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   27336篇
  免费   1585篇
  国内免费   1155篇
耳鼻咽喉   467篇
儿科学   595篇
妇产科学   68篇
基础医学   1660篇
口腔科学   65篇
临床医学   3082篇
内科学   4675篇
皮肤病学   24篇
神经病学   1895篇
特种医学   2230篇
外科学   8601篇
综合类   3705篇
现状与发展   3篇
预防医学   522篇
眼科学   110篇
药学   981篇
  18篇
中国医学   1026篇
肿瘤学   349篇
  2024年   118篇
  2023年   525篇
  2022年   833篇
  2021年   1165篇
  2020年   1107篇
  2019年   909篇
  2018年   1007篇
  2017年   845篇
  2016年   911篇
  2015年   986篇
  2014年   2007篇
  2013年   1923篇
  2012年   1583篇
  2011年   1665篇
  2010年   1486篇
  2009年   1335篇
  2008年   1192篇
  2007年   1283篇
  2006年   1190篇
  2005年   1000篇
  2004年   871篇
  2003年   787篇
  2002年   615篇
  2001年   547篇
  2000年   476篇
  1999年   451篇
  1998年   379篇
  1997年   365篇
  1996年   300篇
  1995年   289篇
  1994年   256篇
  1993年   245篇
  1992年   201篇
  1991年   147篇
  1990年   118篇
  1989年   124篇
  1988年   109篇
  1987年   93篇
  1986年   90篇
  1985年   97篇
  1984年   79篇
  1983年   41篇
  1982年   88篇
  1981年   57篇
  1980年   45篇
  1979年   42篇
  1978年   26篇
  1977年   19篇
  1976年   15篇
  1975年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
使用Roy-Camille 腰椎、腰骶椎融合术治疗腰椎滑脱14例。采用特制的钢板,一般固定3~4个脊椎。若合并神经根刺激症状可同时作椎板切除、椎间盘摘除、侧隐窝松解术,同时进行丰富的侧后方植骨。经随访平均19个月,均获得骨性融合,无脊髓或神经根损伤等手术并发症。作者认为此手术是治疗腰椎滑脱的比较理想的方法。  相似文献   
72.
本文报告经皮球囊二尖瓣成形术治疗二尖瓣狭窄12例。10例术前平均左房压为18mmHg~40mmHg(26.7±7.15mmHg),术后即刻为4mmHg~18mmHg(10.6±3.86mmHg)P<0.01。跨瓣压差术前10mmHg~40mmHg(19.6±9.05mmHg),术后为0~5mmHg(2.65±2.21mmHg)P<0.01。1例失败,1例术后发生二尖瓣关闭不全急性左心衰竭死亡。  相似文献   
73.
A decrease in ostial pulmonary vein (PV) diameter was observed in patients on the day after radiofrequency ablation of atrial fibrillation (AF). This study examined whether a relative reduction in PV diameter on day 1 (RRPVD1) after the procedure predicts the late development of severe PV stenosis (PVS). The study included 104 consecutive patients (mean age = 55 years, range 46–61, 34 women) with drug refractory AF. Pulmonary vein diameter was measured using MR angiography (MRA) on the day before and on day 1 after the ablation procedure. The MRA was repeated every 3 months after the procedure. Severe PVS was defined as a >70% diameter reduction from the initial ostial diameter. The cut-off of RRPVD1 was prespecified as 25% decrease in initial diameter. The data are presented as medians and interquartile range. A total of 357 PV were treated. The RRPVD1 was 0.0% (0.0–11.1%). Severe PVS was found in 18 PV during a follow-up of 12 months (range 6–13). The log-rank analysis confirmed a strong association between a RRPVD1 ≥25% and the development of PVS (hazard ratio: 7.1; 95% confidence interval 3.8–13.5, P < 0.0001). By multivariate Cox regression model, after adjustment of procedure variables, RRPVD1 was the strongest predictor of development of severe PVS. RRPVD1 ≥25% was a strong independent predictor of development of severe PVS.  相似文献   
74.
Stenosis of the tracheostome is an occasional complication following laryngectomy. Having tried a number of procedures recommended for correction of such stenoses with limited results, we developed a new technique. This technique which is based on multiple Y-V plasties has been applied to 20 patients. Measurements of the stomal area following surgery in 18 patients showed an average increase in stomal size by a factor of 3.8. One patient apparently had no increase of the stoma. In 2, no post-operative measurements were available. Post-operative infection resulted in recurrence of the stenosis in one patient. He was successfully reoperated using the same technique. Follow-up revealed that none of the patients had complaints related to their stoma.  相似文献   
75.
The records of 1018 patients with low back pain in a tertiary spine referral practice were reviewed. One hundred thirty-nine out of 1018 (13.6%) underwent technetium-99m planar bone scanning as part of their investigation. Seventy-three out of 139 scans (52%) showed increased uptake in some area, but only 27 out of 139 (19.4%) showed increased uptake specifically in the low back. Scans consistently yielded no findings with reference to the back when the prescan diagnosis was spinal stenosis, lumbar pain syndrome, herniated nucleus pulposus, or postlaminectomy syndrome. Some scans gave positive findings in patients with a diagnosis of degenerative disc disease, pseudarthrosis, spondylolisthesis, fracture, infection, metabolic disorder, or tumor. Positive scans were generally obtained early after presentation (within 3 months) and negative scans obtained later (after 6 months), suggesting that clinical suspicion is still the main indication for early scanning. Planar bone scanning was helpful in both diagnosis and therapeutic decisionmaking in many conditions.  相似文献   
76.
The aim of this retrospective study of a cohort of 1787 consecutive kidney transplantations was to analyze the risk factors associated with the occurrence of ureteral stenosis and the impact of ureteral stenosis on graft and patient survival. Between January 1990 and December 2002, 1787 renal transplantations were performed at our center. Only stenosis observed after the first month, were considered. Among the parameters studied were: donor age and serum creatinine before procurement; recipient age, cold ischemia time, delayed graft function (DGF), number of arteries and the presence of a double J stent. The follow-up parameters were the number and timing of acute rejection episodes, cytomegalovirus (CMV) infection, acute pyelonephritis, renal function and death. Ureteral stenosis occurred in 4.1% of patients and was correlated with donor age > 65 years (p = 0.001), kidneys with more than 2 arteries (p = 0.009) and DGF (p = 0.016). Ureteral stenosis did not affect 10-year patient and graft survival rates, which were respectively 90% and 64% for the stenosis group, 86% and 63% for the no-stenosis group (p = NS). These data suggest an important role for donor age, number of renal arteries and DGF for the occurrence of ureteral stenosis following renal transplantation.  相似文献   
77.
We report the case of a fracture separation of the articular pillar at the lower cervical spine. The trauma, following a brass knuckles, repeats almost in an experimental way the rotation and extension mechanism given in literature for the genesis of such injuries. From the admission in the orthopaedic service to the surgery, the development went in a characteristic way towards a rotatory displacement. Received: 12 July 2002, Accepted: 18 August 2002 Correspondence to: R. Massicot  相似文献   
78.
颈椎椎体次全切除钛网钉板系统的临床应用   总被引:1,自引:1,他引:0       下载免费PDF全文
目的探讨颈椎前路椎体次全切除钛网钉板植骨融合的临床效果。方法自2001年3月~2003年3月间应用颈前路椎体次全切除钛网植骨融合及钉板固定治疗颈椎管狭窄性疾病22例,其中4例患者行2椎体次全切除3节椎间隙减压手术。术后观察减压、固定、融合及神经功能恢复情况,并行X线摄片或CT扫描检查。结果患者获6~12个月随访,神经功能得到不同程度改善,无加重情况。椎间隙高度无丢失、无成角,均获得骨性融合。术后3d在颈围领固定下下床活动,4周后可恢复较轻工作。结论此术式可避免传统手术方法的缺点,即不取自体髂骨,融合率高,稳定性好,并减压彻底,疗效好,是一种值得推广的新技术。  相似文献   
79.
目的 探讨计算机体层成像多平面重建(CTMPR)在评价椎间融合中的作用,寻找定量评价椎间融合的新方法.方法 13例行腰椎间融合的患者术后1周、3个月、6个月行CTMPR,行椎间融合器(Cage)内植骨CT值定量测量.结果 术后1周Cage内植骨CT值为(619.52±26.97)Hu,术后3个月为(628.69±42.60)Hu,术后6个月为(657.77±37.43)Hu.术后1周与术后3个月相比无显著性差异,与术后6个月相比有显著性差异.结论 CT值的测量在椎间融合的判断中具有高准确性.  相似文献   
80.
Primary aqueductal stenosis is one of the main causes of congenital hydrocephalus in humans and experimental models. The congenitally hydrocephalic rat strain LEW/Jms is one such model. In this report, we describe further detailed histological features of periaqueductal structure, including the posterior commissure, subcommissural organ (SCO), and ependyma, and discuss the changes in these structures in relation to the cause of hydrocephalus. Coronal sections of the aqueduct in normal rats showed that the usual ependyma was absent in the center of the base facing the dorsal side, which was replaced by tall columnar cells. On the other hand, in hydrocephalic rats the ependyma encircled the aqueductal cavity. In midline sagittal sections, normal and hydrocephalic rats showed the SCO, although the SCO in hydrocephalic rats was shorter than in normal rats. There was also a marked difference between normal and hydrocephalic rats in the dorsoventral dimension of the rostral midbrain. In hydrocephalus, this dimension was large in comparison with normal rats. The superior collicular commissure located caudal to the posterior commissure ran along the ventral side of the midbrain in rats with hydrocephalus, and there was a cell-depleted area just dorsal to the superior collicular commissure. The same findings were observed from the 17th day of gestation until the postnatal period. Although the role of the SCO has been widely discussed from the viewpoint of secretory function, the present study indicated that this organ might be involved in the formation of the shape of the aqueduct.  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