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   2419篇
  免费   156篇
  国内免费   16篇
耳鼻咽喉   34篇
儿科学   109篇
妇产科学   74篇
基础医学   265篇
口腔科学   39篇
临床医学   241篇
内科学   451篇
皮肤病学   29篇
神经病学   183篇
特种医学   240篇
外科学   363篇
综合类   38篇
一般理论   3篇
预防医学   166篇
眼科学   19篇
药学   185篇
中国医学   9篇
肿瘤学   143篇
  2022年   12篇
  2021年   27篇
  2020年   22篇
  2019年   31篇
  2018年   36篇
  2017年   18篇
  2016年   58篇
  2015年   70篇
  2014年   49篇
  2013年   87篇
  2012年   71篇
  2011年   88篇
  2010年   82篇
  2009年   66篇
  2008年   97篇
  2007年   85篇
  2006年   75篇
  2005年   95篇
  2004年   67篇
  2003年   62篇
  2002年   82篇
  2001年   74篇
  2000年   78篇
  1999年   79篇
  1998年   42篇
  1997年   59篇
  1996年   64篇
  1995年   49篇
  1994年   38篇
  1993年   35篇
  1992年   53篇
  1991年   50篇
  1990年   42篇
  1989年   58篇
  1988年   50篇
  1987年   70篇
  1986年   55篇
  1985年   45篇
  1984年   38篇
  1983年   37篇
  1982年   18篇
  1981年   16篇
  1980年   13篇
  1979年   24篇
  1978年   26篇
  1977年   21篇
  1976年   25篇
  1974年   18篇
  1972年   14篇
  1969年   14篇
排序方式: 共有2591条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
OBJECTIVE: To examine the effects of human immunodeficiency virus (HIV) on central nervous system (CNS) function in patients receiving antiretroviral therapy (ART) who have suppressed viral loads. METHODS: Event-related brain potentials (ERPs) were recorded from 15 virally suppressed HIV patients and 15 age-, sex-, and education-matched controls while they performed a 3-stimulus auditory oddball task. The amplitude and latency of the P3a, P3b, and early auditory components were examined in HIV patients and controls. RESULTS: Virally suppressed HIV patients on ART were more depressed than controls, as determined by the Beck Depression Inventory (BDI). After controlling for the effects of depression, HIV patients had smaller P2, P3a, and P3b amplitudes and longer P3a and P3b latency than control subjects. BDI scores correlated positively with N1 latency in HIV patients and negatively with P3b amplitude in all subjects. CONCLUSIONS: These electrophysiological results suggest that, even in the absence of detectable levels of HIV in the peripheral blood, viral replication persists in the CNS and continues to cause disease in HIV patients on ART.  相似文献   
6.
Obituary     
  相似文献   
7.
8.
The concave and convex rib-vertebral angle (RVA) at levels T2–T12 was measured on AP radiographs of 19 patients with right convex idiopathic thoracic scoliosis and 10 patients with major thoracic right convex neuromuscular scoliosis. The difference between the angles on the concave and the convex sides, the RVAD, was calculated. The RVAs were also measured on radiographs from three animal groups in which spinal curves had been induced experimentally in a variety of ways. Group 1 comprised 16 rabbits that had been subjected to selective electrostimulation of the latissimus dorsi, the erector spinae and the intercostal muscles. Group 2 comprised four dead rabbits whose spines had been subjected to manual bending. Group 3 comprised eight rabbits that had undergone mechanical elongation of one rib. In both the idiopathic and the neuromuscular group, the convex RVA was smaller than the concave RVA between levels T2 and T8, with a maximal difference between T4 to T5. From T9 to T12 the concave RVA was smaller than the convex. The RVA in relation to the scoliotic segment, i.e. the apex level of the curve and the two neighbouring vertebrae above and below this level, showed similar results. With increasing Cobb angle the RVADs increased linearly with the greatest difference at the second vertebra above the apex. In the three experimental groups the pattern of the RVADs between T6 to T12 was basically similar to the findings of the clinical study. From the results of these clinical and experimental studies, it is concluded that the typical pattern of the RVAs on the concave and convex sides seems to be independent of the underlying cause of the spinal curvature. It is likely that the RVADs result from a passive mechanical adaptation of the ribs to the lateral curvature of the spine.  相似文献   
9.
This double blind, placebo-controlled trial was designed to determine whether intervention with a stepped regimen of trimethoprim-sulfamethoxazole (TMP-SMX) and prednisone would prevent high risk children from developing chronic otitis media with effusion (OME) and recurrent acute otitis media. Forty-two children were enrolled, assigned to treatment with active drug or placebo and then examined at 2-week intervals. They received TMP-SMX (or placebo) during the first 2 weeks, TMP-SMX and prednisone (or placebo) during Weeks 3 and 4 for persistent OME and TMP-SMX (or placebo) for Weeks 5 and 6 if OME was still unresolved. After treatment 48% of active drug and 14% of placebo subjects resolved OME bilaterally (P less than 0.05). Active drug subjects also had fewer acute otitis media episodes than placebo subjects while receiving study treatment (P less than 0.01). Although this treatment regimen produced short term OME resolution, long term benefits were not demonstrated.  相似文献   
10.
Summary. To investigate the ability of various lung-function tests to demonstrate dilatation of peripheral airways, ten asthmatics inhaled increasing doses of a f2-agonist by two different and controlled techniques. Low inspiratory flow with a long post-inspi-ratory pause favoured peripheral deposition, and a high inspiratory flow with a short post-inspiratory pause favoured central deposition of drug in the airways. Ordinary spirometry, maximum expiratory flow rates after breathing air as well as a helium-oxygen mixture, a single breath N2-test and resistance of the respiratory system were obtained before and after each of five terbutaline doses with both inhalation techniques. By using a double-dummy technique, the study could be performed double blinded. Effects were compared at doses giving equal effects on PEF, assumed to represent equal deposition of bronchodilator and effects on central airways. At such ‘iso A PEF doses’, particularly FVC and the slope of phase III of the N2-test improved more following the slow inhalation technique. It is concluded that changes in those tests reflect dilatation in peripheral airways in asthmatics.,  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