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   1716篇
  免费   56篇
  国内免费   7篇
耳鼻咽喉   20篇
儿科学   131篇
妇产科学   28篇
基础医学   250篇
口腔科学   21篇
临床医学   68篇
内科学   414篇
皮肤病学   94篇
神经病学   53篇
特种医学   36篇
外科学   222篇
综合类   55篇
一般理论   1篇
预防医学   85篇
眼科学   8篇
药学   165篇
中国医学   15篇
肿瘤学   113篇
  2023年   11篇
  2022年   16篇
  2021年   29篇
  2020年   23篇
  2019年   28篇
  2018年   47篇
  2017年   39篇
  2016年   38篇
  2015年   54篇
  2014年   46篇
  2013年   83篇
  2012年   144篇
  2011年   129篇
  2010年   73篇
  2009年   87篇
  2008年   91篇
  2007年   85篇
  2006年   107篇
  2005年   113篇
  2004年   90篇
  2003年   78篇
  2002年   69篇
  2001年   11篇
  2000年   17篇
  1999年   20篇
  1998年   16篇
  1997年   15篇
  1996年   10篇
  1995年   9篇
  1994年   13篇
  1992年   16篇
  1991年   14篇
  1990年   13篇
  1989年   16篇
  1988年   9篇
  1987年   12篇
  1986年   8篇
  1985年   5篇
  1984年   14篇
  1983年   6篇
  1982年   5篇
  1979年   5篇
  1977年   7篇
  1976年   6篇
  1975年   5篇
  1974年   6篇
  1973年   5篇
  1970年   4篇
  1969年   3篇
  1968年   3篇
排序方式: 共有1779条查询结果,搜索用时 15 毫秒
21.
An efflux pump inhibitor, SK-20 (5-(3,4-methylenedioxyphenyle)-4 ethyl-2E,4E-pentadienoic acid piperidide), was assessed for its toxicity at three different pharmacological profiles: acute, sub-acute and general pharmacology with pharmacokinetics. In acute study, the SK-20 was found safe up to a dose of 2000 mg/kg (b.wt.); and at sub-acute, dosages of 50 and 100 mg/kg (b.wt.) were found to be safe. However, dosages of 200 mg or above per kg (b.wt.) showed some morphological alterations in cellular architecture of both liver and kidneys in both sexes, viz., mild vascular congestion along with sporadic hemorrhages and infiltration into renal and hepatic parenchyma by mononucleate cell. General pharmacological studies did not result into any alterations in analgesic, convulsions, rectal temperatures and in the rhythm or the rate of the intestinal motility or the secretion of the bile. While the respiratory and the cardiac rate remained normal, the only parameter to show was the blood pressure, which at all the doses tested, showed a tendency toward reduction. Characteristically, the SK-20 at all doses influenced pentobarbital-induced hypnosis positively and negatively to spontaneous motor activity in a dose dependent manner. Pharmacokinetics of SK-20 revealed it to have retention time at 10.2 min and half life 2.47 h.  相似文献   
22.
23.
24.
Estimation of spatial plant distribution of a large area is very tedious and time consuming assignment. In this regard, herbaria of the world are supposed to be the excellent repositories of the plant collections for reference purpose. But many repositories of the world do not have the associated information of the collections and thus it becomes a muddle for future studies. The aim of this study is to know the extent of this mess. Therefore, spatial distribution of Berberidaceae members in NW Himalaya was studied through available herbarium data in three herbaria at Department of Botany, University of Jammu, Janaki Ammal Herbarium, Indian Institute of Integrative Medicine and Herbarium, Department of Botany, Punjabi University. It is observed that the collected specimens in aforesaid herbaria are correctly identified; but simultaneously, proper collection sites and collection dates are not mentioned for some specimens. Therefore, it is difficult to recollect the species. This is also revealed that India harbours 04 genera (Berberis, Epimedium, Mahonia and Nandina) and 22 species of the Berberidaceae, out of which 02 (Berberis and Mahonia) are reported from the NW Himalaya.  相似文献   
25.
26.
A number of physiological changes occur during pregnancy and amongst them, audiological and nasal changes are quite significant. These are mainly due to the changing levels of sex hormones and return to normal once the pregnancy is over. This study was conducted to document these changes. Forty (pregnant 40 and non-pregnant 40) consenting subjects in age group of 20–35 years were assigned to test and control groups. They underwent complete ENT and Obstetric examination. In test group Pure Tone Audiometry was performed in all trimesters of pregnancy and within 3 months of delivery. The subjects in the control group underwent pure tone audiometry only once. The nasal patency was measured by Gertner’s plate method. Results from each trimester and postpartum period were compared. A highly significant difference in pure tone thresholds was observed at frequencies ranging from 125 to 1000 Hz (P < 0.001). However frequencies higher than 1000 Hz demonstrated no significant correlation. Nasal patency as measured by mean area of vapour condensation in all trimesters and control groups was highly significant (P < 0.001). The results of this study confirm that these changes occur in the first trimester and gradually improve during the subsequent trimesters returning to normal in post partum period. However number of pregnancies bear no relationship with these changes  相似文献   
27.
Cardiac transplantation is indicated for patients with end-stage cardiomyopathy secondary to cardiac sarcoidosis. Although rare, recurrent disease has been reported in two cases. The current report presents a case of recurrent cardiac sarcoidosis in a patient 45 months postorthotopic heart transplantation and 40 months following reactivation of latent Mycobacterium tuberculosis infection. The patient was the first to have recurrent disease following an infection that has been proposed to be involved in its pathogenesis. The patient’s interval between transplant and recurrence is the longest reported to date.  相似文献   
28.
29.
Arterial chronic total occlusions (CTO) are a common and clinically relevant problem in patients with coronary artery disease. Percutaneous coronary intervention (PCI) success rates in a wide range of CTO are low, primarily due to inability of guidewire crossing. The pathophysiology of CTO is poorly understood and limits our ability to introduce innovative therapies. Recent studies from our laboratory have suggested that microvessel formation within arterial CTO is a complex process with temporal and regional differences. Moreover, there is evidence from pilot studies that the presence of either microvessels or the particular extracellular matrix environment in the adjacent perivascular tissue can facilitate guidewire crossing and successful PCI. Currently, studies are underway in our experimental CTO model to delineate the pathophysiology of microvessel formation in CTO and its potential role in PCI.  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