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   6858篇
  免费   362篇
  国内免费   57篇
耳鼻咽喉   106篇
儿科学   150篇
妇产科学   92篇
基础医学   807篇
口腔科学   136篇
临床医学   405篇
内科学   2077篇
皮肤病学   96篇
神经病学   561篇
特种医学   233篇
外科学   1315篇
综合类   33篇
一般理论   1篇
预防医学   201篇
眼科学   65篇
药学   364篇
中国医学   8篇
肿瘤学   627篇
  2023年   48篇
  2022年   79篇
  2021年   167篇
  2020年   98篇
  2019年   154篇
  2018年   168篇
  2017年   122篇
  2016年   168篇
  2015年   147篇
  2014年   226篇
  2013年   261篇
  2012年   420篇
  2011年   446篇
  2010年   223篇
  2009年   227篇
  2008年   389篇
  2007年   409篇
  2006年   376篇
  2005年   366篇
  2004年   333篇
  2003年   321篇
  2002年   304篇
  2001年   127篇
  2000年   141篇
  1999年   149篇
  1998年   102篇
  1997年   57篇
  1996年   49篇
  1995年   42篇
  1994年   44篇
  1993年   35篇
  1992年   98篇
  1991年   94篇
  1990年   87篇
  1989年   73篇
  1988年   69篇
  1987年   74篇
  1986年   72篇
  1985年   66篇
  1984年   52篇
  1983年   35篇
  1982年   21篇
  1979年   52篇
  1977年   29篇
  1975年   24篇
  1974年   27篇
  1973年   20篇
  1972年   23篇
  1971年   21篇
  1969年   19篇
排序方式: 共有7277条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
Experimental gene therapy is a promising strategy to prevent ischemia-reperfusion (I/R) injury and allograft rejection after lung transplantation, and methods will eventually be needed to characterize pulmonary transgene expression in vivo in humans. Therefore, we studied positron emission tomography (PET) as a means of performing in vivo molecular imaging in rodent models of lung transplantation. Rats were transfected endotracheally with adenovirus encoding a fusion gene of a mutant Herpes simplex virus-1 thymidine kinase and the green fluorescent protein gene (the former serving as an imaging reporter gene). Twenty-four hours after transfection, lungs were transplanted in groups representing normal transplantation, I/R injury and acute allograft rejection. Imaging was obtained either 24 h after transplantation to study reperfusion injury or 4 days after transplantation to study graft rejection. After imaging, lungs were excised and analyzed for thymidine kinase activity. Imaging detected transgene expression in transplanted lungs even in the presence of acute rejection or I/R injury. The PET imaging signal correlated with in vitro lung tissue assays of thymidine kinase activity (r(2) = 0.534). Thus, noninvasive molecular imaging with PET is a feasible, sensitive and quantitative method for characterizing pulmonary transgene expression in experimental lung transplantation.  相似文献   
5.
Summary Total body bone mineral (TBBM) content in rats was measured by dual photon absorptiometry (DPA). TBBM showed significant increases over 4 weeks in control groups with significant bone loss over the same time in prednisolone-injected rats on low calcium feed. Daily injections of calcitonin significantly reduced loss of bone mass. Both prednisolone- and prednisolone-calcitonin-injected groups showed significantly elevated serum alkaline phosphatase with the prednisolone-calcitonin group also exhibiting elevated serum calcium and phosphate levels, confirming the impact of the experimental protocol. TBBM measured by DPA in all groups correlated well (r=0.928,P<0.001 n=20) with the total ash weight suggesting that the method reflects total skeletal mineral content in the small animal. TBBM measurement by DPA proves well-suited to monitoring bone mineral in a small animal experimental setting.  相似文献   
6.
7.
8.
Skull metastasis of thyroid carcinoma is rare. The majority of skull metastases of thyroid carcinoma are of the follicular subtype, rather than thyroid papillary carcinoma. In this report, a 55-year-old woman with skull metastasis from thyroid papillary carcinoma is presented. The metastatic lesion of the skull was hypervascular and osteolytic, and the bleeding was profuse during resection. There have been only four reports of skull metastasis from thyroid papillary carcinoma. The mean period from the initial diagnosis of thyroid carcinoma until the detection of skull metastasis is 23.3 years, whereas in this patient, it was about 2 years. Therefore, in the clinical course of thyroid papillary carcinoma, skull metastasis should be considered, and the patient should be meticulously followed up.  相似文献   
9.
Five hemiplegic patients with intractable epilepsy were studied with transcranial magnetic stimulation (TMS) before and after various surgical treatments. These patients had unilateral widespread cerebral lesions acquired at various times, including congenital, infantile and childhood injury. Motor evoked potentials (MEPs) of the abductor pollicis brevis (APB) muscles were simultaneously recorded on both sides following TMS of the motor cortex in the respective hemisphere using a figure-8 or circular coil. In all patients with congenital disease, the abolition of motor function in the affected hemisphere was estimated by magnetic MEPs, and the hemiplegia did not deteriorate after functional hemispherectomy (HS) was performed in two of them. In two patients with acquired disease, HS was not performed because it was shown by magnetic maps that the motor function in the affected hemisphere remained. Furthermore, it was shown by electric MEPs using subdural electrodes that a patient who had had encephalitis in early childhood had a reorganised motor area in the parietal cortex of the affected hemisphere. The present findings indicate that magnetic MEPs are a very useful non-invasive method of assessing whether the motor area in the affected hemisphere can be resected in hemiplegic patients with intractable epilepsy.  相似文献   
10.
This report presents the effect of repeated heating every 24 hrs using bleomycin (BLM) which, although seemingly contrary to the usual agreement that hyperthermia should be carried out with a long interval due to thermotolerance, holds many possibilities. FM3A cells on the foot pad of C3H mouse were immersed in a heated water bath at 43 and 44°C for 30 min. The effect of repeated heating was appreciated by an improved growth curve and 50 day survival compared to mice which received heating twice with a 96-hr interval. Repeated heating every 24 hrs 5 times with BLM suppressed tumor growth significantly as compared to heating twice with a 96-hr interval without BLM. The longest survival time was obtained by the repeated heating with BLM among all protocols. There is therefore a good possibility that more effective results could be obtained clinically by repeated heating over a short period.  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