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   37383篇
  免费   1818篇
  国内免费   168篇
耳鼻咽喉   496篇
儿科学   683篇
妇产科学   435篇
基础医学   4668篇
口腔科学   1160篇
临床医学   2585篇
内科学   8689篇
皮肤病学   778篇
神经病学   3521篇
特种医学   1872篇
外国民族医学   1篇
外科学   5642篇
综合类   145篇
一般理论   6篇
预防医学   1217篇
眼科学   755篇
药学   2393篇
中国医学   74篇
肿瘤学   4249篇
  2023年   188篇
  2022年   354篇
  2021年   632篇
  2020年   358篇
  2019年   464篇
  2018年   588篇
  2017年   501篇
  2016年   639篇
  2015年   607篇
  2014年   805篇
  2013年   990篇
  2012年   1625篇
  2011年   1652篇
  2010年   1024篇
  2009年   884篇
  2008年   1566篇
  2007年   1838篇
  2006年   1677篇
  2005年   1628篇
  2004年   1664篇
  2003年   1559篇
  2002年   1610篇
  2001年   1337篇
  2000年   1432篇
  1999年   1295篇
  1998年   502篇
  1997年   416篇
  1996年   396篇
  1995年   342篇
  1994年   339篇
  1993年   315篇
  1992年   1005篇
  1991年   874篇
  1990年   835篇
  1989年   822篇
  1988年   782篇
  1987年   774篇
  1986年   677篇
  1985年   633篇
  1984年   432篇
  1983年   355篇
  1979年   300篇
  1978年   203篇
  1977年   179篇
  1974年   193篇
  1973年   168篇
  1972年   162篇
  1971年   183篇
  1970年   156篇
  1969年   176篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
We report a case of a diaphragmatic hernia after a heart transplant operation. A 43-year-old woman, who underwent orthotropic heart transplantation for hypertrophic cadiomyopathy two year earlier, presented with vomiting and epigastric pain. A computed tomography scan showed that the stomach and transverse colon were dislocated in the left thoracic cavity. We diagnosed left diaphragmatic hernia incarceration and performed laparoscopic repair of the diaphragmatic hernia. A 12 × 8 cm diaphragmatic defect was found intraoperatively on the ventrolateral aspect of the left diaphragm, and the stomach with volvulus had herniated into the thorax through the defect. The hernia was considered to be iatrogenic. The diaphragmatic defect was large, and the diaphragm was thinning. We closed the defect by mesh repair. Laparoscopic mesh repair of the diaphragmatic hernia could be performed safely and with minimal invasiveness.  相似文献   
4.
5.
We prospectively evaluated the effectiveness of contrast-enhanced ultrasonography (CEUS) for differentiation of benign versus malignant portal vein thrombosis (PVT). We studied a total of 43 patients with chronic liver disease, hepatocellular carcinoma-suggestive nodules and confirmed PVT, in whom the nature of the PVT was confirmed by follow-up imaging (US, computed tomography and/or magnetic resonance imaging) performed up to 6 mo after CEUS. PVT was assessed by US, Doppler US and CEUS with respect to vessel wall disruption and/or invasion, color Doppler vascularization, pulsed Doppler vascularization pattern and CEUS enhancement and vascularization pattern, and thrombi were classified as benign or malignant based on these findings. Follow-up studies revealed malignant PVT in 22 of the 43 patients (51%) and benign PVT in 21 patients (49%). CEUS findings were consistent with follow-up studies in 41 of the 43 patients (95%), with κ?=?0.903 (p < 0.0001), sensitivity?=?91% and specificity?=?100%, indicating that CEUS can be confidently used to differentiate benign from malignant portal vein thrombosis in the setting of chronic liver disease.  相似文献   
6.
7.
Background: Gastrointestinal stromal tumors (GIST) are one of the most common mesenchymal tumors of the gastrointestinal tract. GIST are defined by positive immunohistochemical staining for KIT or CD34 and thus are generally diagnosed after surgery. Because small GIST are rarely diagnosed before surgery, the clinical course of these small tumors is not clear. The aim of the present study was to follow changes in size and configuration of small GIST that were pathologically confirmed using endoscopic ultrasonography‐guided fine‐needle aspiration biopsy (EUS‐FNAB). Methods: Between July 1997 and December 2003, 16 tumors in 16 patients (10 men and 6 women) with an immunohistochemical diagnosis of GIST were regularly followed in our hospital. The median patient age when EUS‐FNAB was performed was 62 years (range 26–82 years) and the median follow‐up period was 4.9 years (range 0.5–9.6 years). Results: Fourteen tumors showed no remarkable changes in size and shape during follow up compared with the initial diagnosis. Two tumors enlarged: one tumor approximately doubled its diameter in 8 years and the other tumor increased from 1.8 cm at diagnosis to up to 10 cm after only 2 years. Doubling time of the latter tumor was calculated as 3.1 months. Conclusions: We conclude that EUS‐FNAB might be a good modality for final diagnosis of GIST without surgery, and that GIST without rapid growth on follow up can be endoscopically followed.  相似文献   
8.
From April 1989 to December 2004, we performed liver biopsy on 475 patients and obtained biopsy proven 35 cases of non-alcoholic fatty liver. Among them, 18 cases were diagnosed as non-alcoholic steatohepatitis (NASH). During the last three years, we have tried to detect NASH using ultrasonography and elevated value of serum ferritin (> 300 ng/ml). All of the eligible 7 cases biopsied during the course were diagnosed as NASH. In these 7 cases, ALT levels improved after the body weight loss accompanied by the parallel decrease of serum ferritin levels. Measurement of serum ferritin is useful in the detection of NASH but the normal value of ferritin cannot rule out the possibility of NASH.  相似文献   
9.
Carbon monoxide (CO), a byproduct of heme catalysis, was shown to have potent cytoprotective and anti-inflammatory effects. In vivo recipient CO inhalation at low concentrations prevented ischemia/reperfusion (I/R) injury associated with small intestinal transplantation (SITx). This study examined whether ex vivo delivery of CO in University of Wisconsin (UW) solution could ameliorate intestinal I/R injury. Orthotopic syngenic SITx was performed in Lewis rats after 6 h cold preservation in control UW or UW that was bubbled with CO gas (0.1-5%) (CO-UW). Recipient survival with intestinal grafts preserved in 5%, but not 0.1%, CO-UW improved to 86.7% (13/15) from 53% (9/17) with control UW. At 3 h after SITx, grafts stored in 5% CO-UW showed improved intestinal barrier function, less mucosal denudation and reduced inflammatory mediator upregulation compared to those in control UW. Preservation in CO-UW associated with reduced vascular resistance (end preservation), increased graft cyclic guanosine monophosphate levels (1 h), and improved graft blood flow (1 h). Protective effects of CO-UW were reversed by ODQ, an inhibitor of soluble guanylyl cyclase. In vitro culture experiment also showed better preservation of vascular endothelial cells with CO-UW. The study suggests that ex vivo CO delivery into UW solution would be a simple and innovative therapeutic strategy to prevent transplant-induced I/R injury.  相似文献   
10.
We report a case of biliary cystadenocarcinoma which recurred 41 months postoperatively. A 60-year-old woman was admitted for further examination of multiple metastatic tumors and a large amount of ascites. Systemic administration of 5FU and CDDP caused her CEA level to decrease gradually and abdominal computed tomography revealed considerable reduction of the metastatic tumors and ascites. Since her general condition had improved, chemotherapy was continued in the outpatient clinic.  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