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   21988篇
  免费   994篇
  国内免费   168篇
耳鼻咽喉   253篇
儿科学   382篇
妇产科学   350篇
基础医学   3261篇
口腔科学   354篇
临床医学   1954篇
内科学   4140篇
皮肤病学   731篇
神经病学   2724篇
特种医学   1202篇
外科学   2734篇
综合类   152篇
一般理论   6篇
预防医学   959篇
眼科学   505篇
药学   1756篇
中国医学   28篇
肿瘤学   1659篇
  2023年   92篇
  2022年   154篇
  2021年   274篇
  2020年   232篇
  2019年   280篇
  2018年   379篇
  2017年   301篇
  2016年   425篇
  2015年   469篇
  2014年   658篇
  2013年   824篇
  2012年   1294篇
  2011年   1374篇
  2010年   779篇
  2009年   798篇
  2008年   1432篇
  2007年   1486篇
  2006年   1559篇
  2005年   1577篇
  2004年   1439篇
  2003年   1474篇
  2002年   1389篇
  2001年   257篇
  2000年   214篇
  1999年   290篇
  1998年   329篇
  1997年   271篇
  1996年   214篇
  1995年   175篇
  1994年   195篇
  1993年   149篇
  1992年   103篇
  1991年   119篇
  1990年   113篇
  1989年   101篇
  1988年   99篇
  1987年   64篇
  1986年   66篇
  1985年   75篇
  1984年   87篇
  1983年   81篇
  1982年   82篇
  1981年   94篇
  1980年   71篇
  1979年   65篇
  1978年   49篇
  1977年   60篇
  1976年   65篇
  1974年   59篇
  1954年   48篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
Fungal infections still represent a serious complication after organ transplantation. Early diagnosis and aggressive treatment are crucial. Because of the many diagnostic problems involved, we present a case of mucormycosis--primarily affecting the paranasal sinuses with later intracranial extension--in a highly immunized recipient of a third renal transplant. Although fungal infection was suspected from various imaging techniques, only the detection of typical fungal hyphae in the infected tissue was diagnostic. Neither the blood tests and cerebrospinal fluid examinations performed nor cultures from maxillary sinus fluid were of any diagnostic help. Surgical debridement from a transnasal as well as an intracranial approach and systemic amphotericin B together with the discontinuation of immunosuppression after removal of the rejected graft were able to save the patient. This case stresses the importance of early diagnosis that can only be made from tissue biopsies and allows appropriate timely treatment.  相似文献   
22.
Because of the insecure status of knowledge about the actual pathomorphologic changes that occur in whiplash injury, the diagnosis, therapy, and expert assessment of its sequelae still present considerable problems. These are further compounded by the high incidence of this injury in Germany and the very good insurance cover the persons concerned generally have. The initial diagnostic examinations should include a detailed and well-documented clinical examination, and the most precise record possible of how the injury was sustained should be elicited. Plain X-rays are standard diagnostic procedures; functional X-rays and MRI are recommended when instability is suspected or neurological symptoms are present. The first aim of treatment must be the relief or attenuation of pain, followed by improvement of the function. Immobilization of the cervical spine by means of a Schanz collar is rather detrimental. Varied vegetative symptoms require the involvement of different specialists in the treatment at an early stage. Expert assessment for insurance purposes is complicated because the consequences of the accident cannot be objectified, and expecially because the insurance companies require differentiation between the degenerative changes that were present before the injury was sustained in many cases and the symptoms actually caused by the injury.  相似文献   
23.
24.
Aesthetics are as valuable in the posterior region as they are in the anterior. While the former is sometimes overlooked due to the limited visibility of posterior teeth, it is important that the clinician follow guidelines to ensure a high-quality restoration in this region. Restoring posterior teeth with direct resin can be accomplished through conservative and aesthetic treatment; however, it can also be challenging and time consuming to achieve exceptional aesthetics. Highlighting the importance of occlusal anatomy to the success of a direct resin restoration, this presentation outlines requisites to achieve this result. Learning Objectives: This article discusses guidelines for the aesthetic buildup of posterior restorations with direct resin techniques. Upon reading this article, the reader should Realize how the aesthetics of posterior restorations can be enhanced through the application of intensive composite shades. Understand the importance of occlusal design when building the restoration.  相似文献   
25.
Pantothenate kinase-associated neurodegeneration (PKAN) is a rare autosomal recessive disorder with onset in childhood and rapid progression. There is no causative and insufficient symptomatic drug therapy. Deep brain stimulation (DBS) of the internal pallidum (GPi) has been reported to improve motor function. Most case reports, however, are limited to short observational periods. The impact of DBS on the progression and life expectancy in PKAN is unknown. We present a 5-year outcome and video documentation of bilateral GPi-DBS of an adolescent patient suffering from genetically defined PKAN.  相似文献   
26.
Dopamine agonists have been recommended as early treatment for Parkinson's disease (PD), alone or combined with levodopa. Piribedil is a non-ergot selective D(2)/D(3) agonist with alpha(2) antagonist properties shown to be effective in the treatment of PD. This 12-month international, randomized, double-blind trial aimed to assess the efficacy of piribedil 150 mg versus bromocriptine 25 mg, in early combination with levodopa in Stage I to III PD patients. Motor efficacy was assessed using the Unified Parkinson's Disease Rating Scale (UPDRS III, Items 18-31) as improvement from baseline. Response rate was defined as a 30% improvement. Among the 425 randomly assigned patients, 178 were also included in a substudy on cognitive follow-up evaluated by a dysexecutive syndrome oriented battery. A relevant improvement in UPDRS III over the 12-month study duration was observed both in the piribedil and bromocriptine groups (-7.9 +/- 9.7 points from baseline versus -8.0 +/- 9.5; not significant [n.s.]) with a response rate of 58.4% and 55.3% (n.s.), respectively. Piribedil and bromocriptine resulted in similar improvement on all UPDRS III subscores. Piribedil patients required less levodopa dose increase than those on bromocriptine. Cognitive performance remained generally unchanged in both groups, with a significant effect of piribedil limited to the Wisconsin Card Sorting Test. An overall good tolerability of piribedil was observed. Early combination of piribedil 150 mg with levodopa resulted in significant long-term improvement of all motor symptoms in PD patients insufficiently controlled by levodopa alone. Taking into account both efficacy and acceptability in the long-term, piribedil proved in this bromocriptine controlled study to be an effective and safe treatment for PD.  相似文献   
27.
Sporadic amyotrophic lateral sclerosis is an idiopathic human degenerative disease of spinal cord and brain motor neurons. Prior studies demonstrated that most patients with amyotrophic lateral sclerosis posses immunoglobulins that bind to purified L-type voltage-gated calcium channels, that titers of anti–voltage-gated calcium channel antibodies correlate with disease progression rates, and that amyotrophic lateral sclerosis patient-derived antibodies (ALS IgG) produce electrophysiological changes in the function of voltage-gated calcium channels. Using Western transfer immunoblots and enzyme-linked immunosorbent assays, the calcium ionophore–forming α1 subunig of the voltage-gated calcium channel is now identified as the major voltage-gated calcium channel antigen to which ALS IgG binds. Additionally, the binding of an L-type voltage-gated calcium channel α1 subunit–directed monoclonal antibody, which itself mimics the effects of ALS IgG on skeletal muscle voltage-gated calcium channel currents, is selectively prevented by preaddition of ALS IgG. Voltage-gated calcium channel–binding IgG from patients with Lambert-Eaton myasthenic syndrome appears to be differentiated from ALS IgG by the reactivity of the former to both α1 and β subunits of the calcium channel. These assays provide further evidence linking amyotrophic lateral sclerosis to an autoimmune process, and suggest one means to differentiate immunoglobulins from patients with amyotrophic lateral sclerosis from those of patients with another autoimmune disease expressing calcium channel antibodies.  相似文献   
28.
29.
30.
The hypothesis was tested that an initial lithium-tricyclic antidepressant (TCA) combination has a better antidepressant effect than standard TCA treatment in non-refractory depression at the beginning of an episode. Twenty bipolar melancholic type depressed inpatients under lithium-TCA treatment were compared with 20 patients with the same diagnosis and TCA-placebo treatment for 5 weeks under double-blind conditions. All patients were male. Initial lithium-TCA treatment reduced depressive symptoms significantly more than antidepressant treatment with TCA and placebo after 5 weeks, but not in weeks 1 or 2. It can be concluded that lithium augmentation of TCA treatment should be started even at the beginning of antidepressant TCA treatment to provide a better treatment response in those patients who will profit from long-term lithium prophylaxis, e.g. bipolar patients with melancholic type depression.  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