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   88212篇
  免费   7123篇
  国内免费   1911篇
耳鼻咽喉   558篇
儿科学   4052篇
妇产科学   1278篇
基础医学   8897篇
口腔科学   1203篇
临床医学   12106篇
内科学   13969篇
皮肤病学   929篇
神经病学   2819篇
特种医学   2403篇
外国民族医学   3篇
外科学   11012篇
综合类   12836篇
现状与发展   15篇
预防医学   13434篇
眼科学   458篇
药学   6989篇
  101篇
中国医学   1999篇
肿瘤学   2185篇
  2024年   278篇
  2023年   1604篇
  2022年   3371篇
  2021年   4615篇
  2020年   4274篇
  2019年   3170篇
  2018年   3066篇
  2017年   3072篇
  2016年   3331篇
  2015年   3370篇
  2014年   5690篇
  2013年   6375篇
  2012年   5340篇
  2011年   5594篇
  2010年   4219篇
  2009年   3984篇
  2008年   3793篇
  2007年   3887篇
  2006年   3771篇
  2005年   3306篇
  2004年   3007篇
  2003年   2768篇
  2002年   1755篇
  2001年   1611篇
  2000年   1286篇
  1999年   1196篇
  1998年   1031篇
  1997年   948篇
  1996年   790篇
  1995年   768篇
  1994年   704篇
  1993年   622篇
  1992年   614篇
  1991年   516篇
  1990年   419篇
  1989年   412篇
  1988年   349篇
  1987年   305篇
  1986年   278篇
  1985年   351篇
  1984年   248篇
  1983年   184篇
  1982年   225篇
  1981年   175篇
  1980年   125篇
  1979年   100篇
  1978年   88篇
  1977年   69篇
  1976年   67篇
  1975年   26篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
PurposeTo determine if cone-beam CT and digital subtraction angiography analysis of pelvic arterial anatomy has predictive value for radiation exposure and technical success of prostatic artery embolization (PAE).Materials and MethodsThis prospective, nonrandomized, single-center study included 104 consecutive patients with lower urinary tract symptoms secondary to benign prostatic hyperplasia. Cone-beam CT was performed in 160/208 (76.9%) hemipelves to determine prostatic artery (PA) origin. Classification of pelvic arterial tortuosity was possible in 73/104 (70.2%) patients. Learning curves of 2 interventionalists who performed 86.5% of PAEs were analyzed.ResultsTortuosity of pelvic arteries was classified as mild in 25 (34.2%) patients median age 64 years, moderate in 40 (54.8%) patients median age 69 years, and severe in 8 (11.0%) patients median age 70 years (mild vs moderate, P = .002; mild vs severe, P = .019); median fluoroscopy times were 24, 36, and 46 minutes (P = .008, P = .023); median contrast volumes were 105, 122.5, and 142 mL (P = .029, P = .064); and bilateral PAE rates were 84.0%, 77.5%, and 62.5% (P = .437), respectively. PA origin from superior vesical artery was most frequent (27.5%) and showed higher dose area product (median 402.4 vs 218 Gy ∙ cm2, P = .033) and fluoroscopy time (median 42.5 vs 27 min, P = .01) compared with PA origin from obturator artery, which was least frequent. Interventionalist experience revealed significant impact on procedure times (median 159 vs 130 min, P = .006).ConclusionsTortuosity of pelvic arteries was more frequent in older patients and predicted worse technical outcomes of PAE. PA origin from obturator artery was associated with lower dose area product and fluoroscopy time, especially compared with PA origin from superior vesical artery. Interventionalist experience showed significant influence on technical outcome.  相似文献   
2.

Background

Whether prolonged operative time is an independent risk factor for subsequent surgical site infection (SSI) and periprosthetic joint infection (PJI) following total joint arthroplasty (TJA) remains a clinically significant and underexplored issue. The aim of this study is to investigate the association between operative time and the risk of subsequent SSI and PJI in patients undergoing primary TJA.

Methods

We retrospectively reviewed 17,342 primary unilateral total knee arthroplasty and total hip arthroplasty performed at a single institution between 2005 and 2016, with a minimum follow-up of 1 year. A multivariate logistic regression model was conducted to identify the association between operative time and the development of SSI within 90 days and PJI within 1 year.

Results

Overall, the incidence of 90-day SSI and 1-year PJI was 1.2% and 0.8%, respectively. Patients with an operative time of >90 minutes had a significantly higher incidence of SSI and PJI (2.1% and 1.4%, respectively) compared to cases lasting between 60 and 90 minutes (1.1% and 0.7%), and those lasting ≤60 minutes (0.9% and 0.7%, P < .01). In the multivariate model, the risk for infection increased by an odds ratio of 1.346 (95% confidential interval 1.114-1.627) for 90-day SSI and 1.253 (95% confidential interval 1.060-1.481) for 1-year PJI for each 20-minute increase in operative time.

Conclusion

In patients undergoing primary TJA, each 20-minute increase in operative time was associated with nearly a 25% increased risk of subsequent PJI. We advocate that surgeons pay close attention to this underappreciated risk factor while maintaining safe operative practices, which minimize unnecessary steps and wasted time in the operating room.  相似文献   
3.
目的:比较经鼻导管高流量吸氧(HFNC)与经鼻气道正压通气(nCPAP)在重症毛细支气管炎呼吸支持中的应用价值,为临床治疗方案的选择提供参考。方法:选取2016年12月至2018年12月我院儿科收治的重症毛细支气管炎患儿90例,采用随机数字表法分为观察组和对照组各45例。两组患儿入院后均给予常规综合治疗以保证呼吸道通畅,在此基础上观察组采用HFNC治疗,对照组采用nCPAP治疗,比较两组患儿治疗前和治疗24 h后呼吸频率、经皮血氧饱和度(TcSO2)、呼吸窘迫评分体系(CSS)评分、动脉血氧分压(PaO2)等呼吸相关指标及治疗前后临床症状体征改善情况。结果:两组患儿治疗24 h后呼吸频率、CSS评分均降低,且观察组降低程度更大,TcSO2、PaO2于治疗24 h后升高,观察组升高幅度较对照组明显;治疗后两组患儿咳嗽及肺部湿啰音、肺部炎症情况均改善,观察组症状体征消失时间早于对照组,差异均有统计学意义(P<0.05)。结论:重症毛细支气管炎患儿采用HFNC治疗可明显改善通气功能和临床症状,治疗效果优于nCPAP治疗,可扩大样本量进一步观察。  相似文献   
4.
目的:分析鼻塞式同步间歇正压通气(NIPPV)联合布地奈德雾化治疗ARDS(新生儿急性呼吸窘迫综合征)疾病的临床应用效果。方法:纳入病例是2017年5月—2019年11月收治的104例ARDS新生儿,随机平均分为两组。参照组52例采纳CPAP(持续气道正压通气通气)治疗,实验组52例采纳NIPPV+布地奈德雾化治疗,对比两组呼吸机通气时间、用氧时间、住院时间、血气指标以及并发症发生情况。结果:实验组呼吸机通气时间、用氧时间、住院时间均明显短于参照组,差异有统计学意义P<0.05;实验组治疗3 d后PaCO2明显低于参照组,实验组治疗3 d后PH以及PaO2明显高于参照组,差异有统计学意义P<0.05;实验组并发症发生率(3.85%,2/52)明显低于参照组(21.15%,11/52),差异有统计学意义P<0.05。结论:NIPPV+布地奈德雾化可有效缩短ARDS患者机械通气时间,改善血气指标,降低并发症发生率,值得借鉴。  相似文献   
5.
目的通过研究肺表面活性物质(PS)结合持续气道正压通气(CPAP)治疗新生儿呼吸窘迫综合征(NRDS)的治疗效果,进一步指导NRDS的临床治疗。方法选取于2017年4月-2018年10月间在本院收治的80例确诊为新生儿呼吸窘迫综合征的患儿作为研究对象,随机将患儿分为试验组和对照组,对照组给予持续气道正压通气治疗,试验组在对照组的基础上联合使用PS治疗。结果试验组对于呼吸窘迫缓解的有效率明显高于对照组,在气管插管内滴入PS治疗后试验组的血气情况明显优于对照组,且试验组患儿副作用发生率明显低于对照组,以上指标差异具有统计学意义,P <0.05。结论 PS结合CPAP在新生儿呼吸窘迫综合征的治疗中疗效很好。  相似文献   
6.
7.
Objective: To report a case of labour induction during extracorporeal membrane oxygenation (ECMO) support in a patient with acute respiratory distress syndrome (ARDS) caused by influenza and review of the literature.

Methods: Case report and the literature search of all English articles on delivery while on ECMO in patients with ARDS caused by influenza.

Results: A 25-year-old pregnant woman was initiated with ECMO due to severe ARDS caused by influenza A (H1N1) virus. When the patient had symptoms of colporrhagia and uterine contractions, the medical team decided to start labour induction while on ECMO. There were in total five case reports identified. Maternal oxygenation was improved after delivery and ECMO was successfully discontinued.

Conclusions: Maternal oxygenation was improved after delivery, which may be beneficial to reduce the duration of ECMO. Caesarean section (CS) may be the most used mode and labour induction could be another option. The procedure should be performed by an experienced ECMO team, cooperating with the obstetrician, anaesthesiologist, and ICU doctors.  相似文献   

8.
目的:探讨福赛类杆菌与人类唾液富脯蛋白相互作用的蛋白分子。方法:Western—blot方法。将人工合成唾液富脯蛋白用生物素标记,福赛类杆菌全菌蛋白凝胶电泳,半干转移至纤维膜上,观察二者的相互作用。结果:富脯蛋白能与分子量为85KD、65KD、60KD、以及49KD的福赛类杆菌蛋白发生结合。结论:福赛类杆菌存在与人类唾液富脯蛋白相互结合的粘附素。  相似文献   
9.
目的治疗顽固性下颌磨牙根尖周炎。并尽量减少对牙周膜的机械性损伤。方法采用下牙槽神经阻滞麻醉,并配合局部麻醉。拔牙钳的尖置放于釉牙骨质界以上,采用颊舌向摆动的方式将患牙拔下。在不断滴有生理盐水的条件下,立即用高速车针磨除患牙根尖2 ̄3mm的牙体组织,根管内3 ̄5mm深的充填物要用圆钻将其清除,再用牙胶尖和氢氧化钙糊剂充填。将患牙再植入牙槽窝之前,务必用生理盐水将牙槽窝冲洗干净,要求严格控制在15分钟内完成再植,并尽量减少对牙周膜的机械性损伤。再植牙齿一般不需要夹板固定,必要时可采用缝线缝合固定。结果我们选择的5例患者,术后随访1 ̄2年,1例患者再植失败,4例患者再植成功。结论特异性再植术治疗顽固性下颌磨牙根尖周炎疗效理想,而且较易掌握。  相似文献   
10.
AIM: To evaluate the usefulness of urodynamic study in young men with lower urinary tract symptoms (LUTS). METHODS: We reviewed the charts of 50 men with LUTS aged 50 years and below. Those with neurological diseases, urethral trauma or strictures were excluded. All underwent multichannel urodynamic studies (UDS). The pre- and post-UDS diagnoses and treatment modalities were compared. RESULTS: Mean age was 38.1 years (17-49). The main pre-UDS diagnoses included prostatitis in seven (14%), overactive bladder in seventeen (34%) and benign prostatic hyperplasia in nine (18%). Pre-UDS management ranged from anticholingeric agents for thirteen (26%), alpha-adrenergic antagonists for nine (18%), antibiotics for six (12%). Abnormal UDS were noted in 36 (72%), including detrusor overactivity in 9 (18%), detrusor underactivity/acontractility in 5 (10%) and bladder outlet obstruction in 21 (42%). Fourteen (28%) had primary bladder neck dysfunction and five (10%) had benign prostatic hyperplasia. Post-UDS management included anticholingeric agents for ten (26%), alpha-adrenergic antagonists for seventeen (34%), catheterization for four (10%), behavioral therapy for three (6%), surgery for three (6%). None were prescribed antibiotics. Following UDS, the diagnosis had to be updated in 40 (80%) and concomitant change in management was required in 34 (68%). CONCLUSION: Young men presenting with LUTS have different underlying etiologies. Clinical diagnosis and treatment are often empiric and inaccurate. Urodynamic study is useful in the evaluation of this group of patients as it aids in arriving at an accurate diagnosis and guides treatment therapy.  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