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   3680篇
  免费   168篇
  国内免费   22篇
耳鼻咽喉   26篇
儿科学   109篇
妇产科学   41篇
基础医学   434篇
口腔科学   105篇
临床医学   273篇
内科学   1065篇
皮肤病学   59篇
神经病学   271篇
特种医学   159篇
外科学   553篇
综合类   27篇
一般理论   1篇
预防医学   160篇
眼科学   26篇
药学   236篇
中国医学   5篇
肿瘤学   320篇
  2022年   30篇
  2021年   79篇
  2020年   34篇
  2019年   58篇
  2018年   63篇
  2017年   38篇
  2016年   63篇
  2015年   62篇
  2014年   77篇
  2013年   115篇
  2012年   160篇
  2011年   204篇
  2010年   102篇
  2009年   122篇
  2008年   191篇
  2007年   195篇
  2006年   176篇
  2005年   164篇
  2004年   153篇
  2003年   145篇
  2002年   158篇
  2001年   104篇
  2000年   115篇
  1999年   105篇
  1998年   58篇
  1997年   23篇
  1996年   28篇
  1995年   26篇
  1994年   18篇
  1993年   21篇
  1992年   83篇
  1991年   78篇
  1990年   81篇
  1989年   68篇
  1988年   61篇
  1987年   67篇
  1986年   67篇
  1985年   61篇
  1984年   47篇
  1983年   32篇
  1982年   16篇
  1979年   46篇
  1977年   27篇
  1976年   16篇
  1975年   24篇
  1974年   26篇
  1973年   20篇
  1972年   23篇
  1971年   21篇
  1969年   18篇
排序方式: 共有3870条查询结果,搜索用时 359 毫秒
1.
2.
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   
3.
4.
5.
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   
6.
7.
8.
The CA-50 enzyme immunoassay kit (EIA kit) that has been developed with the use of C-50 monoclonal antibody prepared by L. Lindholm et al. was evaluated for diagnosis of human cancer. The levels of CA-50 in the sera were determined using this kit supplied from Mitsui Pharmaceuticals, Inc. Co. in 759 healthy donors, 728 patients with benign disease and 1,263 untreated patients with cancer. A CA-50 concentration of 40 U/ml of serum was used as the cut-off value. Patients with pancreatic cancer and patients with bile duct cancer had high positive incidence of 75% and 68%, respectively, compared with a low positive incidence of under 40% in patients with other cancers. On the other hand, positive rates in patients with benign disease were as low as 13%. Comparison of the serum levels of CA-50 with CA19-9 in the same samples did not exhibit complete positive correlation in patients with pancreatic cancer, patients with bile duct cancer and patients with liver cancer. These findings indicated that C-50 antibody reacted with two epitopes of CA19-9 and sialosyllactotetraose. From the above results, the usefulness of CA-50 as a tumor marker for pancreatic cancer and bile duct cancer was recognized with this EIA kit.  相似文献   
9.
Farmer's lung disease is one type of hypersensitivity pneumonitis (HP) in dairy farmers, and is usually caused by Micropolyspora faeni (Mf). It has been reported that the positive rate of precipitin antibody to Mf in smoking dairy farmers is one-eighth to one-half of that in nonsmoking dairy farmers. To clarify the mechanism of this phenomenon, by using an experimental HP model in rabbits, we investigated 1) the effects of short (5 weeks) and long (20 weeks)-term cigarette smoke exposure on the antibody formation, 2) the effects of 30 weeks of smoke exposure on the accessory cell function of alveolar macrophages (AM). Smoking exerted variable influences on antibody production, depending on the duration of smoke exposure, and we confirmed that long-term smoke exposure had suppressive effects. In addition AM from smoked rabbits suppressed lymphoproliferative response to autologous spleen cells. It was concluded that in this experimental HP, smoking affects the functions of both AM and lymphocytes, and that it suppresses antibody production as long as the smoke exposure continues.  相似文献   
10.
In seven patients undergoing right hemicolectomy for benign or malignant diseases, latero-lateral end anastomoses were made using stapling devices, LS (linear stapler) and GIA (gastrointestinal anastomosis). As no complications directly related to the anastomosis occurred, we conclude that anastomosis using stapling devices for right hemicolectomy is a safe and rapid procedure.  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