全文获取类型
收费全文 | 1894篇 |
免费 | 179篇 |
专业分类
2073篇 |
出版年
2023年 | 13篇 |
2022年 | 31篇 |
2021年 | 41篇 |
2020年 | 20篇 |
2019年 | 27篇 |
2018年 | 31篇 |
2017年 | 39篇 |
2016年 | 56篇 |
2015年 | 76篇 |
2014年 | 96篇 |
2013年 | 114篇 |
2012年 | 149篇 |
2011年 | 145篇 |
2010年 | 86篇 |
2009年 | 81篇 |
2008年 | 108篇 |
2007年 | 99篇 |
2006年 | 101篇 |
2005年 | 107篇 |
2004年 | 113篇 |
2003年 | 82篇 |
2002年 | 86篇 |
2001年 | 23篇 |
2000年 | 16篇 |
1999年 | 22篇 |
1998年 | 27篇 |
1997年 | 14篇 |
1996年 | 21篇 |
1995年 | 27篇 |
1994年 | 19篇 |
1993年 | 11篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 9篇 |
1989年 | 10篇 |
1988年 | 10篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 15篇 |
1984年 | 12篇 |
1983年 | 7篇 |
1982年 | 9篇 |
1981年 | 7篇 |
1980年 | 9篇 |
1977年 | 6篇 |
1975年 | 7篇 |
1972年 | 7篇 |
1971年 | 5篇 |
1969年 | 5篇 |
1967年 | 5篇 |
排序方式: 共有2073条查询结果,搜索用时 15 毫秒
41.
Carla Perrotta Silke Kleefeld Anthony Staines Prerna Tewari Anneclaire J. De Roos Dalsu Baris Brenda Birmann Brian Chiu Wendy Cozen Nikolaus Becker Lenka Foretova Marc Maynadié Alexandra Nieters Silvia de Sanjosé Lucia Miligi Adele Seniori Costantini Mark Purdue John Spinelli Pierluigi Cocco 《Cancer epidemiology》2013,37(3):300-305
Objective: We investigated occupational risk of multiple myeloma (MM) in a pooled analysis of five international case–control studies. Methods: We calculated the odds ratio and its 95% confidence interval for selected occupations with unconditional regression analysis in 1959 MM cases and 6192 controls, by pooling study-specific risks using random-effects meta-analysis. Exposure to organic solvents was assessed with a job-exposure matrix (JEM). Results: Gardeners and nursery workers combined, most likely exposed to pesticides, showed a 50% increase in risk (OR = 1.50, 95% CI 0.9–2.3), while other farming jobs did not. Metal processors (OR = 1.55, 95% CI 0.9–2.3), female cleaners (OR = 1.32, 95% CI 1.0–1.8), and high level exposure to organic solvents (OR = 1.38, 95% CI 0.96–1.8) also showed moderately increased risks. Conclusions: Additional case–control studies of MM aetiology are warranted to further investigate the nature of the repeatedly reported increase in MM risk in several occupational groups. 相似文献
42.
43.
Kevin M. DeCock Brenda Jones Sugantha Govindarajan Allan G. Redeker 《The Western journal of medicine》1988,148(3):307-309
In assessing the prevalence of hepatitis δ (delta) virus (HDV) infection in 358 patients with acute hepatitis B seen in Los Angeles between 1983 and 1985 and in 196 patients with chronic hepatitis B followed between 1980 and 1985, we found that 23% of patients with chronic and 5% of patients with acute hepatitis B were infected with HDV. Among patients with chronic hepatitis B, the prevalence of HDV infection was 73% in intravenous drug users and 14% in homosexual men. Acute coinfection with the hepatitis B virus was also more frequent in drug users (8%) than in other groups. δ-Hepatitis is a common infection in hepatitis B virus carriers in Los Angeles, particularly in drug addicts, but also in homosexual men who do not abuse drugs intravenously. 相似文献
44.
45.
Daniel Cortez Kari Erickson Gurumurthy Hiremath Nathan Rodgers Brenda Dugas Elizabeth Braunlin Rebecca Ameduri Jamie L. Lohr 《Indian pacing and electrophysiology journal》2021,21(1):25-28
IntroductionPediatric patients with cardiomyopathies are at risk for sudden death and may need implantable cardioverter defibrillators (ICD’s), but given their small size and duration of use, children are at increased risk for complications associated with ICD use. The subcutaneous ICD presents a favorable option for children without pacing indications. Unfortunately, initial pediatric studies have demonstrated a high complication rate, likely due to the 3-incision technique employed.Material and methodsPatients with ICD but no pacing indication were retrospectively reviewed after implantation of subcutaneous ICD via the two-incision technique. In half of the patients, 10-J impedance test was also performed to compare with impedance obtained after defibrillation threshold testing with 65-J.ResultsTwelve patients were included. The median age was 14 years (range 10–16 years) with eight males included (72.7%). The median weight was 55 kg (range 29 kg–75.1 kg). Follow-up had a median of 11.5 months (range 2–27 months). The median body mass index was 18.4 kg/m squared (range 15.5–27.9 kg/m squared). One patient suffered a minor complication after tearing off the incisional adhesive strips early and required a non-invasive repair in clinic. Shock impedance had a median of 55 J (range 48–68 J). There was one appropriate shock/charge and no inappropriate shocks during follow-up.ConclusionThe two-incision, intermuscular technique appears to have a lower acute complication rate than prior reports, in our cohort of 12 pediatric patients. 相似文献
46.
47.
María Belén Pisano Griselda Oria Geraldine Beskow Javier Aguilar Brenda Konigheim María Luisa Cacace Luis Aguirre Marina Stein Marta Silvia Contigiani 《PLoS neglected tropical diseases》2013,7(12)
Venezuelan equine encephalitis viruses (VEEV) are responsible for human diseases in the Americas, producing severe or mild illness with symptoms indistinguishable from dengue and other arboviral diseases. For this reason, many cases remain without certain diagnosis. Seroprevalence studies for VEEV subtypes IAB, ID, IF (Mosso das Pedras virus; MDPV), IV (Pixuna virus; PIXV) and VI (Rio Negro virus; RNV) were conducted in persons from Northern provinces of Argentina: Salta, Chaco and Corrientes, using plaque reduction neutralization test (PRNT). RNV was detected in all studied provinces. Chaco presented the highest prevalence of this virus (14.1%). Antibodies against VEEV IAB and -for the first time- against MDPV and PIXV were also detected in Chaco province. In Corrientes, seroprevalence against RNV was 1.3% in the pediatric population, indicating recent infections. In Salta, this was the first investigation of VEEV members, and antibodies against RNV and PIXV were detected. These results provide evidence of circulation of many VEE viruses in Northern Argentina, showing that surveillance of these infectious agents should be intensified. 相似文献
48.
Stephen E. Kaiser Yu Qiu Julie E. Coats Kai Mao Daniel J. Klionsky Brenda A. Schulman 《Autophagy》2013,9(5):778-780
Central to most forms of autophagy are two ubiquitin-like proteins (UBLs), Atg8 and Atg12, which play important roles in autophagosome biogenesis, substrate recruitment to autophagosomes, and other aspects of autophagy. Typically, UBLs are activated by an E1 enzyme that (1) catalyzes adenylation of the UBL C terminus, (2) transiently covalently captures the UBL through a reactive thioester bond between the E1 active site cysteine and the UBL C terminus, and (3) promotes transfer of the UBL C terminus to the catalytic cysteine of an E2 conjugating enzyme. The E2, and often an E3 ligase enzyme, catalyzes attachment of the UBL C terminus to a primary amine group on a substrate. Here, we summarize our recent work reporting the structural and mechanistic basis for E1-E2 protein interactions in autophagy. 相似文献
49.
Shawnita Sealy-Jefferson Brenda W. Gillespie Allison E. Aiello Mary N. Haan Lewis B. Morgenstern Lynda D. Lisabeth 《PloS one》2013,8(6)
Background
Persistent pathogens have been proposed as risk factors for stroke; however, the evidence remains inconclusive. Mexican Americans have an increased risk of stroke especially at younger ages, as well as a higher prevalence of infections caused by several persistent pathogens.Methodology/Principal
Findings Using data from the Sacramento Area Latino Study on Aging (n = 1621), the authors used discrete-time regression to examine associations between stroke risk and (1) immunoglobulin G antibody levels to Helicobacter pylori (H. pylori), Cytomegalovirus, Varicella Zoster Virus, Toxoplasma gondii and Herpes simplex virus 1, and (2) concurrent exposure to several pathogens (pathogen burden), defined as: (a) summed sero-positivity, (b) number of pathogens eliciting high antibody levels, and (c) average antibody level. Models were adjusted for socio-demographics and stroke risk factors. Antibody levels to H. pylori predicted incident stroke in fully adjusted models (Odds Ratio: 1.58; 95% Confidence Interval: 1.09, 2.28). No significant associations were found between stroke risk and antibody levels to the other four pathogens. No associations were found for pathogen burden and incident stroke in fully adjusted models.Conclusions/Significance
Our results suggest that exposure to H. pylori may be a stroke risk factor in Mexican Americans and may contribute to ethnic differences in stroke risk given the increased prevalence of exposure to H. pylori in this population. Future studies are needed to confirm this association. 相似文献50.
Oroh Stery Brenda Mustopa Apon Zaenal Budiarti Sri Budiarto Bugi Ratno 《Molecular biology reports》2020,47(10):7567-7573
Molecular Biology Reports - Enteropathogenic Escherichia coli (EPEC) is a bioagent that causes diarrhea through the formation of biofilm. The recalcitrant of EPEC to the current conventional... 相似文献