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   1612篇
  免费   82篇
  国内免费   4篇
耳鼻咽喉   15篇
儿科学   38篇
妇产科学   32篇
基础医学   242篇
口腔科学   161篇
临床医学   71篇
内科学   297篇
皮肤病学   10篇
神经病学   170篇
特种医学   50篇
外科学   294篇
综合类   14篇
预防医学   116篇
眼科学   20篇
药学   95篇
中国医学   9篇
肿瘤学   64篇
  2023年   8篇
  2022年   20篇
  2021年   40篇
  2020年   29篇
  2019年   22篇
  2018年   39篇
  2017年   32篇
  2016年   45篇
  2015年   59篇
  2014年   51篇
  2013年   93篇
  2012年   145篇
  2011年   148篇
  2010年   81篇
  2009年   77篇
  2008年   126篇
  2007年   133篇
  2006年   100篇
  2005年   102篇
  2004年   82篇
  2003年   83篇
  2002年   68篇
  2001年   3篇
  2000年   5篇
  1999年   4篇
  1998年   8篇
  1997年   6篇
  1996年   6篇
  1995年   4篇
  1994年   7篇
  1993年   2篇
  1992年   4篇
  1991年   4篇
  1990年   5篇
  1989年   4篇
  1987年   3篇
  1986年   2篇
  1985年   2篇
  1984年   5篇
  1980年   4篇
  1978年   3篇
  1976年   3篇
  1975年   2篇
  1973年   3篇
  1972年   6篇
  1969年   5篇
  1968年   2篇
  1964年   2篇
  1959年   2篇
  1946年   1篇
排序方式: 共有1698条查询结果,搜索用时 15 毫秒
1.
2.
Submitral ventricular aneurysm is a thoroughly studied pathology but is not well known due to its rarity. Clinically, it is manifested by symptoms and signs of heart failure, mitral regurgitation and/or ventricular arrhythmias, and may be associated with thromboembolic phenomena and myocardial ischemia due to compression of the coronary arteries by the aneurysm. A rare complication of this type of aneurysm is rupture into the left atrium. Transthoracic echocardiography plays an important role in the definitive diagnosis of this pathology, although the role of transesophageal echocardiography in the evaluation of these patients is less known. We report a case of a submitral ventricular aneurysm complicated by rupture into the left atrium, which was diagnosed by transesophageal echocardiography.  相似文献   
3.
Percutaneous transvenous mitral commissurotomy was performed successfully via the transjugular approach in a patient with severe rheumatic mitral stenosis and obstruction of the inferior vena cava due to prior liver transplantation. This case demonstrates the advantage of the jugular approach in patients with difficult anatomy.  相似文献   
4.
Background: We performed a phase I study of a novel system of complete hepatic venous isolation and extracorporeal chemofiltration in patients with unresectable hepatocellular carcinoma (HCC) to determine (a) whether systemic exposure to doxorubicin could be limited after high-dose hepatic arterial infusion (HAI), and (b) the hepatic maximum tolerated dose (MTD) of doxorubicin. Methods: Ten patients with biopsy-proven HCC were treated with 20-min HAI of doxorubicin (17 total treatments). Two patients were treated with doxorubicin 60 mg/m2, three patients were treated at 90 mg/m2, and five patients received 120 mg/m2. A newly developed dual-balloon vena cava catheter was advanced from the femoral vein, and the balloons were inflated to isolate and capture total hepatic venous outflow. The hepatic venous blood was pumped through extracorporeal carbon chemofilters before return of the blood to the systemic circulation. Results: Peak systemic doxorubicin levels were an average 85.6% lower than were peak prefilter levels (p<0.01). Because all catheters were placed percutaneously and because the chemofiltration markedly limited systemic chemotherapy exposure, patients were discharged 1 day after 16 of the 17 treatments. The hepatic and systemic MTD of doxorubicin in this treatment protocol was 120 mg/m2. Conclusions: This novel system of complete hepatic venous isolation and chemofiltration limits systemic chemotherapy toxicity and will allow use of higher doses of chemotherapeutic agents to treat HCC. The results of this study were presented at the 46th Annual Cancer Symposium of The Society of Surgical Oncology, Los Angeles, California, March 18–21, 1993.  相似文献   
5.
6.
The C-terminal third of intimin binds to its translocated receptor (Tir) to promote attaching and effacing lesion formation during infection with enteropathogenic Escherichia coli (EPEC). We observed that the adherence of EPEC strains to HEp-2 cells was reduced and that actin polymerization was blocked by antibody raised against the C-terminal third of intimin alpha.  相似文献   
7.
IGFII and H19 genes are expressed only from one allele due to genomic imprinting, biallelic expression (loss of imprinting) being associated with the tumorigenic process of different types of tumors. The mechanism responsible for genomic imprinting is not yet determined, although DNA methylation has been considered the main genetic event for an imprinted mark. In the current study, the authors analyzed the imprinting status and expression levels of the IGFII and H19 genes in 27 cases of Juvenile Nasopharyngeal Angiofibroma (JNA) using RFLPs, RT-PCR, and Southern and Northern Blots. The authors found that four out of eight informative cases (50%) for ApaI/IFGII polymorphism showed biallelic expression of IFGII whereas none of the nine informative cases for the polymorphism showed biallelic expression of the H19 gene. Overexpression of IFGII was observed in 8 out of 22 cases (36.4%), and 7 out of 19 cases (36.8%) showed H19 overexpression. Hypomethylation was found only in the H19 gene in six out of eight cases analyzed. Therefore, our results demonstrate that alterations in the IFGII/H19 imprinted region occur in JNA.  相似文献   
8.
Cells of Brucella melitensis strain 16 M were labeled with (32)P. When injected into normal guinea pigs, labeled, viable bacteria were taken up and inactivated in liver and spleen during the 60 min after infection. Both uptake and inactivation increased if brucellae were coated with antibrucella antibody. Neither viability nor radioactivity were lost when labeled brucellae were incubated for 60 min in vitro with normal guinea pig blood, liver homogenates, or in defined medium. Incubation for 12 h with antibrucella rabbit immunoglobulin G similarly was innocuous. Livers were removed from infected animals at various times up to 60 min after injection and were separated into subcellular fractions. The numbers of total (determined by radioactivity measurements) and viable brucellae as well as the acid phosphatase activity in the various fractions were determined. Total bacteria and acid phosphatase activity were progressively transferred from the mitochondrial plus light mitochondrial (M + L) fraction to the nuclear (N) fraction. Viability of brucellae declined more rapidly in the N fraction than in other fractions. Examination of M + L fractions by isopycnic centrifugation showed a decrease in viability of both free brucellae and those in particles. The results indicated the formation of bacteria-containing heterolysosomes which progressively increased in size and in which brucellae were inactivated. The antibrucella activity of phagocytes of guinea pig liver in vivo appeared to be greater than that of peritoneal macrophages from immune rabbits or of bovine leukocytes studied in vitro.  相似文献   
9.
10.
Journal of Public Health - The Comparative Risk Assessment (CRA) framework comprehensively evaluates the impact of exposure to risk factors on health populations using the counterfactual causal...  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