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   181篇
  免费   8篇
  国内免费   1篇
儿科学   10篇
妇产科学   3篇
基础医学   13篇
口腔科学   1篇
临床医学   8篇
内科学   32篇
皮肤病学   8篇
神经病学   4篇
特种医学   57篇
外科学   7篇
综合类   11篇
预防医学   8篇
眼科学   3篇
药学   13篇
肿瘤学   12篇
  2024年   1篇
  2022年   2篇
  2020年   1篇
  2018年   1篇
  2017年   1篇
  2016年   2篇
  2014年   4篇
  2013年   7篇
  2012年   1篇
  2011年   2篇
  2010年   4篇
  2009年   11篇
  2008年   6篇
  2007年   6篇
  2006年   3篇
  2005年   6篇
  2004年   3篇
  2003年   1篇
  2001年   3篇
  2000年   1篇
  1999年   3篇
  1998年   7篇
  1997年   12篇
  1996年   10篇
  1995年   12篇
  1994年   8篇
  1993年   14篇
  1992年   3篇
  1991年   1篇
  1990年   3篇
  1989年   7篇
  1988年   10篇
  1987年   10篇
  1986年   6篇
  1985年   3篇
  1983年   1篇
  1982年   2篇
  1981年   3篇
  1980年   1篇
  1979年   1篇
  1978年   2篇
  1977年   3篇
  1976年   1篇
  1970年   1篇
排序方式: 共有190条查询结果,搜索用时 0 毫秒
11.
Aim: To describe cardiorespiratory fitness and body mass index (BMI) values in a representative population of 9-year-old Norwegian children in two rural communities and compare present values with previous findings.
Methods: Two hundred and fifty-nine 9-year-old children were invited, and 256 participated in this study. Maximal oxygen uptake was directly measured during a continuous progressive treadmill protocol. Body mass and height were also measured.
Results: The mean ± SD relative maximal oxygen uptake was 52.8 ± 6.5 for boys and 46.9 ± 7.2 mL/kg/min for girls. Eight percent of the boys and 16.8% of the girls were classified as overweight, and 1.6% of the boys and 6.9% of the girls as obese. Mean age, body mass, height and Ponderal index were not significantly different between sexes. Girls had a higher BMI than boys (p = 0.05).
Conclusion: Compared to earlier Norwegian studies, children's BMI values seem to have increased substantially. This increase is most pronounced in girls. When assessing these differences using the PI, this increase is less marked. Comparing maximal oxygen uptake data with that in earlier Nordic studies, there is no evidence that fitness has declined among 9-year olds. However, the limitations of the few earlier studies make reliable comparisons difficult.  相似文献   
12.
BACKGROUND: Brainstem gliomas are highly heterogeneous tumors both in their clinical manifestation and in their pathology. Despite significant advances in the surgery for brainstem gliomas many aspects of this pathology are still unelear. OBJECTIVE: To evaluate the clinical, radiological and surgical outcome of 40 focal "intrinsic" brainstem gliomas and propose a surgical strategyoriented classification. MATERIALS AND METHODS: A total of 40 focal ‘intrinsie’ ("expanding variety") tumors have been operated over a period of 8.5-years (January 1998-June 2007). Our criteria included patients with (1) well-defined gadolinium enhancing tumor, (2) relatively long duration of symptoms (〉 six months) and (3) good neurological functional status and independent for all activities of davy living. The cutoff size of 2 cm was not rigidly adhered to. RESULTS: The "intrinsic" brainstem tumors were classified into three types: Expanding, diffuse infiltrative and pure ventral varieties.  相似文献   
13.
14.
15.
Radiologically guided balloon catheters were used to dilate 94 gastrointestinal strictures in 92 patients over a 6-year period. Fifty strictures were esophageal and 44 nonesophageal (22 gastroenterostomies, 11 antral-pyloric strictures, four colorectal strictures, four enteroenterostomies, and three miscellaneous strictures). Factors influencing the success of stricture intubation included patient age, stricture location (esophageal vs. nonesophageal and proximal vs. distal esophageal), and association with a surgical anastomosis. Malignancy was associated with greater postdilation irregularity and a smaller increase in stricture diameter, as measured radiographically. Procedural failures occurred in 8% of cases (2% of esophageal and 30% of nonesophageal lesions). Two small, asymptomatic mucosal tears were seen after dilation (one esophageal and one colonic); no other procedural complications occurred. Following successful dilation, 16 patients (17%; six with esophageal and ten with non-esophageal strictures) had recurrence of symptoms during short-term (30-day) follow-up.  相似文献   
16.
17.
M. Thomas  M. Behari  GK Ahuja 《Headache》1991,31(9):613-615
Flunarizine, a calcium channel blocker is considered useful in migraine prophylaxis. We report the first Indian trial with this drug. Fifteen patients with migraine were studied in a 6 months double-blind, placebo-controlled crossover trial. Flunarizine was superior to placebo in reducing the severity and duration of the individual attacks though there was no statistically significant effect on frequency of migraine attacks. The side effects most frequently caused by flunarizine were weight gain and daytime sleepiness.  相似文献   
18.
Carrier-directed anti-hapten responses by b-cell subsets   总被引:2,自引:2,他引:2       下载免费PDF全文
The capacity of the trinitrophenyl (TNP) haptenic group, coupled to a series of chemically dissimilar carriers, to cross-stimulate putative T- dependent and T-independent murine B-cell subpepulations was determined by using an in vitro limiting dilution technique to generate primary IgM responses. It was found that TNP-Ficoll and TNP-dextran, two T- independent antigens with little or no polyclonal mitogenicity, stimulate the same population of anti-TNP precursors, which is distinct from the precursor population activated by TNP-bacterial lipopolysaccharide (LPS), a T-independent polyclonal mitogen, or TNP-horse erythrocytes (HRBC), a T-dependent antigen. On the other hand, TNP-LPS and TNP-HRBC activate the same precursor population, indicating that LPS can substitute for the T- cell signal in T-dependent B-cell responses, whereas nonmitogenic T- independent antigens cannot. However, the cumulative evidence from this and other laboratories strongly indicates that LPS and T-dependent antigens activate B cells by different mechanisms. Of particular interest, LPS is incapable of activating B cells responsive to weakly- or nonmitogenic T-independent antigens. Based on clonal burst size, T-dependent antigens are capable of inducing greater antigen-specific B-cell proliferation than T-independent antigens. However, TNP conjugates of Ficoll and dextran, which are relatively poor inducers of polyclonal B-cell activation, induced larger anti-TNP clones than did TNP-LPS, a strong polyclonal mitogen. The findings reinforce the evidence favoring existence of multiple B- cell subpopulations with distinctive activation pathways. They also strengthen the proposition that a given B-cell subset can be activated by more than one mechanism.  相似文献   
19.
20.
目的:应用RNA干扰技术设计构建针对血管内皮细胞生长因子受体KDR的小干扰RNA,并观察脂质体转染肺癌细胞A549后的干扰效果。方法:实验于2005-03/2006-01在沈阳医学院生物化学及分子生物学教研室完成。①设计针对KDR编码区有短发夹结构的3条mRNA序列,经退火成互补双链,克隆到pGCsi.H1/neo/GFP载体中构建3个重组质粒,分别命名为KDR-siRNA1、KDR-siRNA2和KDR-siRNA3。②设立5组:小干扰RNA组,分别转染KDR-siRNA1、KDR-siRNA2和KDR-siRNA3;阳性对照组,转染pGCsi.H1/neo/siGFP,该质粒载体中的插入序列为针对绿色荧光蛋白的小干扰RNA,不干扰待研究的内源性基因;阴性对照组,转染pGCsi.H1/neo/GFP/NON,该载体为不干扰任何内源性基因的小干扰RNA;空白对照组,转染pGCsi.H1/neo/GFP空载体;正常对照组,不进行任何转染。③对重组质粒进行酶切鉴定、DNA测序分析;脂质体法转染质粒至肺癌A549细胞株后,实时定量PCR检测KDRmRNA的水平变化;细胞计数法绘制细胞生长曲线。结果:①小干扰RNA表达载体的鉴定:KDR-siRNA1、KDR-siRNA2和KDR-siRNA3表达载体用限制性内切酶NdeⅠ和SmaⅠ进行单酶切后,均产生约713bp、5480bp和2403bp、3790bp两个片段,与预期结果相同。测序结果与设计的编码相应短发夹状KDR-小干扰RNA的寡核苷酸序列一致,证明KDR-小干扰RNA真核表达载体构建成功。②KDR-小干扰RNA对A549细胞中KDRmRNA水平的影响:与阳性对照组、阴性对照组、空白对照组和正常对照组的A549细胞相比,KDR-siRNA1,2,3表达载体转染后的A549细胞KDR基因表达水平均明显受到抑制,抑制率分别为64%、81%和72%,其中以KDR-siRNA2抑制作用最为明显。③KDR-小干扰RNA对A549细胞生长的影响:阳性对照组、阴性对照组、空白对照组、正常对照组的A549细胞生长趋势较为一致,且生长速度均明显高于转染3种KDR-小干扰RNA表达载体的A549细胞,从接种第2天开始差异有显著性意义(t=15.29~17.65,P均<0.01)。结论:血管内皮细胞生长因子受体KDR靶向RNA干扰重组质粒构建成功,该载体能有效抑制肺癌A549细胞KDR基因表达与细胞增殖。  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