全文获取类型
收费全文 | 40667篇 |
免费 | 4292篇 |
国内免费 | 2719篇 |
专业分类
耳鼻咽喉 | 298篇 |
儿科学 | 516篇 |
妇产科学 | 461篇 |
基础医学 | 4752篇 |
口腔科学 | 839篇 |
临床医学 | 5281篇 |
内科学 | 5930篇 |
皮肤病学 | 430篇 |
神经病学 | 1860篇 |
特种医学 | 1463篇 |
外国民族医学 | 17篇 |
外科学 | 4309篇 |
综合类 | 6962篇 |
现状与发展 | 12篇 |
一般理论 | 15篇 |
预防医学 | 2983篇 |
眼科学 | 1339篇 |
药学 | 4002篇 |
58篇 | |
中国医学 | 2414篇 |
肿瘤学 | 3737篇 |
出版年
2024年 | 166篇 |
2023年 | 764篇 |
2022年 | 1827篇 |
2021年 | 2362篇 |
2020年 | 1734篇 |
2019年 | 1502篇 |
2018年 | 1522篇 |
2017年 | 1380篇 |
2016年 | 1289篇 |
2015年 | 1932篇 |
2014年 | 2420篇 |
2013年 | 2245篇 |
2012年 | 3123篇 |
2011年 | 3411篇 |
2010年 | 2182篇 |
2009年 | 1839篇 |
2008年 | 2215篇 |
2007年 | 2146篇 |
2006年 | 2188篇 |
2005年 | 1845篇 |
2004年 | 1343篇 |
2003年 | 1155篇 |
2002年 | 968篇 |
2001年 | 849篇 |
2000年 | 803篇 |
1999年 | 827篇 |
1998年 | 530篇 |
1997年 | 487篇 |
1996年 | 372篇 |
1995年 | 326篇 |
1994年 | 324篇 |
1993年 | 185篇 |
1992年 | 238篇 |
1991年 | 190篇 |
1990年 | 152篇 |
1989年 | 197篇 |
1988年 | 133篇 |
1987年 | 137篇 |
1986年 | 63篇 |
1985年 | 71篇 |
1984年 | 46篇 |
1983年 | 30篇 |
1982年 | 26篇 |
1981年 | 26篇 |
1980年 | 19篇 |
1979年 | 26篇 |
1978年 | 11篇 |
1977年 | 5篇 |
1975年 | 9篇 |
1974年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
92.
John D. Friedman Daniel S. Berman Hosen Kiat James Bietendorf Mark Hyun Kenneth F. Van Train Fan Ping Wang 《Journal of nuclear cardiology》1994,1(4):382-388
Background
To assess the accuracy of rest and treadmill exercise first-pass radionuclide ventriculographic measurements of left ventricular ejection fraction (LVEF), 40 patients underwent treadmill exercise first-pass and bicycle exercise equilibrium radionuclide ventriculography. To determine the frequency of technically adequate treadmill exercise first-pass studies, an additional 128 consecutive patients undergoing treadmill exercise first-pass procedures during stress99mTc-labeled sestamibi myocardial perfusion studies were assessed.Methods and Results
The treadmill exercise first-pass procedure used a multicrystal camera and an241Am point source to allow for correction of patient motion. Excellent correlations were observed between resting first-pass and resting equilibrium LVEF (r=0.91; standard error of the estimate=5.6). A high correlation was also observed between treadmill exercise first-pass and bicycle equilibrium exercise LVEF measurements (r=0.85, standard error of the estimate=7.6). Treadmill first-pass LVEF systematically underestimated the bicycle equilibrium LVEF. Intraobserver agreement for rest and exercise first-pass LVEF was high (r values of 0.98 and 0.94, respectively). Of the 168 consecutive treadmill exercise first-pass studies evaluated for technical adequacy, 21 (12.5%) were deemed technically inadequate, with most of the sources of error being avoidable. The frequency of technically adequate studies was as high (87%) in high levels of exercise (Bruce stages 3 and 4) as in lower levels (88%). The findings of this study validate the first-pass treadmill exercise LVEF measurement.Conclusion
This procedure now provides the option for combining the information of peak treadmill exercise LVEF with measurements of exercise myocardial perfusion from the same injection of radioactivity. 相似文献93.
Vagal Nerve Monitoring during Parapharyngeal Space Tumor Removal 总被引:1,自引:0,他引:1
The vagus nerve innervates the intrinsic and extrinsic laryngeal musculature as well as the complex pharyngeal plexus. Acute paralysis of this nerve results in dysfunctional speech, deglutition, and airway protection. These untoward effects, which lead to additional infectious and aerodigestive complications, may arise following manipulation of the vagus nerve during the surgical removal of a variety of neoplasms found in the parapharyngeal space.The vagal nerve has been intraoperatively monitored in an effort to maintain its anatomic and functional integrity. Bipolar hook-wire electrodes are introduced transcutaneously through the cricothyroid membrane and are guided into the vocalis muscle by an assistant performing direct laryngoscopy. Continuous, real-time monitoring of the vagal nerve is provided by audio and visual feedback to the operating surgeon. Potentially injurious stretching, heating, and compression of the nerve are easily detected, and monopolar stimulation of the nerve is used to map the nerve's course through the tumor bed.This presentation outlines our technique for vagal nerve monitoring in patients with tumors of the parapharyngeal space and intact preoperative vocal cord mobility. Selected cases are presented and illustrated through intraoperative and postoperative videotapes. 相似文献
94.
The aim of this study was to compare the survival of 116 patients with breast cancer initially treated at the First Teaching Hospital (FTH) of Norman Bethune University of Medical Sciences located in Changchun, China, from 1986 to 1991 with the survival of 886 patients seen in the “Hipital du Saint-Sacrement” (HSS) located in Quebec City, Canada, from 1987 to 1992. The clinical data were collected from the hospital records at FTH. The vital status for Chinese patients was obtained from letters of follow-up or the records of local police offices. The list of patients treated at HSS and the data for each woman were extracted from computerized data banks. The major variables studied included age at diagnosis, tumor size at pathology (cm), number of lymph nodes involved, breast surgery and adjuvant treatments of breast cancer (chemotherapy, radiotherapy, immuno-therapy). Age at diagnosis was substantially lower among patients with breast cancer seen at FTH compared to those treated at HSS (x) 1 2 =60.95,P<0.0001). The average age at diagnosis for Chinese women was about 10 years less than that for Canadian women. Patients in the two hospitals differed with respect to tumor size at pathology (x 2 2 =6.67,P=0.036). The proportion of patients with tumor size larger than 2.0 cm was larger at FTH (48.3%) than at HSS (41.1%). The mean tumor size at pathology was 3.0 cm (standard deviation =2.1 cm) for patients treated at FTH, but 2.6 cm (standard deviation=1.8 cm) for women treated at HSS (P=0.07). The proportion of women with lymph node involvement was greater at FTH (61.1 % than that at HSS (37.3%) (x 1 2 =16.51,P<0.0001). Surgical treatment of breast cancer varied considerably. In Changchun, radical mastectomy was frequent for any stage of breast cancer patients, but partial mastectomy was never performed. The situation was reversed in Quebec. The five year observed survival was 74.2% (standard error, 0.05) among breast cancer patients seen at FTH compared to 76.0% (standard error, 0.02) among women treated at HSS. After adjustments of confounding factors, there were no significant difference in five year observed survival between the patients treated at the two hospitals (P=0.42). 相似文献
95.
目的 探索不健康行为生活方式与高尿酸血症的关系,以及高血压、血脂异常的效应修饰作用,为预防高尿酸血症提供理论依据。方法 采用横断面调查研究设计,基于2021年10-12月来自四川省、贵州省28个地级市和重庆市33个区(县)中国铁路成都局集团有限公司的西南职业人群队列基线数据,通过问卷调查、体格测量及实验室生化检测收集研究对象的人口学特征、行为生活方式、慢性非传染性疾病患病情况。不健康行为生活方式得分根据吸烟、饮酒、膳食模式、体力活动和低体重/超重状况进行评分,分值越高不健康行为生活方式越多。采用多因素logistic回归模型分析不健康行为生活方式评分、吸烟状况、饮酒状况等与高尿酸血症的关系,采用分层分析探索高血压等疾病对不健康行为生活方式与高尿酸血症之间关系的修饰效应。结果 共纳入11 748名研究对象,高尿酸血症患病率为34.4%。多因素logistic回归分析显示,现在吸/既往吸烟、现在饮/既往饮酒及BMI异常是高尿酸血症患病的危险因素,不健康行为生活方式对高尿酸血症患病风险呈现累积效应,随着得分的升高,高尿酸血症患病风险升高,OR值由1.64(95%CI:1.34~2.00)上升至2.89(95%CI:2.39~3.50)。分层分析结果显示,在高血压及血脂异常人群中,不健康行为生活方式对高尿酸血症患病风险影响更大。结论 多种不健康行为生活方式的共存会升高高尿酸血症患病风险,这一效应在高血压、血脂异常人群中更明显。及时纠正不健康行为生活方式,并控制高血压和血脂异常,降低患高尿酸血症的风险。 相似文献
96.
目的 探讨上海市≥50岁人群维生素D水平与握力的关系。方法 数据来源于WHO全球老龄化与成人健康研究我国上海市2018-2019年数据,采用logistic回归模型分析维生素D水平与握力的关系,进一步按照性别、年龄及乳制品摄入情况进行分层;采用限制性立方样条曲线绘制维生素D水平与低握力的剂量-反应曲线。结果 共4 391人纳入研究,其中男性2 054人(46.8%);年龄(67.02±8.81)岁;低握力1 421人(32.4%);维生素D不足及缺乏分别为1 533人(34.9%)和401人(9.1%)。在调整相关混杂因素后,logistic回归分析结果显示,维生素D缺乏的人群发生低握力的风险更高(OR=1.41,95%CI:1.09~1.83);在男性中,调整相关混杂因素后,维生素D缺乏与低握力发生风险呈显著正相关(OR=1.67,95%CI:1.12~2.50),而女性中两者之间无关联(OR=1.30,95%CI:0.97~1.74);在60~69岁及≥80岁年龄组中,调整相关混杂因素后,维生素D缺乏与低握力发生风险呈显著正相关(OR=1.57,95%CI:1.05~2.35;OR=2.40,95%CI:1.08~5.31),在乳制品摄入<250 ml/d的人群中,调整相关混杂因素后,二者之间呈显著正相关(OR=1.57,95%CI:1.17~2.09),而在乳制品摄入≥250 ml/d的人群中无明显关联。限制性立方条样图显示,低握力的发生风险可能随维生素D含量的上升而降低,但差异无统计学意义(P>0.05)。结论 维生素D水平与握力存在一定的关系,维生素D缺乏人群出现低握力的风险更高。 相似文献
97.
98.
恶性肿瘤脑转移预后与原发肿瘤类型有关,一般而言,肾癌脑转移患者中位生存比其它恶性肿瘤的要差。脑转移最佳治疗仍有争论,但就大多数患者而言全脑放射仍是主要治疗方法。本文分析32例肾癌术后脑转移单纯全脑放射治疗结果,以探讨肾癌脑转移治疗及相关预后因素。1临床资料与方法1.亚临床资料我院1992年元月~1997年4月共32例肾癌术后脑转移接受全脑放射治疗,其中男22例,女10例,中位年龄52.5(32~64.5)岁。原发肿瘤组织学类型包括肾细胞癌27例,Wilm’s瘤3例和混合细胞癌2例。左肾癌14例,右肾癌18例,32例全部作了肾癌根治术。… 相似文献
99.
目的:探讨异丙酚乳剂用于腹腔镜胆囊切除术麻醉中的优缺点。方法:100例施行腹腔镜胆囊切除术患者,随机分为异丙酚组40例,硫喷妥钠组60例。观察记录两组患者手术前、给药后1min、气管插管时、插管后5min、CO2气腹后3min血流动力学各参数并观察停药后患者苏醒情况及麻醉副作用等。结果:异丙酚比硫喷妥钠更适用于腹腔镜胆囊切除术麻醉,但也要注意异丙酚对呼吸、循环系统功能的抑制作用。 相似文献
100.
α-细辛脑对气管纤毛运动的影响 总被引:44,自引:0,他引:44
目的:研究α-细辛脑对气管纤毛运动的影响,探讨其祛痰作用机理。方法:采用鸽子在体气管和家兔离体气管试验:设空白、阳性对照组及α-细辛脑高、中、低剂理组,以墨汁走距和运行速度作为气管纤毛运动指标,各试验组与空白对照组进行t检验。比较其组间差异。结果:给浅度麻醉的鸽子静脉注射α-细辛脑32mg/kg、16mg/kg、8mg/kg,墨汁走距分别为(1.17±0.12)cm,(1.15±0.17)cm和( 相似文献