全文获取类型
收费全文 | 1437528篇 |
免费 | 117748篇 |
国内免费 | 3398篇 |
专业分类
耳鼻咽喉 | 18773篇 |
儿科学 | 47262篇 |
妇产科学 | 41544篇 |
基础医学 | 204216篇 |
口腔科学 | 38261篇 |
临床医学 | 129309篇 |
内科学 | 290015篇 |
皮肤病学 | 33745篇 |
神经病学 | 119576篇 |
特种医学 | 55023篇 |
外国民族医学 | 464篇 |
外科学 | 215047篇 |
综合类 | 33143篇 |
现状与发展 | 3篇 |
一般理论 | 526篇 |
预防医学 | 112695篇 |
眼科学 | 31946篇 |
药学 | 100851篇 |
1篇 | |
中国医学 | 3378篇 |
肿瘤学 | 82896篇 |
出版年
2021年 | 11737篇 |
2019年 | 12480篇 |
2018年 | 17554篇 |
2017年 | 13343篇 |
2016年 | 14975篇 |
2015年 | 16813篇 |
2014年 | 23739篇 |
2013年 | 35023篇 |
2012年 | 47730篇 |
2011年 | 50316篇 |
2010年 | 29441篇 |
2009年 | 28233篇 |
2008年 | 46352篇 |
2007年 | 48869篇 |
2006年 | 49274篇 |
2005年 | 47751篇 |
2004年 | 45493篇 |
2003年 | 43285篇 |
2002年 | 41640篇 |
2001年 | 73204篇 |
2000年 | 74728篇 |
1999年 | 61784篇 |
1998年 | 17275篇 |
1997年 | 15643篇 |
1996年 | 15807篇 |
1995年 | 14942篇 |
1994年 | 13569篇 |
1993年 | 12723篇 |
1992年 | 45970篇 |
1991年 | 43591篇 |
1990年 | 41592篇 |
1989年 | 39657篇 |
1988年 | 36272篇 |
1987年 | 35434篇 |
1986年 | 32933篇 |
1985年 | 31339篇 |
1984年 | 23898篇 |
1983年 | 20099篇 |
1982年 | 12287篇 |
1981年 | 10830篇 |
1979年 | 20742篇 |
1978年 | 14620篇 |
1977年 | 12115篇 |
1976年 | 11386篇 |
1975年 | 11638篇 |
1974年 | 14010篇 |
1973年 | 13563篇 |
1972年 | 12652篇 |
1971年 | 11484篇 |
1970年 | 10931篇 |
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
11.
Deitelzweig Steve Luo Xuemei Nguyen Jennifer L. Malhotra Deepa Emir Birol Russ Cristina Li Xiaoyan Lee Theodore C. Ferri Mauricio Wiederkehr Danny Reimbaeva Maya Barnes Geoffrey D. Piazza Gregory 《Journal of thrombosis and thrombolysis》2022,54(4):696-696
Journal of Thrombosis and Thrombolysis - 相似文献
12.
13.
Victoria L. Parker Matthew C. Winter John A. Tidy Barry W. Hancock Julia E. Palmer Naveed Sarwar Baljeet Kaur Katie McDonald Xianne Aguiar Kamaljit Singh Nick Unsworth Imran Jabbar Allan A. Pacey Robert F. Harrison Michael J. Seckl 《International journal of cancer. Journal international du cancer》2023,152(5):986-997
Gestational trophoblastic neoplasia (GTN) patients are treated according to the eight-variable International Federation of Gynaecology and Obstetrics (FIGO) scoring system, that aims to predict first-line single-agent chemotherapy resistance. FIGO is imperfect with one-third of low-risk patients developing disease resistance to first-line single-agent chemotherapy. We aimed to generate simplified models that improve upon FIGO. Logistic regression (LR) and multilayer perceptron (MLP) modelling (n = 4191) generated six models (M1-6). M1, all eight FIGO variables (scored data); M2, all eight FIGO variables (scored and raw data); M3, nonimaging variables (scored data); M4, nonimaging variables (scored and raw data); M5, imaging variables (scored data); and M6, pretreatment hCG (raw data) + imaging variables (scored data). Performance was compared to FIGO using true and false positive rates, positive and negative predictive values, diagnostic odds ratio, receiver operating characteristic (ROC) curves, Bland-Altman calibration plots, decision curve analysis and contingency tables. M1-6 were calibrated and outperformed FIGO on true positive rate and positive predictive value. Using LR and MLP, M1, M2 and M4 generated small improvements to the ROC curve and decision curve analysis. M3, M5 and M6 matched FIGO or performed less well. Compared to FIGO, most (excluding LR M4 and MLP M5) had significant discordance in patient classification (McNemar's test P < .05); 55-112 undertreated, 46-206 overtreated. Statistical modelling yielded only small gains over FIGO performance, arising through recategorisation of treatment-resistant patients, with a significant proportion of under/overtreatment as the available data have been used a priori to allocate primary chemotherapy. Streamlining FIGO should now be the focus. 相似文献
14.
Kevin Kyung Ho Choi Santosh Sanagapalli 《World journal of gastrointestinal oncology》2022,14(3):568-586
Barrett's esophagus (BE) is the precursor to esophageal adenocarcinoma (EAC). Progression to cancer typically occurs in a stepwise fashion through worsening dysplasia and ultimately, invasive neoplasia. Established EAC with deep involvement of the esophageal wall and/or metastatic disease is invariably associated with poor long-term survival rates. This guides the rationale of surveillance of Barrett’s in an attempt to treat lesions at an earlier, and potentially curative stage. The last two decades have seen a paradigm shift in management of Barrett’s with rapid expansion in the role of endoscopic eradication therapy (EET) for management of dysplastic and early neoplastic BE, and there have been substantial changes to international consensus guidelines for management of early BE based on evolving evidence. This review aims to assist the physician in the therapeutic decision-making process with patients by comprehensive review and summary of literature surrounding natural history of Barrett’s by histological stage, and the effectiveness of interventions in attenuating the risk posed by its natural history. Key findings were as follows. Non-dysplastic Barrett’s is associated with extremely low risk of progression, and interventions cannot be justified. The annual risk of cancer progression in low grade dysplasia is between 1%-3%; EET can be offered though evidence for its benefit remains confined to highly select settings. High-grade dysplasia progresses to cancer in 5%-10% per year; EET is similarly effective to and less morbid than surgery and should be routinely performed for this indication. Risk of nodal metastases in intramucosal cancer is 2%-4%, which is comparable to operative mortality rate, so EET is usually preferred. Submucosal cancer is associated with nodal metastases in 14%-41% hence surgery remains standard of care, except for select situations. 相似文献
15.
Triposkiadis Filippos Xanthopoulos Andrew Skoularigis John Starling Randall C. 《Heart failure reviews》2022,27(6):1991-2003
Heart Failure Reviews - The nitric oxide (NO)–guanylate cyclase (GC)–cyclic guanosine monophosphate (cGMP) pathway plays an important role in cardiovascular, pulmonary and renal... 相似文献
16.
Comprehensive evidence regarding the treatment of non-anaemic iron deficiency in patients undergoing valvular heart surgery is lacking. This study aimed to investigate the association between non-anaemic iron deficiency and postoperative outcomes in these patients. We retrospectively analysed 321 patients of which 180 (56%) had iron deficiency (defined as serum ferritin < 100 ng.ml-1 or < 300 ng.ml-1 with transferrin saturation < 20%). While the iron-deficient group had lower pre-operative haemoglobin levels than the non-iron deficient group (median (IQR [range]) 134 (127–141 [120–172]) g.l-1, 143 (133–150 [120–179]) g.l-1, p = 0.001), there was no between-group difference in allogeneic red blood cell transfusion. Median (IQR [range]) days alive and out of hospital at postoperative day 90 was 1 day shorter in the iron-deficient group (80 (77–82 [9–85]) days vs. 81 (79–83 [0–85]) days, p = 0.026). In multivariable analysis, only cardiopulmonary bypass duration (p = 0.032) and intra-operative allogeneic red blood cell transfusion (p = 0.011) were significantly associated with reduced days alive and out of hospital at postoperative day 90. Iron deficiency did not exert any adverse influence on secondary outcomes except length of hospital stay. Our findings indicate that non-anaemic iron deficiency alone is not associated with adverse effects in patients undergoing valvular heart surgery when it does not translate into an increased risk of allogeneic transfusion. 相似文献
17.
Post-induction hypotension is common and associated with postoperative complications. We hypothesised that pneumatic leg compression reduces post-induction hypotension in elderly patients undergoing robot-assisted laparoscopic prostatectomy. In this double-blind randomised study, patients were allocated randomly to the pneumatic leg compression group (n = 50) or control (n = 50). In the intervention group, pneumatic leg compression was initiated before induction of anaesthesia. In the control group, pneumatic leg compression was initiated 20 min after anaesthesia induction. The primary outcome was the incidence of post-induction hypotension in these groups. Post-induction hypotension was defined as systolic blood pressure < 90 mmHg during the first 20 min after induction. Haemodynamic variables and area under the curve of post-induction systolic blood pressure over time were assessed. Complications associated with pneumatic leg compression were recorded, including: peripheral neuropathy; compartment syndrome; extensive bullae beneath the leg sleeves; and pulmonary thromboembolism. The incidence of post-induction hypotension decreased in the pneumatic leg compression group compared with that in the control group; 5 (10%) vs. 29 (58%), respectively, p < 0.001. In the pneumatic leg compression group, the lowest systolic, diastolic and mean blood pressures 20 min after induction of anaesthesia were significantly greater than the control group. Pneumatic leg compression resulted in an increased area under the curve of systolic blood pressure in the first 20 min after induction, p = 0.001. There were no pneumatic leg compression-related complications. Pneumatic leg compression reduced post-induction hypotension in elderly patients undergoing robot-assisted laparoscopic prostatectomy, suggesting that it is an effective and safe intervention to prevent post-induction hypotension among elderly patients undergoing general anaesthesia. 相似文献
18.
19.
20.