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   1756篇
  免费   90篇
  国内免费   4篇
耳鼻咽喉   9篇
儿科学   44篇
妇产科学   45篇
基础医学   200篇
口腔科学   44篇
临床医学   226篇
内科学   403篇
皮肤病学   21篇
神经病学   161篇
特种医学   43篇
外科学   307篇
综合类   3篇
预防医学   63篇
眼科学   35篇
药学   92篇
中国医学   3篇
肿瘤学   151篇
  2023年   11篇
  2022年   30篇
  2021年   52篇
  2020年   32篇
  2019年   46篇
  2018年   55篇
  2017年   36篇
  2016年   64篇
  2015年   56篇
  2014年   77篇
  2013年   80篇
  2012年   145篇
  2011年   131篇
  2010年   68篇
  2009年   68篇
  2008年   88篇
  2007年   104篇
  2006年   79篇
  2005年   110篇
  2004年   95篇
  2003年   88篇
  2002年   80篇
  2001年   16篇
  2000年   26篇
  1999年   22篇
  1998年   15篇
  1997年   11篇
  1996年   14篇
  1995年   9篇
  1994年   6篇
  1993年   5篇
  1992年   11篇
  1991年   8篇
  1990年   7篇
  1989年   9篇
  1988年   11篇
  1987年   13篇
  1986年   13篇
  1985年   8篇
  1984年   5篇
  1983年   11篇
  1982年   3篇
  1981年   3篇
  1980年   3篇
  1979年   4篇
  1978年   2篇
  1977年   3篇
  1975年   6篇
  1967年   2篇
  1882年   1篇
排序方式: 共有1850条查询结果,搜索用时 421 毫秒
21.
· Background: The aim of this study was to evaluate the focal electroretinogram (FERG), an objective indicator of outer retinal function, in nonexudative age-related macular degeneration (NE-AMD), and to compare FERG results with morphological lesions assessed by stereoscopic fundus photographs and fluorescein angiograms. · Methods: Twenty-five patients (25 eyes) with bilateral NE-AMD (visual acuity of the study eyes ≥0.4) as well as 10 age- and sex-matched control subjects (10 eyes) were evaluated. FERGs were recorded from the macular region (9°) in response to sinusoidal stimuli flickered at 32 Hz. Amplitude and phase angle of the Fourier-analyzed FERG fundamental component were measured. Fundus lesions were graded from color slides according to the Wisconsin age-related maculopathy grading system [15]. Fluorescein angiograms were evaluated by an image analysis technique to compute the area with pathological hyperfluorescence (associated with drusen and/or retinal pigment epithelial atrophy) within the macular (approximately 9°×9°) region. · Results: Compared to control eyes, NE-AMD eyes had a reduction in the mean FERG amplitude (57% loss, P<0.001) with no phase changes. Amplitudes of individual affected eyes were negatively correlated with either the Wisconsin grading score (r=–0.63, P<0.001) or the percentage area of pathological hyperfluorescence (r=–0.70, P<0.01). Eyes with minimal NE-AMD lesions (Wisconsin score ≤6) and normal acuity had a lower mean amplitude (47% loss, P<0.05) than that of control eyes. · Conclusions: The results indicate that, in NE-AMD, the FERG is altered in parallel with the extent and severity of fundus lesions. However, a functional impairment of outer macular layers, which is detected by FERG losses, could precede morphological changes typical of more advanced disease. Received: 6 March 1998 Revised version received: 5 June 1998 Accepted: 17 June 1998  相似文献   
22.
In our Institute we have performed 124 vertical banded gastroplasties. Patients with a follow-up beyond 3 months were studied with a barium meal, in order to evaluate the efficiency of surgery and the eventual complications. Seventy-nine patients have had one or more X-ray investigations at various times after surgery (for a total of 136 studies). The first 20 patients were routinely studied at 1, 2 and 3 years after the operation; the next 32 patients were studied for features such as vomiting, poor weight loss or low food intake; the last 27 patients were studied with an early overlook beginning 3 months after surgery. We noted gastroesophageal reflux in eight (10.1%) cases, outlet dilatation in four (5%) cases, outlet substenosis (diameter 6-8 mm) in 13 (16.4%) cases, outlet stenosis (diameter ≤5 mm) in four (5%) cases, peanut-type deformation in three (3.7%) cases, and staple-line disruption in 17 (21.5%) cases. The staple-line disruption was correlated in the first part of the series with a reinforcement of such a suture, while the last 27 patients, with vertical stapling carried out with a 4-row stapler without reinforcement, did not present any disruption. The radiographic examination gives information about weight loss and side effects.  相似文献   
23.
The experience with living donors for intestinal transplantation is limited. However, Intestinal Registry data suggest that the outcomes of the procedure are comparable with those obtained with intestinal transplant from deceased donors. In selected cases, this strategy may have a role in the treatment of patients with irreversible intestinal failure suffering life-threatening complications from total parenteral nutrition. The present review covers most of the published data on this topic between 2003 and 2006, with special reference to living donor intestinal transplantation of pediatric recipients.  相似文献   
24.
Background. Neuronal voltage-dependent sodium channel antagonists have been shown to provide neuroprotection in focal and global cerebral ischemic models. We hypothesized that retrograde spinal cord venous perfusion with phenytoin, a neuronal voltage-dependent sodium channel antagonist, would provide protection during prolonged spinal cord ischemia.

Methods. In a rabbit model, spinal cord ischemia was induced for 45 minutes. Six groups of animals were studied. Controls (group I, n = 8) received no intervention during aortic cross-clamping. Group II (n = 8) received systemic phenytoin (100 mg). Group III (n = 4) received systemic phenytoin (200 mg).Group IV (n = 8) received retrograde infusion of room temperature saline (22°C) only. Group V (n = 8) and group VI (n = 9) received retrograde infusion of 50 mg and 100 mg of phenytoin, respectively, (infusion rate: 0.8 mL · kg−1 · min−1 during the ischemic period). Mean arterial blood pressure was monitored continuously. Animals were allowed to recover for 24 hours before assessment of neurologic function using the Tarlov scale.

Results. Tarlov scores (0 = complete paraplegia, 1 = slight lower limb movement, 2 = sits with assistance, 3 = sits alone, 4 = weak hop, 5 = normal hop) were as follows (mean ± SEM): group I, 0.50 ± 0.50; group II, 0.25 ± 0.46; group IV, 1.63 ± 0.56; group V, 4.13 ± 0.23; and group VI, 4.22 ± 0.22 (p < 0.0001 V, VI versus I, II, IV by analysis of variance). No differences in mean arterial blood pressure were observed. All animals in group III became profoundly hypotensive and died before the conclusion of the 45-minute ischemic time.

Conclusions. Retrograde venous perfusion of the spinal cord with phenytoin, a voltage-sensitive sodium channel blocker, is safe and provides significant protection during prolonged spinal cord ischemia.  相似文献   

25.
26.
27.
28.
The aim of the review is to describe the different techniques and materials available to reconstruct the tarsoconjunctival layer of the eyelid; to analyze their indications, advantages, and disadvantages.

We searched the Cochrane, PubMed, and Ovid MEDLINE databases for English articles published between January 1990 and January 2017 using variations of the following key words: “posterior lamella,” “eyelid reconstruction,” “tarsoconjunctival,” “flap,” and “graft.” Two reviewers checked the abstracts of the articles found to eliminate redundant or not relevant articles. The references of the identified articles were screened manually to include relevant works not found through the initial search.

The search identified 174 articles. Only a few articles with a therapeutic level of evidence were found. Techniques for the posterior lamellar reconstruction can be categorized as local, regional, and distant flaps; tarsoconjunctival, heterotopic, homologous, and heterologous grafts. Several techniques and variations on the techniques exist to reconstruct the posterior lamella, and, for similar indications, there’s no evidence of the primacy of one over the other. Defect size and location as well as patient features must guide the oculoplastic surgeon’s choice. The use of biomaterials can avoid possible complications of the donor site.  相似文献   

29.
Glatiramer acetate (GA) is a synthetic amino acid polymer, used for relapsing-remitting multiple sclerosis. The most common adverse effect of GA is a skin reaction at the injection site with a probable IgE-mediated mechanism. We report a case of a 45-year-old woman with multiple sclerosis and urticaria to interferon-β1a, who underwent a challenge test to GA. She presented itching wheals at the intradermal sites. A month later the patient repeated the test and presented the same reactions of the first test. The next day she continued the test with subcutaneous injections. One hour later she presented a flare up of the reactions appeared during the previous 2 tests. No reactions appeared at the subcutaneous injection sites. The patient also presented dyspnea. Flare-up reactions are characterized by the reactivation of previously positive reactions to intradermal or skin tests triggered by patch testing and after systemic provocation with an allergen. The phenomenon is not common to drugs. The mechanisms involved in this reaction seem to be heterogeneous and are not completely understood. To our knowledge this is the first case of allergic reaction to GA manifested as a flare-up reaction during challenge test.  相似文献   
30.
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