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   513篇
  免费   39篇
  国内免费   5篇
耳鼻咽喉   5篇
儿科学   49篇
妇产科学   3篇
基础医学   33篇
口腔科学   15篇
临床医学   65篇
内科学   96篇
皮肤病学   3篇
神经病学   21篇
特种医学   147篇
外科学   29篇
综合类   30篇
预防医学   24篇
眼科学   2篇
药学   23篇
肿瘤学   12篇
  2023年   1篇
  2022年   1篇
  2021年   4篇
  2020年   1篇
  2019年   2篇
  2018年   9篇
  2017年   6篇
  2016年   10篇
  2015年   13篇
  2014年   19篇
  2013年   21篇
  2012年   9篇
  2011年   3篇
  2010年   11篇
  2009年   8篇
  2008年   10篇
  2007年   11篇
  2006年   12篇
  2005年   9篇
  2004年   12篇
  2003年   10篇
  2002年   12篇
  2001年   12篇
  2000年   7篇
  1999年   16篇
  1998年   30篇
  1997年   33篇
  1996年   34篇
  1995年   30篇
  1994年   31篇
  1993年   21篇
  1992年   6篇
  1991年   6篇
  1990年   5篇
  1989年   13篇
  1988年   17篇
  1987年   17篇
  1986年   16篇
  1985年   15篇
  1984年   8篇
  1983年   11篇
  1982年   5篇
  1981年   9篇
  1980年   5篇
  1979年   2篇
  1978年   2篇
  1977年   3篇
  1976年   6篇
  1975年   2篇
  1971年   1篇
排序方式: 共有557条查询结果,搜索用时 15 毫秒
21.
22.
23.
A genetic contribution to a broad range of epilepsies has been postulated, and particularly copy number variations (CNVs) have emerged as significant genetic risk factors. However, the role of CNVs in patients with epilepsies with complex phenotypes is not known. Therefore, we investigated the role of CNVs in patients with unclassified epilepsies and complex phenotypes. A total of 222 patients from three European countries, including patients with structural lesions on magnetic resonance imaging (MRI), dysmorphic features, and multiple congenital anomalies, were clinically evaluated and screened for CNVs. MRI findings including acquired or developmental lesions and patient characteristics were subdivided and analyzed in subgroups. MRI data were available for 88.3% of patients, of whom 41.6% had abnormal MRI findings. Eighty-eight rare CNVs were discovered in 71 out of 222 patients (31.9%). Segregation of all identified variants could be assessed in 42 patients, 11 of which were de novo. The frequency of all structural variants and de novo variants was not statistically different between patients with or without MRI abnormalities or MRI subcategories. Patients with dysmorphic features were more likely to carry a rare CNV. Genome-wide screening methods for rare CNVs may provide clues for the genetic etiology in patients with a broader range of epilepsies than previously anticipated, including in patients with various brain anomalies detectable by MRI. Performing genome-wide screens for rare CNVs can be a valuable contribution to the routine diagnostic workup in patients with a broad range of childhood epilepsies.  相似文献   
24.
25.
26.
Andrews  PC; Babior  BM 《Blood》1984,64(4):883-890
A study was conducted on the phosphorylation of proteins in the neutrophil cytosol in response to phorbol myristate acetate (PMA) and N- formyl-methionyl-leucyl-phenylalanine (fMLP). Autoradiography of gel electrophoretograms prepared from neutrophils incubated with 32Pi in the presence and absence of the activators showed nine proteins whose state of phosphorylation was affected by neutrophil activation. 32P was gained by eight of these proteins and was lost by the ninth. For all but one of these proteins, the change in the extent of labeling appeared to reach completion by one to two minutes. It was possible to quantitate the changes in 32P content of three of the nine proteins. One of these was the 20-kD protein that lost label when the neutrophils were activated. Quantitation showed that over half the 32P present in this protein in the resting state was gone within 0.2 minutes after activation. The other two were proteins weighing 11 and 69 kD. The phosphorylation characteristics of these two proteins differed, depending on whether activation had been carried out with PMA or fMLP. These differences in protein phosphorylation support other evidence suggesting that PMA and fMLP do not activate neutrophils by identical biochemical pathways. Differences in phosphorylation between resting and activated cells were not affected by dibutyryl cyclic guanosine monophosphate (cGMP), dibutyryl cyclic adenosine monophosphate (cAMP), theophylline, aspirin, hydrocortisone, or colchicine. The differences were abolished, however, by 30 mumol/L trifluoperazine. This finding is consistent with the hypothesis that the calcium/calmodulin system plays a biochemical role in the activation of neutrophils.  相似文献   
27.

Background  

We determined the effects of two antibiotic policies (predominance of either β-lactam antibiotics or fluroquinolones) on acquisition with third-generation cephalosporin-resistant Enterobacteriaceae (CRE) and fluoroquinolone-resistant CRE (FCRE) in two ICUs, with monitoring of other variables that may influence acquisition.  相似文献   
28.
We report an unusual case of localized congenital tuberculosis otitis in a preterm infant. Unlike disseminated congenital cases, the manifestations of localized otitis are associated with a triad of signs: (i) regional lymphadenopathy in the absence of typical systemic features of tuberculosis; (ii) delayed onset of presentation; and (iii) refractory otitis unresponsive to conventional antimicrobial agents. The need for greater diligence in looking for neonatal tuberculosis is emphasized, especially in an ethnic or socioeconomic environment where the disease is prevalent. Congenital tuberculosis, otitis, preterm
PC Ng, Department of Paediatrics, Level 6, Clinical Sciences Building, Prince of Wales Hospital, Shatin, NT, Hong Kong  相似文献   
29.
OBJECTIVE: We prospectively studied children with and without maternally transmitted HIV-1 infection born to mothers infected with HIV-1 to determine the incidence of chronic radiographic lung changes (CRC) and to correlate these changes with clinical assessments. SUBJECTS AND METHODS: Between 1990 and 1997, we scored 3050 chest radiographs using a standardized form. Group I children (n = 201) were HIV-1-infected at enrollment. Group II children (n = 512) were enrolled prenatally or before 28 days postpartum and subsequently subdivided into group IIa (n = 86), children identified as HIV-1-infected; and group IIb (n = 426), those who were HIV-1-uninfected. CRC were defined as parenchymal consolidations or nodular disease lasting 3 months or more or increased bronchovascular markings or reticular densities lasting 6 months or more. Morbidity was assessed by CD4 counts, viral load, the presence of low oxygen saturation, wheezing, tachypnea, crackles, and clubbing. RESULTS: The cumulative incidence of chronic radiographic lung changes in HIV-1-infected children was 32.8% by 4 years old, with increased bronchovascular markings or reticular densities being most common. Chronic changes were associated with lower CD4 cell counts and higher viral loads. Resolution of these chronic changes was associated with decreasing CD4 cell counts but not with lower rates of clinical findings, viral load, or difference in survival. CONCLUSION: With increased survival, CRC are becoming more common. The resolution of these changes may indicate immunologic deterioration rather than clinical improvement.  相似文献   
30.
OBJECT: The aim of this study was to assess the incidence and outcome of procedure-related rupture of intracranial aneurysms in patients treated with Guglielmi detachable coils (GDCs) and to identify risk factors for this complication. METHODS: Procedure-related rupture occurred in seven of 264 treated aneurysms in 239 consecutive patients. Aneurysm size, history of previous subarachnoid hemorrhage (SAH) caused by the treated aneurysm, timing of treatment after SAH, and the use of a temporary occlusion balloon in the seven procedures in which rupture occurred were compared with the remaining 257 procedures, and these findings were correlated with data from 13 studies in the literature, in which results of 2030 aneurysm treatments were reported. CONCLUSIONS: Procedure-related rupture of intracranial aneurysms during GDC treatment occurs in 2.5% of cases and is responsible for 1% of treatment-related deaths. Risk factors are as follows: small aneurysm size, previous SAH, and probably the use of a temporary occlusion balloon.  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