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   82801篇
  免费   10060篇
  国内免费   1992篇
耳鼻咽喉   500篇
儿科学   1602篇
妇产科学   1046篇
基础医学   5924篇
口腔科学   2849篇
临床医学   11750篇
内科学   9740篇
皮肤病学   1019篇
神经病学   6938篇
特种医学   2351篇
外国民族医学   13篇
外科学   7825篇
综合类   12725篇
现状与发展   8篇
一般理论   29篇
预防医学   8182篇
眼科学   1286篇
药学   9665篇
  523篇
中国医学   6694篇
肿瘤学   4184篇
  2024年   371篇
  2023年   1810篇
  2022年   2927篇
  2021年   4657篇
  2020年   5072篇
  2019年   3978篇
  2018年   3731篇
  2017年   4066篇
  2016年   3886篇
  2015年   3517篇
  2014年   5974篇
  2013年   6686篇
  2012年   5123篇
  2011年   5399篇
  2010年   4266篇
  2009年   3778篇
  2008年   3731篇
  2007年   3729篇
  2006年   3278篇
  2005年   2662篇
  2004年   2326篇
  2003年   2045篇
  2002年   1699篇
  2001年   1263篇
  2000年   1062篇
  1999年   862篇
  1998年   727篇
  1997年   688篇
  1996年   598篇
  1995年   503篇
  1994年   494篇
  1993年   356篇
  1992年   399篇
  1991年   342篇
  1990年   337篇
  1989年   311篇
  1988年   288篇
  1987年   248篇
  1986年   198篇
  1985年   242篇
  1984年   209篇
  1983年   158篇
  1982年   161篇
  1981年   160篇
  1980年   125篇
  1979年   84篇
  1978年   60篇
  1977年   59篇
  1976年   56篇
  1975年   43篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
Abstract Thirty-nine patients with schizophrenia, diagnosed according to DSM-III-R, who were under 15 years of age, were studied in two groups; 16 subjects with obsessive-compulsive symptoms during the prodromal phase, and 23 with no obsessive-compulsive disorders. The group with obsessive-compulsive symptoms during the prodromal phase was characterized by a higher ratio of males, higher incidences of perinatal and brain computed tomography (CT) abnormalities, fewer hereditary factors, longer duration of the prodromal phase, and a higher incidence of insidious onset and negative symptoms compared with the group without such prodromal symptoms. Schizophrenic patients with obsessive-compulsive symptoms during the prodromal phase were clinically distinct from those without, which suggests the possibility of subtype categorization.  相似文献   
102.
Little is known about whether patients with photosensitive disorders exhibit a different ultraviolet erythema time course from subjects with a normal response to sunlight. We have described the application of an instrument for ambulatory monitoring of the development of ultraviolet erythema by a reflectance method in a group of patients with chronic actinic dermatitis (CAD) and in a group of normal subjects. Investigations of the time course have been reported previously but the techniques used relied upon manual measurement. Consequently sampling frequencies have been considerably lower than the one-minute sample rate used here. We have not demonstrated any difference in the rate at which erythema develops and peaks between patients with CAD and subjects with a normal response to sunlight.  相似文献   
103.
对2054例住院病人进行回顾性临床分析中,发现有52例诊断为酒精所致精神障碍,发生率为2.53%,均为男性,平均年龄44.2±9.0岁,发生率呈逐年增加趋势。嗜酒的原因与遗传、职业、文化水平、民族风俗有关,黎族患者占27例(51.92%)。临床以幻觉、被害妄想、妒嫉妄想、行为障碍为多见。治疗:使用奋乃静23例(44.23%)的频率较高,显效率88.46%。长期大量酗酒,可致躯体损害,复发达11例(21.15%)。早期限制及戒酒可减少躯体的损害。  相似文献   
104.
In the 19th century, investigators recognized that addiction to opiates involves tolerance and dependence. In the United States, the National Academy of Sciences and the Public Health Service initiated systematic investigations into opiate addiction in 1929. Tolerance and dependence to morphine, the prototype for opiate drugs, were the emphasis of human studies for the next fifty years. This presentation highlights salient features of tolerance and dependence learned in these studies and relates these findings to clinical use in treating pain.  相似文献   
105.
α-L-岩藻糖苷酶测定的临床应用   总被引:1,自引:0,他引:1  
侯振江  张宗英 《华夏医学》2003,16(5):742-743
研究结果表明AFU测定对肝癌的诊断具有较高的敏感性和特异性,其价值优于AFP,两项指标联合检测可提高阳性检出率。动态监测有利于肝癌的早期诊断、鉴别诊断,并可作为转移、复发的指标,也可用于白血病及卵巢癌的诊断。  相似文献   
106.
《Physiotherapy》1997,83(6):284-289
This paper describes a method of systematic reviewing. This method puts much emphasis on the methodological quality of the randomised clinical trials involved. Various items concerning the internal validity, precision and relevance of the studies are scored in such a way that next to the methodological quality the amount of uncertainty about it also becomes visible. These quality assessments are not only useful for systematic reviews, but also have an educational function for researchers with respect to the design and publication of a clinical trial.  相似文献   
107.
In this study, human umbilical vein and human saphenous vein endothelial cells were seeded on glass and exposed to fluid shear in a parallel-plate flow chamber. Cell retention, morphology and migration were studied as a function of shear stress and of adhesion time prior to exposure to shear. Three-hour and 24-h adhesion times gave rise to comparable cell retention values after 2 h of flow for both cell types. Cell retention decreased from 85 to 20% as shear stress increased from 88 to 264 dynes cm−2 (8.8 to 26 Pa). Mean spreading areas decreased after the onset of flow, but subsequently stabilized to plateau values, which were smaller at higher shear stresses. Shape factors increased faster to higher values as cells were exposed to higher shear stresses, without any obvious preference in orientation of the cells with respect to the direction of flow. Migration was unidirectional with flow and linear with time. Migration was faster for cells which had adhered for 24 h than for cells which had adhered for 3 h and was accompanied by the presence of fibrillar structures left behind on the surface upstream of migrating cells. It is concluded that after 3 h adhesion to glass, cells have adhered with an adhesion strength that does not substantially increase during the next 21 h. However, during this time changes in cell-substratum interactions seem to occur judging by the differences in, e.g., migration rates.  相似文献   
108.
109.
Comprehensive renal function tests were performed in 84 patients with analgesic nephropathy, 33 glomerulonephritis patients matched for creatinine clearance, and 30 control subjects. A system of 1-day renal function tests including urine microscopy, creatinine clearance, phenolsulphonphthalein excretion, urine concentration and acidification, and electrolyte excretion, was used. Patients with analgesic nephropathy were found to have significant sterile pyuria and haematuria, even those with mild renal insufficiency, significantly reduced concentrating ability and a distal acidifying defect, and a tendency to impaired sodium conservation. These function defects are consistent with the primary lesion of renal papillary necrosis in analgesic nephropathy; the detection of these defects have implications in patient management.  相似文献   
110.
 Acute exposure to ethanol produces deficits in sustained attention in humans, but these attentional deficits have not been modeled in animals. In this study, an operant task was used to investigate the effects of low and moderate doses of ethanol on sustained attention in rats. Performance on a two-choice reaction time task over a 1-h session was assessed immediately following administration of ethanol (0.0, 0.5, 0.75, 1.0 and 1.5 g/kg IP). Each rat was required to respond to a light stimulus of variable duration (20, 100, and 500 ms) occurring at one of two locations. Under control and saline conditions, increases in stimulus length systematically increased choice accuracy and decreased reaction time. Ethanol produced a dose-dependent decrease in choice accuracy that interacted with time, with an initial impairment that was stimulus length-dependent followed by a general vigilance decrement. The data demonstrate that ethanol impaired the ability of rats to direct and sustain attention to brief, infrequent stimuli, and provide a model for further investigations into the underlying neurobiological mechanisms for ethanol-induced attentional deficits. Received: 19 March 1996 / Final version: 30 August 1996  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