全文获取类型
收费全文 | 4062篇 |
免费 | 260篇 |
国内免费 | 2篇 |
专业分类
4324篇 |
出版年
2023年 | 20篇 |
2022年 | 53篇 |
2021年 | 99篇 |
2020年 | 59篇 |
2019年 | 71篇 |
2018年 | 101篇 |
2017年 | 93篇 |
2016年 | 133篇 |
2015年 | 217篇 |
2014年 | 197篇 |
2013年 | 283篇 |
2012年 | 340篇 |
2011年 | 362篇 |
2010年 | 218篇 |
2009年 | 180篇 |
2008年 | 249篇 |
2007年 | 243篇 |
2006年 | 207篇 |
2005年 | 205篇 |
2004年 | 173篇 |
2003年 | 170篇 |
2002年 | 146篇 |
2001年 | 38篇 |
2000年 | 32篇 |
1999年 | 24篇 |
1998年 | 34篇 |
1997年 | 31篇 |
1996年 | 23篇 |
1995年 | 25篇 |
1994年 | 19篇 |
1993年 | 30篇 |
1992年 | 16篇 |
1991年 | 9篇 |
1990年 | 16篇 |
1989年 | 14篇 |
1988年 | 8篇 |
1987年 | 11篇 |
1986年 | 11篇 |
1985年 | 12篇 |
1984年 | 16篇 |
1983年 | 11篇 |
1982年 | 17篇 |
1981年 | 6篇 |
1980年 | 12篇 |
1979年 | 9篇 |
1977年 | 7篇 |
1976年 | 6篇 |
1975年 | 6篇 |
1974年 | 16篇 |
1966年 | 5篇 |
排序方式: 共有4324条查询结果,搜索用时 46 毫秒
101.
Martin Stepan Teresa Cobo Ivana Musilova Helena Hornychova Bo Jacobsson Marian Kacerovsky 《PloS one》2016,11(3)
Objective
This study evaluated maternal C-reactive protein (CRP) as a predictor of microbial invasion of the amniotic cavity (MIAC) and histological chorioamnionitis (HCA) in women with preterm prelabor rupture of the membranes (PPROM) before and after 32 weeks of gestation.Methods
This study was a prospective observational cohort study of 386 women. Maternal serum CRP concentrations were evaluated, and amniotic fluid samples were obtained via transabdominal amniocentesis at the time of admission. Placentas underwent histopathological examination after delivery. MIAC was defined based on a positive PCR for Ureaplasma species, Mycoplasma hominis and Chlamydia trachomatis and/or positive 16S rRNA gene amplification. HCA was defined based on the Salafia classification.Results
Maternal CRP was significantly higher in women with MIAC and HCA (median 9.0 mg/l) than in women with HCA alone (median 6.9 mg/l), MIAC alone (median 7.4 mg/l) and without MIAC or HCA (median 4.5 mg/l) (p<0.0001). CRP was a weak predictor of the occurrence of MIAC and HCA before and after 32 weeks of gestation. Only the 95th percentile of CRP and PPROM before 32 weeks exhibited a false-positive rate of 1%, a positive predictive value of 90% and a positive likelihood ratio of 13.2 to predict MIAC and HCA. However, the low sensitivity of 15% limits the clinical utility of this detection.Conclusion
CRP is a poor predictor of the occurrence of MIAC and HCA, even at early gestational ages. 相似文献102.
103.
104.
105.
Carla D. Jorge Nuno Borges Irina Bagyan Andreas Bilstein Helena Santos 《Extremophiles : life under extreme conditions》2016,20(3):251-259
Protein misfolding, aggregation and deposition in the brain, in the form of amyloid, are implicated in the etiology of several neurodegenerative disorders, such as Alzheimer’s, Parkinson’s and prion diseases. Drugs available on the market reduce the symptoms, but they are not a cure. Therefore, it is urgent to identify promising targets and develop effective drugs. Preservation of protein native conformation and/or inhibition of protein aggregation seem pertinent targets for drug development. Several studies have shown that organic solutes, produced by extremophilic microorganisms in response to osmotic and/or heat stress, prevent denaturation and aggregation of model proteins. Among these stress solutes, mannosylglycerate, mannosylglyceramide, di-myo-inositol phosphate, diglycerol phosphate and ectoine are effective in preventing amyloid formation by Alzheimer’s Aβ peptide and/or α-synuclein in vitro. Moreover, mannosylglycerate is a potent inhibitor of Aβ and α-synuclein aggregation in living cells, and mannosylglyceramide and ectoine inhibit aggregation and reduce prion peptide-induced toxicity in human cells. This review focuses on the efficacy of stress solutes from hyper/thermophiles and ectoines to prevent amyloid formation in vitro and in vivo and their potential application in drug development against protein misfolding diseases. Current and envisaged applications of these extremolytes in neurodegenerative diseases and healthcare will also be addressed. 相似文献
106.
107.
Ana Paula Kallaur Josiane Lopes Sayonara Rangel Oliveira Andrea Name Colado Simão Edna Maria Vissoci Reiche Elaine Regina Delicato de Almeida Helena Kaminami Morimoto Wildea Lice Carvalho Jennings de Pereira Daniele Frizon Alfieri Sueli Donizete Borelli Domacio Ramon Kaimen-Maciel Michael Maes 《Molecular neurobiology》2016,53(8):5191-5202
108.
109.
Decker Helena Piermartiri Tetsade C. B. Nedel Cláudia B. Romão Luciana F. Francisco Sheila S. Dal-Cim Tharine Boeck Carina R. Moura-Neto Vivaldo Tasca Carla I. 《Purinergic signalling》2019,15(4):439-450
Purinergic Signalling - The guanine-based purines (GBPs) have essential extracellular functions such as modulation of glutamatergic transmission and trophic effects on neurons and astrocytes. We... 相似文献
110.
Helena Lee Jennifer Scott Helen Griffiths Jay E. Self Andrew Lotery 《Pigment cell & melanoma research》2019,32(5):657-671
Albinism is a group of disorders characterized by pigment deficiency and abnormal retinal development. Despite being a common cause for visual impairment worldwide, there is a paucity of treatments and patients typically suffer lifelong visual disability. Residual plasticity of the developing retina in young children with albinism has been demonstrated, suggesting a post‐natal window for therapeutic rescue. L‐3, 4 dihydroxyphenylalanine (L‐DOPA), a key signalling molecule which is essential for normal retinal development, is known to be deficient in albinism. In this study, we demonstrate for the first time that post‐natal L‐DOPA supplementation can rescue retinal development, morphology and visual function in a murine model of human albinism, but only if administered from birth or 15 days post‐natal age. 相似文献