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   94923篇
  免费   8767篇
  国内免费   2605篇
耳鼻咽喉   673篇
儿科学   2476篇
妇产科学   722篇
基础医学   5333篇
口腔科学   548篇
临床医学   15636篇
内科学   25274篇
皮肤病学   529篇
神经病学   4944篇
特种医学   3359篇
外国民族医学   2篇
外科学   9562篇
综合类   16058篇
现状与发展   4篇
一般理论   1篇
预防医学   5525篇
眼科学   999篇
药学   8055篇
  117篇
中国医学   4961篇
肿瘤学   1517篇
  2024年   368篇
  2023年   1781篇
  2022年   3255篇
  2021年   4806篇
  2020年   4647篇
  2019年   4021篇
  2018年   3699篇
  2017年   3663篇
  2016年   3494篇
  2015年   3329篇
  2014年   6524篇
  2013年   6259篇
  2012年   4990篇
  2011年   5352篇
  2010年   4416篇
  2009年   4115篇
  2008年   4392篇
  2007年   4564篇
  2006年   3984篇
  2005年   3518篇
  2004年   2814篇
  2003年   2507篇
  2002年   2126篇
  2001年   2052篇
  2000年   1662篇
  1999年   1528篇
  1998年   1300篇
  1997年   1264篇
  1996年   1051篇
  1995年   1039篇
  1994年   961篇
  1993年   779篇
  1992年   794篇
  1991年   685篇
  1990年   581篇
  1989年   475篇
  1988年   459篇
  1987年   434篇
  1986年   377篇
  1985年   382篇
  1984年   386篇
  1983年   254篇
  1982年   277篇
  1981年   186篇
  1980年   157篇
  1979年   148篇
  1978年   137篇
  1977年   69篇
  1976年   76篇
  1975年   50篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
徐育红  王建安 《浙江医学》2004,26(6):407-409
目的探讨原发性高血压(EH)患者微量白蛋白尿(MCA)与血压及左室重塑的关系.方法 84名EH患者按24h尿微量白蛋白值分为微量白蛋白尿组(MCA组)和正常白蛋白尿组(NMCA组),进行动态血压、心脏超声检测,比较两组动态血压值、左室重量指数(LVMI)及左室重塑的特点.结果 MCA组平均收缩压、平均舒张压、脉压、平均动脉压均高于NMCA组(均P<0.01);MCA组LVMI、左室肥厚与向心性肥厚的发生率均高于NMCA组(均P<0.01),正常构型率低于NMCA组(P=0.01).LVMI与尿微量白蛋白值、平均收缩压、平均舒张压均呈显著的正相关(均P<0.05).结论合并有MCA的EH患者血压较高,LVMI较大,左室肥厚与向心性肥厚的发生率较高.MCA与血压及左室重塑密切相关.  相似文献   
92.
自身免疫性感音神经性聋豚鼠的子代内耳生理功能研究   总被引:4,自引:4,他引:0  
目的 :观察自身免疫性感音神经性聋 (ASHL)母豚鼠所产子代内耳生理功能的变化 ,探讨针对内耳的自身免疫因素对子代内耳生理功能的影响及其改变特点。方法 :同种内耳抗原 (CIEAg)持续免疫孕豚鼠 ,采用耳蜗电图 (记录cAP、CM )和眼震电图仪 (记录自发性眼震和冷热空气试验 )测试母鼠和子鼠的听觉和前庭功能 ,并检测血清特异性体液免疫反应。结果 :ASHL模型母豚鼠所产子鼠血清中发现有特异性抗体水平升高 ,部分 (3 /9)出现听觉损伤。非ASHL母鼠和对照组母鼠所产子代未见明显异常。结论 :ASHL雌鼠所产子代可出现感音神经性聋 ,其内耳损伤和功能障碍极可能与针对内耳组织的自身免疫反应 (尤其是体液免疫 )有关 ,从而提示内耳自身免疫因素可能为部分先天性非遗传性感音神经性聋的病因之一。  相似文献   
93.
Genetic contributions to Parkinson's disease   总被引:8,自引:0,他引:8  
Sporadic Parkinson's disease (PD) is a common neurodegenerative disorder, characterized by the loss of midbrain dopamine neurons and Lewy body inclusions. It is thought to result from a complex interaction between multiple predisposing genes and environmental influences, although these interactions are still poorly understood. Several causative genes have been identified in different families. Mutations in two genes [α-synuclein and nuclear receptor-related 1 (Nurr1)] cause the same pathology, and a third locus on chromosome 2 also causes this pathology. Other familial PD mutations have identified genes involved in the ubiquitin–proteasome system [parkin and ubiquitin C-terminal hydroxylase L1 (UCHL1)], although such cases do not produce Lewy bodies. These studies highlight critical cellular proteins and mechanisms for dopamine neuron survival as disrupted in Parkinson's disease. Understanding the genetic variations impacting on dopamine neurons may illuminate other molecular mechanisms involved. Additional candidate genes involved in dopamine cell survival, dopamine synthesis, metabolism and function, energy supply, oxidative stress, and cellular detoxification have been indicated by transgenic animal models and/or screened in human populations with differing results. Genetic variation in genes known to produce different patterns and types of neurodegeneration that may impact on the function of dopamine neurons are also reviewed. These studies suggest that environment and genetic background are likely to have a significant influence on susceptibility to Parkinson's disease. The identification of multiple genes predisposing to Parkinson's disease will assist in determining the cellular pathway/s leading to the neurodegeneration observed in this disease.  相似文献   
94.
Objective To study the pulmonary functions of pediatric ALI/ARDS(acute lung injury/acute respiratory distress syndrome) survivors. Method A prospective cohort study of all survivors of ALI/ARDS in the PICU of Beijing Children's Hospital was performed. Patients were divided into three groups(0-3 years of age,3 ~ 7 years of age, and over 7 years of age) and followed up three months after diagnosis. Results There were 36 survivors in total of 44 ALl patients, three patients lost follow-up, 12 died and 21 survived. Five survivors refused to participate in the study because of asymptomatic, and one was unable to participate because of lymphoma com-bined with sepsis. A total of 15 children completed the whole survey (11 patients were less than 3 years old, andfour were over 7 years of age). Twelve patients had no discomfort in their respiratory tracts. Three months after be-ing enrolled, the pulmonary functions of all children improved, especially in terms of tidal volume and respiratory compliance (P<0.05). Conclusions The abnormal respiratory symptoms and signs in most children disap-peared three months after discharge. Most survivors still have pulmonary dysfunction at 3 monthes after discharge, but better than discharge.  相似文献   
95.
Klein [Klein, A. S. (2006). Separating transducer nonlinearities and multiplicative noise in contrast discrimination. Vision Research, 46, 4279-4293] questions the existence of intrinsic singularities in two-alternative force-choice (2AFC) Signal Detection Theory (SDT) models, suggesting that the singularities found in Katkov et al. [Katkov, M., Tsodyks, M., & Sagi, D. (2006a). Singularities in the inverse modeling of 2AFC contrast discrimination data. Vision Research, 46, 259-266; Katkov, M., Tsodyks, M., & Sagi, D. (2006b). Analysis of two-alternative force-choice Signal Detection Theory model. Journal of Mathematical Psychology, 50, 411-420] are due to discarding higher order terms in the Taylor expansion of d' and/or limited to steep psychometric functions. Here we provide some simple intuitive examples that illustrate the results described in Katkov et al. (2006a, 2006b). We show, for the constant noise model, that singularities exist when exact values of d' are computed and that the singularities are not limited to steep psychometric functions. In these cases the disambiguation of the different models requires millions of trials.  相似文献   
96.
基于临床流程功能需求的生理监测仪配置评估   总被引:1,自引:0,他引:1  
病人生理监测仪是临床医学的主要仪器之一,由于所涉及的技术流程定位不同,功能需求也就不同,其功能配置也应有所不同。本文从分解分析生理监测仪相关应用领域的技术定位功能需求出发,讨论卫生技术装备管理的功能配置评估。  相似文献   
97.
本文应用XD—Ⅰ型微电脑程序刺激器检查26例患者,在窦房结功能检查中测定了窦房结恢复时间、窦房传导时间及固有心率;在房室传导功能的估计中测定了文氏点,2∶1阻滞点及房室结的有效不应期;在室上性心动过速中测定了旁路不应期,房室结双通道,折返区及折返性心动过速区;还进行了心脏负荷试验及右束支不应期等方面的测定。并就其方法,判断标准及临床意义等分别作了讨论。  相似文献   
98.
Summary. Heart rate responses to stepwise and periodic changes in lung volume were studied in seven young healthy males. Stepwise inspiration and expiration both resulted in an increase in heart rate followed by a rapid decrease in heart rate. The fastest heart rate was reached in 1·6 ± 0·5 s and in 3·6 ± 1·4 s in response to inspiration and expiration, respectively (P < 0·01). The slowest heart rate was reached in 4·8± 1·0 s and in 7·6± 1·9 s in response to inspiration and expiration, respectively (P < 0·01). Following this biphasic change the heart rate returned to a steady level. The difference between the fastest and the slowest heart rates was significantly larger in response to inspiration (21·7 ± 7·3 beats per minute) than in response to expiration (12·0±7·3 beats per minute; P < 0·01). Periodic changes in lung volume were performed with frequencies from 3·0 to 12·0 respirations per minute (r.p.m.). The changes in heart rate showed a constant amplitude in the frequency range below 5·5 r.p.m. Maximal heart rate changes were found at frequencies of 5·5 to 7·0 r.p.m. Changes in heart rate decreased in a linear manner on a log-log scale in the frequency range above 7·0 r.p.m. The relation between frequency and changes in heart rate is explained by interference between the transient changes in heart rate induced both by inspiration and by expiration. It is concluded that if heart rate changes in response to periodic changes in lung volume are to be used as a measure of vagal function a number of factors have to be taken into consideration and to simplify the analysis of heart rate responses to breathing we recommend, instead, the use of the transient changes in heart rate induced by stepwise changes in lung volume.  相似文献   
99.
100.
目的 观察经皮椎体成形术(PVP)中骨水泥对老年骨质疏松症患者凝血功能的影响.方法 于椎弓根穿刺前10 min、注入骨水泥后1、20 min、2 h分别抽血检测11例患者的凝血功能相关指标,包括血浆凝血酶原时间(PT)、活化的部分凝血酶原时间(APTT)、血浆纤维蛋白原(FIB)和鱼精蛋白副凝固实验(3P实验),并汇总数据进行统计学分析.结果 PVP中骨水泥注入后20 min,PT缩短、FIB增高、3P实验阳性率升高(P<0.05),骨水泥注入2 h后基本恢复至注入前水平.除1例患者PTA术后2 h稍高于正常值(126%),其余患者各个时间点的各项指标均在正常参考值范围内.结论 PVP术中注入骨水泥对于凝血功能正常的患者基本安全,但在注入后会产生一过性轻微的高凝倾向.  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