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   220049篇
  免费   17513篇
  国内免费   7065篇
耳鼻咽喉   1274篇
儿科学   7662篇
妇产科学   1570篇
基础医学   19481篇
口腔科学   3619篇
临床医学   23337篇
内科学   55632篇
皮肤病学   2721篇
神经病学   26098篇
特种医学   6378篇
外国民族医学   4篇
外科学   17083篇
综合类   30244篇
现状与发展   31篇
一般理论   9篇
预防医学   17937篇
眼科学   2408篇
药学   15183篇
  185篇
中国医学   9980篇
肿瘤学   3791篇
  2024年   528篇
  2023年   4420篇
  2022年   7703篇
  2021年   11857篇
  2020年   11094篇
  2019年   8429篇
  2018年   8345篇
  2017年   8245篇
  2016年   8558篇
  2015年   8257篇
  2014年   15642篇
  2013年   17075篇
  2012年   12785篇
  2011年   13812篇
  2010年   10880篇
  2009年   10469篇
  2008年   10480篇
  2007年   10125篇
  2006年   9026篇
  2005年   7433篇
  2004年   6327篇
  2003年   5440篇
  2002年   4575篇
  2001年   3960篇
  2000年   3299篇
  1999年   2824篇
  1998年   2704篇
  1997年   2385篇
  1996年   2136篇
  1995年   1931篇
  1994年   1781篇
  1993年   1519篇
  1992年   1457篇
  1991年   1280篇
  1990年   1015篇
  1989年   858篇
  1988年   806篇
  1987年   732篇
  1986年   635篇
  1985年   737篇
  1984年   618篇
  1983年   380篇
  1982年   447篇
  1981年   377篇
  1980年   283篇
  1979年   247篇
  1978年   185篇
  1977年   164篇
  1976年   135篇
  1975年   50篇
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
991.
Norovirus infections have been described as self-limiting diseases of short duration. An investigation of a norovirus outbreak in a university hospital provided evidence for severe clinical features in patients with several underlying diseases. Clinical outcomes of norovirus infection were defined. Risk-factor analysis targeting underlying diseases and medication was performed using multivariate analyses. In five outbreak wards, 84 patients and 60 nurses were infected (an overall attack rate of 32% in patients, and 76% in nurses). The causative agent was the new variant Grimsby virus. Severe clinical features, including acute renal failure, arrhythmia and signs of acute graft organ rejection in renal transplant patients, were observed in seven (8.3%) patients. In multivariate analyses, cardiovascular disease (OR 17.1, 95% CI 2.17-403) and renal transplant (OR 13.0, 95% CI 1.63-281) were risk-factors for a potassium decrease of >20%. Age >65 years (OR 11.6, 95% CI 1.89-224) was a risk-factor for diarrhoea lasting >2 days. Immunosuppression (OR 5.7, 95% CI 1.78-20.1) was a risk-factor for a creatinine increase of >10%. Norovirus infections in patients with underlying conditions such as cardiovascular disease, renal transplant and immunosuppressive therapy may lead to severe consequences typified by decreased potassium levels, increased levels of C-reactive protein and creatine phosphokinase. In the elderly, norovirus infection may lead to an increased duration of diarrhoea. Therefore patients at risk should be hospitalised early and monitored frequently. Strict preventional measures should be implemented as early as possible to minimise the risk of nosocomial outbreaks.  相似文献   
992.
目的 了解衡阳地区性传播疾病(STD)患者病原体感染情况。方法 对2420例可疑STD患者进行检测:淋病奈瑟菌(NG)、解脲脲原体(UU)、人型支原体(MH)采用培养法;沙眼衣原体(CT)、人乳头瘤病毒(HPV)、单纯疱疹病毒(HSV)核酸采用聚合酶链反应(PCR)法;梅毒螺旋体(TP)采用快速血浆反应素环状卡片试验(RPR)和TP-PA法。结果 STD病原体阳性检出率为38.1%(922/2420)。在922例中UU占29.6%,CT20.8%,HPV17.8%,NG17.4%,MH6.3%,HSV4.2%,TP3.9%。结论 衡阳地区STD患者中UU感染率最高,CT和HPV次之,TP感染率最低。  相似文献   
993.
994.
R啨sum啨   Objectif D啨tecterparcytom啨triedefluxler啨sidumorbideminimal(RMM)chezlesenfantsatteintsdeB LLAet啨valuersasignificationclinique . M啨thodes  5 8enfantsatte  相似文献   
995.
目的 观察应用胫骨横向骨搬移法对犬下肢缺血性疾病动物模型的血管再生效果。方法 将 2 0只犬制成下肢缺血性疾病动物模型 ,建模后 1周对犬的后肢施行胫骨横向骨搬移术 ,即在胫骨内侧嵴开一个 5cm× 1cm骨窗 ,以特制的支架每天 1mm速度向外牵拉。分别于不同时期处死动物 ,通过皮温测定 ,光镜下测量血管密度 ,血管造影等方法来观察血管再生情况。结果 在不同时相点观察到伴随着骨的搬移 ,有明显的毛细血管再生现象 (以第 7~ 2 1天为著 )。结论 应用胫骨横向骨搬移法可对犬下肢缺血性疾病动物模型产生明显的血管再生 ,有明显的治疗效果  相似文献   
996.
目的探讨血清中氨基酸的含量变化与短暂性脑缺血和脑梗死体积大小的关系以及对急性缺血性脑血管病的超早期诊断的意义。方法选择发病6h以内的急性缺血性脑血管病(AICVD)患者80例,其中脑梗死(CI)组57例,短暂性脑缺血(TIA)组23例,CI组中大体积梗死19例,中体积梗死22例,小体积梗死16例,各取血清进行高效液相色谱法分析测定血清Glu和GABA。结果TIA组的超早期血清中L-Glu、GABA含量高于对照组,低于CI组;CI组超早期血清中L-Glu、GABA含量高于对照组和TIA组;超早期梗死灶体积大小与血清中L-Glu、GABA含量呈正相关,含量越高,梗死灶体积越大。结论患者血清中L-Glu、GABA含量高低,对急性缺血性脑血管病的超早期诊断有一定的临床价值。  相似文献   
997.
998.
This study investigated the prevalence of specific Toxoplasma gondii IgG in pregnancy, the incidence of congenital toxoplasmosis and the prevalence trend of T. gondii infection among pregnant Polish women between 1998 and 2003. The study population comprised 4916 women who were admitted to the Polish Mother's Memorial Hospital Research Institute in Łódź. Their sera were tested for specific IgG and IgM antibodies to T. gondii, and the incidence of T. gondii infection was calculated from the increase in prevalence rates of IgG antibodies in various age groups. Specific IgG antibody was found in 41.3% (95% CI 39.9–42.7) of pregnant women, and the prevalence of IgG increased with age. The linear trend was significant (p <0.001), with an annual seroconversion rate of 0.7% (95% CI 0.004–0.010). The risk of primary infection was estimated to be 0.5% for 9 months, i.e., an incidence of 5/1000 pregnancies. Assuming a 30% maternofetal transmission rate, 1.5/1000 neonates were infected in utero. Seroprevalence during the 6-year study period decreased from 45.4% in 1998 to 39.4% in 2003, with a yearly decline in prevalence of 1.0% (p 0.02). The most important contributory factor to this decline was the group of women aged 19–29 years, among whom seroprevalence decreased significantly (p 0.007). Specific IgM was found in 244 (4.9%) women.  相似文献   
999.
股骨头骨骺缺血再灌注模型的建立   总被引:9,自引:1,他引:8  
目的:建立缺血再灌注引起幼年兔股骨头骨骺细胞损伤的模型。方法:取12只1kg左右幼年新西兰兔,月龄,性别不限。切开兔髋关节囊,切断圆韧带,显露股骨颈,取皮筋对股骨颈进行加压,皮筋拉力约0.5kg,阻断股骨头骺动静脉血供6h、24h。松开皮筋分别恢复血供6h、24h、168h后取兔股骨头标本。结果:在取标本前进行同位素骨扫描及腹主动脉造影,证实缺血及再灌注有效。常规HE染色及胶原染色病理切片显示:单纯股骨头骨骺缺血6h骨骺骨细胞变性不明显,缺血24h组骨骺骨细胞变性;缺血24h股骨头再灌注168h后骨细胞明显坏死。结论:缺血再灌注可加重幼年兔股骨头骨骺骨细胞损伤。  相似文献   
1000.
BACKGROUND: The plasma kallikrein-kinin system (PKKS) has been implicated in cardiovascular disease, but activation of the PKKS has not been directly probed in individuals at risk of coronary heart disease (CHD) or stroke. OBJECTIVE: To determine the involvement of the PKKS, including factor XI, in cardiovascular disease occurring in a nested case-control study from the Second Northwick Park Heart Study (NPHS-II). METHODS AND RESULTS: After a median follow-up of 10.7 years, 287 cases of CHD and stroke had been recorded and 542 age-matched controls were selected. When FXIIa-C1 esterase inhibitor (C1-inhibitor) concentrations were divided into tertiles (lowest tertile as reference), the odds ratios (ORs) at 95% CIs for CHD were 0.52 (0.34-0.80) in the middle tertile and 0.73 (0.49-1.09) in the highest tertile (P = 0.01 for the overall difference; P = 0.01 for CHD and stroke combined). For kallikrein-C1-inhibitor complexes, the ORs for stroke were 0.29 (0.12-0.72) and 0.67 (0.30-1.52) in the middle and high tertiles, respectively (P = 0.02). FXIIa-C1-inhibitor and kallikrein-C1-inhibitor complexes were negatively related to smoking and fibrinogen (P < 0.005). FXIa-inhibitor complexes correlated strongly with FXIIa-inhibitor complexes. CONCLUSIONS: Lower levels of inhibitory complexes of the PKKS enzymes and particularly of FXIIa contribute to the risk of CHD and stroke in middle-aged men. This observation supports the involvement of the PKKS in atherothrombosis.  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