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   16871篇
  免费   1006篇
  国内免费   686篇
耳鼻咽喉   178篇
儿科学   577篇
妇产科学   302篇
基础医学   1282篇
口腔科学   158篇
临床医学   1545篇
内科学   4996篇
皮肤病学   194篇
神经病学   889篇
特种医学   270篇
外科学   852篇
综合类   2572篇
一般理论   2篇
预防医学   2479篇
眼科学   311篇
药学   680篇
  5篇
中国医学   971篇
肿瘤学   300篇
  2024年   50篇
  2023年   378篇
  2022年   845篇
  2021年   989篇
  2020年   963篇
  2019年   763篇
  2018年   705篇
  2017年   608篇
  2016年   672篇
  2015年   711篇
  2014年   1282篇
  2013年   1398篇
  2012年   981篇
  2011年   1129篇
  2010年   947篇
  2009年   806篇
  2008年   739篇
  2007年   651篇
  2006年   507篇
  2005年   458篇
  2004年   377篇
  2003年   417篇
  2002年   285篇
  2001年   250篇
  2000年   171篇
  1999年   144篇
  1998年   111篇
  1997年   132篇
  1996年   92篇
  1995年   73篇
  1994年   76篇
  1993年   47篇
  1992年   43篇
  1991年   45篇
  1990年   35篇
  1989年   24篇
  1987年   33篇
  1985年   52篇
  1984年   62篇
  1983年   40篇
  1982年   38篇
  1981年   44篇
  1980年   60篇
  1979年   48篇
  1978年   32篇
  1976年   28篇
  1974年   23篇
  1973年   33篇
  1972年   25篇
  1971年   25篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
11.
Analysis of HLA DRB1 and DQB1 Bam HI RFLPs revealed four DRB1 (4.8, 5.2, 6.0 and 7.0 kb) fragments and a 3.2 kb DQB1 fragment to be significantly increased in Caucasians with seropositive RA compared to healthy individuals. The 4.8, 5.2 and 7.0 kb DRB1 fragments were found in 86.5% of RA patients and in 56% of the controls (p = 10(-3), relative risk (RR) = 5.0), while the 6.0 kb fragment was found in 79% of RA patients compared to 32% of controls (p = 2 x 10(-5), RR = 8.0). The 3.2 kb DQB1 fragment was observed in 63.5% of RA patients versus 38.0% of controls (p = 10(-2), RR = 2.8). Analysis of these fragments relative to HLA phenotypes revealed that the 4.8, 5.2 and 7.0 kb DRB1 fragments were strongly correlated with DR4, -7, -9 and -w53 serotypes, the 6.0 kb RFLP with DR4 and the 3.2 kb DQB1 fragment with DR1 and DQw1. Using probes specific for the 5' or 3' regions of the DRB1 gene, the 5.2 and 6.0 kb DRB RFLPs were mapped to the 5' end and the 4.8 and 7.0 kb RFLPs to the 3' end of the DRB1 gene. A probe generated from the second exon of the DRB4 (DRw53) gene recognized only the 5.2 and the 6.0 kb RFLPs corroborating the 5' location of these RFLPs. Family studies further confirmed that these RFLP's segregated with HLA phenotypes.  相似文献   
12.
The dielectric properties (conductivity, kappa and relative permittivity, epsilon) of excised rat lung are modified by lung air and water content. The measurements of these quantities were made over the frequency range of 10 kHz to 100 MHz with an open-ended coaxial probe. The following relationships were analyzed in an oleic acid-induced pulmonary edema model using 18 animals: the spectra of kappa, epsilon and the loss tangent as a function of lung air and water content. Secondly, an isolated-perfused lung system was produced to induce a gradual increase in lung water. The time course of kappa, epsilon and the loss tangent for one excised lung was analyzed. The principal findings were: (i) a decrease in kappa and epsilon with increasing air content, (ii) an increase in kappa and epsilon with increasing water content, and (iii) a good correlation between lung water content and maximum loss tangent that was insensitive to changes in air content. We conclude that this technique could provide a quantitative assessment of lung water during pulmonary edema formation.  相似文献   
13.
14.
15.
16.
ObjectivesA global outbreak of monkeypox virus infections in human beings has been described since April 2022. The objectives of this study were to describe the clinical characteristics and complications of patients with a monkeypox infection.MethodsAll consecutive patients with a polymerase chain reaction (PCR)–confirmed monkeypox infection seen in a French referral centre were included.ResultsBetween 21 May and 5 July 2022, 264 patients had a PCR-confirmed monkeypox infection. Among them, 262 (262/264, 99%) were men, 245 (245/259, 95%) were men who have sex with men, and 90 (90/216, 42%) practiced chemsex in the last 3 months. Seventy-three (73/256, 29%) patients were living with human immunodeficiency virus infection, and 120 (120/169, 71%) patients were taking pre-exposure prophylaxis against human immunodeficiency virus infection. Overall, 112 (112/236, 47%) patients had contact with a confirmed monkeypox case; it was of sexual nature for 95% of the contacts (86/91). Monkeypox virus PCR was positive on the skin in 252 patients, on the oropharyngeal sample in 150 patients, and on blood in eight patients. The majority of patients presented with fever (171/253, 68%) and adenopathy (174/251, 69%). Skin lesions mostly affected the genital (135/252, 54%) and perianal (100/251, 40%) areas. Overall, 17 (17/264, 6%) patients were hospitalized; none of them were immunocompromised. Complications requiring hospitalization included cellulitis (n = 4), paronychia (n = 3), severe anal and digestive involvement (n = 4), non-cardia angina with dysphagia (n = 4), blepharitis (n = 1), and keratitis (n = 1). Surgical management was required in four patients.ConclusionThe current outbreak of monkeypox infections has specific characteristics: it occurs in the men who have sex with men community; known contact is mostly sexual; perineal and anal areas are frequently affected; and severe complications include superinfected skin lesions, paronychia, cellulitis, anal and digestive involvement, angina with dysphagia, and ocular involvement.  相似文献   
17.
The experimental hepatic cirrhosis was induced either by bile duct ligation (BDL) or by pretreatment with dimethylnitrosamine (DMNA). The pharmacokinetics of theophylline were studied after a single intravenous or a single oral administration. Using the ultrafiltration method, protein-drug binding experiments were also carried out. The bilirubin level was several-fold increased by BDL, but not by DMNA treatment. The albumin content was decreased in both cirrhotic groups. The total clearance (Clt, ml/kg/hr) of theophylline in both hepatic cirrhosis groups significantly decreased and the terminal half-life (t1/2) in the cirrhotic rats was increased about two-fold after intravenous and oral administration. The volume of distribution at steady state (Vdss, ml/kg) was increased slightly in the cirrhotic groups. Protein binding in BDL (8.67±4.85%) decreased about four-folds, but in DMNA (73.00±9.85%) similar result, was observed as compared with the control. Increased free fraction of theophylline did not increase the volume of distribution in BDL. Therefore decreased total body clearance of theophylline was mainly due to decreased intrinsic clearance of theophylline in the liver. The absolute bioavailability of theophylline in these experiments was between 63.8 and 72.8%(66.1% in BDL, 63.8% in Sham operated and Control, 72.8% in DMNA). These results suggest that in the experimental hepatic cirrhosis model, administration route does not affect the disposition of theophylline.  相似文献   
18.
深圳市一孩先天性残疾家庭的二孩同类病研究   总被引:1,自引:0,他引:1  
本文对深圳市1990~1997年因独生子女先天残疾通过病残儿鉴定再生育二孩的家庭进行调查,并以同期通过鉴定的后天性残疾家庭为内对照,以农村地区一孩先天残疾未经病残儿鉴定生育二孩的家庭为外对照,了解其二孩先天残疾再发情况,尤其是同类病的再发情况,拟对独生子女病残儿医学鉴定和二胎生育指标的审批工作效果进行评价,为优生工作提供依据。研究结果表明,鉴定组一孩先天残疾家庭二孩先天残疾的患病率为5.81%,与广州市1986~1991年情况类似(5.9%),高于外省(辽宁1990~1992年为1.35%)。鉴定组二胎同类病发生率为2.8%,非鉴定组为4.55%,两组比较虽无统计学差异,但病种上却有不同,鉴定组为再发风险低的血友病、先天性共转性内斜视、脑萎缩,而非鉴定组为再发风险高的先天聋哑、进行性肌萎缩。提示病残儿鉴定工作颇有成效,避免了相当一部分遗传病家庭再次生育残疾儿,但某些环节有待进一步完善;对农村一胎先天残疾家庭生育二胎也必须纳入管理范围。  相似文献   
19.
本文就硒的生理作用,缺乏硒的临床表现,硒代谢异常与各种疾病的关系,硒在营养支持中的作用补充本时的注意事项进行了综述,旨在进一步阐明硒在营养支持中的作用。  相似文献   
20.
肉毒碱治疗TPN大鼠肝脂肪变性的研究   总被引:4,自引:1,他引:3  
Liang L  Luo S  Zheng J  Huang J 《中华外科杂志》1999,37(8):500-502,I033
目的 探讨在全胃肠外营养(TPN)中补充肉毒碱减轻肝脂肪变性的作用。方法 18只正常Wistar大鼠和19只肝硬化Wistar大鼠分别随机分为6组,A1组、A2组,自由进食和进水(各6只);B1组、B2组,TPN(分别6只、7只);C1组、 ,TPN加肉毒碱(各6只)。各组实验结束后测肝功能,肝脂肪及行肝脏的组织学检查。结果 TPN组肝内脂肪显著2,TPN+肉毒碱组肝内脂肪明显减少。结论 在TPN  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