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   262篇
  免费   10篇
  国内免费   36篇
耳鼻咽喉   1篇
儿科学   9篇
妇产科学   5篇
基础医学   15篇
口腔科学   7篇
临床医学   44篇
内科学   72篇
皮肤病学   6篇
神经病学   10篇
特种医学   67篇
外科学   19篇
综合类   19篇
预防医学   7篇
眼科学   1篇
药学   18篇
肿瘤学   8篇
  2020年   1篇
  2018年   2篇
  2017年   2篇
  2016年   4篇
  2014年   6篇
  2013年   4篇
  2012年   4篇
  2011年   5篇
  2010年   13篇
  2009年   13篇
  2008年   6篇
  2007年   28篇
  2006年   3篇
  2005年   7篇
  2004年   5篇
  2003年   4篇
  2002年   4篇
  2001年   7篇
  2000年   3篇
  1999年   2篇
  1998年   18篇
  1997年   14篇
  1996年   17篇
  1995年   8篇
  1994年   14篇
  1993年   20篇
  1992年   1篇
  1991年   3篇
  1990年   5篇
  1989年   9篇
  1988年   7篇
  1987年   2篇
  1986年   4篇
  1985年   8篇
  1984年   4篇
  1983年   1篇
  1982年   1篇
  1981年   6篇
  1980年   11篇
  1976年   3篇
  1975年   1篇
  1968年   1篇
  1959年   3篇
  1958年   1篇
  1957年   3篇
  1956年   4篇
  1954年   8篇
  1949年   3篇
  1948年   4篇
  1946年   1篇
排序方式: 共有308条查询结果,搜索用时 180 毫秒
91.
92.
93.
异丙酚复合氯胺酮全麻诱导对血流动力学的影响   总被引:3,自引:2,他引:1  
张捍平  柴伟  杜洪印 《医学争鸣》2001,22(7):590-590
0 引言 我们观察氯胺酮对异丙酚静脉复合诱导时血流动力学的影响 ,并以芬太尼复合异丙酚全麻诱导做对照研究 .1 对象和方法1.1 对象  30例 ASA ~ 级择期行全麻手术的患者 .男2 0例 ,女 10例 ,年龄 18~ 5 5岁 ,体质量 49~ 75 kg,随机分为两组 ,A组为异丙酚复合氯胺酮组 ,B组为异丙酚复合芬太尼组 ,每组 15例 .1.2 方法 术前 30 min im苯巴比妥钠 0 .1g,阿托品 0 .5mg. A组诱导为 iv异丙酚 2 mg· kg- 1 ,氯胺酮 1mg· kg- 1及维库溴胺 0 .1mg· kg- 1 . B组为 iv异丙酚 2 m g· kg- 1 ,芬太尼 2 μg· kg- 1 及维库溴胺 0 .1mg…  相似文献   
94.
Focal non-epidermolytic palmoplantar keratoderma (PPK or palmoplantar ectodermal dysplasia type III) is associated with oesophageal cancer in three families: two large pedigrees located in Liverpool, UK and in the midwestern American states and one smaller family from Germany. In these families, the PPK is inherited as autosomal dominant and has a late onset, usually manifesting between 7 and 8 years of age. The disease is characterised by thickening of the pressure areas of the soles, but is not restricted to the feet and also presents with oral leukokeratosis and follicular hyperkeratosis. The disease locus [previously termed the "tylosis oesophageal cancer gene' (TOC) locus] has been mapped to 17q23-qter by linkage analysis. This region is located telomeric to the keratin 16 gene, in which mutations have been identified in focal PPK families who show no increased cancer risk. We describe the close mapping of this locus to the interval between AFMb054zf9 and D17S1603 using haplotype analysis of additional Genethon markers in the region and show that although the American family is unlikely to be related to either of the other two, the UK and German pedigrees may share a common descent. This work provides a basis for positional cloning and candidate gene analysis in order to identify a gene that may be involved in familial oesophageal cancer.   相似文献   
95.
Acoustic neuromas: Gd-DTPA enhancement in MR imaging   总被引:1,自引:0,他引:1  
Magnetic resonance (MR) imaging examinations were performed in ten patients with 12 acoustic neuromas before and after intravenous administration of 0.1 mmol/kg body weight gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA). The degree of enhancement was greatest with the inversion recovery sequence 1,500/500/44 (repetition time [TR]/inversion time/echo delay time [TE]), followed by spin-echo (SE) 544/44 (TR/TE) sequences, then by SE 1,500/44 and SE 1,500/80 sequences. After enhancement there was a 50% reduction for measured T1 values, 33% for T2, and no significant change for proton density. There were no toxic effects on patients. Enhanced CT scans failed to demonstrate lesions in six of 12 cases. Air-CT technique improved sensitivity in four of five cases. Enhanced MR imaging added significant clinical information in two small intracanalicular tumors and in one recurrent tumor.  相似文献   
96.
97.
Doi  K; Fujita  H; Ohara  K; Ono  K; Matsui  H; Giger  ML; Chan  HP 《Radiology》1986,161(2):513-518
A digital imaging system that employs a novel scanning x-ray tube, a multiple-slit assembly (MSA), and an image intensifier (II)-TV digital system is described. Use of the MSA can increase x-ray utilization by a factor of 100 over that obtained with single-slit systems. Scatter and veiling glare can be reduced substantially by synthesizing the final image from a number of multiple-slit images, resulting in improvement in contrast sensitivity. An experimental prototype system consisted of a conventional x-ray tube and an II-TV digital system used in conjunction with mechanical scanning of the MSA. Attenuation curves measured with an aluminum stepwedge showed that scatter and veiling glare were eliminated by this approach. Reconstructed images of phantoms were superior to images obtained with conventional wide-beam exposure. Physical parameters related to design of the scanning x-ray tube and a digital system for acquiring images of the chest are discussed.  相似文献   
98.
Left ventricular hypertrophy is well established as a blood pressure independent cardiovascular risk factor in patients on renal replacement therapy. The effects of antihypertensive treatment on myocardial structure and function in renal transplant recipients have been so far only rarely investigated. In a double-blind, placebo-controlled study patients were randomized to the calcium channel blocker nitrendipine or placebo if the transplanted kidney had developed a stable phase. Normotensive patients received nitrendipine 2 x 5 mg daily or placebo, hypertensive patients received 2 x 10 mg up to 2 x 20 mg nitrendipine daily or placebo. To achieve adequate blood pressure control, all patients with still elevated blood pressure on study medication received antihypertensive drugs other than calcium channels blockers. Ambulatory blood pressure recording and 2D-guided M-mode echocardiography were performed at baseline and upon completion of the study. In addition, laboratory workup (including serum creatinine and lipids) was done, and serum aldosterone, plasma renin activity, plasma angiotensin II and blood glucose levels were measured in all patients at baseline and after at least 12 months of therapy. Ambulatory blood pressure was almost identical between both groups at study baseline and follow-up. In renal transplant patients on nitrendipine, posterior wall thickness (-0.10 +/- 1.77 mm) and septal wall thickness (-0.83 +/- 2.23 mm) did not change significantly from baseline. In contrast, posterior wall thickness (0.71 +/- 0.92 mm, P < 0.01) and septal wall thickness (0.97 +/- 2.20 mm, P < 0.05) increased in patients on placebo, which differed from the observed changes on nitrendipine (ANOVA: P = 0.093 and P = 0.048, respectively). Relative wall thickness, a parameter for concentric left ventricular hypertrophy, became numerically smaller on nitrendipine therapy from 0.46 +/- 0.07 to 0.44 +/- 0.09 (-0.02 +/- 0.09, NS) but increased from 0.42 +/- 0.08 to 0.48 +/- 0.08 in the placebo arm (+0.04 +/- 0.08, P < 0.02), which was also significant between the two groups (ANOVA: P = 0.036). Endocrine parameters, lipids and blood glucose were not different between the two groups. We conclude from these data that the calcium channel blocker nitrendipine exerted beneficial effects on cardiac structure in patients after renal transplantation independent of blood pressure.   相似文献   
99.
以己二酸为起始原料,成功地合成了有手性季碳中心的内酯化合物(—)-Mialyngolide(1),其中关键的步骤采用手性相转移催化剂进行立体选择烷基化反应,此合成路线短,总收率为10.5%。  相似文献   
100.
以己二酸为起始原料,成功地合成了有手性季碳中心的内酯化合物(—)-Mialyngolide(1),其中关键的步骤采用手性相转移催化剂进行立体选择烷基化反应,此合成路线短,总收率为10.5%。  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