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   254742篇
  免费   18886篇
  国内免费   7555篇
耳鼻咽喉   1807篇
儿科学   9479篇
妇产科学   2399篇
基础医学   23118篇
口腔科学   4441篇
临床医学   26505篇
内科学   62000篇
皮肤病学   3326篇
神经病学   29084篇
特种医学   7097篇
外国民族医学   12篇
外科学   20884篇
综合类   32037篇
现状与发展   33篇
一般理论   11篇
预防医学   21250篇
眼科学   3286篇
药学   17477篇
  205篇
中国医学   11302篇
肿瘤学   5430篇
  2024年   743篇
  2023年   5165篇
  2022年   9367篇
  2021年   13285篇
  2020年   12317篇
  2019年   10680篇
  2018年   10326篇
  2017年   9533篇
  2016年   9438篇
  2015年   9290篇
  2014年   17835篇
  2013年   19882篇
  2012年   14609篇
  2011年   16053篇
  2010年   12355篇
  2009年   11770篇
  2008年   11698篇
  2007年   11032篇
  2006年   9698篇
  2005年   8097篇
  2004年   6974篇
  2003年   5994篇
  2002年   5017篇
  2001年   4353篇
  2000年   3740篇
  1999年   3149篇
  1998年   2942篇
  1997年   2648篇
  1996年   2317篇
  1995年   2082篇
  1994年   1928篇
  1993年   1628篇
  1992年   1524篇
  1991年   1366篇
  1990年   1098篇
  1989年   934篇
  1988年   863篇
  1987年   786篇
  1986年   678篇
  1985年   1214篇
  1984年   1155篇
  1983年   748篇
  1982年   884篇
  1981年   771篇
  1980年   626篇
  1979年   561篇
  1978年   462篇
  1977年   374篇
  1976年   351篇
  1975年   290篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
The purpose of this study was to determine the effects of unilateral versus bilateral subthalamic nucleus (STN) stimulation on quantitative measures of walking and reaching in Parkinson's disease (PD). We used kinematic measures and the Unified Parkinson's Disease Rating Scale (UPDRS) motor subscale (subscale III) to evaluate the movement of 6 people with PD who had bilateral STN stimulators implanted for at least 6 months and withheld their anti-parkinson medication for at least 8 hours. Subjects were studied with both stimulators off, one on, and both on. Kinematic data were collected as subjects walked, reached to a target, and were rated using the UPDRS motor subscale. STN stimulation improved walking speed and stride length, with the greatest benefit from bilateral stimulation. Reaching speed was improved by unilateral STN stimulation alone, with no additive effect of bilateral stimulation. UPDRS motor subscale ratings paralleled the kinematic findings. STN stimulation did not restore PD subjects' movements to the level of age-matched controls. Overall, these results provide further evidence that the basal ganglia pathways involved in control of walking and reaching may be distinct. We speculate that basal ganglia may influence walking through bilateral pedunculopontine projections and reaching through ipsilateral thalamocortical projections. Our findings also suggest that maximal improvement of walking requires bilateral rather than unilateral STN stimulation.  相似文献   
62.
63.
分别采用联合火箭免疫电泳技术和酶法对49例冠心病患者和50例健康人血清载脂蛋白 A_1(apoA_1),载脂蛋白 B_(100)(apoB_(100)),以及血清总胆固醇(TC)、甘油三酯(TG),高密度脂蛋白胆固醇(HDL—ch)的含量进行了测定。结果冠心病患者血清 apoB_(100)(0.99±0.26g/L)明显高于健康人(0.62±0.18g/L);而apoA_1/apoB_(100)比值(1.22±0.35)则明显低于健康人(2.12±0.49);TC,TG,HDL-ch 的含量亦有统计学意义。提示,在预示冠心病危险因素的各种脂类及脂蛋白中,以 apoB_(100)增高 apoA_1/apoB_(100)比值降低最为灵敏,最为准确,且高于单纯测定TC,TG 和 HDL-ch。  相似文献   
64.
Summary The authors report the third published case of a Lhermitte-Duclos disease diagnosed preoperatively with the help of MRI, stressing its possible extension beyond the limits of the posterior fossa. The pertinent literature is reviewed concerning the clinical and radiological picture of this disease, as well as the different pathogenic hypothesis.  相似文献   
65.
The progressive degeneration of the brain seen in dementia is often accompanied by behavioural disturbances. Aggressive behaviour is one of the most serious of these disturbances and is a common cause for psychiatric referral, admission to hospital and drug treatment. In this article, we discuss the conceptual issues associated with defining aggressive behaviour in cognitively impaired patients. We then review the aetiology, epidemiology, methods of assessment, and management of aggressive behaviour in elderly people with dementia.  相似文献   
66.
Movement-related potentials were recorded preceding self-paced voluntary movements in patients with Parkinson's disease and in healthy subjects of the same age group. We compared the Readiness Potential preceding joystick movements in a fixed direction and preceding joystick movements in freely selected directions. In normal subjects the Readiness Potential amplitude was higher preceding freely selected movements than preceding movements in a fixed direction. The Readiness Potential in Parkinson patients failed to be modified by the different modes of movement selection. The modulation of the Readiness Potential by different ways of preparing for movement might be due to the supplementary motor area (SMA) being more strongly engaged by tasks requiring internal control of movements than by tasks that are externally structured. The results suggest that this task-dependent variation of SMA activity is reduced in Parkinson's disease. A failing capacity to adapt SMA activity to different task demands has previously been suggested by evidence from positron emission tomography studies using similar tasks.  相似文献   
67.
Background Coronary heart disease (CHD) is a major cause of morbidity and mortality in the UK. The aim of this study was to screen inpatients with mild or borderline intellectual disability, many of whom also have mental illness, for risk factors for CHD. Methods Cross sectional survey. Participants were interviewed, measured and had blood samples taken. Results Of the 53 participants, 20 (37.7%) were overweight and 18 (34.0%) obese. The mean body mass index (BMI) of those participants prescribed regular antipsychotics was higher than those who were not. Nine (20.9%) had waist circumference measurements placing them at increased risk of CHD and 21 (48.8%) were at substantially increased risk. Twenty-eight (52.8%) were current smokers. Of the 49 participants who had their blood pressure measured, 3 (6.1%) had readings above the reference range. Of the 19 participants who had random blood tests, one (5.3%) had an elevated cholesterol level. Conclusions In this population there was a high prevalence of two risk factors for CHD (obesity and smoking), requiring ongoing monitoring and long-term measures to reduce risk.  相似文献   
68.
Anecdotal reports suggest that dysgeusia may be related to a variety of systemic factors, including bladder outflow obstruction. This is a hospital-based case-controlled study involving 111 patients who were admitted to urological wards for transurethral resection of the prostate for benign prostatic disease with age- and sex-matched control of 137 subjects. We used a semi-structured questionnaire by a trained interviewer at admission (preoperative), at the postoperative period and at follow-up between 4–6 months (median 5 months). Analysis used unpaired t-test and X2 test. The incidence of dysgeusia was 22% in the study group and 13% in the control group (P=N.S.). However, strikingly, the dysgeusia in the study group was relieved promptly by relief of urinary obstruction in 100% of cases and did not return within the follow-up period. The mechanism of the dysgeusia associated with dysuria in benign prostatic disease is unknown, but we suggest that the dysgeusia could be from the stress of dysuria or due to a release of an unknown chemical from the urinary tract or an overflow of neural impulse from pontine/cortical micturition centres to the taste centres. An association between dysgeusia and dysuria has not been described before.  相似文献   
69.
文章针对目前医学生“网络成瘾症”的现状进行了分析,并指出了产生的原因和解决问题的办法,以求达到标本兼治。最后提出三点预防医学生“网络成瘾症”的对策:一是高校及其附属医院要为医学生营造宽松愉快的学习、生活环境;二是呼吁家长关注医学生身心发展的特殊规律,建立良好的家庭环境;三是建立和完善与网络社会相应的法律法规,规范医学生的网上行为。  相似文献   
70.
Aims The Type 1 diabetes susceptibility locus, IDDM2, has been mapped to a variable number of tandem repeats (VNTR) region 5′ upstream of the insulin (INS) and insulin‐like growth factor (IGF2) genes on chromosome 11p15. The function of the VNTR is uncertain; however, it may influence the thymic expression of the insulin gene and affect the development of immune self‐tolerance. The aim of this study was to investigate whether the INS VNTR region is a Type 1 diabetes‐specific locus or acting as a general autoimmunity gene. Methods We genotyped the INS‐IGF2 VNTR [using the surrogate INS?23 HphI single nucleotide polymorphism (SNP)] in 823 Graves’ disease (GD)/multiple sclerosis (MS) families, 1433 GD/MS patients and 837 healthy control subjects. Results We found no evidence of excess transmission of the allele associated with Type 1 diabetes to individuals affected by GD or MS within the families. Analysis of the case–control dataset showed no genotypic or allelic difference between the two populations. Conclusions These data suggest that the INS‐IGF2 VNTR is acting as a Type 1 diabetes‐specific susceptibility gene rather than as an influence on general autoimmunity.  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