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   2808篇
  免费   174篇
  国内免费   22篇
耳鼻咽喉   60篇
儿科学   132篇
妇产科学   120篇
基础医学   234篇
口腔科学   129篇
临床医学   265篇
内科学   669篇
皮肤病学   76篇
神经病学   250篇
特种医学   116篇
外科学   500篇
综合类   36篇
一般理论   1篇
预防医学   89篇
眼科学   93篇
药学   106篇
中国医学   2篇
肿瘤学   126篇
  2024年   1篇
  2023年   35篇
  2022年   45篇
  2021年   110篇
  2020年   94篇
  2019年   103篇
  2018年   103篇
  2017年   106篇
  2016年   111篇
  2015年   140篇
  2014年   148篇
  2013年   183篇
  2012年   222篇
  2011年   206篇
  2010年   139篇
  2009年   117篇
  2008年   217篇
  2007年   211篇
  2006年   179篇
  2005年   181篇
  2004年   133篇
  2003年   95篇
  2002年   41篇
  2001年   25篇
  2000年   16篇
  1999年   15篇
  1998年   6篇
  1997年   4篇
  1996年   4篇
  1995年   1篇
  1993年   2篇
  1992年   2篇
  1991年   1篇
  1990年   2篇
  1988年   2篇
  1987年   2篇
  1986年   1篇
  1909年   1篇
排序方式: 共有3004条查询结果,搜索用时 15 毫秒
1.
Chronic myeloproliferative disorders such as polycythemia vera (PV), essential thrombocytosis (ET), and idiopathic myelofibrosis arise from clonal proliferation of neoplastic stem cells in the bone marrow. Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases that have potential to degrade all types of extracellular matrix (ECM) and also play a role in remodeling of the ECM. It is known that MMPs play a role in bone marrow remodeling.The primary goal of our study is to explore the relationship between chronic myeloproliferative diseases and some of MMP gene polymorphisms. The demonstration of a relationship will help to understand whether these polymorphisms may be a potential early diagnosis marker of the diseases.Patients were selected from outpatient clinics of Turgut Ozal University Hospital, Ankara, Turkey, between December 2010 and May 2011. Twenty-eight patients that previously diagnosed and followed-up with PV, 17 with secondary polycythemia (SP), and 12 with ET were enrolled in the study, along with a control group of 22 healthy people.DNA was isolated from peripheral blood. Using polymerase chain reaction–restriction fragment length polymorphism method, MMP2 and MMP9 gene polymorphisms were analyzed with agarose gel electrophoresis. There was a statistically significant difference between the study groups and the control group in terms of Gln279Arg polymorphisms rates of MMP9. The highest MMP9 Gln279Arg polymorphism rate was observed in the ET group. But nobody from the control group had polymorphic MMP9. There was no statistically significant difference between the groups in terms of MMP2-735 C > T polymorphism rates.In conclusion, MMP9 gene Gln279Arg polymorphism was associated with ET, SP, and PV diseases. Hence, we believe that these gene polymorphisms may play a role in the mechanism of bone marrow fibrosis and may be a factor that increases the risk of thrombosis. Illumination of the molecular basis of the relationship between MMP-thrombosis and MMP-fibrosis provides a better understanding of the pathophysiology of PV and ET diseases and will allow new approaches to diagnosis and treatment.  相似文献   
2.
3.
4.
5.
6.
This study aimed to determine the effect of acute brucellosis on the auditory system. Forty-two patients with acute brucellosis were evaluated clinically, and with serological and audiological tests, before and after treatment. Hearing threshold averages were calculated at 11 different frequencies (250-8000 Hz) of the auditory airway, and statistical analysis was performed. The average hearing thresholds were > 20 dB, with standard audiometry at 6000-8000 Hz, and < 20 dB at all other frequencies. After treatment, the average auditory threshold decreased to < 20 dB at 6000-8000 Hz (p < 0.0001). Pure-tone hearing thresholds were improved at all frequencies after treatment, with statistically significant differences at all frequencies except 12,000, 14,000 and 16 000 Hz (p < 0.05). There was no permanent hearing loss caused by acute brucellosis, and hearing thresholds were restored after treatment. It was concluded that acute brucellosis affects the auditory system, especially at high frequencies, and that patients with all forms of brucellosis should be evaluated for hearing loss.  相似文献   
7.
A rare case of thymic carcinoma with multiple brain metastasis is reported. In our extensive review of the literature only six of 30 reports of intracranial thymoma metastasis describe multiple metastases. A 38-year-old man presented with signs of raised intracranial pressure that had began 15 days previously. Cranial MRI revealed over 70 cystic lesions in the supra and infratentorial regions. Stereotactic biopsy was planned. On the second day of his admission he deteriorated and died the following day. The autopsy revealed a mass in the mediastinum. In the brain parenchyma were multiple cystic lesions between 0.5 and 3 cm in diameter. Histopathologically they were diagnosed as metastases from the thymic carcinoma. The mean survival with a single brain metastasis is approximately 256 days, whereas with multiple brain metastases it is only 64 days, thus treatment of this tumor demands prompt surgery whenever possible and optimal adjuvant therapy.  相似文献   
8.
9.
Brucellosis is a multisystemic disease that rarely leads to a fatal outcome. While reticuloendothelial system organs are mostly affected, peritonitis and posthepatitic cirrhosis are also complications of brucellosis, though they are very rare. Brucella spp. can also trigger immunological reactions. We report a case of brucellosis with peritonitis, renal failure and leucocytoclastic vasculitis caused by Brucella melitensis, which led to a fatal outcome. Brucellosis should be considered in the differential diagnosis of vasculitic diseases, especially in endemic areas.  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