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   15382篇
  免费   1310篇
  国内免费   280篇
耳鼻咽喉   56篇
儿科学   412篇
妇产科学   223篇
基础医学   1767篇
口腔科学   228篇
临床医学   2193篇
内科学   1939篇
皮肤病学   117篇
神经病学   951篇
特种医学   244篇
外国民族医学   3篇
外科学   686篇
综合类   1910篇
现状与发展   1篇
一般理论   1篇
预防医学   3832篇
眼科学   71篇
药学   1116篇
  15篇
中国医学   629篇
肿瘤学   578篇
  2024年   29篇
  2023年   269篇
  2022年   468篇
  2021年   677篇
  2020年   661篇
  2019年   619篇
  2018年   583篇
  2017年   571篇
  2016年   568篇
  2015年   543篇
  2014年   1208篇
  2013年   1310篇
  2012年   983篇
  2011年   1128篇
  2010年   888篇
  2009年   746篇
  2008年   704篇
  2007年   684篇
  2006年   556篇
  2005年   491篇
  2004年   418篇
  2003年   369篇
  2002年   266篇
  2001年   217篇
  2000年   209篇
  1999年   170篇
  1998年   120篇
  1997年   166篇
  1996年   117篇
  1995年   121篇
  1994年   117篇
  1993年   73篇
  1992年   84篇
  1991年   84篇
  1990年   60篇
  1989年   56篇
  1988年   41篇
  1987年   52篇
  1986年   36篇
  1985年   72篇
  1984年   80篇
  1983年   48篇
  1982年   50篇
  1981年   30篇
  1980年   50篇
  1979年   31篇
  1978年   31篇
  1976年   20篇
  1975年   17篇
  1973年   17篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
羧基化多壁碳纳米管修饰电极伏安法测定多巴胺   总被引:7,自引:2,他引:5  
目的 :研究用羧基化多壁碳纳米管修饰电极伏安法测定痕量多巴胺 (DA)的效果。方法 :采用涂布法制成羧基化多壁碳纳米管修饰电极 ;在pH =5 .4的KH2 PO4 Na2 HPO4缓冲溶液中 ,采用该修饰电极伏安法测定DA。结果 :该修饰电极对DA有着显著的电催化作用 ,与裸玻碳电极相比较 ,其灵敏度大大提高 ,在2 .0× 10 -7~ 6 .0× 10 -4mol/L浓度范围内 ,DA的氧化峰电流与浓度成良好的线性关系 ,检测限为 5 .0× 10 -8mol/L。将该修饰电极用于盐酸多巴胺针剂的测定 ,相对平均偏差为 1.4 % ,平均回收率为 99.2 %。结论 :该修饰电极响应快 ,灵敏度高 ,稳定性好 ,寿命长 ,适合于具有电活性生物分子的测定  相似文献   
82.
目的 分离和纯化母婴血型不合母体的特异性高效价的IgG抗体。方法 采用半饱和硫酸铵低温沉淀法分离IgG抗体,SephedexA50层析柱纯化,然后用B型红细胞(RBC)吸收放散IgG,用聚乙二醇(PEG)沉淀,真空泵脱水回收IgO。结果 200ml血浆经半饱和硫酸铵低温沉淀后得IgG粗制品2.26g,Sephedex A50层析柱纯化后得纯制品1.84g,经B型RBC吸收放散后得特异性IgG 0.55g,回收率达29.89%(0.55/1.84)。结论 采用半饱和硫酸铵低温沉淀法分离高效价IgG抗体,可以获得高纯度的IgG。  相似文献   
83.
The primary purpose of this study was to apply an occupational therapy programme for social skills training based on a cognitive-behavioural frame of reference to individuals with long-term mental illness. The goal of the social skills training group was to enable patients to develop verbal and non-verbal communication skills that could be generalised to everyday interpersonal encounters. A case example of the application of social skills training with a 38-year-old single male with a diagnosis of paranoid schizophrenia is described. The Group-Interaction Skills Survey developed by the author served as an outcome measure. Qualitative data confirmed the researcher's hypothesis that individuals with long-term mental illness can benefit from social skills training using a combination of role-playing, sociodrama, videotape recordings and creative media. Copyright © 1996 Whurr Publishers Ltd.  相似文献   
84.
85.
This introduction traces the increasing awareness of the prevalence of child sexual abuse over the last 20 years, examines the nature and consequences of such abuse and summarizes current information on the use of group treatment and its evaluation with sexually abused children and adolescents and their parents. Four examples of group treatment with different populations of abused children are described in this issue.  相似文献   
86.
本文定义了一类“近乎双线性”系统。可用以近似一类奇异摄动双线性系统,而且可以描述某些实际工业对象。并发现其控制器的设计较方便。文中还给出了一种简单的反馈控制器的设计方法。又对一类多输入双线性系统,提出一种设计反馈控制器的改进方案,根据Lyapunov定理得到一非线性反馈控制律。以上设计方法分别对某合成氨反应器作了应用研究,仿真结果表明了方法的有效性。  相似文献   
87.
本文报道了8例新生儿溶血病的不典型临床表现及其实验窒检查。其中ABO不合7例,Rh不合1例。不典型表现是黄疸均在生后48小时后出现,还可出现后期贫血、低钙性抽搐、迁延性黄疸、肝炎综合征等,对其机制进行了探讨。  相似文献   
88.
目的 探讨互动微信群结合病例教学(case-based learning,CBL)在血管外科见习教学中的应用效果。方法 对随机分组的128名在血管外科临床见习的7年制学生分别实施互动微信群结合CBL(试验组)和单纯CBL(对照组);用统一的考核方法评估两组学生接受专业理论及临床知识的情况,评价两种教学在血管外科见习中的教学效果。用SPSS 22.0进行t检验。结果 试验组的理论考试成绩为(86.36±7.42)分,临床考试成绩为(88.44±7.62)分,高于对照组的(84.71±6.72)分和(86.22±6.41)分;试验组学生在学习兴趣、课堂气氛、自学能力、临床思维和团队精神共5方面的满意度也高于对照组。结论 互动微信群结合CBL能提高血管外科临床见习的教学效果,提高学生的自学能力及临床思维能力。  相似文献   
89.
The afferent thalamic connections to cortical fields important for control of head movement in space were analysed by intracortical retrograde tracer injections. The proprioceptive/vestibular area 3aV, the neck-trunk region of area 3a, receives two thirds of its thalamic projections from the oral and superior ventroposterior nucleus (VPO/VPS), which is considered as the proprioceptive relay of the ventroposterior complex (Kaas et al., J. Comp. Neurol. 226:211-240, 1984). The parieto-insular vestibular cortex (PIVC, area retroinsularis, Ri) receives its main thalamic input from posterior parts of the ventroposterior complex and from the medial pulvinar. Anatomical evidence is presented that the posterior region of the ventroposterior complex is a special compartment within this principal somatosensory relay complex. The parietotemporal association area T3, mainly involved in visual-optokinetic signal processing, receives a substantial input from the medial, the lateral, and the inferior pulvinar. Dual tracer experiments revealed that about 5% of the thalamic neurons projecting to 3aV were spatially intermingled with neurons projecting to areas PIVC or T3. This spatial intermingling was distributed over small but numerous, circumscribed thalamic regions, called "common patches," which were found mainly in the intralaminar nuclei, the posterior group of thalamic nuclei, and the caudal parts of the ventroposterior complex. The "common patches" may indicate a functional coupling of area 3aV with the PIVC or area T3 on the thalamic level. In control experiments thalamic projections to the granular insula Ig and the anterior part of area 7, two cerebral structures connected with the vestibular cortical areas, were studied. Some overlap in the thalamic relay structures projecting to these areas with those projecting to the vestibular cortices was found. A quantitative evaluation of thalamic regions projecting to different cortical structures was performed by constructing so-called "thalamograms." A scheme was developed that describes the afferent thalamic connections by which vestibular, visual-optokinetic, and proprioceptive signals reach the vestibular cortical areas PIVC and 3aV.  相似文献   
90.
In some individuals, breathing is greater than at rest following voluntary hyperventilation. Most previous investigations have employed short hyperventilation periods; here we examine the time course of cardio-respiratory measures before, during, and after a 5-min voluntary hyperventilation, maintaining isocapnia throughout. We examined the possible co-involvement of the cardiovascular system; hypothesising that post-hyperventilation hyperpnoea results from an increase in autonomic arousal. In four subjects (two males, two females) of 18 (nine males, nine females) we observed a post-hyperventilation hyperpnoea, characterised by a slow decline of ventilation toward resting levels with a time constant of 109.0 +/- 16.1s. By contrast, heart rate, and systolic and diastolic blood pressure were unchanged from rest during and after voluntary hyperventilation for all subjects. We concluded that males and females were equally likely to exhibit post-hyperventilation hyperpnoea, and suggest that they may be characterised by an increased resting heart rate and the choice of breathing frequency to increase ventilation during the voluntary hyperventilation. We further concluded that post-hyperventilation hyperpnoea is rare, but when present is a strong and lasting phenomenon, and that it is not the result of an increased autonomic arousal.  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