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   17篇
  国内免费   1篇
耳鼻咽喉   1篇
儿科学   3篇
妇产科学   3篇
基础医学   35篇
口腔科学   4篇
临床医学   24篇
内科学   75篇
皮肤病学   22篇
神经病学   5篇
特种医学   55篇
外科学   42篇
综合类   17篇
预防医学   17篇
眼科学   2篇
药学   23篇
肿瘤学   6篇
  2020年   4篇
  2019年   5篇
  2018年   1篇
  2017年   1篇
  2016年   3篇
  2015年   7篇
  2014年   10篇
  2013年   12篇
  2012年   11篇
  2011年   16篇
  2010年   12篇
  2009年   12篇
  2008年   8篇
  2007年   14篇
  2006年   28篇
  2005年   12篇
  2004年   17篇
  2003年   14篇
  2002年   18篇
  2001年   18篇
  2000年   12篇
  1999年   18篇
  1998年   4篇
  1997年   4篇
  1996年   6篇
  1995年   4篇
  1994年   4篇
  1993年   5篇
  1992年   4篇
  1991年   5篇
  1990年   6篇
  1989年   4篇
  1988年   4篇
  1987年   1篇
  1986年   2篇
  1985年   2篇
  1984年   2篇
  1981年   2篇
  1980年   2篇
  1979年   2篇
  1978年   1篇
  1977年   2篇
  1976年   2篇
  1975年   3篇
  1974年   2篇
  1973年   2篇
  1972年   1篇
  1970年   1篇
  1965年   1篇
  1904年   1篇
排序方式: 共有334条查询结果,搜索用时 0 毫秒
1.
2.
3.
High rates of sex and drug risk behaviors have been documented among Latino migrant men in the US. Whether these behaviors were established in the migrants’ home countries or were adopted in the US has not been described and has implications for prevention strategies. Quarterly surveys were conducted to gather information on selected sex and drug risk practices of Latino migrant men who arrived in New Orleans after Hurricane Katrina seeking work. Both kappa scores and McNemar’s tests were performed to determine if practice of these behaviors in home country was similar to practice post-emigration to the US. Female sex worker (FSW) patronage, same sex encounters (MSM), and crack cocaine use was more likely to occur post- rather than pre-emigration. Of those who ever engaged in these selected behaviors, most adopted the behavior in the US (i.e., 75.8 % of FSW patrons, 72.7 % of MSM participants, and 85.7 % of crack cocaine users), with the exception of binge drinking (26.8 %). Men who were living with a family member were less likely to adopt FSW patronage OR = 0.27, CI = 0.10–0.76, whereas men who earned >$465 per week were more likely to adopt crack cocaine use OR = 6.29 CI = 1.29, 30.57. Interventions that facilitate the maintenance of family cohesion and provide strategies for financial management may be useful for reducing sex and drug risk among newly arrived migrants.  相似文献   
4.
Described as asymptomatic and an incidental finding on a plain x-ray film, the “pelvic digit” is a rare congenital anomaly. A 35-year-old man is of a rare symptomatic pelvic digit that warranted surgical excision. Its importance lies in its differentiation from acquired abnormalities due to trauma such as myositis ossificans and avulsion injuries of pelvis. If this entity is kept in mind, unnecessary investigations or interventions can be avoided.  相似文献   
5.
6.

Purpose:

To automatically analyze the time course of collateralization in a rat hindlimb ischemia model based on signal intensity distribution (SID).

Materials and Methods:

Time‐of‐flight magnetic resonance angiograms (TOF‐MRA) were acquired in eight rats at 2, 7, and 21 days after unilateral femoral artery ligation. Analysis was performed on maximum intensity projections filtered with multiscale vessel enhancement filter. Differences in SID between ligated limb and a reference region were monitored over time and compared to manual collateral artery identification.

Results:

The differences in SID correlated well with the number of collateral arteries found with manual quantification. The time courses of ultrasmall (diameter ?0.5 mm) and small (diameter ≈0.5 mm) collateral artery development could be differentiated, revealing that maturation of the collaterals and enlargement of their feeding arteries occurred mainly after the first week postligation.

Conclusion:

SID analysis performed on axial maximum intensity projections is easy to implement, fast, and objective and provides more insight in the time course of arteriogenesis than manual identification. J. Magn. Reson. Imaging 2012;379‐386. © 2011 Wiley Periodicals, Inc.
  相似文献   
7.
8.
Thymic cortical epithelium induces self tolerance   总被引:4,自引:0,他引:4  
Because of its role in positive selection, the ability of cortical epithelium to induce tolerance is controversial. On the one hand, experiments with transplanted thymuses showed that the recipients were functionally tolerant of all the antigens expressed by the cells of those thymuses, including cells of the cortical epithelium. On the other, the keratin 14 (K14) transgenic mouse strain, which expresses MHC class II on cortical epithelium under the control of the K14 promoter, does not seem to be tolerant of the transgenic MHC molecule. Here we tested whether the lack of tolerance in the K14 mouse might be more apparent than real. We found that K14 mice are indeed completely tolerant of K14 cortical thymic epithelium, whereas they remain reactive to tissues that express the same MHC allele under normal genetic control. These results establish the ability of cortical epithelium to induce central tolerance, and impinge on several of the models concerning positive selection of newly developing T cells.  相似文献   
9.
The purpose of this study was to determine the sensitivity and specificity of three different methods of cytomegalovirus (CMV) detection for AIDS patients at risk for CMV retinitis. Patients with CD4(+) counts of <100/microl and negative baseline screening eye examinations were tested for CMV infection by (i) pp65 antigenemia expression in leukocytes, (ii) the Digene Hybrid Capture CMV DNA System, and (iii) the Roche Amplicor Qualitative PCR Test. The incidence of CMV retinitis in our study of 296 patients at the Medical Center of Louisiana-New Orleans HIV Outpatient Clinic was 7. 2 per 100 person-years (a total of 20 episodes in 18 patients from April 1997 to February 1999). Receiver operating characteristic curves were calculated for each assay to determine optimal cutoff points which maximized the sensitivity and specificity of each assay. The sensitivities of the assays compared to the eye examinations were 80% for the pp65 antigenemia assay (cutoff, >0 cell per 1.5 x 10(5) leukocytes), 85% for the Digene assay (cutoff, 1,400 genome copies/ml of whole blood), and 60% for the Amplicor assay. The specificities of the assays were 84, 84, and 87%, respectively. The Digene assay with a cutoff of >/=1,400 genome copies/ml gave optimal sensitivity and specificity and was found to have predictive values equal to those of the more technically cumbersome antigenemia assay.  相似文献   
10.
Urokinase in gastrointestinal tract bleeding   总被引:3,自引:0,他引:3  
Glickerman  DJ; Kowdley  KV; Rosch  J 《Radiology》1988,168(2):375-376
Selective urokinase infusion into the superior mesenteric artery allowed the accurate determination of the site of small bowel bleeding in a patient with recurrent lower gastrointestinal bleeding who bled despite resective surgery and who had negative findings on four angiograms. Fibrinolytic agents are useful in rare cases in which the need for successful and accurate diagnosis outweighs the risks of reactivating the bleeding.  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