全文获取类型
收费全文 | 2221篇 |
免费 | 135篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 94篇 |
妇产科学 | 35篇 |
基础医学 | 420篇 |
口腔科学 | 19篇 |
临床医学 | 294篇 |
内科学 | 450篇 |
皮肤病学 | 45篇 |
神经病学 | 219篇 |
特种医学 | 45篇 |
外科学 | 168篇 |
综合类 | 12篇 |
预防医学 | 210篇 |
眼科学 | 28篇 |
药学 | 188篇 |
中国医学 | 3篇 |
肿瘤学 | 130篇 |
出版年
2023年 | 17篇 |
2022年 | 17篇 |
2021年 | 45篇 |
2020年 | 31篇 |
2019年 | 45篇 |
2018年 | 63篇 |
2017年 | 45篇 |
2016年 | 54篇 |
2015年 | 57篇 |
2014年 | 87篇 |
2013年 | 117篇 |
2012年 | 181篇 |
2011年 | 200篇 |
2010年 | 104篇 |
2009年 | 94篇 |
2008年 | 159篇 |
2007年 | 152篇 |
2006年 | 144篇 |
2005年 | 128篇 |
2004年 | 106篇 |
2003年 | 114篇 |
2002年 | 90篇 |
2001年 | 19篇 |
2000年 | 14篇 |
1999年 | 23篇 |
1998年 | 25篇 |
1997年 | 15篇 |
1996年 | 17篇 |
1995年 | 11篇 |
1994年 | 12篇 |
1993年 | 9篇 |
1992年 | 6篇 |
1991年 | 6篇 |
1990年 | 10篇 |
1989年 | 15篇 |
1988年 | 9篇 |
1987年 | 9篇 |
1986年 | 7篇 |
1985年 | 12篇 |
1984年 | 7篇 |
1982年 | 9篇 |
1981年 | 5篇 |
1980年 | 9篇 |
1979年 | 8篇 |
1977年 | 8篇 |
1976年 | 6篇 |
1973年 | 4篇 |
1972年 | 4篇 |
1971年 | 5篇 |
1967年 | 5篇 |
排序方式: 共有2371条查询结果,搜索用时 15 毫秒
51.
Gai McMichael Santhosh Girirajan Andres Moreno-De-Luca Jozef Gecz Chloe Shard Lam Son Nguyen Jillian Nicholl Catherine Gibson Eric Haan Evan Eichler Christa Lese Martin Alastair MacLennan 《European journal of human genetics : EJHG》2014,22(1):40-45
Recent studies have established the role of rare copy number variants (CNVs) in several neurological disorders but the contribution of rare CNVs to cerebral palsy (CP) is not known. Fifty Caucasian families having children with CP were studied using two microarray designs. Potentially pathogenic, rare (<1% population frequency) CNVs were identified, and their frequency determined, by comparing the CNVs found in cases with 8329 adult controls with no known neurological disorders. Ten of the 50 cases (20%) had rare CNVs of potential relevance to CP; there were a total of 14 CNVs, which were observed in <0.1% (<8/8329) of the control population. Eight inherited from an unaffected mother: a 751-kb deletion including FSCB, a 1.5-Mb duplication of 7q21.13, a 534-kb duplication of 15q11.2, a 446-kb duplication including CTNND2, a 219-kb duplication including MCPH1, a 169-kb duplication of 22q13.33, a 64-kb duplication of MC2R, and a 135-bp exonic deletion of SLC06A1. Three inherited from an unaffected father: a 386-kb deletion of 12p12.2-p12.1, a 234-kb duplication of 10q26.13, and a 4-kb exonic deletion of COPS3. The inheritance was unknown for three CNVs: a 157-bp exonic deletion of ACOX1, a 693-kb duplication of 17q25.3, and a 265-kb duplication of DAAM1. This is the first systematic study of CNVs in CP, and although it did not identify de novo mutations, has shown inherited, rare CNVs involving potentially pathogenic genes and pathways requiring further investigation. 相似文献
52.
Samuel D. Banister Richard C. Kevin Lewis Martin Axel Adams Christa Macdonald Jamie J. Manning Rochelle Boyd Michael Cunningham Marc Y. Stevens Iain S. McGregor Michelle Glass Mark Connor Roy R. Gerona 《Drug testing and analysis》2019,11(7):976-989
5F‐PY‐PICA and 5F‐PY‐PINACA are pyrrolidinyl 1‐(5‐fluoropentyl)ind (az)ole‐3‐carboxamides identified in 2015 as putative synthetic cannabinoid receptor agonist (SCRA) new psychoactive substances (NPS). 5F‐PY‐PICA, 5F‐PY‐PINACA, and analogs featuring variation of the 1‐alkyl substituent or contraction, expansion, or scission of the pyrrolidine ring were synthesized and characterized by nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography–quadrupole time‐of‐flight–mass spectrometry (LC–QTOF–MS). In competitive binding experiments against HEK293 cells expressing human cannabinoid receptor type 1 (hCB1) or type 2 (hCB2), all analogs showed minimal affinity for CB1 (pKi < 5), although several demonstrated moderate CB2 binding (pKi 5.45–6.99). In fluorescence‐based membrane potential assays using AtT20‐hCB1 or ‐hCB2 cells, none of the compounds (at 10 μM) produced an effect >50% of the classical cannabinoid agonist CP55,940 (at 1 μM) at hCB1, although several showed slightly higher relative efficacy at hCB2. Expansion of the pyrrolidine ring of 5F‐PY‐PICA to an azepane ( 8 ) conferred the greatest hCB2 affinity (pKi 6.99) and activity (pEC50 7.54, Emax 72%) within the series. Unlike other SCRA NPS evaluated in vivo using radio biotelemetry, 5F‐PY‐PICA and 5F‐PY‐PINACA did not produce cannabimimetic effects (hypothermia, bradycardia) in mice at doses up to 10 mg/kg. 相似文献
53.
54.
Bang CN Greve AM Boman K Egstrup K Gohlke-Baerwolf C Køber L Nienaber CA Ray S Rossebø AB Wachtell K 《American heart journal》2012,163(4):690-696
55.
Meune C Twerenbold R Drexler B Balmelli C Wolf C Haaf P Reichlin T Irfan A Reiter M Zellweger C Meissner J Stelzig C Freese M Capodarve I Mueller C 《The American journal of cardiology》2012,109(8):1117-1123
We hypothesized that midregional pro-A-type natriuretic peptide (MR-proANP), the stable midregional epitope of proANP, might be useful in the early diagnosis and risk stratification of patients with suspected acute myocardial infarction (AMI). In this multicenter study we measured MR-proANP, cardiac troponin T (cTnT), and high-sensitive cTnT (hs-cTnT) at presentation in 675 consecutive patients presenting to the emergency department with suspected AMI. The final diagnosis was adjudicated by 2 independent cardiologists. Patients were followed 360 days for mortality and AMI. AMI was the final diagnosis in 119 patients (18%). Median MR-proANP levels at presentation were significantly higher in patients with AMI (189 pmol/L, interquartile range 97 to 341) versus patients with another final diagnosis (83 pmol/L, 49 to 144, p <0.001). However, neither the combination of MR-proANP with cTnT nor its combination with hs-cTnT significantly improved diagnostic accuracy as quantified by area under the receiver operating characteristic curve (0.91 vs 0.89 for cTnT alone, p = 0.086; 0.95 vs 0.96 for hs-cTnT, respectively, p = 0.02). Cumulative 360-day mortality/AMI rates were 2.4% in the first, 3.6% in the second, 9.5% in the third, and 18.8% in the fourth quartiles of MR-proANP (p <0.001). MR-proANP (area under the curve 0.76) predicted mortality/AMI independently of and more accurately than cTnT (area under the curve 0.62), hs-cTnT (area under the curve 0.71), and Thrombolysis In Myocardial Infarction risk score (area under the curve 0.72). Net reclassification improvements offered by the additional use of MR-proANP were 0.388 (p <0.001), 0.425 (p <0.001), and 0.217 (p = 0.007), respectively. In conclusion, MR-proANP improves risk prediction for 360-day mortality/AMI but does not seem to help in the early diagnosis of AMI. 相似文献
56.
57.
For decades, hematopoietic stem cells (HSCs) were thought to be a homogeneous population of cells with flexible behavior. Now a new picture has emerged: The HSC compartment consists of several subpopulations of HSCs each with distinct, preprogrammed differentiation and proliferation behaviors. These programs are epigenetically fixed and are stably bequeathed to all daughter HSCs on self-renewal. HSCs within each subset are remarkably similar in their self- renewal and differentiation behaviors, to the point where their life span can be predicted with mathematical certainty. Three subsets can be distinguished when HSCs are classified by their differentiation capacity: myeloid-biased, balanced, and lymphoid-biased HSCs. The relative number of the HSC subsets is developmentally regulated. Lymphoid-biased HSCs are found predominantly early in the life of an organism, whereas myeloid-biased HSCs accumulate in aged mice and humans. Thus, the discovery of distinct subpopulations of HSCs has led to a new understanding of HCS aging. This finding has implications for other aspects of HSC biology and applications in re-generative medicine. The possibility that other adult tissue stem cells show similar heterogeneity and mechanisms of aging is discussed. 相似文献
58.
M Reincke E Fischer S Gerum K Merkle S Schulz A Pallauf M Quinkler G Hanslik K Lang S Hahner B Allolio C Meisinger R Holle F Beuschlein M Bidlingmaier S Endres;Participants of the German Conn's Registry-Else Kröner-Fresenius-Hyperaldosteronism Registry 《Hypertension》2012,60(3):618-624
In comparison with essential hypertension, primary aldosteronism (PA) is associated with an increased risk of cardiovascular morbidity. To date, no data on mortality have been published. We assessed mortality of patients treated for PA within the German Conn's registry and identified risk factors for adverse outcome in a case-control study. Patients with confirmed PA treated in 3 university centers in Germany since 1994 were included in the analysis. All of the patients were contacted in 2009 and 2010 to verify life status. Subjects from the population-based F3 survey of the Cooperative Health Research in the Region of Augsburg served as controls. Final analyses were based on 600 normotensive controls, 600 hypertensive controls, and 300 patients with PA. Kaplan-Meyer survival curves were calculated for both cohorts. Ten-year overall survival was 95% in normotensive controls, 90% in hypertensive controls, and 90% in patients with PA (P value not significant). In multivariate analysis, age (hazard ratio, 1.09 per year [95% CI, 1.03-1.14]), angina pectoris (hazard ratio, 3.6 [95% CI, 1.04-12.04]), and diabetes mellitus (hazard ratio, 2.55 [95% CI, 1.07-6.09]) were associated with an increase in all-cause mortality, whereas hypokalemia (hazard ratio, 0.41 per mmol/L [95% CI, 0.17-0.99]) was associated with reduced mortality. Cardiovascular mortality was the main cause of death in PA (50% versus 34% in hypertensive controls; P<0.05). These data indicate that cardiovascular mortality is increased in patients treated for PA, whereas all-cause mortality is not different from matched hypertensive controls. 相似文献
59.
Lutz Philipp Breitling Heiko Müller Christa Stegmaier Matthias Kliegel Hermann Brenner 《Experimental gerontology》2012
Objectives
Recent animal studies have suggested a key role for cellular prion protein (PrPc) in the pathological consequences of amyloid plaque formation, the hallmark of Alzheimer's disease. This epidemiological study investigated whether serum concentrations of PrPc are associated with cognitive functioning in humans.Design, Setting, Participants
Cross-sectional study of 1,322 participants from the elderly general population in Germany, aged 65 + years at baseline (2000–2002).Measurements
Cognitive functioning was assessed by the COGTEL phone interview 5 years after baseline. Serum PrPc was determined by a commercial immunoassay.Results
In multiple linear regression adjusted for important confounders, subjects in higher PrPc quintiles appeared to have lower cognitive functioning scores than those in the lowest PrPc quintile. Spline regression suggested pronounced non-linearity with an inverse association between PrPc and cognitive functioning levelling off beyond median PrPc. Cognitive subdomain-specific models produced somewhat heterogeneous results.Conclusion
The findings are suggestive of an independent association of PrPc with cognitive functioning in humans. Confirmatory and longitudinal studies are needed to elucidate the potential of PrPc for applications in early risk stratification for cognitive impairment. 相似文献60.
Elisabeth V.C. Friedrich Reinhold Scherer Christa Neuper 《Clinical neurophysiology》2013,124(1):61-69
ObjectiveThe aim of this study was to examine the temporal stability of event-related desynchronization/synchronization (ERD/S) patterns over several sessions as a function of mental task, frequency band, brain region and time interval during the imagery period.MethodsNine volunteers participated in four sessions within 2 weeks of multi-channel EEG recordings. They performed seven mental tasks (i.e. mental rotation, word association, auditory imagery, mental subtraction, spatial navigation, imagery of familiar faces, motor imagery) during 7-s imagery periods. Cronbach’s alpha coefficients were calculated over sessions to evaluate the stability of ERD/S values.ResultsThe word association, mental subtraction and spatial navigation task showed highest stability. Cronbach’s alpha coefficients were highest in the alpha bands (7–10, 10–13 Hz), poorer in the beta bands (13–20, 20–30 Hz) and poorest in the theta band (4–7 Hz). In the majority of tasks, the first time interval and posterior left regions showed highest stability and strongest ERD in the alpha and beta bands.ConclusionStability of ERD/S is strongly dependent on the specific task and differs between time intervals of the imagery period. Furthermore, stability was related to ERD in the alpha and beta bands.SignificanceThe reliability of brain activation patterns is highly relevant for brain–computer interface developments. 相似文献