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   401篇
  免费   39篇
  国内免费   7篇
耳鼻咽喉   8篇
儿科学   10篇
妇产科学   1篇
基础医学   29篇
口腔科学   12篇
临床医学   42篇
内科学   55篇
皮肤病学   3篇
神经病学   20篇
特种医学   23篇
外科学   36篇
综合类   49篇
一般理论   3篇
预防医学   57篇
眼科学   1篇
药学   63篇
中国医学   27篇
肿瘤学   8篇
  2024年   3篇
  2023年   8篇
  2022年   10篇
  2021年   11篇
  2020年   12篇
  2019年   14篇
  2018年   19篇
  2017年   9篇
  2016年   7篇
  2015年   17篇
  2014年   25篇
  2013年   29篇
  2012年   18篇
  2011年   37篇
  2010年   27篇
  2009年   15篇
  2008年   16篇
  2007年   19篇
  2006年   21篇
  2005年   12篇
  2004年   10篇
  2003年   11篇
  2002年   10篇
  2001年   6篇
  2000年   4篇
  1999年   4篇
  1998年   12篇
  1997年   4篇
  1996年   9篇
  1995年   10篇
  1994年   5篇
  1993年   1篇
  1991年   2篇
  1990年   1篇
  1989年   1篇
  1988年   3篇
  1987年   3篇
  1985年   6篇
  1984年   2篇
  1981年   3篇
  1979年   1篇
  1978年   3篇
  1977年   3篇
  1976年   1篇
  1975年   1篇
  1972年   1篇
  1965年   1篇
排序方式: 共有447条查询结果,搜索用时 125 毫秒
41.
42.
Summary— Neurotrophins, like the nerve growth factor (NGF), trigger a variety of biological effects in their targets. Stimulating effects on antioxidant defenses have been postulated to underlie neurotrophic influence on neuron survival and maintenance. To test whether NGF is capable of inducing changes in glutathione-related enzymes in the aged cognitively impaired brain, glutathione reductase (GRD), glutathione S-transferase (GST) and total glutathione peroxidase (GPX) activities were measured in the striatum, septum, hippocampus and frontal cortex of four Sprague-Dawley rat groups: young (2 months old), aged (20 months old) untreated, aged cytochrome c-treated, and aged NGF-treated (icv delivery, 34 4mUg during 28 days). All the aged rats utilized in the study were memory impaired according to their performance in the Morris water maze test. These aged rats showed increases in the activities of septal and hippocampal GST, as well as, in the hippocampal, striatal and cortical GPX. These increases could be interpreted as compensatory responses to cope with the oxidative damage that has been accumulated by the aged brain. The increases in hippocampal and cortical GPX activity were attenuated by NGF treatment, whereas the neurotrophin induced an increase in GRD activity in the striatum of aged rats. These results point out GRD and GPX as possible targets of the neurotrophic effects.  相似文献   
43.
目的:揭示蒙脱石层状晶体结构及层间吸附和膨胀性能,为其作为药物和药剂辅料提供科学依据。方法:将样品提纯,获得粒径小于1μm的胶体,制成取向样品,进行X-射线定向衍射分析。结果:得到了有关蒙脱石层间域在不同条件下的变化规律。结论:蒙脱石的层间吸附是可能的,而且定向衍射方法可以定量测定其层间距离。  相似文献   
44.
化学信息修饰法及其在复杂混合物分析中的应用   总被引:2,自引:0,他引:2  
目的:提出一种未知干扰共存下复杂混合物快速定量分析的新方法.方法:对待测未知干扰共存混合物体系的化学信息进行原位数学修饰,使其符合导数光谱法数学模型的匹配要求,去除未知干扰对测定的影响.结果:测定未知干扰共存下安钠咖注射液中苯甲酸钠的含量,平均回收率100.1%,RSD=2.5%(n=4).结论:运用数学手段改造待测复杂混合物的化学信息特征,使其符合指定解析方法数学模型的匹配要求,可以成功应用于未知干扰共存下复杂混合物的快速定量分析.  相似文献   
45.
Tuberculous mediastinal lymphadenopathy in adults   总被引:2,自引:0,他引:2  
Liu  CI; Fields  WR; Shaw  CI 《Radiology》1978,126(2):369
  相似文献   
46.
Primary antibody deficiencies are chronic conditions and the patients usually need lifelong replacement therapy with gammaglobulin to prevent or reduce infections It has been shown that the gammaglobulm can be given safely as subcutaneous infusions, instead of intramuscular injections or intravenous infusions The major aim of this multi-centre study was to investigate the perceptions of the subcutaneous method among patients using it, both in hospital settings and as self-infusions at home The study included 152 patients 89 women, 63 men, mean age 44 years (range 18-76) Data were collected by using questionnaires The patients were found to have a strongly positive attitude towards receiving the replacement therapy as subcutaneous infusions, perceived the method as effective in preventing infections and wished to retain the treatment However, the younger patients found the subcutaneous infusions more uncomfortable and were less determined to continue with the therapy as compared with the older individuals The responsibility for self-infusions at home was accepted by the patients, leading to an increased independence from the health care personnel and to a feeling of flexibility and freedom As these patients have a chronic disease and are in need of lifelong treatment, it is important to discuss the development of structured education and training programmes in which special emphasis is placed on the support of the younger patients It is suggested that Orem's nursing model of self-care may serve as a conceptual framework for nurses working in this specific area of nursing care  相似文献   
47.
Uterine rupture in Nigeria   总被引:1,自引:0,他引:1  
Uterine rupture in the developing world remains a significant problem. We treated 45 such cases. The predisposing factors included cephalopelvic disproportion (62%), grand multiparity (33%), previous cesarean section (24%), placental pathology (15%) and abnormal presentation (20%). The factors associated with maternal death included sepsis (71%), macerated stillborn infant (60%), vulvar edema (50%), hand presentation (50%), prolonged labor (42%) and hysterectomy (37.5%). Hemodynamic resuscitation and prompt surgical intervention remain the mainstays of therapy.  相似文献   
48.
目的探讨维甲酸受体诱导基因1(retinoic receptor-induced gene 1,RRIG1)在人乳腺癌组织中的表达及其与患者临床病理参数的关系。方法以GAPDH为内对照采用实时荧光定量逆转录聚合酶链反应法(real time quantitative reverse transcrip-tion polymerase chain reaction,RQ RT-PCR)检测76例新鲜乳腺浸润性导管癌组织5、例导管原位癌组织和20例乳腺良性增生组织中RRIG1 mRNA的表达水平,并分析其与患者临床病理参数的关系。结果乳腺导管原位癌、浸润性导管癌组织中RRIG1 mRNA相对表达水平(3.5±2.1、6.7±4.1)明显低于良性增生组织(10.2±6.5),差异具有统计学意义(P=0.004,P=0.036);乳腺浸润性导管癌中淋巴结转移组RRIG1 mRNA相对表达水平(5.2±3.1)明显低于无淋巴结转移组(7.48±4.5),两组之间差异具有统计学意义(P=0.023)。结论 RRIG1可能作为一种新的抑癌基因参与乳腺癌的发生、浸润和转移,对乳腺癌早期诊断和预后评估具有重要的参考价值。  相似文献   
49.
目的 比较卡维地洛与美托洛尔治疗高原慢性心力衰竭(CHF)的疗效.方法 90例CHF患者随机分成3组:常规治疗组(20例)给予血管紧张素转化酶抑制剂、利尿剂、地高辛等常规心力衰竭治疗.美托洛尔组(34例)、卡维地洛组(36例)在上述治疗基础上分别给予美托洛尔50 mg,2次/d;卡维地洛25 mg,2次/d口服.随访半年,治疗前、后采用超声心动图测定患者心功能并进行疗效观察.结果 治疗后美托洛尔组、卡维地洛组左心室舒张末期内径(LVEDD)[分别为(57.3±6.5)、(57.2±6.9)mm]和左心室收缩末期内径(LVSED)[分别为(46.6±7.0)、(44.0±6.9)mm]显著低于常规治疗组[分别为(64.7±9.1)、(53.4±9.8)mm],左心室射血分数(LVEF)显著高于常规治疗组[分别为(47.5±8.1)%、(52.9±8.5)%、(42.8±9.2)%](P均<0.05).卡维地洛组LVEF改善优于美托洛尔组(P<0.05).死亡情况:常规治疗组4例,美托洛尔组1例,卡维地洛组无死亡.美托洛尔组、卡维地洛组病死率均明显低于常规治疗组(P均<0.05).结论 美托洛尔、卡维地洛均可明显改善高原CHF患者心功能.卡维地洛疗效及耐受性略优于美托洛尔.
Abstract:
Objective To compare the effect of carvedilol and motoprolol on high altitude chronic congestive heart failure (CHF). Methods Ninety patients with high altitude chronic CHF were divided into three groups randomly:Twenty patients in the regular treatment group treated with angiotensin-converting enzyme inhibitor (ACEI) ,diuretics and digoxin; motoprolol (50 mg twice daily) was given in the motoprolol group( 34cases) additional to regular treatment; carvedilol (25 mg twice daily) was given in the carvedilol group(36cases ) additional to regular treatment. All the patients were followed up for six months and measured the changes of cardiac function by echocardiography. Results Left ventricular end-diastolic dimension (LVEDD) was ( 57. 3 ± 6. 5 ) mm and (57.2 ± 6. 9) mm in the carvedilol group and the motoprolol group respectively, and left ventricular end-systolic dimension (LVESD) was (46. 6 ± 7.0) mm and (44. 0 ± 6. 9 ) mm in the carvedilol group and the motoprolol group respectively, which were all significantly smaller than that in the regular treatment group ([64.7 ±9. 1]mm and [53.4 ±9.8]mm for LVEDD and LVESD,respectively) (Ps <0.05). Left ventricular ejection fraction (LVEF) in the carvedilol group and the motoprolol group ( [47.5 ± 8. 1] % and [52. 9 ±8.5] % ,respectively) was higher than that in regular treatment group( [42. 8 ±9. 2]% ) (Ps <0. 05).The improvement of LVEF in the carvedilol group was better than that in the motoprolol group (P < 0. 05 ). One case died in the motoprolol group and no death in the carvedilol group,4 cases died in the regular treatment group,the mortality in the motoprolol group and the carvedilol group was significantly lower than that in the regular treatment group. Conclusion Carvedilol and motoprolol significantly improved cardiac function in high latitude CHF patients,and the effect of Carvedilol is slightly better than that of motoprolol.  相似文献   
50.
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