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   267842篇
  免费   22096篇
  国内免费   9962篇
耳鼻咽喉   1266篇
儿科学   9242篇
妇产科学   1756篇
基础医学   23298篇
口腔科学   3696篇
临床医学   27240篇
内科学   68365篇
皮肤病学   2905篇
神经病学   26596篇
特种医学   8397篇
外国民族医学   19篇
外科学   23239篇
综合类   39351篇
现状与发展   47篇
一般理论   9篇
预防医学   20220篇
眼科学   2423篇
药学   20750篇
  207篇
中国医学   13941篇
肿瘤学   6933篇
  2024年   508篇
  2023年   5090篇
  2022年   7098篇
  2021年   13654篇
  2020年   12807篇
  2019年   9965篇
  2018年   9822篇
  2017年   10127篇
  2016年   10806篇
  2015年   10284篇
  2014年   18769篇
  2013年   20490篇
  2012年   15671篇
  2011年   17069篇
  2010年   13400篇
  2009年   12922篇
  2008年   12925篇
  2007年   12669篇
  2006年   11598篇
  2005年   9598篇
  2004年   8061篇
  2003年   6958篇
  2002年   5955篇
  2001年   5220篇
  2000年   4328篇
  1999年   3706篇
  1998年   3538篇
  1997年   3109篇
  1996年   2804篇
  1995年   2507篇
  1994年   2334篇
  1993年   1973篇
  1992年   1864篇
  1991年   1614篇
  1990年   1339篇
  1989年   1145篇
  1988年   1047篇
  1987年   920篇
  1986年   816篇
  1985年   958篇
  1984年   819篇
  1983年   513篇
  1982年   600篇
  1981年   515篇
  1980年   411篇
  1979年   350篇
  1978年   290篇
  1977年   246篇
  1976年   233篇
  1975年   102篇
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
991.
成人体外循环术后精神症状原因分析   总被引:9,自引:0,他引:9  
目的 研究成人体外循环手术以后发生精神症状的高危因素。方法 对52例16岁以上的体外循环手术后发生精神症状的病人进行分析。结果 主要表现有认知障碍、情感障碍、意志行为障碍及意识障碍。男女之间无明显差异,而在患者年龄、术前心功能、既往精神病史、监护室监护时间等方面精神病组和健康组间存在显著差异。结论 成人体外循环手术后发生精神症状的高危因素有患者年龄、术前心功能、既往精神病史、心脏病史、监护室停留时间等,应高度重视加强护理和观察。  相似文献   
992.
Summary: Strategies used in molecular genetics have changed modern neurology. The gene or genes responsible for several major neurologic diseases have now been identified using "reverse" or positional genetics. Unexpected new genetic mechanisms have been discovered in human neurologic diseases, including (a) identical mutations of the prion protein gene in Creutzfeldt-Jakob disease and fatal familial insomnia with the phenotypic expression directed by an accompanying polymorphism; (b) stable duplications of chromosome 17 in Charcot-Marie-Tooth disease (type 1 A) that involve many genes, only one of which appears to cause neuropathy; and (c) highly variable, dynamic mutations in myotonic dystrophy, fragile X syndrome, and Kennedy's syndrome that modulate variable expressivity in multiple tissues. There is growing recognition that neurologic diseases are often complex genetic diseases with multifactorial rather than simple modes of inheritance. For example, genetic association/linkage strategies have interacted with biochemistry and immunopathology studies to produce new insights into the disease mechanism of late-onset Alzheimer's disease. The role of apolipoprotein E in late-onset Alzheimer's disease is an example of how new analytical techniques of genetic disease can be applied to dissect multiple genes. Similar research strategies are suggested for the study of epilepsy as a complex disease.  相似文献   
993.
Summary Ninety outpatients with Alzheimer's disease according to ICD-10 diagnostic draft criteria were studied to test the hypothesis that cases with a familial aggregation are different from cases without such an aggregation with respect to cognitive impairment. In all cases the diagnosis of Alzheimer's disease was confirmed by prospective observation within 12 months of initial evaluation. Patients were divided into two groups: one consisting of 23 patients with a familial aggregation, the other consisting of 67 patients without secondary cases among first-degree relatives. By means oft-tests differences in impairment of cognitive functions between the groups were calculated. The results did not yield statistically significant differences between the groups for any of the neuropsychologically investigated cognitive deficits. Thus the hypothesis that the presence of a familial aggregation may lead to a distinct phenotype in Alzheimer's disease was not confirmed.  相似文献   
994.
ABSTRACT. A double balloon technique was used for anal tonometry in 22 infants. The weight was less than 2500 g in 10 of the infants. Ileus or delayed passage of meconium was seen in 9 infants. Thirteen infants had not revealed any symptoms of intestinal obstruction during the first week of life. In all cases, except one, it was possible to demonstrate reflexes from the internal anal sphincter. In 18 infants normal curves were registered from the internal anal sphincter. None of these developed Hirschsprung's disease. In 3 infants a pathological pattern of contractions of the internal anal sphincter was demonstrated. Two of them proved to have Hirschsprung's disease. In the third case normal reflexes were registered after one year. Possibly the innervation of rectum and the internal anal sphincter was disrupted during the neonatal period in connection with enterocolitis and ileus, thus representing a reversible case of achalasia.  相似文献   
995.
The reliability of antigliadin antibodies of IgA and IgG classes for the diagnosis and follow-up of coeliac disease was evaluated by ELISA tests. Forty coeliac patients, 41 patients with other gastrointestinal diseases and 50 healthy subjects were studied. IgA antigliadin antibodies were detected in all patients on unrestricted diet and in those on a challenge with a gluten-containing diet. A low incidence of positivities was found in patients on a gluten free-diet, while no positivity was found in controls or gastrointestinal patients. IgG determination, in contrast, showed poor specificity. Our data suggest that a positive IgA antigliadin test may be a reliable marker for the presence of active coeliac disease, which should be confirmed by intestinal biopsy; it is, moreover, a good marker for monitoring patients, since elevated values might suggest non-compliance with the diet.  相似文献   
996.
本文自1991年1月以来.进行了静脉输注胎肝细胞悬液干扰化疗药物降白副反应的医学序贯试验。实验组病人静脉输注4~6月胎龄胎肝细胞悬液1600~4000ml(浓度5~7×109个/L),对照组按常规方法升白。通过28例病人的序贯试验发现化疗期间输注胎肝细胞悬液的病人骨髓抑制发生延迟,持续时间短,程度减轻,从而为化疗正常进行提供基本条件。结论;胎肝细胞悬液输注可干扰化疗药物降白副反应的发生。  相似文献   
997.
Hepatobiliary scintigraphy in a patient with bilhemia   总被引:1,自引:0,他引:1  
A 4-year-old child referred for acute jaundice following percutaneous needle biopsy of the liver underwent hepatobiliary scintigraphy. Although all conventional liver tests suggested preservation of hepatocyte function, the tracer uptake in the liver appeared dramatically reduced at scintigraphy and the blood pool activity did not decrease significantly until the end of the study. Visualization of the bile ducts indicated, however, that the tracer was taken up by the hepatocyte and further excreted into the biliary tree. There was no tracer pooling in the biliary tree although no bowel activity was observed, even on delayed images. The association of persistent blood pool activity, bile duct visualization without tracer pooling, and nonvisualization of the bowel was caused by a continuous recirculation of the tracer from the biliary tree into the bloodstream. The presence of a biliovenous fistula was further proven by percutaneous transhepatic cholangiography performed 24 h later. Since 1975, only 16 cases of bilhemia have been reported. To the best of our knowledge the scintigraphic pattern of this rare but lifethreatening complication has not previously been reported.  相似文献   
998.
Models of Parkinson's disease.   总被引:2,自引:0,他引:2  
Parkinson's disease (PD) is a heterogenous disease likely to be caused by more than one specific aetiological factor. In rare familial cases of PD with similar clinical features to the idiopathic form of the disease, the underlying genetic cause has been identified. These PD-associated genes have been manipulated to create animal and cell culture models of the disease that have helped to further our understanding of the pathogenesis of PD, particularly concerning causes of the selective loss of dopaminergic neurons at the molecular level. In addition, these models will aid the future development of rational therapeutic strategies. This study briefly reviews toxin-induced models and the genetics of PD. It focuses on recently developed animal models of PD, as well as in vitro approaches to model the disease.  相似文献   
999.
目的 进一步了解肝癌患者的异常免疫状态,探讨血清、腹水中可溶性肿瘤坏死因子受体-p55(sTNFR-p55)检测的临床意义。方法 以双单抗夹心酶免疫吸附法检测了25例肝癌患者和25例肝硬化患者的血清、腹水中血清sTNFR-p55水平并以正常人为对照。结果肝癌病人血清sTNFR-p55浓度[(0.74±0.50)ng/ml]显著高于正常人[(0.37±0.03)ng/ml]和肝硬化患者和[(0.35±0.02)ng/ml],P<0.01。肝癌病人腹水sTNFR-p55浓度[(1.11±1.25)ng/ml]亦显著高于肝硬化患者[(0.33±0.03)ng/ml],P<0.01。肝癌、肝硬化患者血清与腹水的sTNFR-p55水平显著相关。肝癌患者血清sTNFR-p55水平与外周血TBil和AFP呈正相关(r=0.524,P=0.01和r=0.234,P=0.03)。结论 sTNFR-p55的检测对反映肝癌患者的异常免疫状态和肿瘤诊断具有实用价值。  相似文献   
1000.
Background : A retrospective analysis of 103 case records from 1978 to 1996 with a provisional diagnosis of Buerger's disease was undertaken at the Department of Surgery, University of Hong Kong, Queen Mary Hospital. The aim of the study was to elucidate the clinical course and evaluate the results of surgical intervention of Buerger's disease in Hong Kong Chinese people. Methods : Fourteen patients were subsequently excluded from the study because of inability to fulfil our diagnostic criteria. Data on clinical presentation, investigations, indications and results of surgical intervention were reviewed. Sympathectomies and arterial reconstructions were performed on 42 and four patients, respectively, for critical ischaemia or rest pain. Outcome was analysed with respect to the rate of ulcer healing, pattern of recurrence and limb loss. Results : The patients were all young male heavy smokers with a mean age of 36.5 years. The majority of patients (80%) presented with ischaemic ulceration or gangrene. Vascular reconstruction was undertaken in four patients and satisfactory long-term results were obtained in three patients. Sympathectomy was able to relieve symptoms in 87% of operated patients and ischaemic ulceration healed in 2.6 (mean) ± 1.7 (SD) months after the operation. If the patient continued to smoke, surgical intervention did not exempt the patient from a relapse or amputation. Conclusion : Sympathectomy provides short-term pain relief and promotes ulcer healing in patients with Buerger's disease but carries no long-term benefit. Complete abstinence from smoking is the only means of arresting the progression of the disease.  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