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   23663篇
  免费   1347篇
  国内免费   436篇
耳鼻咽喉   58篇
儿科学   193篇
妇产科学   51篇
基础医学   853篇
口腔科学   146篇
临床医学   2654篇
内科学   4312篇
皮肤病学   29篇
神经病学   1483篇
特种医学   8124篇
外国民族医学   1篇
外科学   1288篇
综合类   3019篇
现状与发展   1篇
预防医学   543篇
眼科学   1413篇
药学   748篇
  9篇
中国医学   107篇
肿瘤学   414篇
  2024年   45篇
  2023年   361篇
  2022年   627篇
  2021年   758篇
  2020年   734篇
  2019年   665篇
  2018年   767篇
  2017年   593篇
  2016年   593篇
  2015年   677篇
  2014年   1315篇
  2013年   1207篇
  2012年   1244篇
  2011年   1363篇
  2010年   1235篇
  2009年   1297篇
  2008年   1319篇
  2007年   1439篇
  2006年   1183篇
  2005年   1001篇
  2004年   850篇
  2003年   730篇
  2002年   697篇
  2001年   631篇
  2000年   444篇
  1999年   387篇
  1998年   438篇
  1997年   401篇
  1996年   283篇
  1995年   349篇
  1994年   315篇
  1993年   237篇
  1992年   195篇
  1991年   145篇
  1990年   104篇
  1989年   80篇
  1988年   66篇
  1987年   66篇
  1986年   61篇
  1985年   99篇
  1984年   74篇
  1983年   40篇
  1982年   65篇
  1981年   62篇
  1980年   56篇
  1979年   39篇
  1978年   41篇
  1977年   29篇
  1976年   18篇
  1975年   11篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Whistling face syndrome or cranio-carpotarsal dysplasia is a very rare disorder that consists of a characteristics facies and digital abnormalities. Magnetic resonance imaging investigation of the brain in this syndrome has not been reported previously. This communication describes the brain malformations in an infant with the syndrome, which covered delayed myelination, thickened and infolded cortices (cortical dysplasia), dysplastic corpus callosum, and agenesis of the inferior vermis.  相似文献   
42.
三阶段心理护理在MRI增强扫描护理中的体会   总被引:5,自引:0,他引:5  
目的 对比研究三阶段心理护理对MR增强扫描患者顺利完成榆查的价值.方法 一般护理组和心理护理组各126例,分别观察两组在造影检查过程中不良反应出现的情况,并分别计数.结果 心理护理组的不良后果发生率低于一般护理组,X2检验P<0.05,差异有显著性.结论 运用三阶段心理护理能有效地降低MR增强扫描中出现的不良后果,具有良好的临床应用价值.  相似文献   
43.
Combined direct injection venography (DIV) and equilibrium angiography (EA) were performed in 13 patients, by injecting in vitro labeled 99mTc autologous RBC, via pedal veins, and imaging the first pass and the equilibrium phase. This paired comparative study of DIV with EA shows that DIV has advantages over EA because it provides selective information on the deep venous system from the calves to the inferior vena cava. DIV provides information on the flow dynamics and the high contrast first pass images provide better definition of non filling venous segments as well as visualization of collaterals. When using 99mTc-MAA, lung perfusion can also be imaged. DIV is recommended as the procedure of choice for the diagnosis of DVT and EA should be employed only when pedal vein injection is not possible.  相似文献   
44.
Magnetic resonance imaging enhanced with a macromolecular contrast medium (MMCM), albumin-Gd-DTPA, was used to estimate the plasma volume in vivo in the myocardium, lung, liver, and skeletal muscle of 10 normal rats. The plasma volumes of the same tissues in a parallel group of six rats were estimated in vitro by a conventional radioisotopic technique (111In-transferrin). Plasma volumes of myocardium, lung, liver, and skeletal muscle estimated by the MR technique (μl plas. ia cc-1 of tissue) were 101,109,163, and 11.0, respectively, while plasma volumes measured by the In-transferrin radioisotope technique (mg plasma g-1 of tissue) were 78.6, 215,143, and 11-2, respectively. Assuming a ratio of densities of aerated lung to blood of 0.45 and of other tissues to blood of 1.0, correlation between the methods was excellent (R2 = 0.99) indicating that MR imaging enhanced with MMCM permits reliable in vivo estimation of tissue plasma volume in the rat.  相似文献   
45.
视盘血管炎——关于混合型的研讨   总被引:2,自引:0,他引:2  
对60例(63眼)视盘血管炎的临床分型进行了探讨,结果表明,除分为Ⅰ、Ⅱ两型外,尚存在混合型,当视盘睫状血管炎性病变波及中央静脉,或两个血管系统同时受炎症侵犯时,即可再现混合型的临床表现,视盘明显水肿,视网膜静脉迂张,散在渗出,出血,动脉狭细。眼底荧光血管造影可见视盘荧光早期充盈明显迟缓,后期渗漏面积〉2.0PD,视网膜循环时间延长,混合型兼有Ⅰ,Ⅱ两型的临床特征,应作为一个独立类型存在,同时观察  相似文献   
46.
We report on 2 unrelated Brazilian girls, born to nonconsanguineous parents, and presenting structural central nervous system defects, hydrocephaly, macrocephaly, craniosynostosis, prominent forehead, anophthalmia, and abnormal nares. These patients may have a previously undescribed recurrent-pattern cerebro-oculo-nasal syndrome. © 1993 Wiley-Liss, Inc.  相似文献   
47.
Summary The authors review the literature on subarachnoid haemorrhage of unknown aetiology (SAHUE) and analyze a personal series of 212 patients diagnosed as SAHUE. These patients represent 30% of all cases of primary SAH admitted over a 14.5 year period.The age, sex, antecedents and initial clinical presentation of patients with SAHUE were indistinguishable from those of patients with subarachnoid haemorrhage due to ruptured aneurysm (SAHRA). However, the present series of SAHUE compare favourably with both a personal and a previously reported series of SAHRA insofar as clinical grade on admission (94% of patients in grades I–II of Botterell), presence of blood on CT (51%), vasospasm (5%), ischaemic deficits (3.3%), persistent hydrocephalus (3.5%), rebleeding (6%) and fatal result (3.9%) are concerned.The amount of blood on CT scan in our patients with SAHUE was associated with a significantly higher incidence of brain ischaemia and hydrocephalus but did not correlate with the Botterell grade on admission or final outcome, which were good in the majority of cases regardless of the presence or not of visible cisternal haemorrhage. The results of the present series confirm that the final prognosis of patients with primary SAH showing normal four-vessel cerebral angiography is essentially favourable.  相似文献   
48.
Tentorial sinus     
Summary The authors report a case of tentorial sinus draining the telencephalic and diencephalic tributaries of the basal vein. Dorsally the sinus joined the straight sinus and later the confluence of the sinuses. Attention should be paid to this normal variation whenever a transtentorial surgical approach is considered.
Sinus de la tenteAspect radiologique et anatomique, à propos d'un cas
Résumé Les auteurs rapportent un cas de sinus de la tente du cervelet drainant les affluents télencéphaliques et diencéphaliques de la veine basale. En arrière, le sinus rejoint le sinus droit puis le torcular. Une attention particulière pré-opératoire devrait être accordée à la mise en évidence de cette variété lorsqu'une approche transtentorielle est discutée.
  相似文献   
49.
We describe clinical and chromosomal findings in two patients with del(4q). Patient 1, with interstitial deletion (4)(q21.1q25), had craniofacial and skeletal anomalies and died at 8 months of hydrocephalus. Patient 2, with interstitial deletion (4)(q25q27), had craniofacial and skeletal anomalies with congenital hypotonia and developmental delay. These patients shared certain manifestations with other del(4q) patients but did not have Rieger anomaly. Clinical variability among patients with interstitial deletions of 4q may be related to variable expression, variable deletion, or imprinting of genes within the 4q region. © 1995 Wiley-Liss, Inc.  相似文献   
50.
Some variation in the phenotype of patients with dup(18q) is recognized. Our patient has the phenotype described for dup(18qter).  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