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   95399篇
  免费   5978篇
  国内免费   2691篇
耳鼻咽喉   455篇
儿科学   1217篇
妇产科学   833篇
基础医学   5895篇
口腔科学   926篇
临床医学   13644篇
内科学   28835篇
皮肤病学   146篇
神经病学   4895篇
特种医学   6478篇
外国民族医学   3篇
外科学   10816篇
综合类   15810篇
现状与发展   7篇
预防医学   2361篇
眼科学   2056篇
药学   6032篇
  69篇
中国医学   2824篇
肿瘤学   766篇
  2024年   125篇
  2023年   1456篇
  2022年   2235篇
  2021年   3952篇
  2020年   3608篇
  2019年   3042篇
  2018年   3167篇
  2017年   2839篇
  2016年   2877篇
  2015年   3150篇
  2014年   6615篇
  2013年   6386篇
  2012年   5419篇
  2011年   5969篇
  2010年   4956篇
  2009年   4876篇
  2008年   5071篇
  2007年   5180篇
  2006年   4666篇
  2005年   3923篇
  2004年   3112篇
  2003年   2639篇
  2002年   2229篇
  2001年   2052篇
  2000年   1573篇
  1999年   1394篇
  1998年   1402篇
  1997年   1329篇
  1996年   1072篇
  1995年   1007篇
  1994年   820篇
  1993年   753篇
  1992年   662篇
  1991年   566篇
  1990年   473篇
  1989年   382篇
  1988年   393篇
  1987年   376篇
  1986年   319篇
  1985年   359篇
  1984年   328篇
  1983年   211篇
  1982年   253篇
  1981年   210篇
  1980年   146篇
  1979年   143篇
  1978年   108篇
  1977年   80篇
  1976年   62篇
  1975年   40篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
BackgroundDistortion is an intrinsic phenomenon associated with image-intensified fluoroscopy that is both poorly understood and infrequently appreciated by orthopedic surgeons. Little information exists regarding its potential influence on intraoperative parameters during orthopedic surgery, let alone during direct anterior (DA) total hip arthroplasty (THA). The purpose of this study was to quantify the amount of potential error caused by fluoroscopic distortion during DA THA.MethodsIntra-operative fluoroscopic pelvic images from 74 DA THAs were reviewed by two independent readers. All images were obtained using the same fluoroscopic C-arm unit with a radiopaque grid attached to the image intensifier. The vertical distortion from a straight central horizontal line at the peripheries of images were measured and summed to yield the combined vertical distortion similar to how a surgeon calculates a side to side comparison of limb lengths. Simple linear regression was used to evaluate associations between total distortion and patient demographics, operating theaters, and various operative parameters.ResultsThe average combined distortion was 10.0mm (range 2.0-20.0mm). There was a significant difference in the average distortion observed in different theaters (P < .001). There was no association between distortion and patient demographics or fluoroscopic time (all, P > .05).ConclusionFluoroscopic distortion is unpredictable and can cause a substantial amount of error when comparing limb lengths during DA THA. This is a critical finding as this amount of inaccuracy could lead to unintended implant positioning and limb-length discrepancies if unaccounted for.  相似文献   
992.
BackgroundThe direct anterior approach (DAA) is a popular approach to total hip arthroplasty (THA). Unlike the posterior approach, the importance of anterior capsular management is unknown. This randomized controlled trial compares capsular repair versus capsulectomy.MethodsThis single-surgeon, single-blinded, parallel-group randomized controlled trial occurred between 2013 and 2016. Patients undergoing unilateral, primary THA for osteoarthritis consented to undergo blinded, simple randomization to anterior capsulotomy with repair or anterior capsulectomy. Primary outcome measures included hip range of motion, hip flexion strength, and pain with seated hip flexion. Secondary outcome measures included surgical time, estimated blood loss, postoperative complications, and hip disability and osteoarthritis outcome score. Data were prospectively collected intraoperatively, six weeks, six months, an average of over 5 years postoperatively.ResultsNinety-eight patients were ultimately enrolled in the trial; 50 received capsulectomy and 48 received capsulotomy. No significant differences were seen in preoperative demographics or in primary or secondary outcomes during this study. No difference was seen in pain at final follow-up at average > 5 years postoperatively.ConclusionThis study demonstrates that capsular management in DAA THA does not affect postoperative pain or range of motion. The anterior capsule’s role in prosthetic stability after DAA THA remains uncertain, but it does not currently appear that repair provides benefit and may lead to increased surgical time and blood loss. As such, capsular management in DAA THA is at surgeon discretion.  相似文献   
993.
BackgroundCurved periacetabular osteotomy (CPO) is performed via an anterior approach without detachment of the hip abductor muscles. This study aimed to evaluate the abductor muscle status shortly after CPO on magnetic resonance imaging (MRI).MethodsWe prospectively evaluated 38 hips in 38 patients 1 week and 3 months after CPO between October 2017 and July 2019. The status of the abductor muscles was assessed on MRI using the following criteria: grade 0, normal; grade I, strain/edema; grade II, partial tear; and grade III, complete tear. We also evaluated associations between muscle status and patients’ characteristics.ResultsOne week after CPO, the gluteus maximus was classified as grade 0 in all patients. The gluteus medius was grade 0 in 84.2% of patients and grade I in 15.8%. The gluteus minimus was grade I in 55.3% of patients and grade II in 44.7%. Three months after CPO, both the gluteus maximus and gluteus medius were grade 0 in all patients, while the gluteus minimus was still grade I in 47.4%. There were no significant differences between patients with a grade 0 and grade I gluteus minimus at 3 months after CPO in patients’ characteristics (age and body mass index) or clinical scores (Harris Hip Score and Japanese Orthopedics Association score).ConclusionBoth the gluteus minimus and medius showed abnormal appearances on MRI 1 week after CPO, whereas only the gluteus minimus showed abnormalities 3 months after CPO. This abductor muscle status did not affect the postoperative Harris Hip Score or Japanese Orthopedics Association score.  相似文献   
994.
BackgroundDexamethasone has been shown to reduce postoperative pain and opioid consumption for total joint arthroplasty patients; however, its impact on patients who received neuraxial anesthesia (NA) is not well described. We examined the impact of perioperative dexamethasone on outcomes for patients undergoing direct anterior approach total hip arthroplasty (THA) under NA.MethodsA retrospective review was conducted for 376 THA patients from a single institution. Univariate analysis was used to compare postoperative outcomes for 164 THA patients receiving dexamethasone compared to 212 who did not receive dexamethasone.ResultsNo differences in age, gender, body mass index, or American Society of Anesthesiologists (ASA) Score were observed between the groups. Patients receiving perioperative dexamethasone reported statistically significantly lower postanesthesia care unit (PACU) pain numeric rating scale (Dexamethasone 1.6 vs No dexamethasone 2.3, P = .014) and received lower PACU morphine milligram equivalents (MME) (Dexamethasone 8.57 vs No dexamethasone 11.44, P < .001). Patients receiving dexamethasone had significantly shorter LOS (Dexamethasone 29.40 vs No dexamethasone 35.26 hrs., P < .001).ConclusionPerioperative dexamethasone is associated with decreased postoperative pain and narcotic consumption, and shorter length of stay for patients undergoing primary direct anterior approach THA with NA.  相似文献   
995.
996.
ObjectiveA high coronary artery calcification score (CACS) may be associated with high mortality in patients undergoing hemodialysis (HD). Recently, effects of iron on vascular smooth muscle cell calcification have been described. We aimed to investigate the relationships between iron, CACS, and mortality in HD patients.MethodsWe studied 173 consecutive patients who were undergoing maintenance HD. Laboratory data and Agatston’s CACS were obtained at baseline for two groups of patients: those with CACS ≥400 (n = 109) and those with CACS <400 (n = 64). Logistic regression analyses for CACS ≥400 and Cox proportional hazard analyses for mortality were conducted.ResultsThe median (interquartile range) age and duration of dialysis of the participants were 67 (60–75) years and 73 (37–138) months, respectively. Serum iron (Fe) and transferrin saturation (TSAT) levels were significantly lower in participants with CACS ≥400 than in those with CACS <400, although the serum ferritin concentration did not differ between the groups. TSAT ≥21% was significantly associated with CACS ≥400 (odds ratio 0.46, p<0.05). TSAT ≥17%, Fe ≥63 µg/dL, and ferritin ≥200 ng/mL appear to protect against 5-year all-cause mortality in HD patients, independent of conventional risk factors of all-cause mortality (p < 0.05).ConclusionWe have identified associations between iron, CACS, and mortality in HD patients. Lower TSAT was found to be an independent predictor of CACS ≥400, and iron deficiency (low TSAT, iron, or ferritin) was a significant predictor of 5-year all-cause mortality in HD patients.  相似文献   
997.
Anomalous coronary arteries occur in as many as 12% of patients with tetralogy of Fallot (TOF). In patients with this condition, pulmonary hypoplasia can be prohibitive in performing a valve-sparing repair, subsequently resulting in various techniques to preserve the anomalous coronary artery. The management strategy is often complex in such a situation. We report on a case of TOF with an anomalous right coronary artery crossing the right ventricular outflow tract, with an unusual course of the right ventricular (RV) branch, which precluded placement of a valved conduit. In this case, we performed a successful repair with mobilization of the anomalous coronary artery and reconstruction of the right ventricular outflow tract with a limited transannular patch.  相似文献   
998.
In the context of collateral circulation of the heart, the role of extra-cardiac collateral arteries has been thought to be negligible. We present a case in which such collateral vessel acted as a rescue, subsequent to a failed revascularisation attempt. With surgeons nowadays considering ‘less is more’ in terms of grafting in coronary artery bypass grafting (CABG), and more evidence arising in favour of medical therapy, we need to re-assess the role of these collateral vessels in the coronary circulation.  相似文献   
999.
田甜  景慧  荆莉 《护理学杂志》2021,36(12):26-30
目的 分析与提取颈动脉支架植入术后患者发生谵妄的危险因素,为针对性干预提供参考.方法 统计350例颈动脉狭窄支架植入术后患者谵妄发生率,行单因素和多因素分析获得术后患者谵妄相关危险因素,基此构建列线图预测模型,采用校正曲线和ROC曲线评估其准确度和区分度.结果 60例术后发生谵妄,发生率17.14%;高龄、术前NIHSS评分和术前焦虑是术后发生谵妄的独立危险因素(均P<0.05);由3项独立危险因素构建的谵妄风险列线图预测模型,预测曲线和观察曲线基本吻合,AUC=0.888.结论 颈动脉支架植入术后患者谵妄发生率较高;高龄、术前焦虑及脑卒中倾向是术后患者发生谵妄的危险因素;构建的列线图预测模型具有较好的准确度和区分度,可提高筛选效能.  相似文献   
1000.
BackgroundTardy ulnar nerve palsy is the development of late onset ulnar nerve dysfunction and is usually treated by open anterior transposition of ulnar nerve. Open technique is done using a longitudinal incision about 6–8 inch. in length with chances of development of medial antebrachial cutaneous nerve neuromas.PurposeIn this study, we describe the technique of Endoscopic Anterior Transposition of Ulnar Nerve (EATUN procedure) to treat tardy ulnar nerve palsy and analyze the results.MethodsSeven patients diagnosed to have tardy ulnar nerve palsy was treated by EATUN. The humerus-elbow-wrist angle (HEW), pre- and post-operative intrinsic muscle power and sensory assessment, Dellon scores, and the Q-DASH was analyzed.ResultsThe minimum follow-up was 12 months (Mean 27.4 months, Range 12–36 months). Improvement in Dellon and Q-DASH scores following EATUN procedure was statistically significant. There was objective improvement of intrinsic muscle power and sensation on follow-up, though not statistically significant. No instance of neuroma of the medial cutaneous nerve of forearm was noted.ConclusionsThe endoscopic anterior transposition of the ulnar nerve is a good option in surgical management of tardy ulnar nerve palsy.Level of evidenceTherapeutic Level IV.Supplementary InformationThe online version contains supplementary material available at 10.1007/s43465-021-00366-w.  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