全文获取类型
| 收费全文 | 2446473篇 |
| 免费 | 197298篇 |
| 国内免费 | 8230篇 |
专业分类
| 耳鼻咽喉 | 32109篇 |
| 儿科学 | 80451篇 |
| 妇产科学 | 68566篇 |
| 基础医学 | 341043篇 |
| 口腔科学 | 66915篇 |
| 临床医学 | 222163篇 |
| 内科学 | 492307篇 |
| 皮肤病学 | 58036篇 |
| 神经病学 | 203059篇 |
| 特种医学 | 96413篇 |
| 外国民族医学 | 711篇 |
| 外科学 | 371665篇 |
| 综合类 | 58401篇 |
| 现状与发展 | 4篇 |
| 一般理论 | 864篇 |
| 预防医学 | 196614篇 |
| 眼科学 | 54116篇 |
| 药学 | 171821篇 |
| 6篇 | |
| 中国医学 | 5035篇 |
| 肿瘤学 | 131702篇 |
出版年
| 2018年 | 26790篇 |
| 2017年 | 20730篇 |
| 2016年 | 24025篇 |
| 2015年 | 26918篇 |
| 2014年 | 37927篇 |
| 2013年 | 56731篇 |
| 2012年 | 73129篇 |
| 2011年 | 78325篇 |
| 2010年 | 47525篇 |
| 2009年 | 45791篇 |
| 2008年 | 72723篇 |
| 2007年 | 77171篇 |
| 2006年 | 78413篇 |
| 2005年 | 76072篇 |
| 2004年 | 72644篇 |
| 2003年 | 69841篇 |
| 2002年 | 66827篇 |
| 2001年 | 118858篇 |
| 2000年 | 121869篇 |
| 1999年 | 101515篇 |
| 1998年 | 30016篇 |
| 1997年 | 26984篇 |
| 1996年 | 27741篇 |
| 1995年 | 27152篇 |
| 1994年 | 24952篇 |
| 1993年 | 23486篇 |
| 1992年 | 80444篇 |
| 1991年 | 77657篇 |
| 1990年 | 74556篇 |
| 1989年 | 71051篇 |
| 1988年 | 65603篇 |
| 1987年 | 64254篇 |
| 1986年 | 60391篇 |
| 1985年 | 58023篇 |
| 1984年 | 44286篇 |
| 1983年 | 37417篇 |
| 1982年 | 23202篇 |
| 1981年 | 20730篇 |
| 1980年 | 19312篇 |
| 1979年 | 39678篇 |
| 1978年 | 28408篇 |
| 1977年 | 23807篇 |
| 1976年 | 22067篇 |
| 1975年 | 22875篇 |
| 1974年 | 27184篇 |
| 1973年 | 26180篇 |
| 1972年 | 24447篇 |
| 1971年 | 22392篇 |
| 1970年 | 20880篇 |
| 1969年 | 19448篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
11.
12.
Hanna Lee Mary K. Tan Andrew T. Yan Paul Angaran Paul Dorian Claudia Bucci Jean C. Gregoire Alan D. Bell Martin S. Green Peter L. Gross Allan Skanes Charles R. Kerr L. Brent Mitchell Jafna L. Cox Vidal Essebag Brett Heilbron Krishnan Ramanathan Carl Fournier Shaun G. Goodman 《The Canadian journal of cardiology》2019,35(2):160-168
Background
Physicians treating nonvalvular atrial fibrillation (AF) assess stroke and bleeding risks when deciding on anticoagulation. The agreement between empirical and physician-estimated risks is unclear. Furthermore, the association between patient and physician sex and anticoagulation decision-making is uncertain.Methods
We pooled data from 2 national primary care physician chart audit databases of patients with AF (Facilitating Review and Education to Optimize Stroke Prevention in Atrial Fibrillation and Coordinated National Network to Engage Physicians in the Care and Treatment of Patients with Atrial Fibrillation Chart Audit) with a combined 1035 physicians (133 female, 902 male) and 10,927 patients (4567 female and 6360 male).Results
Male physicians underestimated stroke risk in female patients and overestimated risk in male patients. Female physicians estimated stroke risk well in female patients but underestimated the risk in male patients. Risk of bleeding was underestimated in all. Despite differences in risk assessment by physician and patient sex, > 90% of patients received anticoagulation across all subgroups. There was modest agreement between physician estimated and calculated (ie, CHADS2 score) stroke risk: Kappa scores were 0.41 (0.35-0.47) for female physicians and 0.34 (0.32-0.36) for male physicians.Conclusions
Our study is the first to examine the association between patient and physician sex influences and stroke and bleeding risk estimation in AF. Although there were differences in agreement between physician estimated stroke risk and calculated CHADS2 scores, these differences were small and unlikely to affect clinical practice; further, despite any perceived differences in the accuracy of risk assessment by sex, most patients received anticoagulation. 相似文献13.
N. V. Bashmakova G. N. Chistiakova I. A. Gazieva Y. M. Trapeznikova D. O. Mazurov 《Gynecological endocrinology》2015,31(10):31-33
AbstractThis study was undertaken to compare the concentrations of pro- and anti-angiogenic growth factors, nitric oxide (NO) stable metabolites in maternal serum and embryonic left ventricular (LV) isovolumic relaxation time (IRT, ms) during the first trimester in two groups of women: with pregnancy conceived by assisted reproductive technologies (ART, n?=?39) and normally conceived (control group, n?=?68) pregnancy. The concentration of vasoconstrictor endothelin 1 was 45.5 times more in ART than in control group. On the contrary, the concentrations of NO stable metabolites in ART were 1.9 times less than in control women. The assessment of angiogenic suppressors in ART women demonstrates the decrease in s-endoglin concentration was 1.6 times and in soluble receptor to vascular endothelial growth factor concentration was 2.0 times in comparison with control group. There was a significant increase in LV IRT in ART embryos in comparison to control ones. These data suggest significant changes in pro- anti-angiogenic factors balance and increase in vascular impedance in ART-conceived embryos. 相似文献
14.
K.-C. Sung D.-C. Seo S.-J. Lee M.-Y. Lee S.H. Wild C.D. Byrne 《Nutrition, metabolism, and cardiovascular diseases : NMCD》2019,29(5):489-495
Background and aims
It is not known whether non alcoholic fatty liver disease (NAFLD) is a risk factor for diabetes in non obese, non centrally-obese subjects. Our aim was to investigate relationships between fatty liver, insulin resistance and a biomarker score for liver fibrosis with incident diabetes at follow up, in subjects who were neither obese nor centrally-obese.Methods and results
As many as 70,303 subjects with a body mass index (BMI) < 25 kg/m2 and without diabetes were followed up for a maximum of 7.9 years. At baseline, fatty liver was identified by liver ultrasound, insulin resistance (IR) by homeostatic model assessment of insulin resistance (HOMA-IR) ≥2.0, and central obesity by waist circumference (waist circumference ≥90 cm (men) and ≥85 cm (women). The Fibrosis-4 (FIB-4 score) was used to estimate extent of liver fibrosis. Cox proportional hazards models adjusted for confounders were used to estimate hazard ratios (aHRs) for incident diabetes. As many as 852 incident cases of diabetes occurred during follow up (median [IQR] 3.71 [2.03] years). Mean ± SD BMI was 22.8 ± 1.8 and 21.7 ± 2.0 kg/m2 in subjects with and without diabetes at follow up. In subjects without central obesity and with fatty liver, aHRs (95% CI) for incident diabetes at follow up were 2.17 (1.56, 3.03) for men, and 2.86 (1.50,5.46) for women. Similar aHRs for incident diabetes occurred with fatty liver, IR and the highest quartile of FIB-4 combined, in men; and there was a non significant trend toward increased risk in women.Conclusions
In normal weight, non-centrally obese subjects NAFLD is an independent risk factor for incident diabetes. 相似文献15.
16.
Anand Dayama Nikolaos Tsilimparis Stephen Kolakowski Nathaniel M. Matolo Misty D. Humphries 《Journal of vascular surgery》2019,69(1):156-163.e1
Background
Chronic limb-threatening ischemia (CLTI), defined as ischemic rest pain or tissue loss secondary to arterial insufficiency, is caused by multilevel arterial disease with frequent, severe infrageniculate disease. The rise in CLTI is in part the result of increasing worldwide prevalence of diabetes, renal insufficiency, and advanced aging of the population. The aim of this study was to compare a bypass-first with an endovascular-first revascularization strategy in patients with CLTI due to infrageniculate arterial disease.Methods
We reviewed the American College of Surgeons National Surgical Quality Improvement Program targeted lower extremity revascularization database from 2012 to 2015 to identify patients with CLTI and isolated infrageniculate arterial disease who underwent primary infrageniculate bypass or endovascular intervention. We excluded patients with a history of ipsilateral revascularization and proximal interventions. The end points were major adverse limb event (MALE), major adverse cardiovascular event (MACE), amputation at 30 days, reintervention, patency, and mortality. Multivariable logistic regression was used to determine the association of a bypass-first or an endovascular-first intervention with outcomes.Results
There were 1355 CLTI patients undergoing first-time revascularization to the infrageniculate arteries (821 endovascular-first revascularizations and 534 bypass-first revascularizations) identified. There was no significant difference in adjusted rate of 30-day MALE in the bypass-first vs endovascular-first revascularization cohort (9% vs 11.2%; odds ratio [OR], 0.73; 95% confidence interval [CI], 0.50-1.08). However, the incidence of transtibial or proximal amputation was lower in the bypass-first cohort (4.3% vs 7.4%; OR, 0.60; CI, 0.36-0.98). Patients with bypass-first revascularization had higher wound complication rates (9.7% vs 3.7%; OR, 2.75; CI, 1.71-4.42) compared with patients in the endovascular-first cohort. Compared with the endovascular-first cohort, the incidence of 30-day MACE was significantly higher in bypass-first patients (6.9% vs 2.6%; adjusted OR, 3.88; CI, 2.18-6.88), and 30-day mortality rates were 3.23% vs 1.8% (adjusted OR, 2.77; CI, 1.26-6.11). There was no difference in 30-day untreated loss of patency, reintervention of treated arterial segment, readmissions, and reoperations between the two cohorts. In subgroup analysis after exclusion of dialysis patients, there was also no significant difference in MALE or amputation between the bypass-first and endovascular-first cohorts.Conclusions
CLTI patients with isolated infrageniculate arterial disease treated by a bypass-first approach have a significantly lower 30-day amputation. However, this benefit was not observed when dialysis patients were excluded. The bypass-first cohort had a higher incidence of MACE compared with an endovascular-first strategy. These results reaffirm the need for randomized controlled trials, such as the Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL-2) trial and Best Endovascular vs Best Surgical Therapy in Patients with Critical Limb Ischemia (BEST-CLI), to provide level 1 evidence for the role of endovascular-first vs bypass-first revascularization strategies in the treatment of this population of challenging patients. 相似文献17.
Chronic transplant dysfunction is a complex dynamic pathogenic process. Clinically, a decrease in glomerular filtration rate (GFR) becomes apparent leading to chronic renal insufficiency and dialysis or death from cardiovascular events. Chronic transplant dysfunction can develop into a chronic alIograft nephropathy (CAN) as a specific entity with dynamic progression. CAN includes a collection of immunologic and non-immunologic factors, rejection, ischemia time, donor and recipient characteristics and toxicity of calcineurin inhibitors. Despite improvements in immunosuppression, the long-range prognosis of renal allografts has not improved. Whether modern immunosuppressive concepts with reduction or avoidance of calcineurin inhibitors and a therapy based on antimetabolites, such as mycophenolate or mTOR-inhibitors could lead to a prolongation of transplant survival, remains to be seen. 相似文献
18.
Lalia Y. Ibrahim Krank P. DiFilippo Geremy E. Steed Manuel D. Cerqueira 《Journal of nuclear cardiology》2006,13(6):855-866
Conclusion Several quality-control measures take place before (patient and camera preparation) and during SPECT acquisition to achieve
high-quality images. Not uncommonly, technologists and physicians are left with suboptimal images that have to be addressed
to reach the “right answer” for patient diagnosis and hence management. In many cases patients may be reimaged, especially
if the problem is detected early, but in other cases either the patient has left the nuclear laboratory or there is an inevitable
problem that, even with reimaging, will not be resolved. In these situations the technologist and physician have to seek the
available techniques to obtain the best images possible. These resources are discussed in this issue as an aid in quality
control to obtain the best possible images. 相似文献
19.
D B Irving J L Cook H B Menz 《Journal of Science and Medicine in Sport》2006,9(1-2):11-22; discussion 23-4
20.