全文获取类型
收费全文 | 75511篇 |
免费 | 6556篇 |
国内免费 | 1956篇 |
出版年
2022年 | 474篇 |
2021年 | 1770篇 |
2020年 | 1317篇 |
2019年 | 1524篇 |
2018年 | 1717篇 |
2017年 | 1353篇 |
2016年 | 1940篇 |
2015年 | 2735篇 |
2014年 | 3269篇 |
2013年 | 3619篇 |
2012年 | 4308篇 |
2011年 | 4033篇 |
2010年 | 2571篇 |
2009年 | 2283篇 |
2008年 | 2853篇 |
2007年 | 2682篇 |
2006年 | 2516篇 |
2005年 | 2154篇 |
2004年 | 1984篇 |
2003年 | 1788篇 |
2002年 | 1636篇 |
2001年 | 3332篇 |
2000年 | 3055篇 |
1999年 | 2385篇 |
1998年 | 964篇 |
1997年 | 832篇 |
1996年 | 800篇 |
1995年 | 726篇 |
1994年 | 704篇 |
1993年 | 554篇 |
1992年 | 1605篇 |
1991年 | 1409篇 |
1990年 | 1389篇 |
1989年 | 1287篇 |
1988年 | 1110篇 |
1987年 | 1086篇 |
1986年 | 952篇 |
1985年 | 924篇 |
1984年 | 681篇 |
1983年 | 605篇 |
1979年 | 703篇 |
1978年 | 504篇 |
1977年 | 465篇 |
1975年 | 551篇 |
1974年 | 619篇 |
1973年 | 602篇 |
1972年 | 608篇 |
1971年 | 584篇 |
1970年 | 545篇 |
1969年 | 551篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
Z. Kato Seiji Fukuda Shunji Tomatsu Hugo Vega Teruo Yasunaga Atsushi Yamagishi Naoto Yamada A. Valencia Luis Alejandro Barrera Kazuko Sukegawa Tadao Orii Naomi Kondo 《Human genetics》1997,101(1):97-101
Mucopolysaccharidosis IVA (MPS IVA) is an autosomal recessive lysosomal storage disorder caused by a genetic defect in N-acetylgalactosamine-6-sulfate
sulfatase (GALNS). In previous studies, we have found two common mutations in Caucasians and Japanese, respectively. To characterize
the mutational spectrum in various ethnic groups, mutations in the GALNS gene in Colombian MPS IVA patients were investigated,
and genetic backgrounds were extensively analyzed to identify racial origin, based on mitochondrial DNA (mtDNA) lineages.
Three novel missense mutations never identified previously in other populations and found in 16 out of 19 Colombian MPS IVA
unrelated alleles account for 84.2% of the alleles in this study. The G301C and S162F mutations account for 68.4% and 10.5%
of mutations, respectively, whereas the remaining F69V is limited to a single allele. The skewed prevalence of G301C in only
Colombian patients and haplotype analysis by restriction fragment length polymorphisms in the GALNS gene suggest that G301C
originated from a common ancestor. Investigation of the genetic background by means of mtDNA lineages indicate that all our
patients are probably of native American descent.
Received: 2 January 1997 / Accepted: 10 June 1997 相似文献
5.
6.
Currently, many diabetic cardiomyopathy (DC) studies focus on either in vitro molecular pathways or in vivo whole-heart properties such as ejection fraction. However, as DC is primarily a disease caused by changes in structural and functional properties, such studies may not precisely identify the influence of hyperglycemia or hyperlipidemia in producing specific cellular changes, such as increased myocardial stiffness or diastolic dysfunction. To address this need, we developed an in vitro approach to examine how structural and functional properties may change as a result of a diabetic environment. Particle-tracking microrheology was used to characterize the biomechanical properties of cardiac myocytes and fibroblasts under hyperglycemia or hyperlipidemic conditions. We showed that myocytes, but not fibroblasts, exhibited increased stiffness under diabetic conditions. Hyperlipidemia, but not hyperglycemia, led to increased cFos expression. Although direct application of reactive oxygen species had only limited effects that altered myocyte properties, the antioxidant N-acetylcysteine had broader effects in limiting glucose or fatty-acid alterations. Changes consistent with clinical DC alterations occur in cells cultured in elevated glucose or fatty acids. However, the individual roles of glucose, reactive oxygen species, and fatty acids are varied, suggesting multiple pathway involvement. 相似文献
7.
Whereas the left atrial appendage plays a rather minor role under physiological circumstances, it gains an importance in patients with atrial fibrillation. Compelling evidence has revealed that the left atrial appendage is implicated as the source of thrombus in the vast majority of strokes in atrial fibrillation. Oral anticoagulation remains the standard of care for stroke prevention in atrial fibrillation; nevertheless, this treatment has several limitations and is often contraindicated, particularly in the elderly population in whom the risk of stroke is high. Therefore, occluding the left atrial appendage is a logical approach to prevent thrombus formation and subsequent cardioembolic events in these patients. We present a review of clinical outcomes of patients with atrial fibrillation undergoing left atrial appendage closure and the challenges faced in this field. 相似文献
8.
9.
10.