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   316篇
  免费   23篇
  国内免费   2篇
儿科学   9篇
基础医学   63篇
口腔科学   8篇
临床医学   14篇
内科学   37篇
皮肤病学   7篇
神经病学   18篇
特种医学   65篇
外科学   33篇
综合类   3篇
一般理论   1篇
预防医学   8篇
眼科学   3篇
药学   21篇
肿瘤学   51篇
  2021年   4篇
  2020年   5篇
  2019年   2篇
  2018年   3篇
  2017年   4篇
  2016年   3篇
  2015年   7篇
  2014年   3篇
  2013年   3篇
  2012年   16篇
  2011年   14篇
  2010年   11篇
  2009年   12篇
  2008年   15篇
  2007年   11篇
  2006年   13篇
  2005年   8篇
  2004年   12篇
  2003年   11篇
  2002年   8篇
  2001年   4篇
  2000年   7篇
  1999年   8篇
  1998年   13篇
  1997年   19篇
  1996年   12篇
  1995年   5篇
  1992年   11篇
  1991年   8篇
  1990年   2篇
  1989年   7篇
  1988年   7篇
  1987年   11篇
  1986年   7篇
  1985年   11篇
  1984年   4篇
  1983年   5篇
  1982年   2篇
  1981年   4篇
  1980年   2篇
  1976年   5篇
  1975年   2篇
  1974年   3篇
  1973年   7篇
  1972年   1篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
  1968年   1篇
  1967年   1篇
排序方式: 共有341条查询结果,搜索用时 15 毫秒
1.
2.
3.
99mTc-labeled nucleotides as tumor-seeking radiodiagnostic agents.   总被引:1,自引:1,他引:0       下载免费PDF全文
Several lines of human tumor cells in monolayer and soft agar cultures allow permeation of low levels of adenine nucleotides through their plasma membranes, while, in general, untransformed cells do not incorporate adenine nucleotides into their cellular pools without prior degradation of the nucleotides to adenosine. This study determined the uptake of 99mTc-radiolabeled chelated forms of adenine nucleotides, 99mTc-Ap4A (diadenosine 5',5"',P1,P4-tetraphosphate) and 99mTc-ATP chelates as radiodiagnostic agents suitable for the in vivo detection of tumors by radionuclide imaging. Biodistribution studies revealed that Ap4A accumulated preferentially in RT-24 tumors implanted in rats and that V2 carcinoma implanted in rabbits could be readily visualized by in vivo imaging. The biodistribution at various time points showed increased tumor-to-muscle ratios after 99mTc-Ap4A or 99mTc-ATP injections when compared with a nonspecific marker of the extracellular fluid space, 99mTc-labeled diethylenetriaminepentaacetic acid and with an agent known to localize in some tumors, 67Ga-labeled citrate. Studies of ectoenzymatic activities of virus-transformed animal cells and their untransformed counterparts in monolayer cultures showed marked decreases in the ectoenzymatic activities that degrade Ap4A in the transformed cells. Incorporation of en bloc [3H, 32P]Ap4A into cellular acid-soluble nucleotide pools of certain transformed cells was observed. Normal untransformed cells incorporated the radioactive label only by prior degradation to [3H]adenosine and 32Pi.  相似文献   
4.
A skeletal seeking radiopharmaceutical labeled with a long-lived radionuclide was developed to evaluate regional bone formation and its subsequent resorption. The agent is [phosphonate (phenylmethylene hydroxy) bis]-I-125 or I-125 PA. Tissue distribution studies in mice (N=16) showed approximately 40% of the administered dose to be retained by the skeleton up to 336 hours post IV injection. The percentage of the dose accumulated by the thyroid gland remained at less than 0.5%, indicating minimal deiodination of the I-125 PA. Whole body retention studies in the same species revealed a triexponential release pattern with the longest component comprising 33% of the dose with a biologic half-life of 962 days. A fractured rat tibia model was studied with I-125 PA and Tc-99m MDP. Chronic loss of the I-125 PA relative to normal tibia was quantitated: five days (62.8%); 30 days (47.4%). Concomitant increased uptake of the Tc-99m MDP was observed at the fracture site relative to normal: five days (186%); 30 days (1,041%). The above data suggest that I-125 PA can be utilized to measure acute bone formation and chronic resorption.  相似文献   
5.
A comprehensive mutational scanning test for the p53 coding region based on multiplex PCR and two-dimensional DNA electrophoresis was designed and evaluated. In a 2-step multiplex PCR, the p53 coding region (exons 2-11) was amplified as a single 8646-bp fragment by long- distance PCR in step one. This fragment served as a template for the subsequent co-amplification of the individual exons in two multiplex groups in step two. The multiplex products were then separated, first on the basis of size in non-denaturant polyacrylamide gels and then on the basis of sequence by denaturing gradient gel electrophoresis (DGGE). Primers for optimal PCR, melting behavior and 2-D gel distribution were designed using a recently developed computer program. The resulting two-dimensional gene scanning (TDGS) test was evaluated by screening, in a blinded fashion, 29 coded DNA samples from Li- Fraumeni syndrome patients with previously identified germline mutations. All mutations were correctly detected. This assay provides an accurate, cost-effective and non-radioactive method for simultaneous mutational scanning of all p53 coding exons.   相似文献   
6.
7.
Journal of Neurology - In Italy, lockdown due to COVID-19 health emergency started on March 10 and partially ended on May 3rd, 2020. There was a significant increase of psychological distress and...  相似文献   
8.
Diaphragmatic lesions are usually congenital bronchogenic cysts. A patient with a known diaphragmatic cyst presented with new onset right upper quadrant pain. Repeat imaging showed enlargement of the cyst, the CA19–9 cancer marker was raised at 312iu/ml (normal: <27iu/ml) and positron emission tomography combined with computed tomography showed focally increased uptake in the cystic wall. In view of symptoms and risk of neoplasia, the lesion was excised. Histology showed a benign epidermoid cyst. Features falsely suggesting neoplasia have been reported previously with benign splenic cysts but not with a benign diaphragmatic epidermoid cyst.  相似文献   
9.
We report a case of a celiac trunk stenting using a steerable guiding catheter, to fix a residual endoleak following fenestrated endovascular repair (FEVAR) of a thoraco‐abdominal aortic aneurysm (TAAA). A systematic search of the literature about the use of steerable catheters was also performed on Pubmed according to the PRISMA Guidelines, including all papers in which the device was used for in vivo endovascular procedures. In our case report, the patient had undergone a failed attempt of cannulation due to the presence of a severely angulated and stenosed ostium of the vessel. A steerable catheter was then used to fix the residual endoleak. The search of the Literature retrieved 544 papers. Of them, 13 met the inclusion criteria and were therefore assessed. The use of steerable sheaths and catheters was reported as effective and safe for the cannulation of 157 target vessels in 131 endovascular procedures, with a success rate of 95.5% and no complications. The use of a steerable guiding catheter in our experience was safe and effective for the selective cannulation of a severely stenosed and angulated celiac trunk, to correct a residual endoleak after FEVAR for TAAA. Steerable catheters could be useful tools for the selective cannulation of target vessels with a challenging ostium.  相似文献   
10.
We have recently demonstrated that bone sialoprotein (BSP), a bone-matrix protein involved in hydroxyapatite crystal formation, is ectopically expressed in human breast cancers. We explored a possible association between expression of BSP in primary breast cancer and patients' survival. We analyzed BSP expression in 454 breast-cancer patients by immunohistochemistry on archival paraffin-embedded material using an anti-BSP polyclonal antibody. BSP expression was correlated to survival, tumor size, axillary lymph-node status and first site of distant metastasis. Of the breast cancers analyzed, 89% expressed detectable amounts of BSP. We found a statistical association between expression of BSP and poor prognosis as indicated by survival curves analyzed using the log rank and the Gehan methods. BSP expression was significantly higher in breast-cancer patients with axillary lymph-node involvement. Interestingly, survival of patients with positive lymph nodes but BSP-negative tumors was significantly higher than that of patients with no lymph-node involvement but BSP-positive cancers. The frequency of bone metastases was higher in the group of patients with BSP-positive tumors (22%) than in the group with BSP-negative cancers (7%). There was a significant increase in the incidence of lung metastases in patients whose tumors were negative for BSP. Our data show that bone sialoprotein expression in breast cancer is associated with poor prognosis. BSP detection also appears to be a valuable marker with which to identify, among the lymph-node-negative patients, those who have high risk of disease progression. © 1996 Wiley-Liss, Inc.  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