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   4790篇
  免费   262篇
  国内免费   14篇
耳鼻咽喉   38篇
儿科学   234篇
妇产科学   205篇
基础医学   613篇
口腔科学   69篇
临床医学   364篇
内科学   1141篇
皮肤病学   103篇
神经病学   332篇
特种医学   215篇
外科学   529篇
综合类   140篇
预防医学   328篇
眼科学   54篇
药学   318篇
  1篇
中国医学   82篇
肿瘤学   300篇
  2021年   87篇
  2020年   51篇
  2019年   57篇
  2018年   94篇
  2017年   76篇
  2016年   51篇
  2015年   93篇
  2014年   126篇
  2013年   166篇
  2012年   194篇
  2011年   249篇
  2010年   159篇
  2009年   152篇
  2008年   207篇
  2007年   197篇
  2006年   196篇
  2005年   176篇
  2004年   187篇
  2003年   178篇
  2002年   170篇
  2001年   157篇
  2000年   152篇
  1999年   120篇
  1998年   75篇
  1997年   76篇
  1996年   73篇
  1995年   70篇
  1994年   72篇
  1993年   53篇
  1992年   80篇
  1991年   74篇
  1990年   48篇
  1989年   78篇
  1988年   67篇
  1987年   71篇
  1986年   58篇
  1985年   48篇
  1984年   44篇
  1983年   35篇
  1982年   20篇
  1981年   39篇
  1980年   32篇
  1979年   27篇
  1975年   23篇
  1959年   36篇
  1958年   58篇
  1957年   87篇
  1956年   45篇
  1955年   75篇
  1954年   67篇
排序方式: 共有5066条查询结果,搜索用时 593 毫秒
1.
2.
宫腹腔镜联合手术诊治不孕症150例分析   总被引:14,自引:0,他引:14  
目的:探讨宫腹腔镜联合手术在诊治不孕症中的应用。方法:对150例不孕症患者行宫腹腔镜联合手术,对不孕症病因进行诊断,同时行治疗。结果:盆腔粘连和输卵管阻塞是不孕症的主要原因。子宫内膜息肉和正常盆腔占次要比例。子宫内膜异位症和多囊卵巢也是主要病因。150例同时行宫腹腔镜输卵管通液和各种疾病的治疗。联合手术后妊娠率为48.8%。结论:腹腔镜联合手术,在一次麻醉下,可以对不孕的原因全面评价和明确诊断,在诊断同时进行治疗,对不孕症的诊断和治疗有重大的意义,值得推广。  相似文献   
3.
Mutations P225L and P225R were identified in codon 225 of the gene for ornithine transcarbamylase (OTC) in two patients with the neonatal form of OTC deficiency. The mutations occur at a CpG dinucleotide and eliminate a unique MspI restriction site in exon 7 of the OTC gene. They do not alter existing splice sites or create new sites, as judged from the nucleotide sequence. Both mutations are associated with undetectable levels of OTC antigen in liver homogenates, and with either complete lack of OTC activity (P225R mutation) or very small residual activity (0.15% of normal in the P225L mutation). The residual activity observed with P225L exhibits normal pH dependence, little or no increases in the Km values for ornithine and carbamoyl phosphate and normal stability at either 37°C or, in the presence of 0.66 mol/L urea, at 0°C. The latter conditions were used to examine whether the P225L mutation favours dissociation of the active OTC trimer. Given the normal stability and lack of tendency to dissociation of the mutant enzyme, it appears likely that the dramatic reduction in the level of OTC protein is due to inefficient conversion of the mutant OTC precursor polypeptide (pOTC) into the correctly localized, appropriately folded, mature enzyme trimer, suggesting degradation of pOTC in transit to the mitochondria.  相似文献   
4.
5.
6.
A case of life-threatening respiratory distress during a Caesarean section under spinal anaesthesia is reported. Possible causes of the event including anaphylactoid reactions and the methods of their diagnosis are discussed. The most likely cause of the episode was felt to be an anaphylactoid reaction to Syntocinon.  相似文献   
7.
We report the case of a 32-year-old multipara who presented preeclampsia on the fourth day after childbirth without receiving proper treatment that progressed to eclampsia 4 days later. Pregnancy and delivery had been uneventful. The patient presented proteinuria (30 mg/dl), serum total proteins 5.3 g/dl and serum albumin 3.3 g/dl. Blood pressure was controlled with methyldopa, 500 mg at six-hour intervals by intravenous route. The patient presented hypoxemia secondary to bilateral pleural effusion and aspirative pneumonia requiring mechanical ventilation and invasive hemodynamic monitoring. Treatment with cefotaxime, 1 g at six-hour intervals by intravenous route and clindamycin, 600 mg at six-hour intervals by intravenous route was initiated. Sedation was maintained with thiopental sodium, 3 mg/kg/hour in continuous infusion. At dismission, the patient was completely recovered from her clinical picture and needed no antihypertensive therapy. Physiopathologic features and the aforementioned complications are discussed with particular reference to differential diagnosis.  相似文献   
8.
Abstract: This paper dicusses the use of esophageal dilatation with a Rigiflex TTS balloon. This method was used 45 times on 11 patients affected by anastomotic or a severe grade peptic esophageal stenosis. Fluoroscopic guidance was used in 36 procedures (80%) without effecting the mean duration of the treatment (12 minutes). The results were considered satisfactory when these goals had been achieved: a) dilatation of the stenosis over 15 mm; b) a dysphagia free-time of more than 6 months. A satisfactory result was achieved in 10 patients (90.9%), without deaths and major complications. 5 patients received 1 dilatation and the other 5 needed, 3-3-4-7–11 procedures respectively to obtain a satisfactory result. On these basis we consider that its great efficacy, security and tolerability depend on the following characteristics of the Rigiflex TTS balloon: 1) “radial” dilatation; 2) the possibility of introducing the balloon through the operative channel of the fiberscope; 3) direct visualization of the stenosis during dilatation. The following disadvantages with this method are: the absence of a tactile sensation of dilatation and the elevated cost of the instrument. We conclude that the Rigiflex TTS balloon is an important alternative to guide-wire techniques, especially for the treatment of severe esophageal strictures.  相似文献   
9.
We report the case of a 25-year old man with vestibulocochlear and ocular impairment compatible with Cogan's syndrome. Later on, severe headache developed. CT scan showed an ischaemic lesion in the right frontal lobe. Magnetic resonance imaging demonstrated multiple bilateral nodular lesions on T2-weighted sequences. These were unmodified at a second MRI examination performed six months later. Under corticosteroids, the neurological and ophthalmic symptoms disappeared, but the patient remained deaf. We believe that this patient had vasculitis involving the brain, with infarcts. To our knowledge, no case of Cogan's syndrome with cerebral magnetic resonance imaging has yet been reported.  相似文献   
10.
目的:探讨妊娠肝内胆汁淤积症(ICP)患者外周静脉血清、新生儿脐静脉血清中一氧化氮(NO)、内皮素(ET)、丙二醛(MDA)和超氧化物歧化酶(SOD)含量的变化及在ICP发病中的作用。方法:以ICP组28例为研究组,测定其外周静脉血清及新生儿脐静脉血清中的NO、ET、MDA和SOD,以年龄相近的24例正常孕妇作为对照组。结果:ICP患者的MDA和ET含量较正常晚期妊娠显著增高(P<0.01),ICP患者的NO和SOD含量与对照组相比无显著性差异(P>0.05)。母血清中NO、ET、MDA含量均较新生儿脐静脉血清中的含量高,差异有显著性(P<0.01)。结论:妊娠期体内氧化和抗氧化失衡及ET水平的增高可能与ICP的发生、发展有关。  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