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   69411篇
  免费   5666篇
  国内免费   2020篇
耳鼻咽喉   493篇
儿科学   1335篇
妇产科学   605篇
基础医学   5530篇
口腔科学   1827篇
临床医学   8319篇
内科学   10576篇
皮肤病学   425篇
神经病学   3793篇
特种医学   3100篇
外国民族医学   5篇
外科学   6333篇
综合类   10692篇
现状与发展   6篇
预防医学   4588篇
眼科学   4601篇
药学   9238篇
  42篇
中国医学   4509篇
肿瘤学   1080篇
  2024年   106篇
  2023年   1035篇
  2022年   1625篇
  2021年   2828篇
  2020年   2663篇
  2019年   2411篇
  2018年   2505篇
  2017年   2427篇
  2016年   2553篇
  2015年   2538篇
  2014年   4648篇
  2013年   5074篇
  2012年   4303篇
  2011年   4643篇
  2010年   3492篇
  2009年   3097篇
  2008年   3282篇
  2007年   3389篇
  2006年   2990篇
  2005年   2438篇
  2004年   2095篇
  2003年   1754篇
  2002年   1522篇
  2001年   1472篇
  2000年   1163篇
  1999年   1029篇
  1998年   833篇
  1997年   850篇
  1996年   729篇
  1995年   773篇
  1994年   692篇
  1993年   583篇
  1992年   577篇
  1991年   490篇
  1990年   472篇
  1989年   403篇
  1988年   415篇
  1987年   383篇
  1986年   318篇
  1985年   419篇
  1984年   390篇
  1983年   254篇
  1982年   314篇
  1981年   246篇
  1980年   217篇
  1979年   176篇
  1978年   153篇
  1977年   89篇
  1976年   76篇
  1975年   51篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
91.
4132名少年儿童血压状况调查分析   总被引:5,自引:0,他引:5  
目的了解7~14岁少年儿童血压特点,为流行病学及预防成人高血压提供参考数据。方法用统一标准采集血压及有关数据,用概率单位法行正态性检验,确定血压95%参考值范围,对年龄与血压和体质指数进行相关性分析,行U检验、t检验。结果随年龄增大血压也逐渐上升,各年龄段男女之间血压差异无统计学意义。体质指数随年龄增大而增加。血压偏高者其体质指数高于同年龄段中值水平。结论年龄与血压和体质指数呈正相关。血压偏高者体质指数都具有较高中值水平。  相似文献   
92.
BACKGROUND: Decreased plasma adiponectin is associated with impaired endothelial function and, thereby, increased risk for cardiovascular events. Glucocorticoid (GC) affects vascular endothelial cells either favourably or harmfully depending upon the dosages and duration. We examined the effect of GC pulse therapy on vascular endothelial function. METHODS: Fourteen young patients with IgA nephropathy were evaluated for flow-mediated vasodilation (FMD), plasma levels of adiponectin both in high molecular weight (HMW adiponectin) form and in single molecular form (total adiponectin), hepatocyte growth factor (HGF), asymmetric dimethylarginine (ADMA), and high-sensitive C-reactive protein, before and after a course of GC pulse therapy. RESULTS: GC pulse therapy significantly decreased FMD (from 7.2 +/- 2.6 to 5.7 +/- 2.5%, P < 0.01). Meanwhile, plasma adiponectin levels were significantly augmented (total adiponectin: from 10.2 +/- 4.0 to 12.1 +/- 6.3 microg/ml, P < 0.05; HMW: from 6.5 +/- 3.2 to 7.7 +/- 3.3 microg/ml, P < 0.05). In parallel, elevated concentrations of serum HGF (from 0.28 +/- 0.12 to 0.63 +/- 0.38 ng/ml, P < 0.01) and plasma ADMA (from 0.45 +/- 0.07 to 0.53 +/- 0.04 nmol/ml, P < 0.05) were observed. CONCLUSIONS: GC pulse therapy impaired endothelial function while increasing plasma adiponectin levels, which may in turn restore the endothelial function in patients with IgA nephropathy.  相似文献   
93.
1. The relationship between work-rate and the antihypertensive effect of exercise in hypertensives, and the mechanism of that effect, were investigated by a crossover clinical trial. 2. Ten mild hypertensives were randomly divided into two groups. One group performed low work-rate exercise (LWE) on a cycle ergometer for 10 weeks (blood lactate threshold; ~50% of maximum oxygen consumption [V?O2max]). After a 10 week interval without exercise training, these subjects were then switched to a high work-rate exercise (HWE) regimen (4 mmol/ L of blood lactate; ~75% of V?O2max) for another 10 weeks. In the other group, the order of exercise training was reversed. Since two patients withdrew from the protocol during HWE periods, statistical analysis was performed on the data from the remaining eight patients. There were no order effects observed in any of the data from the two groups. 3. During both LWE and HWE, resting blood pressure (BP) fell significantly after the initiation of exercise therapy (P<0.05). Furthermore, the overall effects of 10 weeks of LWE and HWE on BP were not significantly different. 4. The work-rate at the lactate threshold, which reflects physical fitness, had increased significantly by 16 W (P<0.01) after the LWE period and by 11 W (P<0.01) after the HWE. 5. During the LWE period, changes in haemodynamic and humoral variables were not significant, except for a reduction in plasma norepinephrine at week 10 (P<0.05). In the HWE period, changes in haemodynamic and humoral variables were not significant. 6. Based on these findings, LWE is recommended for mild hypertensives because of its safety.  相似文献   
94.
采用淋巴细胞分离液分离外周血中的有核细胞,经细胞裂解液处理,上清提取RNA,沉淀提取DNA,用分离液分离所得红细胞沉淀制备血红蛋白溶液。经对抽提物质量进行评价,发现3种提取物质量均高。本法能从少量外周血中同时分离DNA、RNA及血红蛋白,高效易操作,值得推广。  相似文献   
95.
目的:研究水杨醛-N′-(2-呋喃硫羰基)腙铜配合物(CSFC)在兔体内的药物动力学。方法:10只家兔静脉注射CSFC5mg·kg-1,用反相HPLC法测定血清药物浓度。结果:CSFC的血药浓度-时间曲线符合二室开放模型,主要药动学参数为:T12α=3.4±1.7min,T12β=65.5±14.6min,K12=0.1183±0.0669min-1,K21=0.0228±0.0065min-1,K10=0.1202±0.0407min-1,V0=0.305±0.184L·kg-1,CL=1.896±0.470L·kg-1·h-1,AUC=170.1±57.0mg·min-1·L-1。结论:CSFC在兔体内分布迅速而广泛,消除也较快。家兔静注5mg·kg-1,可维持抗结核杆菌有效血浓度6h。  相似文献   
96.
97.
Thirty women, 25 with incontinence and five asymptomatic volunteer control subjects, were evaluated urodynamically by a variety of techniques, including ultrasound cystourethrography. The ultrasound evaluation was found to be a helpful adjunct in diagnosis. In comparison with radiologic techniques it offers more safety, more comfort, more privacy, more viewing time, and less cost. Bladder and urethral morphology during voiding activity and the amount and direction of urethrovesical mobility are easily determined by utilizing ultrasound techniques.  相似文献   
98.
Data on 232 members of a single pedigree, descended from two pairs of original parents, were made available to the participants of Genetic Analysis Workshop 8 (GAW8). In addition to information concerning age and sex, measurements for 10 quantitative traits and genotypes at 22 polymorphic marker loci were also provided for a subset of 193 of these family members. © 1993 Wiley-Liss, Inc.  相似文献   
99.
100.
精索静脉曲张症不育患者结扎术前后精液质量变化的观察   总被引:3,自引:1,他引:2  
徐志强 《广西医学》2002,24(6):791-792
目的:了解精索内静脉高位结扎术对精索静脉曲张症不育患精液质量的影响。方法:对近三年我院诊治精索静脉曲张症不育患35例,术前、术后精液质量进行比较。结果:术后患精子密度、精子活动率及正常形态精子均明显改善。结论:精索内静脉高位结扎术能提高精索静脉曲张症不育患的生育力。  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