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   3202390篇
  免费   249839篇
  国内免费   5475篇
耳鼻咽喉   45529篇
儿科学   100528篇
妇产科学   86552篇
基础医学   459251篇
口腔科学   92141篇
临床医学   296915篇
内科学   619305篇
皮肤病学   66183篇
神经病学   266561篇
特种医学   125015篇
外国民族医学   1104篇
外科学   472892篇
综合类   74033篇
现状与发展   4篇
一般理论   1448篇
预防医学   263622篇
眼科学   75471篇
药学   238589篇
  12篇
中国医学   5752篇
肿瘤学   166797篇
  2018年   33073篇
  2017年   25498篇
  2016年   28085篇
  2015年   31901篇
  2014年   45467篇
  2013年   69499篇
  2012年   93806篇
  2011年   99518篇
  2010年   58376篇
  2009年   55900篇
  2008年   94364篇
  2007年   100724篇
  2006年   101029篇
  2005年   98673篇
  2004年   94869篇
  2003年   91516篇
  2002年   89973篇
  2001年   143175篇
  2000年   147730篇
  1999年   125132篇
  1998年   36674篇
  1997年   33219篇
  1996年   33229篇
  1995年   31826篇
  1994年   29925篇
  1993年   27980篇
  1992年   101169篇
  1991年   98329篇
  1990年   95078篇
  1989年   91725篇
  1988年   85336篇
  1987年   83876篇
  1986年   79735篇
  1985年   76042篇
  1984年   57812篇
  1983年   49905篇
  1982年   30266篇
  1981年   27095篇
  1979年   54749篇
  1978年   39075篇
  1977年   32886篇
  1976年   30799篇
  1975年   32734篇
  1974年   40194篇
  1973年   38658篇
  1972年   36457篇
  1971年   33818篇
  1970年   31785篇
  1969年   29745篇
  1968年   27280篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
In this paper, we investigate the claim that although the same lexical units are involved in speech production and comprehension, there are separate input and output phoneme layers (Foygel and Dell, 2000). Data from a case series of aphasic patients are used to test this claim by examining the relationship between performance on a test of picture naming and performance on tests of phonological input. Estimates of each patient's semantic-lexical and phonological impairments in speech production were derived from Foygel and Dell's computational model of picture naming. It was found that the strength of the semantic-lexical impairments in speech production was significantly correlated with performance on auditory comprehension tests. This finding is consistent with the claim that the same lexical units are involved in speech comprehension and production. Conversely, the correlations between the strength of the phonological lesions in speech production and performance on tests of phonological input were non-significant, consistent with Foygel and Dell's claim that there are distinct input and output phoneme layers.  相似文献   
992.
A mutant form of ammodytoxin A, a neurotoxic phospholipase A2 from the venom of the long nosed viper Vipera ammodytes ammodytes, was prepared by site-directed mutagenesis, conjugated to a nanogold particle and inoculated into the antero-lateral aspect of one hind limb of female mice. Eight hours later the mice were killed, the soleus muscles of both ipsi- and contra-lateral hind limbs were removed, exposed to a silver enhancing medium and then prepared for transmission electron microscopy. Silver-enhanced particles were subsequently found concentrated in the peri-synaptic area, particularly within the synaptic gutter and the deep synaptic folds, and in many cases had been taken up into the cytoplasm of the terminal boutons of the motor axon. The results suggest that the presynaptic neurotoxicity of snake venom phospholipases A2 involves several components of the neuromuscular apparatus, including intracellular organelles of the motor nerve terminal.  相似文献   
993.
994.
995.
996.
997.
998.
999.
1000.
Diverticulosis is a common colonic disease in industrialized societies and its prevalence increases with age. Acute diverticulitis is defined by diverticular and peridiverticular inflammation and infection. For most patients, outpatient therapy is possible and hospitalization is only indicated if the patient is unable to eat, suffers from an acute attack, has complications or if symptoms fail to improve despite adequate outpatient therapy. The treatment of acute uncomplicated diverticulitis usually consists of broad-spectrum antibiotics covering both aerobic and anaerobic bacteria. Antimicrobial therapy is given for 7 to 10 days but the duration of the treatment can be longer if there are complications. If there is no clinical improvement within 2 or 3 days, repeat CT imaging is appropriate, as this may reveal an abscess, phlegmon or fistula, which might necessitate percutaneous drainage or surgery. The published literature does not support the recommendation of any prophylactic diet or medical treatment for reducing the risk of first or recurrent diverticulitis in patients with diverticulosis.  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