首页 | 官方网站   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   7524篇
  免费   448篇
  国内免费   13篇
医药卫生   7985篇
  2023年   47篇
  2022年   87篇
  2021年   134篇
  2020年   111篇
  2019年   140篇
  2018年   171篇
  2017年   145篇
  2016年   165篇
  2015年   223篇
  2014年   221篇
  2013年   277篇
  2012年   464篇
  2011年   484篇
  2010年   287篇
  2009年   244篇
  2008年   366篇
  2007年   391篇
  2006年   350篇
  2005年   357篇
  2004年   395篇
  2003年   341篇
  2002年   304篇
  2001年   187篇
  2000年   174篇
  1999年   164篇
  1998年   107篇
  1997年   71篇
  1996年   54篇
  1995年   46篇
  1994年   44篇
  1993年   41篇
  1992年   121篇
  1991年   92篇
  1990年   80篇
  1989年   99篇
  1988年   92篇
  1987年   75篇
  1986年   80篇
  1985年   75篇
  1984年   55篇
  1983年   44篇
  1982年   41篇
  1981年   31篇
  1980年   31篇
  1979年   54篇
  1977年   28篇
  1975年   31篇
  1974年   34篇
  1972年   29篇
  1968年   26篇
排序方式: 共有7985条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
S Ii  S Minnerath  K Ii  P J Dyck  S S Sommer 《Neurology》1991,41(6):893-898
We analyzed 11 consecutive unrelated cases of polyneuropathy due to transthyretin amyloidosis. Direct sequencing of the promoter region, exons, and splice junctions revealed that each patient was heterozygous for a mutation: six patients had valine 30 substituted by methionine (V30----M; Portuguese-Japanese type), one had threonine 60 substituted by alanine (T60----A; Appalachian type), and two had serine 77 substituted by tyrosine (S77----Y; Illinois type). In addition, two patients had previously undescribed mutation: phenylalanine 33 substituted by leucine (F33----L) and phenylalanine 64 substituted by leucine (F64----L). From present information, the probands of these novel mutations do not exhibit any pathology that clearly distinguishes them from individuals with the other mutations. The mutations extend the range of mutations associated with amyloidotic polyneuropathy. In our 11 patients, the different mutations did not seem to correlate with distinct clinical phenotypes. We developed PASA assays (PCR amplification of specific alleles) for each of the five mutations. PASA can be used by any diagnostic laboratory that can perform PCR to rapidly detect any of the known mutations. The minority of samples with an undescribed mutation can be sent to a specialty laboratory for delineation of the mutation by direct genomic sequencing. The presently described combination of methods may have widespread utility in the diagnosis of genetic disease.  相似文献   
6.
Acute ischaemia of the vertebrobasilar circulation leads to a variety of clinical manifestation and is mostly due to cardiogenic or artery-to-artery embolism. We describe four neurological emergency situations involving vertebrobasilar artery aclusion of other origins: basilar migraine, extrinsic compression by rheumatoid inflammatory tissue, generalized vasculitis in subacute rheumatic fever and basilar artery dissection. The differential diagnosis of acute vertebrobasilar artery occlusion may have an important impact on patient management.  相似文献   
7.
Persistent developmental stuttering (PDS) shares clinical features with task-specific dystonias. In these dystonias, intracortical inhibition is abnormally weak. We therefore sought to determine intracortical inhibition and intracortical facilitation in PDS. In 18 subjects with PDS since childhood (mean age, 39.4 [SD 13.0] years) and 18 speech-fluent controls (43.6 [14.3] years), we investigated resting and active motor thresholds as well as intracortical inhibition and facilitation of the optimal representation of the abductor digiti minimi of the dominant hand using transcranial magnetic stimulation. In PDS, the resting and active motor thresholds were increased, whereas intracortical inhibition and facilitation were normal. Normal intracortical excitability makes a pathophysiological analogy between focal dystonia and PDS less likely. The enhanced motor threshold suggests reduced motor cortical neuronal membrane excitability in PDS.  相似文献   
8.
9.
J Katz  A Sommer 《Ophthalmology》1990,97(8):1032-1037
Eighty-eight glaucoma patients and 252 normal subjects underwent C-30-2 testing on the Humphrey Field Analyzer. The effect of fixation losses, high false-positive and false-negative response rates on visual field test results was assessed using the mirror image method of detecting asymmetry across the horizontal meridian, and the Humphrey STATPAC pattern standard deviation (PSD) and mean deviation (MD). Glaucoma patients with poor fixation (greater than or equal to 20%) had less depressed fields and fewer localized defects than those with good fixation. Fixation loss did not affect measures of localized defects or generalized depression among normal subjects. High false-positive rates (greater than or equal to 10%) were associated with less-depressed visual fields among glaucoma patients and normal subjects. Visual fields were depressed by an average of 9 dB for glaucoma patients and 7 dB for normal subjects with high false-negative rates (greater than or equal to 33%), when compared with those with low false-negative rates. Apparent localized defects were observed among normal subjects with high false-negative rates. Most of these defects were located in the superior nasal and adjacent arcuate area.  相似文献   
10.
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-23

京公网安备 11010802026262号