全文获取类型
收费全文 | 1536篇 |
免费 | 69篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 27篇 |
儿科学 | 63篇 |
妇产科学 | 26篇 |
基础医学 | 166篇 |
口腔科学 | 30篇 |
临床医学 | 153篇 |
内科学 | 393篇 |
皮肤病学 | 114篇 |
神经病学 | 40篇 |
特种医学 | 208篇 |
外科学 | 161篇 |
综合类 | 29篇 |
预防医学 | 131篇 |
眼科学 | 9篇 |
药学 | 38篇 |
中国医学 | 3篇 |
肿瘤学 | 47篇 |
出版年
2021年 | 14篇 |
2020年 | 11篇 |
2019年 | 12篇 |
2018年 | 13篇 |
2017年 | 18篇 |
2016年 | 21篇 |
2015年 | 26篇 |
2014年 | 31篇 |
2013年 | 78篇 |
2012年 | 29篇 |
2011年 | 38篇 |
2010年 | 57篇 |
2009年 | 62篇 |
2008年 | 43篇 |
2007年 | 40篇 |
2006年 | 37篇 |
2005年 | 39篇 |
2004年 | 30篇 |
2003年 | 18篇 |
2002年 | 28篇 |
2001年 | 25篇 |
2000年 | 17篇 |
1999年 | 23篇 |
1998年 | 85篇 |
1997年 | 74篇 |
1996年 | 77篇 |
1995年 | 49篇 |
1994年 | 62篇 |
1993年 | 51篇 |
1992年 | 14篇 |
1991年 | 15篇 |
1990年 | 22篇 |
1989年 | 42篇 |
1988年 | 43篇 |
1987年 | 34篇 |
1986年 | 27篇 |
1985年 | 27篇 |
1984年 | 23篇 |
1983年 | 12篇 |
1982年 | 22篇 |
1981年 | 18篇 |
1980年 | 14篇 |
1979年 | 20篇 |
1978年 | 16篇 |
1977年 | 21篇 |
1976年 | 18篇 |
1975年 | 14篇 |
1973年 | 17篇 |
1972年 | 13篇 |
1965年 | 10篇 |
排序方式: 共有1638条查询结果,搜索用时 0 毫秒
11.
12.
13.
14.
Rupture of an intra-aortic balloon counterpulsator (IABCP) demands immediate removal. We report a case of thrombus formation within a Datascope IABCP secondary to IABCP rupture, necessitating surgical exploration for removal. There is a disturbing pattern of balloon ruptures with this type of IABCP. 相似文献
15.
16.
17.
Verschuren MC; Blom B; Bogers AJ; Spits H; van Dongen JJ 《International immunology》1998,10(12):1873-1880
Recombination of deltaRec to psiJalpha will delete the TCR delta gene,
which is thought to play an important role in the bifurcation of the TCR
alphabeta versus TCR gammadelta differentiation lineages. We recently
detected a DNA-binding protein in human thymocytes, the so- called PJA-BP,
which recognizes the psiJalpha gene segment and might be one of the factors
involved in the regulation of preferential deltaRec- psiJalpha
rearrangements. We now investigate PJA-BP expression and its correlation
with TCR delta gene deletion in thymocytes. Our electrophoretic mobility
shift assay experiments showed that the PJA-BP is evolutionary conserved in
human, murine and simian thymocytes. Using a large series of human
hematopoietic malignancies (n = 30), we conclude that PJA-BP expression is
thymocyte specific and seems to be restricted to thymocytes committed to
the TCR alphabeta lineage. Analysis of seven well-defined human thymocyte
subpopulations showed that preferential deltaRec-psiJalpha rearrangements
as well as PJA-BP expression can be detected from the immature
CD34-/CD1+/CD3- /CD4+/CD8alpha+beta- thymocyte differentiation stage
onwards. These experiments indicate that expression of PJA-BP in human
thymocytes starts simultaneously with preferential deltaRec-psiJalpha
rearrangements, which supports our hypothesis that PJA-BP is one of the
factors involved in the preferential recombination of deltaRec to
psiJalpha.
相似文献
18.
Somatic mitochondrial DNA mutations in cortex and substantia nigra in aging and Parkinson's disease 总被引:5,自引:0,他引:5
Simon DK Lin MT Zheng L Liu GJ Ahn CH Kim LM Mauck WM Twu F Beal MF Johns DR 《Neurobiology of aging》2004,25(1):71-81
Oxidative damage to mitochondrial DNA (mtDNA) increases with age in the brain and can induce G:C to T:A and T:A to G:C point mutations. Though rare at any particular site, multiple somatic mtDNA mutations induced by oxidative damage or by other mechanisms may accumulate with age in the brain and thus could play a role in aging and neurodegenerative diseases. However, no prior study has quantified the total burden of mtDNA point mutation subtypes in the brain. Using a highly sensitive cloning and sequencing strategy, we find that the aggregate levels of G:C to T:A and T:A to G:C transversions and of all point mutations increase with age in the frontal cortex (FCtx). In the substantia nigra (SN), the aggregate levels of point mutations in young controls are similar to the levels in the SN or FCtx of elderly subjects. Extrapolation from our data suggests an average of 2.7 (FCtx) to 3.2 (SN) somatic point mutations per mitochondrial genome in elderly subjects. There were no significant differences between Parkinson's disease (PD) patients and age-matched controls in somatic mutation levels. These results indicate that individually rare mtDNA point mutations reach a high aggregate burden in FCtx and SN of elderly subjects. 相似文献
19.
20.
A novel gene that encodes a protein with a putative src homology 3 domain is a candidate gene for familial juvenile nephronophthisis 总被引:3,自引:0,他引:3