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   840篇
  免费   76篇
  国内免费   8篇
耳鼻咽喉   6篇
儿科学   20篇
妇产科学   38篇
基础医学   97篇
口腔科学   28篇
临床医学   81篇
内科学   140篇
皮肤病学   15篇
神经病学   115篇
特种医学   134篇
外科学   71篇
综合类   73篇
预防医学   45篇
眼科学   6篇
药学   21篇
中国医学   4篇
肿瘤学   30篇
  2022年   8篇
  2021年   15篇
  2020年   12篇
  2019年   13篇
  2018年   20篇
  2017年   15篇
  2016年   13篇
  2015年   23篇
  2014年   23篇
  2013年   42篇
  2012年   38篇
  2011年   32篇
  2010年   58篇
  2009年   40篇
  2008年   37篇
  2007年   33篇
  2006年   38篇
  2005年   24篇
  2004年   20篇
  2003年   23篇
  2002年   18篇
  2001年   17篇
  2000年   24篇
  1999年   15篇
  1998年   22篇
  1997年   23篇
  1996年   19篇
  1995年   16篇
  1994年   18篇
  1993年   20篇
  1992年   13篇
  1991年   11篇
  1990年   8篇
  1989年   14篇
  1988年   13篇
  1987年   12篇
  1986年   12篇
  1985年   16篇
  1984年   10篇
  1983年   6篇
  1982年   3篇
  1981年   10篇
  1980年   5篇
  1979年   8篇
  1978年   8篇
  1977年   7篇
  1976年   9篇
  1975年   11篇
  1974年   5篇
  1973年   3篇
排序方式: 共有924条查询结果,搜索用时 15 毫秒
71.
Bilateral vestibulopathy (BV) is characterized by impaired or lost function of both labyrinths or eighth nerves. The diagnosis is routinely established by the head-thrust test, caloric irrigation and rotational testing with electronystagmography to determine the high- and low-frequency deficit of the vestibulo-ocular reflex. All three methods evaluate semicircular canal function only. Vestibular-evoked myogenic potentials (VEMPs) provide a measure of saccular otolith function. The aim of this study was to evaluate the frequency and extent of saccular dysfunction in patients with BV and to correlate saccular with horizontal semicircular canal dysfunction. A total of 84 BV-patients (23 females, mean age 62 +/- 15 (SD) years at the time of diagnosis assessment) were examined with VEMPs, electronystagmography with caloric irrigation and a standardized neuro-ophthalmological and -otological examination; 47 healthy subjects (18 females, mean 56 +/- 19 years) served as controls. Amplitudes P1-N1 were significantly lower in patients with BV compared to controls (mean P1-N1 of all ears 82.1 +/- 50.7 microV in the patients vs. 130.8 +/- 85.9 microV in healthy volunteers). VEMPs were absent unilaterally in four patients with BV and in none bilaterally. In contrast, caloric responses were absent bilaterally in 40 patients. There was no correlation between amplitude P1-N1 and caloric-induced nystagmus. The latencies P1 and N1 were not significantly different between patients and controls. Thus, in our study population saccular function appeared to be less affected than horizontal semicircular canal function.  相似文献   
72.
FA Chiafari  ; RE Wenk 《Transfusion》1990,30(7):648-650
Single-locus DNA probes for tandem repeat sequences are now used in conjunction with particular endonucleases to characterize heritable restriction fragment lengths in parentage tests. Southern blots of this type, however, demonstrate only two attributes of an allele: its length and the presence of nucleotide sequences that are complementary to the probe. Not all restriction fragments of the same apparent length that react with the same probe are identical. Differences between comigrating fragments can be detected by the selection of a restriction enzyme that recognizes sites in a subset of the repeat sequences, and the information content of these loci is therefore increased. This report describes a paternity case in which two brothers appeared, after DNA phenotyping using Hinf I, to be the father. A second phenotyping using Hae III excluded one of the brothers.  相似文献   
73.
After biopsy (n=6) and nephrostomy (n=1) of three native and four transplanted kidneys, gross hematuria, hypertension, and deterioration of function necessitated performance of transarterial embolization. Angiography revealed five arteriovenous fistulas (AVFs), one pseudoaneurysm, and one arteriocaliceal fistula. Superselective catheterization was accomplished using 5 Fr standard diagnostic catheters and 3 Fr coaxial Tracker catheters. Four of five AVFs were embolized successfully by inserting unfibered (2 patients) and fibered (2 patients) platinum coils (diameters 2 mm and 4 mm, respectively). For one AVF, additional injection of butylcyanoacrylate was necessary. The pseudoaneurysm was embolized successfully by such injection, and the arteriocaliceal fistula was occluded using one unfibered 2-mm coil. Embolization stopped the bleeding in all patients. One week after treatment, renal function was improved in 5 patients and remained unaffected in 2. Superselective embolization using Tracker catheters and fibered microcoils is an effective, safe treatment of renal vascular lesions.  相似文献   
74.
125I粒子对Hela细胞杀伤作用的实验研究   总被引:2,自引:0,他引:2  
目的观察体外Hela细胞在^125I粒子照射下细胞凋亡和增殖的规律,探讨^125I粒子对肿瘤的杀伤作用。方法用^125I粒子照射Hela细胞,用不同的方法观察不同剂量和时间点细胞的增殖反应及形态变化。结果受照射细胞发生凋亡,于Ⅱb期出现凋亡小体;细胞凋亡率随累积剂量的增加而增加,于5Gy时出现凋亡率峰值;细胞克隆形成率显著下降,与凋亡形成呈反向关系。并有反剂量率效应。结论^125I粒子对肿瘤的治疗作用可能为早期抑制肿瘤细胞增殖,晚期使肿瘤细胞大量凋亡。  相似文献   
75.
BACKGROUND: Osteopenia with decreased bone mineral density (BMD) is a frequent finding in renal allograft recipients. Data concerning the bone architecture in these patients do not exist, however. METHODS: We compared the bone architecture of 33 randomly assigned women (age 49 +/- 12 years), who had received renal allografts 5.6 +/- 5.3 years before the investigation, with 74 women (age 50 +/- 14 years) who were admitted for osteodensitometry. All patients underwent single-energy computed tomography (SEQCT) and a midvertebral high-resolution tomography with computer-assisted analysis of the trabecular vertebral body architecture. RESULTS: Progressive alteration of bone architecture was associated with increasing vertebral height loss of the vertebral body. Height reduction of a vertebral body of more than 15% was associated with a significantly lower BMD (-2.3 +/- 0.8 versus -1.1 +/- 1.1 standard deviations below normal BMD), a lower trabecular bone area (13 +/- 8% versus 42 +/- 22%) and a lower trabecular diameter (1.4 +/- 0.5 mm versus 2.2 +/- 0.8 mm) compared to recipients without height reduction. In comparison to a matched group of patients with similarly reduced BMD (1.1 +/- 1.2 versus 1.2 +/- 1.1 SD below normal BMD), renal allograft recipients showed a lower number of trabecular plates (5.6 +/- 3.1 versus 7.0 +/- 3.7) and a smaller intertrabecular surface (54 +/- 116 mm versus 75 +/- 138 mm). CONCLUSIONS: Alterations of bone architecture in renal allograft recipients were associated with progressive vertebral height loss. Despite similar bone mineral density, differences of bone architecture could be observed between renal allograft recipients and patients with osteoporosis.   相似文献   
76.
77.
The authors performed a prospective, comparative study of 96 patients (age, 41-87 years) with femoropopliteal artery occlusions. Laser-assisted angioplasty was performed in 64 patients with 9- and 7-F over-the-wire multifiber catheters. Supplemental balloon dilation was performed after laser angioplasty. Thirty-two patients underwent excimer laser angioplasty (ELA), and 32 underwent pulsed dye laser angioplasty (DLA). The remaining 32 patients underwent conventional balloon angioplasty (BA). The length of occlusions was 3-10 cm (mean, 6.3 cm). Lesion characteristics in the three patient groups were similar. Technical success rates were 84% for ELA, 78% for pulsed DLA, and 81% for conventional BA. The 1-year clinical success rate was 69% (22 of 32 patients) in the ELA group, 63% (20 of 32 patients) in the pulsed DLA group, and 66% (21 of 32 patients) in the BA group (differences were not significant). Laser-assisted angioplasty with multifiber catheters in femoropopliteal artery occlusions did not help improve the technical success rate and 1-year clinical success rate when compared with those of conventional BA.  相似文献   
78.
强利敏  法卫玲  陈黎  蔡秋霞 《癌症进展》2021,19(13):1349-1351,1355
目的 探究食管支架置入术(ESP)和内镜下切开术(EIM)在难治性食管癌术后吻合口狭窄治疗中的应用效果.方法 将70例难治性食管癌术后吻合口狭窄患者按照手术方式不同分为ESP组(n=41)与EIM组(n=29).对比两组患者临床疗效、吞咽困难评分及并发症发生情况.结果 两组患者总有效率比较,差异无统计学意义(P>0.05).术前,两组患者Stooler评分比较,差异无统计学意义(P>0.05);术后1个月,两组患者Stooler评分均较术前降低(P<0.05),且EIM组患者Stooler评分明显低于ESP组(P<0.01).ESP组患者术后并发症总发生率高于EIM组(P<0.05).结论 EIM和ESP治疗难治性食管癌吻合口狭窄的临床疗效相当,EIM短期内对患者吞咽困难症状改善作用明显,且具有术后并发症少等优点.  相似文献   
79.
80.
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