首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   177268篇
  免费   14995篇
  国内免费   5562篇
耳鼻咽喉   1173篇
儿科学   3548篇
妇产科学   1764篇
基础医学   25123篇
口腔科学   3288篇
临床医学   17599篇
内科学   22703篇
皮肤病学   2186篇
神经病学   8924篇
特种医学   3873篇
外国民族医学   27篇
外科学   14001篇
综合类   26599篇
现状与发展   16篇
一般理论   28篇
预防医学   13304篇
眼科学   4442篇
药学   23750篇
  98篇
中国医学   9541篇
肿瘤学   15838篇
  2024年   275篇
  2023年   2380篇
  2022年   3502篇
  2021年   6667篇
  2020年   6123篇
  2019年   6038篇
  2018年   5883篇
  2017年   5848篇
  2016年   5906篇
  2015年   5900篇
  2014年   9563篇
  2013年   10931篇
  2012年   8828篇
  2011年   9938篇
  2010年   8569篇
  2009年   8335篇
  2008年   8364篇
  2007年   9418篇
  2006年   8485篇
  2005年   8430篇
  2004年   7370篇
  2003年   6562篇
  2002年   4845篇
  2001年   4739篇
  2000年   3883篇
  1999年   3613篇
  1998年   2617篇
  1997年   2328篇
  1996年   2429篇
  1995年   2311篇
  1994年   2045篇
  1993年   1866篇
  1992年   1646篇
  1991年   1437篇
  1990年   1221篇
  1989年   1143篇
  1988年   1091篇
  1987年   873篇
  1986年   681篇
  1985年   779篇
  1984年   821篇
  1983年   497篇
  1982年   634篇
  1981年   515篇
  1980年   464篇
  1979年   389篇
  1978年   305篇
  1977年   271篇
  1976年   293篇
  1975年   186篇
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
91.
目的分析托珠单抗的安全性风险,为临床合理用药提供参考。方法对世界卫生组织药品不良反应监测数据库、我国药品不良反应监测数据库、国内文献数据库中的不良反应报告情况及国外药监机构风险控制措施等相关资料进行整理与分析。结果应重视托珠单抗临床使用中可能发生的肝功能异常、皮肤损害、过敏反应、胃肠道损害、感染、血液系统损害等不良反应。结论托珠单抗临床使用中,应加强对严重感染及肝功能损害等严重不良反应的安全性监测,促进药品的临床合理使用。  相似文献   
92.
The Impella 5.0, a percutaneously inserted left ventricular assist device, has been used to support patients who have severe heart failure or who are undergoing high-risk percutaneous coronary intervention. We report our surgical placement of the Impella 5.0, through a graft sewn to the aorta, to unload the left ventricle of a 59-year-old man who was undergoing venoarterial extracorporeal membrane oxygenation for postcardiotomy shock. The patient underwent successful placement of a long-term left ventricular assist device before his discharge from the hospital. The versatility of the Impella 5.0 is exemplified in this patient who was successfully bridged to long-term support.  相似文献   
93.
94.
Background and Study AimsIn developing countries, endemic indications, blood shortages, and the scarcity of liver surgeons and intensive care providers can affect liver resection (LR) outcomes, but these have been rarely addressed in the literature. Therefore, in this study we determined risk factors for major complications after LR in a North African general surgery and teaching department.Patients and MethodsFrom January 2010 to December 2015, 213 consecutive LRs were performed on 203 patients. All patients underwent a postoperative follow-up of >90 days. Postoperative complications were assessed according to the Clavien–Dindo (CD) classification of surgical complications. A score of CD ≥III is considered as major postoperative complications. In this study, we analyzed the variables assumed to affect these complications.ResultsThe overall 90-day complication rate was 35.7% (n = 76), including a CD ≥III of 14% (n = 30) and a mortality rate of 6.1% (n = 14). According to the multivariate analysis, a preoperative performance status (PS) of ≥2 (P = 0.011; odds ratios [OR], 6.8; 95% confidence intervals [CI], 1.55–29.8), an estimated intraoperative blood loss of >500 ml (P = 0.002; OR, 3.71; 95% CI, 1.23–11.20), and bilioenteric anastomosis (P < 0.004; OR, 7.76; 95% CI, 1.5–3.89) were independent risk factors for major complications after LR.ConclusionWe recommend that, in the setting of a non-Eastern/non-Western general surgery and teaching department, patients with a PS of ≥2 should undergo a specific selection and preoperative optimization protocol; intermittent clamping indications should be extended; and special attention should paid to patients undergoing LR associated with biliary reconstruction, such as for perihilar cholangiocarcinoma.  相似文献   
95.
96.
In May 2017, the Health and Environmental Sciences Institute's Genetic Toxicology Technical Committee hosted a workshop to discuss whether mode of action (MOA) investigation is enhanced through the application of the adverse outcome pathway (AOP) framework. As AOPs are a relatively new approach in genetic toxicology, this report describes how AOPs could be harnessed to advance MOA analysis of genotoxicity pathways using five example case studies. Each of these genetic toxicology AOPs proposed for further development includes the relevant molecular initiating events, key events, and adverse outcomes (AOs), identification and/or further development of the appropriate assays to link an agent to these events, and discussion regarding the biological plausibility of the proposed AOP. A key difference between these proposed genetic toxicology AOPs versus traditional AOPs is that the AO is a genetic toxicology endpoint of potential significance in risk characterization, in contrast to an adverse state of an organism or a population. The first two detailed case studies describe provisional AOPs for aurora kinase inhibition and tubulin binding, leading to the common AO of aneuploidy. The remaining three case studies highlight provisional AOPs that lead to chromosome breakage or mutation via indirect DNA interaction (inhibition of topoisomerase II, production of cellular reactive oxygen species, and inhibition of DNA synthesis). These case studies serve as starting points for genotoxicity AOPs that could ultimately be published and utilized by the broader toxicology community and illustrate the practical considerations and evidence required to formalize such AOPs so that they may be applied to genetic toxicity evaluation schemes. Environ. Mol. Mutagen. 61:114–134, 2020. © 2019 Wiley Periodicals, Inc.  相似文献   
97.
PurposeTo investigate dynamic variables obtained from retrospective computed tomography angiography for ability to predict thoracic endovascular aortic repair (TEVAR) outcomes in patients with complicated type B aortic dissection (cTBAD).Materials and MethodsSeventy-nine patients with cTBAD who received TEVAR from March 2009 to June 2018 were retrospectively enrolled. Relative true lumen area (r-TLA) was computed at the level of tracheal bifurcation every 5% of all R-R intervals. Parameters that reflect the state of intimal motion were evaluated, including difference between maximum and minimum r-TLA (D-TLA) and true lumen collapse. The endpoints comprised early (≤ 30 days) and late (> 30 days) outcomes after intervention.ResultsOverall early mortality rate was 13.9% (11/79), and early adverse events rate was 24.1% (19/79). Patients who received TEVAR within 2 days of symptom onset demonstrated the worst outcomes. A longer time of r-TLA < 25% in 1 cardiac cycle (P = .049) and larger D-TLA (P < .001) were correlated to an increased early death. In addition, D-TLA was an independent predictor of early mortality. Area under the curve of D-TLA was 0.849 (95% confidence interval 0.730–0.967) for predicting early mortality and 0.742 (95% CI 0.611–0.873) for predicting early adverse events. Survival and event-free survival rates during follow-up were decreased in the D-TLA > 21.5% group compared with the D-TLA ≤ 21.5% group (all P < .001).ConclusionsLarger D-TLA is correlated with worse postoperative outcomes and might be a crucial parameter for future risk stratification in patients with cTBAD.  相似文献   
98.
目的:探讨中西医结合护理干预妊娠晚期合并急性单纯性阑尾炎的临床疗效。方法:将2017 年9 月—2018 年12月于我院接受中西医结合保守治疗的31 例妊娠晚期合并急性单纯性阑尾炎患者作为研究对象,按随机数表法随机分为中西医结合护理组(观察组16 例)与常规护理组(对照组15 例),对照组采取常规护理措施,观察组在对照组的基础上增加中西医结合护理措施,对比两组患者的临床疗效。结果:观察组患者的心理状态变化、新生儿体质状况以及临床疗效等指标等情况均明显优于对照组,且组间对比差异显著有统计学意义(P < 0.05)。结论:中西医结合护理对妊娠晚期合并急性单纯性阑尾炎有较好的临床效果,可减少、甚至避免孕妇因合并急性阑尾炎而造成的打击和创伤。  相似文献   
99.
100.
Determining aortic stenosis (AS) severity is clinically important. Calculating aortic valve (AV) area by means of the continuity equation assumes a circular left ventricular outflow tract (LVOT). The full impact of this assumption in calculating AV area is unknown. Predictors of noncircular LVOT shape in patients with AS are undefined.In 109 adult patients with AS who underwent multiplanar transesophageal echocardiography, we calculated AV area by means of the standard continuity method and by a modified method involving planimetric LVOT area.We found 54 circular, 37 horizontal-oval, 8 vertical-oval, and 10 irregular LVOTs. Area derived by direct planimetry correlated better with the modified than the standard continuity method (r=0.89 vs r=0.85; both P=0.0001). Valve areas of patients with mild, moderate, or severe AS by planimetry were more often mischaracterized with use of the standard than modified method (29 vs 18; P <0.0001). Horizontal-oval AV area derived by planimetry (1.28 ± 0.55 cm2) was underestimated by the standard method (1.05 ± 0.47 cm2; P=0.001), but not by the modified method. Congenital AV morphology and low cardiac index were the only multivariate predictors of horizontal-oval shape. Low cardiac index was the only predictor of noncircular shape.More than half our patients with AS had noncircular LVOTs. Using the modified method reduces mischaracterizations of AS severity. Congenital AV morphology and low cardiac index predict horizontal-oval or noncircular shape. These data suggest the value of direct LVOT measurement to calculate AS severity in patients who have congenital AV or a low cardiac index.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号