全文获取类型
收费全文 | 53865篇 |
免费 | 3750篇 |
国内免费 | 133篇 |
专业分类
耳鼻咽喉 | 433篇 |
儿科学 | 1977篇 |
妇产科学 | 1846篇 |
基础医学 | 6497篇 |
口腔科学 | 1009篇 |
临床医学 | 9084篇 |
内科学 | 9940篇 |
皮肤病学 | 835篇 |
神经病学 | 4754篇 |
特种医学 | 1041篇 |
外国民族医学 | 33篇 |
外科学 | 4702篇 |
综合类 | 726篇 |
一般理论 | 80篇 |
预防医学 | 7389篇 |
眼科学 | 637篇 |
药学 | 3030篇 |
1篇 | |
中国医学 | 138篇 |
肿瘤学 | 3596篇 |
出版年
2023年 | 325篇 |
2022年 | 458篇 |
2021年 | 1150篇 |
2020年 | 766篇 |
2019年 | 1169篇 |
2018年 | 1383篇 |
2017年 | 934篇 |
2016年 | 1055篇 |
2015年 | 1190篇 |
2014年 | 1617篇 |
2013年 | 2591篇 |
2012年 | 3698篇 |
2011年 | 3961篇 |
2010年 | 2147篇 |
2009年 | 1966篇 |
2008年 | 3453篇 |
2007年 | 3886篇 |
2006年 | 3719篇 |
2005年 | 3585篇 |
2004年 | 3439篇 |
2003年 | 3271篇 |
2002年 | 3087篇 |
2001年 | 448篇 |
2000年 | 343篇 |
1999年 | 456篇 |
1998年 | 712篇 |
1997年 | 559篇 |
1996年 | 485篇 |
1995年 | 393篇 |
1994年 | 405篇 |
1993年 | 393篇 |
1992年 | 294篇 |
1991年 | 252篇 |
1990年 | 239篇 |
1989年 | 201篇 |
1988年 | 202篇 |
1987年 | 223篇 |
1986年 | 179篇 |
1985年 | 208篇 |
1984年 | 222篇 |
1983年 | 222篇 |
1982年 | 281篇 |
1981年 | 252篇 |
1980年 | 200篇 |
1979年 | 145篇 |
1978年 | 126篇 |
1977年 | 141篇 |
1976年 | 122篇 |
1975年 | 100篇 |
1973年 | 89篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Postoperative complications: does intensive care unit staff nursing make a difference? 总被引:5,自引:0,他引:5
Dang D Johantgen ME Pronovost PJ Jenckes MW Bass EB 《Heart & lung : the journal of critical care》2002,31(3):219-228
OBJECTIVE: The purpose of this study was to examine the association between intensive care unit nurse (ICU) staffing and the likelihood of complications for patients undergoing abdominal aortic surgery. DESIGN: The study is a retrospective review of hospital discharge data linked to data on ICU organizational characteristics. SETTING: Research took place in ICUs in non-federal, short-stay hospitals in Maryland. PATIENTS: Study included 2606 patients undergoing abdominal aortic surgery in Maryland between January 1994 and December 1996. Outcome Measures: Outcome measures included cardiac, respiratory, and other complications. RESULTS: Cardiac complications occurred in 13% of patients, respiratory complications occurred in 30%, and other complications occurred in 8% of patients. Multiple logistic regression revealed a statistically significant increased likelihood of respiratory complications (odds ratio [OR], 2.33; 95% confidence interval [CI], 1.50-3.60) in abdominal aortic surgery patients cared for in ICUs with low- versus high-intensity nurse staffing, an increased likelihood of cardiac complications (OR, 1.78; CI, 1.16-2.72) and other complications (OR, 1.74; CI, 1.15-2.63) in ICUs with medium- versus high-intensity nurse staffing, after controlling for patient and organizational characteristics. CONCLUSIONS: Within the range of ICU nurse staffing levels present in Maryland hospitals, decreased nurse staffing was significantly associated with an increased risk of complications in patients undergoing abdominal aortic surgery. 相似文献
992.
Idiopathic cholangiopathy in a biliary cast syndrome necessitating liver transplantation following head trauma 总被引:1,自引:0,他引:1
Byrne MF Chong HI O'Donovan D Sheehan KM Leader MB Kay E McCormick PA Broe P Murray FE McCormack A 《European journal of gastroenterology & hepatology》2003,15(4):415-417
The development of total biliary casts is very unusual, especially in patients who have not undergone liver transplantation. The aetiology of these casts is uncertain but several factors are believed to play a role, including periods of fasting, haemolysis, cholangitis and recent surgery. Resultant bile stasis and/or gallbladder hypocontractility promote sludge and subsequent stone formation. Here we present the case of a previously well 66-year-old woman who developed a total biliary cast several weeks after being involved in a road traffic accident during which she sustained head injuries but no obvious liver insult. This cast was removed at laparotomy but the patient had resultant diffuse biliary tree abnormalities and persistent cholestasis and subsequently required a liver transplant. The possible aetiologies of biliary cast formation and subsequently cholangiopathy necessitating transplantation in this patient are described. 相似文献
993.
Hepatic apoptosis and proliferation in male and female rats fed alcohol: role of cytokines 总被引:7,自引:1,他引:7
Colantoni A Idilman R De Maria N La Paglia N Belmonte J Wezeman F Emanuele N Van Thiel DH Kovacs EJ Emanuele MA 《Alcoholism, clinical and experimental research》2003,27(7):1184-1189
Background: The female liver is more sensitive to the toxic effect of chronic alcohol intake than the male liver. The aim of the study was to compare the influence of gender and sex hormonal status on apoptosis and cell proliferation following chronic ethanol intake.
Methods: Male and female rats were pair fed for 8 weeks a liquid diet containing 36% of their total daily calories as ethanol (ETOH group) or sucrose (control group). Liver samples were analyzed for apoptosis and hepatocyte proliferation by immunohistochemistry. The hepatic production of factors able to influence cell death and proliferation, such as tumor necrosis factor alpha (TNFα) and interleukin 6 (IL-6) were determined.
Results: In both male and female rats, ethanol intake promoted apoptosis in the liver. This effect of ethanol was more evident in female than male rat livers. Hepatic TNFα levels, which promote apoptosis, are significantly more elevated in female than in male livers. Hepatic IL-6 production, which promotes hepatocyte proliferation, was induced by ethanol only in males, but not female animals.
Conclusion: This observed difference in cytokine responses may contribute to the enhanced sensitivity of female liver to EtOH-induced injury. 相似文献
Methods: Male and female rats were pair fed for 8 weeks a liquid diet containing 36% of their total daily calories as ethanol (ETOH group) or sucrose (control group). Liver samples were analyzed for apoptosis and hepatocyte proliferation by immunohistochemistry. The hepatic production of factors able to influence cell death and proliferation, such as tumor necrosis factor alpha (TNFα) and interleukin 6 (IL-6) were determined.
Results: In both male and female rats, ethanol intake promoted apoptosis in the liver. This effect of ethanol was more evident in female than male rat livers. Hepatic TNFα levels, which promote apoptosis, are significantly more elevated in female than in male livers. Hepatic IL-6 production, which promotes hepatocyte proliferation, was induced by ethanol only in males, but not female animals.
Conclusion: This observed difference in cytokine responses may contribute to the enhanced sensitivity of female liver to EtOH-induced injury. 相似文献
994.
995.
Lymphokine-induced phagocytosis in angiocentric immunoproliferative lesions (AIL) and malignant lymphoma arising in AIL 总被引:1,自引:1,他引:1
A factor that augmented the phagocytosis of IgG-coated ox red blood cells by the human monocyte/macrophage line U937 was identified in cell culture supernatants from two of two patients with angiocentric peripheral T cell lymphomas, three of three patients with angiocentric immunoproliferative lesions that were not frankly malignant, and one of two patients with T lymphoblastic malignancies. The factor was not present in supernatants derived from 14 nonangiocentric peripheral T cell lymphomas of other histologic types nor in ten cases of B cell lymphoma and two cases of Hodgkin's disease. A similar factor was present in the supernatants of concanavalin A (Con A)-stimulated normal peripheral blood mononuclear cells and in the supernatants of IL-2- dependent T cell lines derived from normal peripheral blood. The factor had an apparent mol wt of greater than 50,000 daltons, was heat labile (100 degrees C for two minutes), and stable at pH 2.0. Its stimulation of phagocytosis was independent of any increase in number of Fc receptors. Thus, this factor is probably not gamma-interferon. This factor may play a pathogenetic role in the hemophagocytic syndromes associated with certain T cell malignancies and immunodeficient states. 相似文献
996.
Global profiling of Shewanella oneidensis MR-1: expression of hypothetical genes and improved functional annotations 总被引:1,自引:0,他引:1 下载免费PDF全文
Kolker E Picone AF Galperin MY Romine MF Higdon R Makarova KS Kolker N Anderson GA Qiu X Auberry KJ Babnigg G Beliaev AS Edlefsen P Elias DA Gorby YA Holzman T Klappenbach JA Konstantinidis KT Land ML Lipton MS McCue LA Monroe M Pasa-Tolic L Pinchuk G Purvine S Serres MH Tsapin S Zakrajsek BA Zhu W Zhou J Larimer FW Lawrence CE Riley M Collart FR Yates JR Smith RD Giometti CS Nealson KH Fredrickson JK Tiedje JM 《Proceedings of the National Academy of Sciences of the United States of America》2005,102(6):2099-2104
997.
Patricia C. Dykes MA PhD RN Srijesa Khasnabish BA Lesley E. Adkison MSN PhD David W. Bates Michael Bogaisky Zoe Burns MPH Diane L. Carroll MSN PhD Eileen Carter MPhil PhD Ann C. Hurley DNSc Emily Jackson MBOE Susan S. Kurian EdD Mary Ellen Lindros EdD Virginia Ryan MSN Maureen Scanlan MSN Linda Spivack MS Mary-Ann Walsh BSN Jason Adelman 《Journal of the American Geriatrics Society》2021,69(12):3595-3601
998.
Ebenezer Oni Oluseye Ogunmoroti Norrina Allen Mouaz H. A-Mallah Ron Blankstein Seth S. Martin Irfan Zeb Mary Cushman Parag H. Joshi Matthew J. Budoff Michael J. Blaha Roger S. Blumenthal Emir Veledar Khurram Nasir 《The American journal of medicine》2021,134(4):519-525
BackgroundThe American Heart Association (AHA) has defined Life's Simple 7 (LS7) as a measure of overall cardiovascular health . Nonalcoholic fatty liver disease (NAFLD) has been involved as a risk factor for cardiovascular disease. We evaluated the association between LS7 and NAFLD.MethodsWe evaluated participants form the Multi-Ethnic Study of Atherosclerosis (MESA) cohort. Cardiovascular health score was calculated from the Life's Simple 7 metrics. A score of 0-8 was considered inadequate, 9-10 average, and 11-14 optimal. NAFLD was defined using noncontrast cardiac computed tomography (CT) and a liver/spleen attenuation ratio (L/S) < 1. Multivariable regression were performed to evaluate the association.ResultsOur cross-sectional analysis of 3901 participants showed 19% (n = 747) had optimal cardiovascular health, 33% (n = 1270) had average, and 48% (n = 1884) had inadequate. White participants were most likely to have an optimal score (51%, n = 378), whereas African American participants had the lowest proportion with optimal scores (16%, n = 120; P < 0.001). The overall prevalence of NAFLD was 18% with a distribution of 7%, 14%, and 25% in the optimal, average, and inadequate score categories, respectively (P < 0.001). Adjusted for risk factors, average and optimal health categories had lower odds of NAFLD compared to those with inadequate scores: odds ratio for average, 0.44 (95% confidence interval 0.36-0.54); optimal, odds ratio 0.19 (95% confidence interval 0.14-0.26). This association was similar across gender, race and age groups.ConclusionA more favorable cardiovascular health score was associated with a lower prevalence of NAFLD. This study may suggest a potential of Life's Simple 7 in the prevention of liver disease. 相似文献
999.
BackgroundWhether deep venous thrombosis involving the pelvic veins or inferior vena cava is associated with higher in-hospital mortality or higher prevalence of in-hospital pulmonary embolism than proximal or distal lower extremity deep venous thrombosis is not known.MethodsThis was a retrospective cohort study based on administrative data from the Nationwide Inpatient Sample, 2016, 2017. Patients hospitalized with a primary diagnosis of deep venous thrombosis at known locations were identified by International Classification of Diseases-10-Clinical Modification codes.ResultsIn-hospital all-cause mortality with deep venous thrombosis involving the inferior vena cava in patients treated only with anticoagulants was 2.2% versus 0.8% with pelvic vein deep venous thrombosis (p<0.0001), 0.7% with proximal deep venous thrombosis (p<0.0001) and 0.2% with distal deep venous thrombosis (p<0.0001). Mortality with anticoagulants was similar with pelvic vein deep venous thrombosis compared with proximal lower extremity deep venous thrombosis, 0.8% versus 0.7% (p=0.39). Lower mortality was shown with pelvic vein deep venous thrombosis treated with thrombolytics than with anticoagulants, 0% versus 0.8% (p<0.0001). In-hospital pulmonary embolism occurred in 11% to 23%, irrespective of the site of deep venous thrombosis.ConclusionPatients with deep venous thrombosis involving the inferior vena cava had higher in-hospital mortality than patients with deep venous thrombosis at other locations. Pelvic vein deep venous thrombosis did not result in higher mortality or more in-hospital pulmonary embolism than proximal lower extremity deep venous thrombosis. The incidence of in-hospital pulmonary embolism was considerable with deep venous thrombosis at all sites. 相似文献
1000.