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   5114篇
  免费   348篇
  国内免费   21篇
耳鼻咽喉   42篇
儿科学   232篇
妇产科学   101篇
基础医学   590篇
口腔科学   116篇
临床医学   415篇
内科学   1114篇
皮肤病学   83篇
神经病学   257篇
特种医学   226篇
外科学   813篇
综合类   81篇
一般理论   2篇
预防医学   280篇
眼科学   178篇
药学   593篇
中国医学   48篇
肿瘤学   312篇
  2023年   36篇
  2022年   129篇
  2021年   199篇
  2020年   116篇
  2019年   138篇
  2018年   174篇
  2017年   122篇
  2016年   135篇
  2015年   153篇
  2014年   228篇
  2013年   270篇
  2012年   376篇
  2011年   414篇
  2010年   219篇
  2009年   176篇
  2008年   318篇
  2007年   309篇
  2006年   272篇
  2005年   227篇
  2004年   229篇
  2003年   191篇
  2002年   199篇
  2001年   59篇
  2000年   44篇
  1999年   55篇
  1998年   37篇
  1997年   27篇
  1996年   24篇
  1995年   28篇
  1994年   13篇
  1993年   26篇
  1992年   35篇
  1991年   37篇
  1990年   35篇
  1989年   30篇
  1988年   24篇
  1987年   28篇
  1986年   20篇
  1984年   35篇
  1983年   17篇
  1982年   20篇
  1981年   20篇
  1980年   22篇
  1979年   23篇
  1978年   13篇
  1974年   11篇
  1973年   18篇
  1972年   11篇
  1970年   14篇
  1968年   11篇
排序方式: 共有5483条查询结果,搜索用时 31 毫秒
111.
112.
113.
114.
115.
Drug product purity and potency are of most significance in the regulatory market as we notice many recalled batches worldwide, particularly in the US and Japan. Olmesartan Medoxomil is an anti-hypertensive drug. The present invention relates to a process for the preparation of Olmesartan Medoxomil with 99.9% purity in an overall 62% yield. The synthesis includes three isolations and one purification with easy plant operations. This process describes the formation and control of each individual impurity in all stages. This process for Olmesartan Medoxomil and its intermediates is competent for industrial production in very short reaction time intervals with an appreciable yield and high purity.  相似文献   
116.
For nearly a decade, silver nanoparticles (AgNPs) have been the most prevalent commercial nanomaterials products widely used in different biomedical applications due to their broad-spectrum antimicrobial activity. However, their poor long-term stability in different environments, namely, pH, ionic strength, and temperature, and cytotoxicity toward mammalian cells has restricted their more extensive applications. Hence, there is urgent need to develop highly biocompatible, non-toxic, and stable silver nanoparticles for wide-ranging environments and applications. In the present study, a simple, sustainable, cost-effective and green method has been developed to prepare highly stable aqueous colloidal silver nanoparticles (AgNPs-EW) using the ovalbumin, ovotransferrin, and ovomucoid of egg-white as reducing and capping agents accomplished under the irradiation of direct sunlight. Then, we evaluated the effects of freezing–drying (lyophilization) and freeze–thaw cycles on the stability of AgNPs-EW in aqueous solution under visual inspection, transmission electron microscopy, and absorbance spectroscopy. In addition, we studied the antibacterial activity against Salmonella typhimurium and Escherichia coli, carried out biocompatibility studies on chicken blood, and tested acute, chronic toxicity in Drosophila melanogaster. The results suggest that AgNPs-EW did not aggregate upon freeze-thawing and lyophilization, thus exhibiting remarkable stability. The antibacterial activity results showed that the AgNPs-EW had the highest antibacterial activity, and the minimum inhibitory concentration (MIC) of AgNPs-EW for E. Coli and S. typhimurium were 4 and 6 μg ml−1, respectively. The biocompatibility study revealed that the AgNPs-EW did not induce any hemolytic effect or structural damage to the cell membranes of chicken erythrocytes up to a concentration of 12 μg ml−1. Similarly, no acute and chronic toxicity was observed on melanization, fecundity, hatchability, viability, and the duration of development in the 1st generation of Drosophila melanogaster at the concentration range of 10 mg L−1 to 100 mg L−1 of AgNPs-EW, and all the flies completed their full developmental cycle. Therefore, the present study successfully demonstrated the green and sustainable preparation of non-toxic AgNPs-EW having good biocompatibility, enhanced colloidal stability, and antibacterial activity. Hence, the synthesized AgNPs-EW could be used for the development of an antimicrobial formulation for controlling microbial infection.

For nearly a decade, silver nanoparticles (AgNPs) have been the most prevalent commercial nanomaterials products widely used in different biomedical applications due to their broad-spectrum antimicrobial activity.  相似文献   
117.
118.
119.
Esophageal squamous papillomatosis is a rare condition associated with human papilloma virus infection and has been complicated by the development of squamous cell carcinoma. Photodynamic therapy using porfimer sodium has been used for the treatment of esophageal cancer but has not been utilized in the treatment of esophageal squamous papillomatosis. We report here the first case of papillomatosis and obstructing squamous cell carcinoma of the esophagus palliated with porfimer sodium photodynamic therapy indicating successful photosensitizer uptake in papilloma-laden tissue. Extensive debulking of papilloma and tumor allowed esophageal recanalization and placement of a self-expanding metal stent for long-term dysphagia palliation. This unique case highlights the combined use of endoscopic techniques for optimal treatment results.  相似文献   
120.
Certain thick FMRFamide-like immunoreactive fibers arising from the ganglion cells of nervus terminalis in the olfactory bulb of Clarias batrachus can be traced centripetally through the medial olfactory tract, telencephalon, lateral preoptic area, tuberal area, and hypothalamohypophysial tract to the pituitary. Following 6 days of bilateral olfactory tract transection, the immunoreactivity in the thick fibers, caudal to the lesion site, was partially eliminated, whereas after 10 and 14 days, it was totally abolished in the processes en route to the pituitary. The results indicate a direct innervation of the pituitary gland by the FMRFamide-like peptide containing fibers of the nervus terminalis.  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