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   192篇
  免费   20篇
  国内免费   48篇
儿科学   10篇
妇产科学   1篇
基础医学   29篇
口腔科学   3篇
临床医学   45篇
内科学   33篇
皮肤病学   2篇
神经病学   5篇
特种医学   44篇
外科学   11篇
综合类   21篇
预防医学   9篇
眼科学   2篇
药学   35篇
中国医学   1篇
肿瘤学   9篇
  2020年   2篇
  2019年   2篇
  2018年   5篇
  2015年   6篇
  2014年   4篇
  2013年   9篇
  2012年   2篇
  2011年   4篇
  2010年   10篇
  2009年   8篇
  2008年   3篇
  2007年   38篇
  2006年   5篇
  2005年   9篇
  2004年   3篇
  2003年   2篇
  2002年   1篇
  2001年   6篇
  2000年   4篇
  1999年   5篇
  1998年   9篇
  1997年   10篇
  1996年   15篇
  1995年   9篇
  1994年   7篇
  1993年   14篇
  1992年   5篇
  1991年   3篇
  1990年   7篇
  1989年   4篇
  1988年   6篇
  1987年   4篇
  1986年   1篇
  1985年   2篇
  1984年   2篇
  1982年   6篇
  1981年   4篇
  1980年   2篇
  1979年   1篇
  1978年   3篇
  1977年   4篇
  1976年   3篇
  1975年   1篇
  1974年   1篇
  1973年   2篇
  1971年   1篇
  1970年   2篇
  1969年   1篇
  1967年   1篇
  1963年   1篇
排序方式: 共有260条查询结果,搜索用时 71 毫秒
91.
Handedness and headache   总被引:1,自引:0,他引:1  
A California handedness study involved 199 male and 74 female cluster headache sufferers as well as 477 migraineurs. Earlier reported data indicated that cluster headache patients had a left-handedness prevalence of over 15%. With the current data the prevalence in males was 11.0% and in females, 8.2%. The corresponding migraine figures were 11.8% and 8.1%. The cluster and migraine headache groups did not differ significantly from each other or from the expected 10% frequency of left-handedness in either sex.  相似文献   
92.
苦红菇化学成分的研究   总被引:1,自引:0,他引:1  
从野生真菌苦红菇(Russula rosacea(Bull)Grrayem,Fr.)子实体酸性部分得到两个新的四环三萜酸化合物,经光谱(IR,1HNMR,13CNMR,MS)、尤其是二维核磁共振(13C-1HCOSY,COLOC,NOEDIFF)谱解析,确定其结构分别如Ⅰ和Ⅱ所示,Ⅰ命名为苦红菇酸A(rosaceaacidA),Ⅱ为苦红菇酸B(rosaceaacidB)。  相似文献   
93.
94.
Catheter-related infections remain a significant cause of method failure in chronic peritoneal dialysis (PD) therapy. Given the increasing antibiotic resistance, such nonpharmacological strategies as local silver devices attract more interest. To establish whether a silver ring device (designed by Grosse-Siestrup in 1992) mounted onto the PD catheter and placed at the exit site at skin level is effective in preventing exit-site and other catheter-related infections, a prospective 12-month, multicenter, controlled study stratified by diabetes status was conducted. The study subjects were assessed by an extensive structured inventory, including a broad spectrum of control variables, such as age, body mass index (BMI), Staphylococcus aureus carrier status, catheter features, mode and quality of PD therapy, comorbidity, and psychosocial rehabilitation. Ten experienced German outpatient dialysis centers (seven adult, three pediatric) participated in the trial. All eligible patients (n=195) from the study area without catheter-related infections during the ascertainment period were included (incidental subjects undergoing PD therapy for at least 3 months). The main outcome measures were the occurrence of first exit-site infections (primary study end point), sinus tract/tunnel infection, and peritonitis. Ninety-seven patients were assigned to the silver ring and 98 patients to the control group. Baseline characteristics of age, sex, proportion of pediatric and incidental patients, S aureus carrier status, and other variables were similar in both groups. The incidence of infections in the silver ring group versus the control group was as follows: 23 of 97 versus 16 of 98 patients had exit-site infections, 12 of 97 versus 12 of 98 patients had sinus tract/tunnel infections, 16 of 97 versus 18 of 98 patients had peritonitis, respectively. Kaplan-Meier analysis for the probability of an infection-free interval showed no statistical difference (log-rank test) between the two groups. Displacement of the silver ring contributed to study termination in 6% of the study group patients, including two patients with catheter loss. Univariate analysis and multiple logistic regression identified younger age (<50 years), low serum albumin level (<35 g/L), number of previously placed PD catheters, short cuff-exit distance (<2 cm), and S aureus nasal carriage as risk factors for the development of exit-site infections. In conclusion, our study does not show any benefit of the silver ring in preventing catheter-related infections in PD patients. Thus, prevention of infection-related method failure in PD still has to rely on conventional antibiotic treatment strategies and less so on alternative methods.  相似文献   
95.
96.
目的:合成抗早老性痴呆药他克林。方法:以邻氨基苯甲酸为原料,经缩合,氯化,氨化反应,制得他克林,结果:每步反庆均经改进,总收率达40.7%,所得产品熔点,IR,^1HNMR光谱数据,与文献报道值一致。结论:本工艺路线方法简单,原料易得,易工业化生产。  相似文献   
97.
Tumor-specific anti-idiotype (anti-Id) monoclonal antibodies (MoAbs) to B-cell lymphomas have been administered to patients, resulting in significant clinical responses. However, clinical responses have been limited by the emergence of Id-negative lymphoma. To overcome the problem of tumor heterogeneity, we conducted a pilot evaluation of the safety and effectiveness of yttrium 90 (90Y)-labeled anti-Id and shared Id (sId) MoAbs in non-Hodgkin's B-cell lymphoma. Nine patients with relapsed B-cell lymphoma in whom tumor was successfully targeted with 111In-labeled anti-Id MoAb were treated with 90Y-labeled anti-Id MoAb. A total of 19 courses (one to four per patient) were administered using 1,000 to 2,320 mg unlabeled clearing MoAb and 10 to 54 mCi 90Y MoAb per patient. Two of nine patients had a complete response, one a partial response, three stable disease, and three disease progression. Time to progression varied from 1 to 12 months. Toxicities were predominately hematologic, and only one patient developed infection and required transfusion. At progression, three of five assessable patients had Id- positive lymphoma and two had Id-negative lymphoma. Human antimouse antibodies (HAMA) did not develop in the patients after treatment. 90Y anti-Id MoAbs demonstrated excellent in vivo stability, produced significantly tumor regression in three of nine patients, exhibited acceptable toxicities, and elicited no HAMA formation. Further investigation of repetitive, low-dose 90Y anti-Id and MoAb therapy is warranted; however, the advantages of a pan B MoAb may prove the latter to be the agent of choice for the radio immunotherapy of B-cell lymphoma.  相似文献   
98.
Magnetic resonance (MR) imaging has given mixed results in the detection of renal masses. To identify the reasons for this and to determine the optimal pulse sequences for evaluating renal tumors, the authors imaged 12 primary renal tumors in vivo and 17 in vitro at 0.35 T. Histopathologic findings for each specimen were closely correlated with the MR images. Four of seven solid tumors imaged in vivo were isointense with surrounding normal renal parenchyma at all pulse sequences. The other three tumors were hyperintense in vivo at T2-weighted sequences. At heavily T2-weighted sequences eight solid tumors were hyperintense in vitro and four were hypointense. There was no correlation between signal intensity and specific tissue type or histologic pattern for solid tumors. The five cystic tumors were well seen both in vivo and in vitro on T2-weighted images. However, the signal intensity of the cyst fluid was an unreliable indicator of benignancy. SE MR imaging at 0.35 T has significant limitations in the detection of solid renal masses.  相似文献   
99.
学术背景:平衡能力是人体的一项重要生理机能,在人类生活中有非常重要的意义.特别是老年人平衡能力下降,直接影响老年人独立生活能力,严重的会引起老年人跌倒,诱发其他疾病.目的:总结老年人平衡能力的国内外研究现状,并展望未来老年人平衡能力研究的发展方向.检索策略:应用计算机检索PubMed数据库1990-12/2007-06有关老年人平衡能力方面的文章,检索词“elderly,balance“,限定文章语言种类为English,共检索到208篇文章.同时应用计算机检索中国期刊全文数据库、万方数据库1997-12/2007-06的相关文章,检索词“老年人、平衡能力“,限定文章语言种类为中文,共检索到85篇文章.对资料进行初审,选取符合研究要求的有关文章找全文.纳入标准:①平衡能力的研究.②老年人平衡特征.③平衡能力评价.④运动干预对平衡能力的研究.排除理由:①较陈旧的文献.②重复研究.文献评价:共19个研究满足全部纳入标准,予以纳入.其中6篇为老年人平衡特征的文献、8篇平衡评价的文献、5篇运动干预老年人平衡影响的文献.资料综合:①平衡能力是人体相关系统功能的集中表现,研究影响平衡能力的前庭系统、视觉系统、躯体感觉、神经系统及肌肉-骨骼等系统功能增龄性的变化趋势,探究导致平衡能力增龄性变化的主要因素是待解决的问题.②平衡测试是定量评定平衡能力的前提,针对老年群体的特殊性,逐步寻求安全、简捷能全面反映其平衡能力的测试方法.③国内专业人员日益提高了对平衡的关注,发表的论文也较多,但由于平衡评定方法不统一,对中国人民平衡能力增龄性变化的研究没有继承性,研究国民的平衡能力增龄性变化是必要的.④众多研究表明,体育锻炼可以延缓平衡能力的衰退.但研究比较分散,运动项目比较单一,探究利于干预的运动项目以及最佳时机是待解决的热点课题.结论:建立一整套适合中国国民平衡能力评价体系,研究国民的平衡能力增龄性变化是十分有必要的,为全民健身活动中的老年人科学地进行健身提供依据.  相似文献   
100.
运用模糊聚类方法分析中药微量元素含量与药效的关系   总被引:2,自引:0,他引:2  
目的:不同中药中各种微量元素的含量数据离散,从含量数据上很难说明不同药物的药物相似性,故运用模糊分类方法研究药物微量元素含量与药物疗效的关系,验证其在药物功效的相似性及不同种类中药定量指标评价方面的作用。方法:实验于2005-10/2006-11在吉林省中医药管理局中药微量元素分析实验室完成。用原子吸收分光光度法检测合欢花、黄芪、石菖蒲、远志、山楂、银杏叶、人参、元肉、蒲黄、酸枣仁、苏木11种中药中钾、钠、钙、镁、铁、铬、镍、锰、铜、锌元素的含量,结合锌/铜比值、镁/钙比值,以数据极差法进行统计指标的标准化处理,以数量积法算出衡量被分类对象之间的相关系数,确定论域上的模糊矩阵。结果:相关系数r=0.50时,合欢花,石菖蒲,远志,人参,元肉,蒲黄,酸枣仁7种药物聚类相似;相关系数r=0.65时,合欢花,石菖蒲,元肉,蒲黄,酸枣仁5种药物聚类相似;r=0.75时,合欢花,石菖蒲,蒲黄3种药物聚类相似。研究还发现:药物中金属元素含量丰富,而且相关系数较大的药物,其药物疗效相似。结论:运用数学与化学计量学方法建立模糊聚类分析模型,可以把离散的数据标准化处理,确定论域上的模糊矩阵可以研究不同药物间的药效相似性,可以对不同种类的中药进行定量指标的明确评价。  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