. Healey Carlos S. Ribas Girish M. Nair 《Indian pacing and electrophysiology journal》2015,15(2):121-124
Defibrillation testing is no longer routinely performed after automatic implantable cardioverter-defibrillator (AICD) implantation. However, certain subjects undergoing AICD implantation may be at higher risk of undersensing of ventricular arrhythmias resulting in potentially fatal outcomes. We present the case of a 30-year-old woman with hypertrophic cardiomyopathy (HCM; ‘asymmetric septal hypertophy’ morphologic variant) and prophylactic AICD who experienced an out of hospital cardiac arrest. AICD interrogation revealed undersensing as a result of intermittent high amplitude electrograms during an episode of ventricular fibrillation (VF). The subject underwent replacement and repositioning of the AICD lead along with pulse generator replacement (that utilized a different VF sensing algorithm) with appropriate sensing of VF and successful defibrillation testing. The presence of intermittent high amplitude electrograms during episodes of VF in AICDs using the AGC function should be recognized as a situation that may necessitate interventions to prevent undersensing and consequent delay in therapy. 相似文献
132.
133.
134.
Montserrat Codina Josep Maria Estanyol María José Fidalgo Josep Lluís Ballescà 《Expert review of proteomics》2015,12(3):255-277
The recent application of mass spectrometry to the study of the sperm cell has led to an unprecedented capacity for identification of sperm proteins in a variety of species. Knowledge of the proteins that make up the sperm cell represents the first step towards understanding its normal function and the molecular anomalies associated with male infertility. The present review starts with an introduction of the sperm cell biology and is followed by the consideration of the methodological key aspects to be aware of during sample sourcing and preparation, including data interpretation. It then overviews the initiatives developed so far towards the completion of the sperm proteome, with a particular focus in human but with the inclusion of some comments on different model species. Finally, all studies performing differential proteomics in infertile patients are reviewed, pointing to future potential applications. 相似文献
135.
Carolina Ramírez-Santana Cristina Castellote Margarida Castell Carolina Moltó-Puigmartí Montserrat RiveroFrancisco J. Pérez-Cano Àngels Franch 《The Journal of nutritional biochemistry》2011,22(5):495-501
Previous studies have demonstrated that the intake of a 1% conjugated linoleic acid (CLA) diet in an 80:20 mixture of cis-9,trans-11 and trans-10,cis-12 exerts age-specific effects on the immune system: immunoglobulin enhancement and proliferative down-modulation in neonatal and adult rats, respectively. The present study evaluates the influence of the same diet on antibody synthesis of early infant Wistar rats during suckling and/or after weaning. Dietary supplementation was performed during suckling and early infancy (4 weeks), only during suckling (3 weeks), or only in early infancy (1 week). CLA content in plasma and serum immunoglobulin (Ig) G, IgM and IgA concentration were determined. Proliferation, cytokines and Ig production were evaluated on isolated splenocytes. Cis-9,trans-11- and trans-10,cis-12-CLA isomers were detected in the plasma of all CLA-supplemented animals, and the highest content was quantified in those rats supplemented over the longest period. These rats also exhibited higher concentrations of serum IgG, IgM and IgA. Moreover, splenocytes from CLA-supplemented rats showed the highest IgM and IgG synthesis and interleukin (IL)-6 production, whereas their proliferative ability was lower. In summary, in infant rats, we observed both the enhance antibody synthesis previously reported in neonates, and the reduced lymphoproliferation previously reported in adults. 相似文献
136.
Research on personality and circadian typology indicates evening-type women are more impulsive and novelty seeking, neither types are more anxious, and morning types tend to be more active, conscientious, and persistent. The purpose of this study is to examine the differences between circadian typologies in the light of the Zuckerman's Alternative Five-Factor Model (AFFM) of personality, which has a strong biological basis, in an adult sample of 412 women 18 to 55 yrs of age. The authors found morning-type women had significant higher scores than evening-type and neither-type women on Activity, and its subscales General Activity and Work Activity. In contrast, evening-type women scored significantly higher than morning-type women on Aggression-Hostility, Impulsive Sensation Seeking, and its subscale Sensation Seeking. In all groups, results were independent of age. These findings are in accordance with those previously obtained in female student samples and add new data on the AFFM. The need of using personality models that are biologically based in the study of circadian rhythms is discussed. 相似文献
137.
Pérez D Crespo M Solé L Prat M Carcasona C Calama E Otal R Gavaldá A Gómez-Angelats M Miralpeix M Puig C 《Bioorganic & medicinal chemistry letters》2011,21(5):1545-1548
The synthesis of diverse functionalized ureas in a semi-parallel fashion is described, as well as their β1/β2-adrenergic activities and the corresponding structure-activity relationship (SAR). We have focused on lipophilicity and duration of action, and we have discovered a strong correlation in this series of molecules. A quantitative structure-activity relationship (QSAR) analysis will be presented that quantifies this relationship. 相似文献
138.
139.
Athanasiadis G Buil A Souto JC Borrell M López S Martinez-Perez A Lathrop M Fontcuberta J Almasy L Soria JM 《PloS one》2011,6(12):e29168
The Protein C anticoagulant pathway regulates blood coagulation by preventing the inadequate formation of thrombi. It has two main plasma components: protein C and protein S. Individuals with protein C or protein S deficiency present a dramatically increased incidence of thromboembolic disorders. Here, we present the results of a genome-wide association study (GWAS) for protein C and protein S plasma levels in a set of extended pedigrees from the Genetic Analysis of Idiopathic Thrombophilia (GAIT) Project. A total number of 397 individuals from 21 families were typed for 307,984 SNPs using the Infinium® 317 k Beadchip (Illumina). Protein C and protein S (free, functional and total) plasma levels were determined with biochemical assays for all participants. Association with phenotypes was investigated through variance component analysis. After correcting for multiple testing, two SNPs for protein C plasma levels (rs867186 and rs8119351) and another two for free protein S plasma levels (rs1413885 and rs1570868) remained significant on a genome-wide level, located in and around the PROCR and the DNAJC6 genomic regions respectively. No SNPs were significantly associated with functional or total protein S plasma levels, although rs1413885 from DNAJC6 showed suggestive association with the functional protein S phenotype, possibly indicating that this locus plays an important role in protein S metabolism. Our results provide evidence that PROCR and DNAJC6 might play a role in protein C and free protein S plasma levels in the population studied, warranting further investigation on the role of these loci in the etiology of venous thromboembolism and other thrombotic diseases. 相似文献
140.
Sexual selection has been proposed as the driving force promoting the rapid evolutionary changes observed in some reproductive genes including protamines. We test this hypothesis in a group of rodents which show marked differences in the intensity of sexual selection. Levels of sperm competition were not associated with the evolutionary rates of protamine 1 but, contrary to expectations, were negatively related to the evolutionary rate of cleaved- and mature-protamine 2. Since both domains were found to be under relaxation, our findings reveal an unforeseen role of sexual selection: to halt the degree of degeneration that proteins within families may experience due to functional redundancy. The degree of relaxation of protamine 2 in this group of rodents is such that in some species it has become dysfunctional and it is not expressed in mature spermatozoa. In contrast, protamine 1 is functionally conserved but shows directed positive selection on specific sites which are functionally relevant such as DNA-anchoring domains and phosphorylation sites. We conclude that in rodents protamine 2 is under relaxation and that sexual selection removes deleterious mutations among species with high levels of sperm competition to maintain the protein functional and the spermatozoa competitive. 相似文献