全文获取类型
收费全文 | 1360篇 |
免费 | 88篇 |
国内免费 | 39篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 45篇 |
妇产科学 | 16篇 |
基础医学 | 163篇 |
口腔科学 | 16篇 |
临床医学 | 135篇 |
内科学 | 293篇 |
皮肤病学 | 12篇 |
神经病学 | 66篇 |
特种医学 | 146篇 |
外科学 | 294篇 |
综合类 | 20篇 |
预防医学 | 36篇 |
眼科学 | 94篇 |
药学 | 96篇 |
中国医学 | 9篇 |
肿瘤学 | 41篇 |
出版年
2021年 | 22篇 |
2020年 | 14篇 |
2019年 | 13篇 |
2018年 | 30篇 |
2017年 | 21篇 |
2016年 | 20篇 |
2015年 | 35篇 |
2014年 | 40篇 |
2013年 | 56篇 |
2012年 | 59篇 |
2011年 | 56篇 |
2010年 | 58篇 |
2009年 | 41篇 |
2008年 | 49篇 |
2007年 | 69篇 |
2006年 | 64篇 |
2005年 | 55篇 |
2004年 | 65篇 |
2003年 | 61篇 |
2002年 | 59篇 |
2001年 | 41篇 |
2000年 | 37篇 |
1999年 | 43篇 |
1998年 | 35篇 |
1997年 | 27篇 |
1996年 | 20篇 |
1995年 | 12篇 |
1994年 | 17篇 |
1993年 | 17篇 |
1992年 | 12篇 |
1991年 | 18篇 |
1990年 | 10篇 |
1989年 | 17篇 |
1988年 | 17篇 |
1987年 | 16篇 |
1986年 | 18篇 |
1985年 | 14篇 |
1984年 | 10篇 |
1983年 | 15篇 |
1980年 | 11篇 |
1979年 | 11篇 |
1976年 | 8篇 |
1939年 | 6篇 |
1930年 | 7篇 |
1926年 | 7篇 |
1924年 | 8篇 |
1841年 | 7篇 |
1840年 | 13篇 |
1838年 | 8篇 |
1830年 | 5篇 |
排序方式: 共有1487条查询结果,搜索用时 31 毫秒
31.
32.
33.
34.
Alyson WM Wong Wen Q Gan Jane Burns Don D Sin Stephan F van Eeden 《Canadian respiratory journal》2008,15(7):361-364
BACKGROUND:
Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is the leading reason for hospitalization in Canada and a significant financial burden on hospital resources. Identifying factors that influence the time a patient spends in the hospital and readmission rates will allow for better use of scarce hospital resources.OBJECTIVES:
To determine the factors that influence length of stay (LOS) in the hospital and readmission for patients with AECOPD in an inner-city hospital.METHODS:
Using the Providence Health Records, a retrospective review of patients admitted to St Paul’s Hospital (Vancouver, British Columbia) during the winter of 2006 to 2007 (six months) with a diagnosis of AECOPD, was conducted. Exacerbations were classified according to Anthonisen criteria to determine the severity of exacerbation on admission. Severity of COPD was scored using the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria. For comparative analysis, severity of disease (GOLD criteria), age, sex and smoking history were matched.RESULTS:
Of 109 admissions reviewed, 66 were single admissions (61%) and 43 were readmissions (39%). The number of readmissions ranged from two to nine (mean of 3.3 readmissions). More than 85% of admissions had the severity of COPD equal to or greater than GOLD stage 3. The significant indicators for readmission were GOLD status (P<0.001), number of related comorbidities (OR 1.47, 95% CI 1.10 to 1.97; P<0.009) and marital status (single) (OR 4.18, 95% CI 1.03 to 17.02; P<0.046). The requirement for social work involvement during hospital admission was associated with a prolonged LOS (P<0.05).CONCLUSIONS:
The results of the present study show that disease severity (GOLD status) and number of comorbidities are associated with readmission rates of patients with AECOPD. Interestingly, social factors such as marital status and the need for social work intervention are also linked to readmission rates and LOS, respectively, in patients with AECOPD. 相似文献35.
36.
Charlotte W Ockeloen Marjolein H Willemsen Sonja de Munnik Bregje WM van Bon Nicole de Leeuw Aad Verrips Sarina G Kant Elizabeth A Jones Han G Brunner Rosa LE van Loon Eric EJ Smeets Mieke M van Haelst Gijs van Haaften Ann Nordgren Helena Malmgren Giedre Grigelioniene Sascha Vermeer Pedro Louro Lina Ramos Thomas JJ Maal Celeste C van Heumen Helger G Yntema Carine EL Carels Tjitske Kleefstra 《European journal of human genetics : EJHG》2015,23(9):1270-1185
Loss-of-function variants in ANKRD11 were identified as the cause of KBG syndrome, an autosomal dominant syndrome with specific dental, neurobehavioural, craniofacial and skeletal anomalies. We present the largest cohort of KBG syndrome cases confirmed by ANKRD11 variants reported so far, consisting of 20 patients from 13 families. Sixteen patients were molecularly diagnosed by Sanger sequencing of ANKRD11, one familial case and three sporadic patients were diagnosed through whole-exome sequencing and one patient was identified through genomewide array analysis. All patients were evaluated by a clinical geneticist. Detailed orofacial phenotyping, including orthodontic evaluation, intra-oral photographs and orthopantomograms, was performed in 10 patients and revealed besides the hallmark feature of macrodontia of central upper incisors, several additional dental anomalies as oligodontia, talon cusps and macrodontia of other teeth. Three-dimensional (3D) stereophotogrammetry was performed in 14 patients and 3D analysis of patients compared with controls showed consistent facial dysmorphisms comprising a bulbous nasal tip, upturned nose with a broad base and a round or triangular face. Many patients exhibited neurobehavioural problems, such as autism spectrum disorder or hyperactivity. One-third of patients presented with (conductive) hearing loss. Congenital heart defects, velopharyngeal insufficiency and hip anomalies were less frequent. On the basis of our observations, we recommend cardiac assessment in children and regular hearing tests in all individuals with a molecular diagnosis of KBG syndrome. As ANKRD11 is a relatively common gene in which sequence variants have been identified in individuals with neurodevelopmental disorders, it seems an important contributor to the aetiology of both sporadic and familial cases. 相似文献
37.
Defective dimerization of von Willebrand factor subunits due to a Cys-> Arg mutation in type IID von Willebrand disease. 下载免费PDF全文
38.
Zusammenfassung Trisäthyleniminobenzochinon (Trenimon) bzw. Actinomycin wurde Ratten zu verschiedenen Zeitpunkten vor und nach der Hepatektomie injiziert. Die Messung des C14-Thymidineinbaus in die DNS der regenerierenden Leber erfolgte jeweils 24 Std nach der Hepatektomie.Es konnte nachgewiesen werden, daß Trenimon noch zu einer Hemmung des Thymidineinbaus in die DNS der regenerierenden Leber führt, wenn die Substanz bis zu 3 Wochen vor der Hepatektomie injiziert wurde. Actinomycin war dagegen bereits wirkungslos, wenn die Injektion 24 Std vor der Hepatektomie erfolgte. Nach der Hepatektomie ließ sich eine Inhibierung des Thymidineinbaus in die DNS noch nachweisen, wenn Actinomycin kurz vor Beginn der DNS-Synthesephase, nämlich 15 Std nach der Hepatektomie, injiziert wurde.
Der Deutschen Forschungsgemeinschaft sei für die Unterstützung dieser Untersuchungen gedankt. 相似文献
The effect of actinomycin and trisethyleneiminobenzoquinone on the DNS synthesis in regenerating rat liver
Summary Rats were injected with trisethyleneiminobenzoquinone (Trenimon) or actinomycin at various times before and after partial hepatectomy.The incorporation of C14-thymidine into the DNS of the regenerating liver was measured 24 hours after hepatectomy. It could be shown, that the inhibition of the thymidine incorporation into the DNA of the regenerating liver by Trenimon was observed when the drug had been administered at early as 3 weeks before the hepatectomy.Actinomycin was ineffective when applied 24 hours before the hepatectomy. On the other hand, an inhibition of the thymidine incorporation was observed 15 hours after the hepatectomy just before the onset of the DNA synthetic phase.
Der Deutschen Forschungsgemeinschaft sei für die Unterstützung dieser Untersuchungen gedankt. 相似文献
39.
Petra Ehling Manuela Cerina Patrick Meuth Tatyana Kanyshkova Pawan Bista Philippe Coulon Sven G. Meuth Hans-Christian Pape Thomas Budde 《Pflügers Archiv : European journal of physiology》2013,465(4):469-480
Mutations in genes coding for Ca2+ channels were found in patients with childhood absence epilepsy (CAE) indicating a contribution of Ca2+-dependent mechanisms to the generation of spike-wave discharges (SWD) in humans. Since the involvement of Ca2+ signals remains unclear, the aim of the present study was to elucidate the function of a Ca2+-dependent K+ channel (BKCa) under physiological conditions and in the pathophysiological state of CAE. The activation of BKCa channels is dependent on both voltage and intracellular Ca2+ concentrations. Moreover, these channels exhibit an outstandingly high level of regulatory heterogeneity that builds the basis for the influence of BKCa channels on different aspects of neuronal activity. Here, we analyse the contribution of BKCa channels to firing of thalamocortical relay neurons, and we test the hypothesis that BKCa channel activity affects the phenotype of a genetic rat model of CAE. We found that the activation of the β2-adrenergic receptor/protein kinase A pathway resulted in BKCa channel inhibition. Furthermore, BKCa channels affect the number of action potentials fired in a burst and produced spike frequency adaptation during tonic activity. The latter result was confirmed by a computer modelling approach. We demonstrate that the β2-adrenergic inhibition of BKCa channels prevents spike frequency adaptation and, thus, might significantly support the tonic firing mode of thalamocortical relay neurons. In addition, we show that BKCa channel functioning differs in epileptic WAG/Rij and thereby likely contributes to highly synchronised, epileptic network activity. 相似文献
40.