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   861篇
  免费   64篇
  国内免费   4篇
耳鼻咽喉   20篇
儿科学   55篇
妇产科学   28篇
基础医学   80篇
口腔科学   69篇
临床医学   78篇
内科学   177篇
皮肤病学   33篇
神经病学   60篇
特种医学   23篇
外科学   166篇
综合类   7篇
一般理论   1篇
预防医学   34篇
眼科学   17篇
药学   41篇
中国医学   2篇
肿瘤学   38篇
  2024年   3篇
  2023年   20篇
  2022年   20篇
  2021年   53篇
  2020年   40篇
  2019年   51篇
  2018年   44篇
  2017年   31篇
  2016年   57篇
  2015年   39篇
  2014年   46篇
  2013年   47篇
  2012年   57篇
  2011年   57篇
  2010年   22篇
  2009年   16篇
  2008年   52篇
  2007年   37篇
  2006年   42篇
  2005年   47篇
  2004年   21篇
  2003年   29篇
  2002年   24篇
  2001年   18篇
  2000年   9篇
  1999年   8篇
  1998年   6篇
  1997年   3篇
  1996年   3篇
  1995年   4篇
  1994年   2篇
  1993年   1篇
  1992年   2篇
  1991年   8篇
  1990年   3篇
  1987年   2篇
  1986年   1篇
  1985年   2篇
  1983年   1篇
  1974年   1篇
排序方式: 共有929条查询结果,搜索用时 15 毫秒
1.
In this prospective study, we investigated the impact of SARS-CoV-2 infection on semen parameters in a cohort of men who had recently recovered from COVID-19. A total of 24 men who had recently recovered from mild COVID-19 were included in the study. Their semen parameters were normal before COVID-19 according to the World Health Organization 2010 reference values. Semen samples were collected from these participants in the recovery phases of COVID-19. To determine the effect of SARS-CoV-2 infection on semen parameters, the patients' pre-COVID-19 and post-COVID-19 semen analyses were compared. The mean age of the participants was 34.7 ± 6.4 years. The median interval between the positive nasopharyngeal swab test and obtaining semen samples was 111.5 (158) days. There was no significant difference in semen parameters before and after COVID-19 in terms of semen volume (p = .56), sperm concentration (p = .06), and progressive motility (p = .14). Total motility (p = .01) and total motile sperm count (p = .02) decreased significantly after SARS-CoV-2 infection compared to the pre-infection values. This study demonstrated that sperm motility and total motile sperm count were the semen parameters which showed a significant reduction in cases with a history of mild COVID-19.  相似文献   
2.
3.
A red-absorbing, water-soluble, and iodinated resorufin derivative (R1) that can be selectively activated with a monoamine oxidase (MAO) enzyme was synthesized, and its potential as a photodynamic therapy (PDT) agent was evaluated. R1 showed high 1O2 generation yields in aqueous solutions upon addition of MAO isoforms, and it was further tested in cell culture studies. R1 induced photocytotoxicity after being triggered by endogenous MAO enzyme in cancer cells with a much higher efficiency in SH-SY5Y neuroblastoma cells with high MAO-A expression. Additionally, R1 displayed differential cytotoxicity between cancer and normal cells, without any considerable dark toxicity. To the best of our knowledge, R1 marks the first example of a resorufin-based photosensitizer (PS) as well as the first anticancer drug that is activated by a MAO enzyme. Remarkably, the target PDT agent was obtained only in three steps as a result of versatile resorufin chemistry.  相似文献   
4.
In this study, the influence of the glass-forming ability (GFA) of a drug on its physical stability in a supersaturated solid dispersion was investigated. Nine drugs were classified according to their GFA using their respective critical cooling rate. Their respective solubility in poly(vinylpyrrolidone-co-vinyl acetate) 6:4 (PVPVA64) was predicted using the melting point depression method based on the Flory-Huggins lattice theory. Supersaturated amorphous solid dispersions at a level of 25% w/w drug above saturation solubility in the polymer were prepared by film-casting, and their respective physical stability at temperatures of 10°C or 20°C above or below their respective Tg (dry conditions) was monitored by the use of polarized light microscopy. This study showed that drugs with good GFA (class 3) on average have higher physical stability in supersaturated amorphous solid dispersion compared to drug with modest GFA (class 2), which in turn have higher physical stability in supersaturated amorphous solid dispersion than drugs with poor GFA (class 1). These results indicate that the GFA of a drug and its physical stability in a supersaturated amorphous solid dispersion stored at a temperature above or below its Tg are correlated.  相似文献   
5.
6.
7.
8.
9.
BackgroundPulmonary and upper limbs function of children with Duchenne muscular dystrophy (DMD) are known to deteriorate throughout the disease process. However, there is a lack of information on the extent of impairments in the early stages of DMD when compared to healthy peers.ObjectiveTo investigate to what extent pulmonary and upper limbs function of children with early stage DMD are impaired.MethodsSixty-one children participated in the study: 31 with Grade 1 DMD (study group) according to the Brooke Upper and Lower Extremity Functional Classification Systems, and 30 age matched healthy peers (control group). Pulmonary function was determined with pulmonary function tests. The Performance of Upper Limb test was used to evaluate the upper limbs function.ResultsStudy and control groups were homogenous in terms of physical characteristics (p > 0.05). Pulmonary and upper limbs function of children with DMD were about 85% and 93% of healthy peers, respectively.ConclusionThis study provides evidence for deterioration of pulmonary and upper limbs function in children with early stage DMD. Better knowledge of deterioration rate over time may help therapists to better plan and update their plan of care.  相似文献   
10.
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