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   2207篇
  免费   191篇
  国内免费   69篇
耳鼻咽喉   36篇
儿科学   101篇
妇产科学   14篇
基础医学   163篇
口腔科学   52篇
临床医学   308篇
内科学   225篇
皮肤病学   14篇
神经病学   30篇
特种医学   104篇
外科学   173篇
综合类   559篇
预防医学   253篇
眼科学   11篇
药学   177篇
  1篇
中国医学   145篇
肿瘤学   101篇
  2024年   5篇
  2023年   13篇
  2022年   45篇
  2021年   49篇
  2020年   56篇
  2019年   30篇
  2018年   31篇
  2017年   58篇
  2016年   39篇
  2015年   54篇
  2014年   109篇
  2013年   147篇
  2012年   187篇
  2011年   207篇
  2010年   211篇
  2009年   179篇
  2008年   193篇
  2007年   165篇
  2006年   110篇
  2005年   91篇
  2004年   68篇
  2003年   67篇
  2002年   29篇
  2001年   37篇
  2000年   19篇
  1999年   14篇
  1997年   9篇
  1996年   8篇
  1995年   7篇
  1994年   6篇
  1992年   5篇
  1990年   6篇
  1989年   10篇
  1988年   10篇
  1987年   17篇
  1986年   9篇
  1985年   12篇
  1984年   14篇
  1982年   7篇
  1981年   7篇
  1980年   9篇
  1979年   11篇
  1974年   5篇
  1965年   5篇
  1963年   4篇
  1958年   5篇
  1957年   7篇
  1956年   9篇
  1955年   7篇
  1954年   8篇
排序方式: 共有2467条查询结果,搜索用时 31 毫秒
1.
IFN-γ和糖皮质激素对哮喘病人T淋巴细胞中的TGF-β的作用   总被引:1,自引:0,他引:1  
目的:探讨C D4 TG F-β,C D8 TG F-β在哮喘发病机制中的作用,了解IFN-γ和糖皮质激素对其的影响。方法:采用Ficoll-H ypague密度梯度离心及贴壁培养法对18例哮喘患者和10例健康对照者外周血单个核细胞进行分离,纯化后,加入地塞米松及IFN-γ培养24h,加入PM A,莫能菌素,艾罗霉素培养4.5h,促使细胞内细胞因子聚集于高尔基体,取培养上清中的淋巴细胞经流式细胞仪检测分析C D4 T、C D8 T淋巴细胞及其细胞内细胞因子TG F-β表达率。结果:C D4 TG F-β、C D8 TG F-β及C D4、C D8细胞内总TG F-β检测结果的比较,哮喘组C D4 TG F-β(15.50±0.15)%、C D8 TG F-β(19.34±0.18)%,与正常对照组(9.57±0.16)%、(13.49±0.26)%比较,显著增高(均P<0.05);加入地塞米松培养的哮喘组C D4 TG F-β,C D8 TG F-β无显著变化(P>0.05),加入IFN-γ培养的哮喘组C D4 TG F-β(7.61±0.09)%、C D8 TG F-β(9.82±0.19)%的变化显著降低(均P<0.05),C D4、CD8细胞内总TG F-β哮喘组(32.42±1.17)%比正常组(20.53±1.02)%显著增加(P<0.05),加地塞米松后无显著变化(P>0.05),加IFN-γ后(16.85±0.14)%,显著降低(P<0.05)。结论:哮喘急性发作期有C D4 TG F-β、C D8 TG F-β升高;地塞米松不能降低哮喘气道重塑;IFN-γ可通过抑制TG F-β的分泌治疗哮喘,降低哮喘气道重塑。  相似文献   
2.
目的评价屈颈MRI对青年性上肢远端肌萎缩症的诊断价值。方法男性患者5例,平均年龄21岁,临床表现为一侧或两侧上肢远端肌萎缩。对照组为健康志愿者,21岁男性8例。2组均行常规及屈颈颈椎MR平扫,矢状、轴面SET1WI、T2WI、液体衰减反转恢复(FLAIR)序列扫描。结果常规颈椎扫描:5例患者下段颈髓变细;屈颈位MR扫描:下颈段颈6以下脊髓前屈、变扁平,矢状径4~6mm,硬膜囊后壁前移,硬膜后间隙明显增宽,可见多发条状、迂曲流空信号影及软组织信号。对照组:常规扫描,下颈段脊髓(颈6~胸2)可见颈膨大,屈颈位脊髓略变细(6~7mm),硬膜囊后壁无前移,硬膜后间隙未见扩张血管影。结论屈颈MRI有助于显示下颈段脊髓及硬膜囊改变,结合临床资料可准确诊断青年性上肢远端肌萎缩症。  相似文献   
3.
ABSTRACT. Hultcrantz R, Angelin B, Einarsson K, Friman L (Departments of Internal Medicine and Roentgenology, Serafimer Hospital, and Department of Internal Medicine, Huddinge University Hospital, Karolinska Institute, Stockholm, Sweden). Spontaneous regression of Budd-Chiari syndrome (hepatic venous occlusion) in a young female. Acta Med Scand 1987; 221:503–7. A case of occlusion of the hepatic veins in an 18-year-old girl is presented. The onset was sudden with massive ascites and markedly impaired general condition. The diagnosis was based on liver biopsy and angiograms of the caval and hepatic veins as well as of the celiac artery. No predisposing factors could be found. The patient was treated conservatively with laparo-centesis and diuretics. Clear improvement was seen after two weeks, and after four weeks she had no ascites and could be discharged. All liver function tests were then normalized. After three months, all diuretics could be withdrawn, and in the following 11 years she has remained completely recovered. The case illustrates that also widespread thrombi of the hepatic veins may sometimes rapidly dissolve spontaneously, with apparent total reconstitution of hepatic function. This case is unusual since previously reported cases have had high mortality rates and, in surviving cases, operative procedures or large doses of diuretics have been required to control the ascites.  相似文献   
4.
AIM: To evaluate the cause of elevated prostate-specific antigen (PSA) in patients with transrectal needle biopsy negative for prostate cancer. METHODS: Serum PSA concentration, prostate volume, and pathologic findings were examined in 223 patients with negative biopsy for prostate cancer. The degree of prostate inflammation was determined by the extent and degree of inflammation shown by biopsy specimens and is expressed as an inflammation score (range: 0-36). RESULTS: A significant correlation was found between PSA concentration and prostate total volume (P=0.0001). Prostate chronic inflammation showed no correlation with PSA concentration (P=0.485, F=0.488). After allocating patients to normal PSA (4 ng/mL) groups, we found that serum PSA concentrations in both groups were predominantly affected by prostate total volume. CONCLUSIONS: An increase in prostate volume appears to be the major contributor to a high serum PSA concentration in patients with negative biopsy for prostate cancer. However, in contrast to previous reports, there was no correlation between the degree of prostate chronic inflammation and serum PSA concentrations.  相似文献   
5.
NATURE AND HEALING OF TIBIAL SHAFT FRACTURES IN ALCOHOL ABUSERS   总被引:3,自引:1,他引:2  
Alcohol abuse is associated with an increased risk of osteopeniaand fractures. Previous histomorphometric studies on iliac crestbone have found decreased bone formation and increased boneresorption in alcohol abusers but it has not been establishedwhether alcohol abuse has any effect on the anatomical locationor the healing time of tibial shaft fractures. We studied, retrospectively,199 adult male patients hospitalized for isolated tibial shaftfracture in the city of Malmö, Sweden, between 1980 and1990. Forty-nine of the patients had earlier been registeredat the Department of Alcohol Diseases and were judged to beproblem drinkers. Abusers sustained their tibial shaft fracturesmore often by falling at ground level (P<0.0001) or froma higher level (P=0.009) and the fractures were more often obliquethan transverse (P=0.002) as compared with non-abusers. Healingtime was impaired in abusers who had sustained a transversefracture (P=0.035), but no difference was observed in healingtime in those with an oblique fracture. We found no differencebetween the abusers and the non-abusers regarding duration ofhospital stay, fracture location, amount of displacement, occurrenceof open fractures or the rate of complications.  相似文献   
6.
本文报告应用国产法莫替丁治疗消化性溃疡45例的近期疗效。治疗组法莫替丁20mg,早晚各服一次;对照组甲氰咪胍400mg,早晚各服一次,两组疗程皆为6周。以胃镜检查为诊断和评价疗效的依据,两组愈合率分别为97.8%,89.9%,上腹疼痛用药后三日缓解率分别为60.9%,30.2%。两组均未出现明显毒副作用,由于抗溃疡新药疗效高,提示今后治疗无合并症消化性溃疡将以药物治疗为主。  相似文献   
7.
目的  探讨精浆中白细胞介素 1β(IL 1β)、白细胞介素 2 (IL 2 )、白细胞介素 4 (IL 4 )、白细胞介素 6 (IL 6 )、白细胞介素 8(IL 8)、白细胞介素 10 (IL 10 )、肿瘤坏死因子 α(TNF α)等细胞因子浓度与不育症患者之间以及精子的各项功能指标之间的相互关系。方法  应用放射免疫分析(RIA)技术对 12 6例不育男性精浆中IL 1β、IL 2、IL 4、IL 6、IL 8、IL 10、TNF α水平进行了检测。结果  不育症组精浆IL 1β、IL 2、IL 6、IL 8、TNF α含量均高于生育组 ,两组间均存在显著性差异(P <0 .0 5或P <0 .0 1) ;精浆IL 4、IL 10含量均低于生育组 ,两组间均存在显著性差异 (P <0 .0 1)。不育症组精浆中IL 1β、IL 2、IL 4、IL 6、IL 8、IL 10、TNF α含量在WBC精液组与非WBC精液组、血清AsAb阳性组与血清AsAb阴性组之间均存在显著性差异 (P <0 .0 5或P <0 .0 1) ;精浆中IL 4、TNF α含量在精子活动力、活动率、精子穿透力、顶体完整率、尾部肿胀率正常组与不正常组之间均存在显著性差异 (P <0 .0 5或P <0 .0 1)。 结论  精浆中IL 1β、IL 2、IL 4、IL 6、IL 8、IL 10、TNF α含量与男性不育症患者之间存在密切关系 ,检测精浆中IL 1β、IL 2、IL 4、IL 6、IL 8、IL 10、TNF α的含量可以反映男性  相似文献   
8.
Dural sinus thrombosis: study using intermediate field strength MR imaging   总被引:1,自引:0,他引:1  
The magnetic resonance (MR) images of six patients with thrombosis of a dural sinus were reviewed. The diagnosis had been verified by computed tomographic scans in three patients and arteriograms in two; in the sixth patient, only MR imaging was used to confirm the clinical syndrome. In all patients, high-intensity signal was seen from the thrombus within the affected dural sinus on all echoes. This persistent signal intensity allowed intravascular clot to be distinguished from normal causes of increased signal such as flow-related enhancement (entry phenomenon) and even-echo rephasing. MR imaging demonstrated the cause of the thrombosis in three patients: two were secondary to adjacent tumors, and one was secondary to unsuspected mastoiditis. Complications such as infarction were also demonstrated. Using MR imaging, one can easily and safely diagnose thrombosis of a dural sinus. MR should be the imaging method of choice in patients suspected of having thrombosis of a dural sinus.  相似文献   
9.
目的:探讨糖尿病周围神经病(DPN)患者的临床特征与神经电生理变化。方法:分析97例DPN患者的临床特征,比较DPN组和对照组的神经传导速度(NCV)、远端潜伏期、远端波幅3个参数。结果:①临床特征以肢体麻木(59%)最多见、其次为疼痛(42%)。②患者组NCV、远端波幅值低于对照组,远端潜伏期比对照组延长;两组3个参数比较,除腓总神经远端波幅、尺神经感觉传导速度和正中、尺、腓肠神经远端潜伏期外,差异均有统计学意义(P<0.05)。结论:①DPN患者临床特征以肢体麻木和疼痛最多见;②检测NCV、远端潜伏期、远端波幅,能较早发现临床患者。  相似文献   
10.
在156例先天性心血管畸形标本的观察和测量中,检出先天性三尖瓣畸形25例(16.02%),其中Ebstein's畸形6例,三尖瓣发育不良14例,三尖瓣缺如1例,三尖瓣瓣叶或/和腱索骑跨4例。用测量及比较解剖学的方法探求三尖瓣畸形与其功能的影响。结果显示:Ebstein's畸形和三尖瓣发育不良的心脏构筑都有明显的变化,而且两者存在一定的差异,同时明确了Ebstein's畸形的病理诊断标准和三尖瓣发育不良的分类。  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