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   632篇
  免费   33篇
  国内免费   8篇
儿科学   15篇
妇产科学   10篇
基础医学   110篇
口腔科学   7篇
临床医学   47篇
内科学   159篇
皮肤病学   19篇
神经病学   62篇
特种医学   1篇
外科学   94篇
综合类   2篇
预防医学   64篇
眼科学   5篇
药学   36篇
中国医学   1篇
肿瘤学   41篇
  2024年   2篇
  2023年   7篇
  2022年   21篇
  2021年   35篇
  2020年   17篇
  2019年   31篇
  2018年   27篇
  2017年   19篇
  2016年   14篇
  2015年   21篇
  2014年   33篇
  2013年   41篇
  2012年   76篇
  2011年   65篇
  2010年   27篇
  2009年   27篇
  2008年   31篇
  2007年   35篇
  2006年   31篇
  2005年   31篇
  2004年   25篇
  2003年   15篇
  2002年   14篇
  2001年   1篇
  2000年   2篇
  1999年   3篇
  1998年   5篇
  1997年   1篇
  1996年   2篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1992年   2篇
  1991年   2篇
  1987年   2篇
  1982年   1篇
  1973年   1篇
  1971年   1篇
  1965年   2篇
排序方式: 共有673条查询结果,搜索用时 0 毫秒
101.
BackgroundApproximately 30% to 50% of patients with moderate/severe asthma have inadequately controlled disease despite adherence to inhaled corticosteroid (ICS)/long-acting β2-agonist (LABA) therapy. Data on prevalence and burden of uncontrolled asthma in specialty settings are lacking.ObjectiveTo evaluate the prevalence and burden of uncontrolled asthma in respiratory specialist clinics in the United States.MethodsAdults with physician-diagnosed asthma attending pulmonary and allergy clinics with self-reported ICS use in the previous 4 weeks completed an electronic questionnaire including the Asthma Control Test and St George’s Respiratory Questionnaire. Additional information was collected using an electronic case report form.ResultsOf 774 patients attending 12 pulmonary and 12 allergy clinics, 53% were not well controlled (mean [SD] Asthma Control Test, 14.3 [3.6] vs 22.4 [1.6] in well-controlled patients). Among ICS/LABA users, 56% were not well controlled, which increased with increasing ICS dose (low-dose 45.7%; high-dose 59.7%). The not well-controlled group reported more respiratory illnesses, more comorbidities, and poorer health-related quality of life (mean [SD] St George’s Respiratory Questionnaire, 46.1 [18.9] vs 19.8 [12.9] in the well-controlled group). These patients also had more asthma exacerbations (≥1 exacerbation, 68.9% vs 43.1%) and increased health care resource utilization (≥1 asthma-related hospitalization, 10.7% vs 2.7%); 27.3% were also receiving systemic corticosteroids. Approximately 40% of the population were eligible for step-up to ICS/LABA/long-acting muscarinic antagonist triple therapy, and 20% were eligible for biologic therapy.ConclusionSubstantial unmet needs exist among patients with inadequately controlled asthma managed in United States specialist settings, which may be addressed by improved patient and physician education, better guideline implementation, and improved adherence.  相似文献   
102.
103.
The development of neural network models has greatly enhanced the comprehension of cognitive phenomena. Here, we show that models using multiplicative processing of inputs are both powerful and simple to train and understand. We believe they are valuable tools for cognitive explorations. Our model can be viewed as a subclass of networks built on sigma-pi units and we show how to derive the Kronecker product representation from the classical sigma-pi unit. We also show how the connectivity requirements of the Kronecker product can be relaxed considering statistical arguments. We use the multiplicative network to implement what we call an Elman topology, that is, a simple recurrent network (SRN) that supports aspects of language processing. As an application, we model the appearance of hallucinated voices after network damage, and show that we can reproduce results previously obtained with SRNs concerning the pathology of schizophrenia.  相似文献   
104.
105.
A conjugate between maleylated albumin and a photosensitizer (PS) shows cell type specific targeting to macrophages via the scavenger receptor. Administration of this conjugate to a tumor-bearing mouse followed by illumination may allow selective destruction of macrophages within tumors. There is accumulating evidence that tumor-associated macrophages contribute to tumor growth, invasiveness, metastasis, and immune suppression. We tested the intravenous (IV) injection of a conjugate between maleylated albumin and chlorin(e6) to BALB/c mice bearing three tumor types with differing proportions of tumor-associated macrophages. The accumulation of PS within the tumors after IV injection and 24 h incubation time was disappointing, and we therefore investigated intratumoral (IT) injection. This gave 20-50 times greater concentrations of PS within the tumor compared to IV injection as determined by tissue extraction. Furthermore the amounts of PS in each tumor type correlated well with the numbers of macrophages both as determined by extraction from bulk tumor and fluorescence quantification and as determined by tissue dissociation to a single cell suspension and two-color flow cytometry with macrophage-specific antibodies. IT injection of nonconjugated PS gave lower tumor accumulation that did not correlate with macrophage content. IT injection of targeted macromolecular delivery systems is an underexplored area and worthy of further study.  相似文献   
106.
Maintenance of subcutaneous cavities with CO2   总被引:1,自引:0,他引:1  
Since mechanical retractors in endoscopic plastic surgery cause certain drawbacks, we developed a model in dogs, which, by insufflating CO2 into a subcutaneous cavity, we were able to maintain. We evaluated the magnitude of subcutaneous emphysema and absorption of CO2 by insufflating different pressures and the efficacy of external pressure on the skin with the purpose of limiting the subcutaneous emphysema. Sixteen dogs were divided in 3 groups, A, B, and C. We controlled the pulmonary function by using a volume-cycle ventilator. In all groups, we maintained a subcutaneous cavity by insufflating CO2. Groups A and C were insufflated at 15 mm Hg; group B, at 8 mm Hg. We placed circumferential Esmarch bandages on the thorax of groups B and C to delimit superiorly and inferiorly the surgical area. Arterial blood gas analyses (ABGA) were taken from the femoral artery 60 minutes after intubation, 60 minutes after Esmarch bandage was placed and at the end of the CO2 insufflation. Statistically, results were analyzed by Wilcoxon test. P < 0.05 was considered statistically significant. Group A showed extensive subcutaneous emphysema. Two dogs died. The systemic increase of the CO2 showed a median of 9.6 mm Hg (P < 0.05). In Group B, Esmarch bandages caused increase in CO2, with a median of 1.65 mm Hg (P < 0.028). None of these dogs showed subcutaneous emphysema during the insufflation after CO2 insufflation pressure augmented with a median of 3.7 mm Hg (P < 0.028). In Group C, chest restriction increased CO2 median of 6.1 mm Hg (P < 0.043), and subcutaneous emphysema shown was less extensive than group A. The CO2 increased after insufflation a median of 16 mm Hg (P < 0.043). CONCLUSIONS: Subcutaneous cavities can be maintained open with CO2 insufflation at 8 mm Hg, limiting perfectly the surgical area; as done with Esmarch bandages, it reduces CO2 absorption and makes this procedure safe.  相似文献   
107.
Maritrema formicae sp. nov. is described from the Patagonian coast, Argentina, based on adults obtained from the kelp gull, Larus dominicanus. The new species fits with the "eroliae complex" and can be distinguished from other related species mainly in shape and size of body, shape, size, and pattern of distribution of cirrus spines, uterus extension, number and size of eggs, vitellarium in a complete ring in all specimens, and its Neotropical distribution. The new species is sympatric with another species of the genus, Maritrema madrynense, which was recorded in the same host and locality.  相似文献   
108.
109.
110.
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