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   144057篇
  免费   48561篇
  国内免费   2728篇
耳鼻咽喉   1959篇
儿科学   5234篇
妇产科学   3516篇
基础医学   20679篇
口腔科学   6131篇
临床医学   31691篇
内科学   32627篇
皮肤病学   8021篇
神经病学   16056篇
特种医学   3877篇
外国民族医学   14篇
外科学   18949篇
综合类   8491篇
现状与发展   14篇
一般理论   33篇
预防医学   9748篇
眼科学   2500篇
药学   10872篇
  32篇
中国医学   3992篇
肿瘤学   10910篇
  2024年   218篇
  2023年   1359篇
  2022年   1604篇
  2021年   3474篇
  2020年   6983篇
  2019年   12008篇
  2018年   12078篇
  2017年   13494篇
  2016年   14072篇
  2015年   14627篇
  2014年   15172篇
  2013年   16189篇
  2012年   8226篇
  2011年   8682篇
  2010年   12603篇
  2009年   8888篇
  2008年   5637篇
  2007年   4499篇
  2006年   4413篇
  2005年   3785篇
  2004年   3429篇
  2003年   3419篇
  2002年   3272篇
  2001年   3067篇
  2000年   2362篇
  1999年   1719篇
  1998年   1078篇
  1997年   1212篇
  1996年   1036篇
  1995年   914篇
  1994年   690篇
  1993年   527篇
  1992年   593篇
  1991年   533篇
  1990年   465篇
  1989年   389篇
  1988年   332篇
  1987年   290篇
  1986年   262篇
  1985年   248篇
  1984年   176篇
  1983年   150篇
  1982年   121篇
  1981年   127篇
  1980年   77篇
  1979年   132篇
  1978年   90篇
  1977年   97篇
  1976年   91篇
  1972年   100篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Serum IgA and IgG functional antibodies and their subclasses to Streptococcus pneumoniae capsular antigen found in two aged‐matched cohorts of children with and without otitis media with effusion The relationship between acute otitis media and otitis media with effusion (OME) is uncertain and the aetiology of OME is multifactorial. Otitis media with effusion may be an inflammatory condition; both bacteria and viral infections could play a part in this inflammation. The four bacteria Streptococcus pneumoniae, Haemophilus influenza, Staphylococcus aureus and Branhamella catarrhalis cause 60% of the infections whereas S. pneumoniae accounts for up to 35%. IgA provides the dominant surface response to polysaccharide and lipopolysaccharide antigens, of which IgA2 is the main subclass. Once the mucosa has been breached, most protection is provided by IgG. IgG2 acts mainly against bacterial capsular antigens. This study looked at two groups of 50 children with and without OME who were aged between 3 and 10 years. The aims were to determine if, firstly, the levels of the serum immunoglobulins were different in the two groups, secondly whether these children made the appropriate antibody response to the capsular antigen to S. pneumoniae (PCP), and finally if there was a delay in the maturity of the IgA response. The total IgG, IgA and all subclass levels were measured using radial immunodiffusion. Levels of functional IgA and IgG were measured using ELISAs (25 patients in each group). The results were analysed with non‐parametric tests. The immunoglobulin levels were within the normal levels for both groups. There were very good correlations between the IgG total anti‐PCP and the IgG2 anti‐PCP (R > 0.9, p = 0.001). There was a good correlation between the levels of both IgG total and IgG2 anti‐PCP against IgA total anti‐PCP in both groups (R > 0.85, p > 0.01). This confirms a normal antibody response between both groups of patients. The ages of the controls and patients (50 samples) were correlated with increasing titres of circulating functional antibodies (P = 0.001). This is highly suggestive of a normal age‐related response. In conclusion, the findings were contradictory to our original hypothesis that there is a subtle difference in surface protection between children with and without OME. We believe that a previous history of recurrent acute otitis media is unrelated to the development of OME after 3 years of age.  相似文献   
82.
83.
84.
85.
86.
87.
A decrease of heteronymous median nerve-evoked inhibition of corticospinal projections to forearm extensor muscles was reported in a group of 10 dystonic patients by Bertolasi and colleagues in 2003. Here we tested the excitability of corticomotoneuronal connections to both wrist extensor (ECR) and flexor (FCR) muscles after conditioning stimulation of median and also radial nerve at rest in a group of 25 patients with focal hand dystonia compared to 20 healthy subjects. We also investigated the effect of the wrist dystonic posture, either in flexion or in extension, on the afferent modulation of ECR and FCR motor evolved potentials (MEPs). The heteronymous (median-induced) but also homonymous (radial-induced) inhibitions (interstimuli intervals 13-21 ms) of ECR MEP size observed in healthy subjects were decreased in patients. In addition, homonymous (median-induced) facilitation of FCR MEP size was also decreased in patients while heteronymous inhibition (radial-induced) was not. Neither the involvement of the target muscle in the dystonic posture nor the origin of the afferent volley (from a dystonic muscle) influenced the degree of impairment of afferent modulation of the MEP. These findings support the view that a global abnormal somatosensory coupling in focal hand dystonia may contribute to an inadequate motor command to wrist muscles.  相似文献   
88.
Chlamydia trachomatis is the most prevalent sexually transmitted microbial infection in the United States. The CDC estimates that 3 million people are infected annually, with approximately 50% of infected men and 75% of infected women having few or no recognized symptoms. C. trachomatis is frequently transferred from mother to infant, and the maternal-infant transfer of this disease may have negative consequences for the newborn, such as prematurity, pneumonia, and conjunctivitis. Ocular prophylaxis with silver nitrate and or antibiotics is ineffective in preventing neonatal chlamydial conjunctivitis. By increasing awareness of the potential adverse consequences, initiating screening and treatment of pregnant women, and advocating for newborn assessment and treatment, nurses can enhance the quality of care for mothers and their infants.  相似文献   
89.
90.
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