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   799篇
  免费   51篇
  国内免费   5篇
耳鼻咽喉   5篇
儿科学   22篇
妇产科学   14篇
基础医学   166篇
口腔科学   33篇
临床医学   68篇
内科学   144篇
皮肤病学   25篇
神经病学   87篇
特种医学   30篇
外科学   53篇
综合类   3篇
一般理论   1篇
预防医学   70篇
眼科学   26篇
药学   63篇
中国医学   3篇
肿瘤学   42篇
  2024年   2篇
  2023年   7篇
  2022年   32篇
  2021年   48篇
  2020年   26篇
  2019年   36篇
  2018年   29篇
  2017年   17篇
  2016年   29篇
  2015年   44篇
  2014年   35篇
  2013年   50篇
  2012年   75篇
  2011年   79篇
  2010年   25篇
  2009年   33篇
  2008年   54篇
  2007年   53篇
  2006年   38篇
  2005年   43篇
  2004年   31篇
  2003年   16篇
  2002年   14篇
  2001年   5篇
  2000年   4篇
  1999年   1篇
  1998年   6篇
  1997年   2篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1992年   3篇
  1991年   3篇
  1990年   1篇
  1988年   2篇
  1984年   1篇
  1982年   2篇
  1981年   1篇
  1977年   2篇
  1975年   1篇
  1947年   1篇
  1933年   1篇
排序方式: 共有855条查询结果,搜索用时 29 毫秒
101.
AIMS: This retrospective study aimed to document and illustrate the histomorphological changes underlying peripheral vascular disease (PVD). More specifically, it aimed to analyse and quantify those changes that lead to lower limb amputations. Histological changes were assessed in relation to various clinical pathologies, and significant correlations were sought thereafter. METHODS: A total of 1305 arterial segments were examined from 58 consecutive patients undergoing a lower limb amputation from January 2002 to December 2003. Serial arterial segments were taken from the femoral, popliteal, anterior tibial, posterior tibial, peroneal, and dorsalis pedis arteries, and the degrees of atherosclerotic stenosis and medial calcification were histologically quantified. RESULTS: Atherosclerosis was associated with severe arterial stenosis. An increased occurrence of severe atherosclerotic narrowing coincided with increasing patient age (p = 0.0166), hypertension (p = 0.0019), and diabetes mellitus (p = 0.0036). The presence of medial calcification was an important pathological feature in patients under 70 years of age (p = 0.0308) and significantly more severe in those with diabetes mellitus (p<0.001). CONCLUSION: Atherosclerosis and medial calcification are significant underlying lesions in diabetic patients undergoing lower limb amputation. Medial calcification can cause significant stiffening of the arterial wall and a reduction in its ability to respond to vasodilator stimuli.  相似文献   
102.
An overview of Gyrodactylus infecting catfishes from the African continent is provided, including new data from Sudan, Senegal, Kenya and Mozambique. Haptoral sclerite morphometry and nuclear ribosomal DNA sequences revealed the presence of eight Gyrodactylus species. On Senegalese Synodontis nigrita, Gyrodactylus synodonti n. sp. and Gyrodactylus nigritae n. sp. are described. These are the first reports of gyrodactylid parasites from mochokid hosts. From the fins of North African catfish Clarias gariepinus collected in Mozambique, Gyrodactylus alekosi n. sp. and Gyrodactylus rysavyi were identified. G. rysavyi was also reported from Kenyan C. gariepinus and Senegalese Clarias anguillaris. From the fins of C. anguillaris studied in Senegal, two more species, Gyrodactylus transvaalensis and Gyrodactylus gelnari n. sp. were recognised. In addition, Gyrodactylus turkanaensis n. sp. from the gills of Kenyan C. gariepinus was described and an undescribed Gyrodactylus sp. was recorded from Sudanese representatives of the same host. Detailed morphometrical and molecular comparisons of the species are presented and discussed. The study highlights the hitherto understudied diversity of viviparous monogenean parasites throughout Africa.  相似文献   
103.
The hazardous chemical contamination of untreated wastewater and secondary effluent from the wastewater treatment plant (WWTP) of the city of Zagreb, Croatia was comprehensively characterized using large-volume solid-phase extraction (SPE) and silica gel fractionation, followed by a detailed analysis of the resulting extracts by a combination of chemical and bioassay methods. Over 100 individual contaminants or closely related-contaminant groups were identified by high-resolution gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/quadrupole time-of-flight mass spectrometry (LC-QTOF). Ecotoxicity profiling of the investigated samples, including cytotoxicity, chronic toxicity and EROD activity; inhibition of the multixenobiotic resistance (MXR), genotoxicicity and estrogenic potential, revealed the most significant contribution of toxic compounds to be present in polar fractions. Wastewater treatment using conventional activated sludge process reduced the initial toxicity of raw wastewater to various extents, ranging from 28% for algal toxicity to 73.2% for an estrogenic activity. The most efficient toxicity removal was observed for the polar compounds.  相似文献   
104.
105.
We present a case of Parkinson's disease patient whose initial symptoms were sick sinus syndrome and orthostatic hypotension. Our case illustrates difficulties in distinguishing syncope of primary cardiac or neurological origin and highlights the importance of a diagnostic workup including neurological examination.  相似文献   
106.
Introduction: Levodopa-induced dyskinesias (LID) appears in more than 50% of Parkinson’s disease patients after 5 years of treatment and clinicians always have to ensure that there is a balance between the beneficial effect of the treatment and the potential complications.

Areas covered: In this review, the authors discuss the treatment of LID. Treatment can be divided into strategies for preventing their occurrence, modification of dopaminergic therapy, and providing more continuous dopaminergic stimulation as well as the use of nondopaminergic drugs.

Expert opinion: Amantadine is currently considered the most effective drug for the treatment of LID. Several compounds developed to target adenosine, adrenergic, glutamatergic, and serotonergic receptors have shown to significantly decrease dyskinesias in animal models. However, despite promising preclinical results, translation to clinical practice remains challenging and majority of these compounds failed to decrease LID in randomized controlled trials with moderate–to-advanced parkinsonian patients. Despite promising results with nondopaminergic drugs, treatment of dyskinesias is still challenging and largely due to their side effects. Future research should focus on developing treatments that can provide continuous dopaminergic delivery throughout the day in a noninvasive manner. Studies on the impact of the early administration of long-acting formulations of levo-3,4-dihydroxy-phenylalanine on dyskinesias are also necessary.  相似文献   

107.
108.
109.
Objectives: Development of therapies for systemic lupus erythematosus (SLE) has in part been limited by the lack of suitable outcome measures in clinical trials. In the present post-hoc analysis of two clinical trials of belimumab, we investigated two potential outcomes, the Lupus Low Disease Activity State (LLDAS) and clinical SLE disease activity index 2000 (cSLEDAI-2K) zero, in relation to SLE responder index 4 (SRI-4).

Methods: A total of 1684 SLE patients from the BLISS-52 (n = 865) and BLISS-76 (n = 819) trials were surveyed. Physician’s Global Assessment (PGA) scores <0.5 (3-point scale) were used for comparisons. We used the chi-square test for comparisons and the phi coefficient for correlations.

Results: At week 52, LLDAS was achieved by 8.6% of patients, cSLEDAI-2K = 0 by 34.5% and SRI-4 by 45.1%. cSLEDAI-2K = 0 showed the strongest correlation with PGA <0.5 (rφ = 0.36, P < 0.001). cSLEDAI-2K = 0 unveiled the superiority of belimumab 10 mg/kg over placebo (P = 0.003) with a magnitude which was comparable to that of SRI-4 (P < 0.001). LLDAS displayed a more moderate separation (P = 0.033).

Conclusions: LLDAS was a stringent measure. cSLEDAI-2K = 0 showed the strongest correlation with the clinician-based evaluation. Being based on the SLEDAI-2K only, cSLEDAI-2K = 0 may be considered a more pragmatic outcome measure in SLE studies compared with composite tools.  相似文献   

110.
We report a very rare case of Streptococcus canis native infective endocarditis in a 73‐year‐old woman living in close contact with her dog. Her echocardiography showed large calcifications in the mitral annulus, massive regurgitation below the posterior leaflet, and adjacent vegetation. Blood culture was positive for Streptococcus Lancefield group G. A coronary artery bypass and mitral valve replacement had to be done. Streptococcus canis was detected in a heart valve using a broad range PCR followed by 16S rRNA and confirmed by tuf gene sequencing, while tissue culture remained negative. The patient was not bitten by her dog nor did she have comorbidities or skin ulcers. She fully recovered.  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