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   16416篇
  免费   1519篇
  国内免费   1166篇
耳鼻咽喉   168篇
儿科学   183篇
妇产科学   172篇
基础医学   1853篇
口腔科学   206篇
临床医学   2113篇
内科学   2266篇
皮肤病学   123篇
神经病学   842篇
特种医学   572篇
外国民族医学   12篇
外科学   1725篇
综合类   3487篇
现状与发展   7篇
一般理论   1篇
预防医学   983篇
眼科学   349篇
药学   1761篇
  18篇
中国医学   1019篇
肿瘤学   1241篇
  2024年   64篇
  2023年   286篇
  2022年   651篇
  2021年   929篇
  2020年   703篇
  2019年   533篇
  2018年   532篇
  2017年   511篇
  2016年   509篇
  2015年   726篇
  2014年   934篇
  2013年   818篇
  2012年   1215篇
  2011年   1295篇
  2010年   917篇
  2009年   728篇
  2008年   874篇
  2007年   871篇
  2006年   884篇
  2005年   820篇
  2004年   556篇
  2003年   498篇
  2002年   466篇
  2001年   430篇
  2000年   361篇
  1999年   392篇
  1998年   235篇
  1997年   253篇
  1996年   200篇
  1995年   178篇
  1994年   134篇
  1993年   75篇
  1992年   90篇
  1991年   88篇
  1990年   86篇
  1989年   66篇
  1988年   43篇
  1987年   43篇
  1986年   49篇
  1985年   24篇
  1984年   11篇
  1983年   8篇
  1982年   6篇
  1981年   2篇
  1979年   5篇
  1974年   1篇
  1972年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
肝尾状叶由于解剖位置特殊,位置深,难以显露,手术难度大,是肝脏外科领域手术操作的难点与研究热点.随着肝血流控制技术的发展、肝实质离断技术的提高,肝尾状叶肿瘤切除率明显提高[1].2006年4月至2008年10月,我科完成单独肝尾状叶血管瘤切除术9例,现将手术技巧与疗效报道如下.  相似文献   
12.
以健康Wistar大白鼠为材料,对微波快速内源性过氧化物酶染色与灌注法显示微血管的方法进行了对比研究。结果,过氧化物酶组织化学法具有不用灌注,操作简单,所用时间短,对血管无扩张、破裂等人为改变的特点,保持了微血管真实的自然形态和管径大小,可以定量或半定量地判定组织器官活体时的血液循环状况。可以用于人及动物的大脑、脊髓、皮肤、耳及食管等组织内微血管形态学研究和定量分析。并对过氧化物酶显示微血管的原理和微波辐射促进染色的原理及特点进行了分析、讨论。  相似文献   
13.
Summary Using histochemical technique, the effects of radiofrequency catheter ablation (RFCA) on the activities of LDH, SDH, CCO, and Ca++-ATPase of guinea-pig ventricular myocytes were examined. The histological changes were observed for comparison. Radiofrequency energy (500 kHz) delivered was 20 WX 10 s. The results were as follows: RFCA resulted in significant impairments in all the four kinds of enzymes but without statistical differences in the areas involved in this energy level. No statistically significant difference was found between the ranges of enzymatic damages and areas of pathological lesions. These findings showed a consistency in areas of the histological and histochemical lesions resulted from RFCA.  相似文献   
14.
小鼠卵细胞质内显微注入单精子受精的实验研究   总被引:8,自引:0,他引:8  
杨益寿  熊素芳  龙文  李鸣  夏明珠  汪昌介 《解剖学报》1998,29(4):441-445,I011
为了探讨提高小鼠卵细胞质内单精子注入受精率的方法,选取鼠龄12-14周的健康昆明白小鼠作为精子和卵子的供体,受用ICSI技术,以受精后二细胞卵裂的形成率为指标,了解不同采卵时间,不同微注射针参数及不同培养液对细胞质单精子注入的影响。结果表明,hCG注射后18-19h采卵,用针尖内径为4-5μm,斜面角度为35-40度的微注射针进行ICSI操作受精后卵子置CZB中培养可获得较多的2细胞胚,卵裂率明显  相似文献   
15.
[目的]比较2,4-二氯苯胺重氮法(DCA)和钒酸盐氧化法检测血清结合胆红素的结果。[方法]根据NCCLS(EP6-P)评价方案,评估两种方法的相关性和偏倚。[结果]两种方法的检测结果相关性良好(r=0.9985),Ⅰ、Ⅱ、Ⅲ组检测结果无差异,Ⅳ组结果有差异。[结论]应建立与方法学相对应的血清结合胆红素参考值范围。  相似文献   
16.
We have examined polyol pathway kinetics in the lenses of rats made diabetic with streptozotocin. At up to 11 days after diabetes induction, the lenses were isolated and subjected to 'pulse-chase' studies: the lenses were incubated with [13C]glucose and lens metabolism followed by [13C]nuclear magnetic resonance (NMR) spectroscopy. Proton NMR spectroscopy was also performed to measure the hexose monophosphate shunt (HMPS) activity. The results showed that (1) the activity of aldose reductase increased initially and decreased after 11 days of diabetes; (2) the fructose pool increased initially but started to decline after 3 days; (3) the HMPS activity increased nearly 40% immediately after diabetes induction; and (4) the turnover rates of glucose, alpha-glycerophosphate (GP), lactate, sorbitol, and fructose were 80.8 +/- 2.6, 10.1 +/- 1.4, 47.7 +/- 3.7, 7.9 +/- 0.9 and 5.2 +/- 2.2 nmol hr-1 lens-1 (34 mg wet weight lens-1), respectively. Up to 35% of lactate appeared to derive from the polyol pathway. Further, GP was rapidly metabolized, although its fate is currently unknown. These results reveal a far more complex pattern of glucose metabolism in the diabetic lens than that in lenses incubated in high glucose.  相似文献   
17.
18.
Pituitary tumors are the most common primary intracranial neoplasms. Although most pituitary tumors are considered typically benign, others can cause severe and progressive disease. The principal aims of pituitary tumor treatment are the elimination or reduction of the tumor mass, normalization of hormone secretion and preservation of remaining pituitary function. In spite of major advances in the therapy of pituitary tumors, for some of the most difficult tumors, current therapies that include medical, surgical and radiotherapeutic methods are often unsatisfactory and there is a need to develop new treatment strategies. Gene therapy, which uses nucleic acids as drugs, has emerged as an attractive therapeutic option for the treatment of pituitary tumors that do not respond to classical treatment strategies if the patients become intolerant to the therapy. The development of animal models for pituitary tumors and hormone hypersecretion has proven to be critical for the implementation of novel treatment strategies and gene therapy approaches. Preclinical trials using several gene therapy approaches for the treatment of anterior pituitary diseases have been successfully implemented. Several issues need to be addressed before clinical implementation becomes a reality, including the development of more effective and safer viral vectors, uncovering novel therapeutic targets and development of targeted expression of therapeutic transgenes. With the development of efficient gene delivery vectors allowing long-term transgene expression with minimal toxicity, gene therapy will become one of the most promising approaches for treating pituitary adenomas.  相似文献   
19.
用放射免疫分析法和比浊法测定PAI0134对大鼠血浆血栓素B2浓度,血小板TXB2生成血小板聚集的影响。静脉注射API013470mg或100mg.kg显著降低血浆TXB2浓度,其降低2率分别为38.8%和51.6%,API0134明显抑制ADP诱导的大鼠血小板聚集和TXB2生成,抑制率分别为27.8%,39.5%,和41.4%,53.6%,两抑制率间呈显著正相关。  相似文献   
20.
PURPOSE: Inclusion-body myopathy, Paget's disease of bone and frontotemporal dementia is an adult-onset autosomal dominant illness (IBMPFD) caused by mutations in the valosin-containing protein (VCP) on chromosome 9p21.1-p12. The penetrance of the gene is 82% for myopathy, 49% for Paget's disease, but may be as low as 30% for frontotemporal dementia. Modifier genes could account for decreased frontotemporal dementia penetrance. In this study apolipoprotein-E (APOE) was evaluated for this role in IBMPFD families based on its known modifier effect in Alzheimer's disease. METHODS: From a database of 231 members of 15 families, 174 had APOE genotype available for analysis. Logistic regressions on APOE genotype and frontotemporal dementia were performed, using appropriate covariates. RESULTS AND CONCLUSION: FTD was associated with APOE 4 genotype (P=0.0002), myopathy (P=0.0006), and age (P=0.01), but not microtubule associated protein tau (MAPT) H2 haplotype (P=0.5) or gender (0.09) after adjustment for membership in pedigrees with at least one APOE 4 genotype. These data suggest a potential link between APOE 4 genotype and the specific form of frontotemporal dementia found in IBMPFD. The molecular basis of this link bears further investigation. We did not observe an association of frontotemporal dementia and H2 MAPT haplotype.  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