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   387篇
  免费   36篇
  国内免费   1篇
耳鼻咽喉   1篇
儿科学   1篇
妇产科学   4篇
基础医学   33篇
口腔科学   1篇
临床医学   25篇
内科学   26篇
皮肤病学   2篇
神经病学   7篇
特种医学   88篇
外科学   116篇
综合类   8篇
一般理论   1篇
预防医学   22篇
眼科学   14篇
药学   7篇
肿瘤学   68篇
  2021年   5篇
  2020年   4篇
  2019年   3篇
  2018年   8篇
  2017年   8篇
  2015年   5篇
  2014年   12篇
  2013年   10篇
  2012年   17篇
  2011年   19篇
  2010年   12篇
  2009年   8篇
  2008年   12篇
  2007年   14篇
  2006年   16篇
  2005年   12篇
  2004年   14篇
  2003年   10篇
  2002年   7篇
  2001年   13篇
  2000年   10篇
  1999年   9篇
  1998年   3篇
  1997年   4篇
  1996年   9篇
  1995年   5篇
  1994年   4篇
  1993年   5篇
  1992年   11篇
  1991年   11篇
  1990年   10篇
  1989年   15篇
  1988年   10篇
  1987年   12篇
  1986年   10篇
  1985年   12篇
  1984年   7篇
  1983年   6篇
  1982年   3篇
  1980年   3篇
  1979年   8篇
  1978年   4篇
  1977年   4篇
  1976年   7篇
  1975年   3篇
  1974年   4篇
  1973年   3篇
  1972年   5篇
  1971年   7篇
  1967年   3篇
排序方式: 共有424条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
After acute estrogen withdrawal in postmenopausal women, administration of anakinra or etanercept, specific blockers of IL-1 and TNF-alpha, respectively, reduced the rise in bone resorption markers to about one half of that in controls. This is consistent with an important role for these immune cytokines in mediating the effect of estrogen deficiency on bone. INTRODUCTION: Studies in rodents have implicated increased production of interleukin (IL)-1 beta and TNF-alpha as mediators of bone loss after ovariectomy, but their roles are unclear in humans whose immune system differs markedly from that of rodents. MATERIALS AND METHODS: We administered transdermal estradiol, 0.1 mg/d, for 60 days to 42 early postmenopausal women. Estrogen treatment was discontinued, and subjects were randomly assigned to intervention groups receiving 3 wk of injections with 0.9% saline, anakinra 100 mg/d, or etanercept 25 mg/twice weekly. Bone turnover was assessed by measuring serum carboxyl-terminal telopeptide of type 1 collagen (CTX) and amino-terminal telopeptide of type 1 collagen (NTX), markers for bone resorption, and serum amino-terminal propeptide of type 1 collagen (P1NP), a marker for bone formation. Results were expressed as percent change in markers from baseline (last 2 days of estrogen treatment and days 20 and 21 of intervention). RESULTS: The percent changes from baseline during intervention for serum CTX, urine NTX, and serum PINP, respectively, were 43.3 +/- 8.0%, 12.0 +/- 7.1%, and -41.0 +/- 2.5% for the control group; 25.9 +/- 6.3%, 9.5 +/- 4.0%, and -37.8 +/- 3.0% for the anakinra group; and 21.7 +/- 5.0%, 0.32 +/- 3.82%, and -34.5 +/- 3.9% for the etanercept group. Compared with the control group, the blunting of the increase in serum CTX fell just below the level of significance (p=0.10) after anakinra treatment, whereas the blunting of the increase in serum CTX (p=0.034) and in urine NTX (p=0.048) were significant after etanercept treatment. Other changes were not significant. CONCLUSIONS: The data are consistent with a role for TNF-alpha, and possibly for IL-1 beta, in mediating increased bone resorption during estrogen deficiency in women. Although either cytokine blocker reduced serum CTX by about one half, the effect of combined blockade could not be tested because of concerns about toxicity. The data do not exclude direct or indirect contributory roles for RANKL or for other cytokines.  相似文献   
5.
A preliminary study of the distribution of the 99mTc complex of hexamethylpropylene amine oxime (HM-PAO) in 12 patients with brain neoplasms before, during, and after radiotherapy has been performed. Untreated brain tumors were found to exhibit a range of 99mTc-HM-PAO uptake, varying from areas of markedly increased isotope activity to photopenic areas, when compared to normal brain tissue. A ratio of 99mTc-HM-PAO tumor uptake to contralateral normal tissue uptake was calculated prior to and during radiotherapy. This ratio tended to return towards unity in lesions responding to therapy. A predictable alteration in whole brain 99mTc-HM-PAO uptake during radiotherapy was not demonstrated. Unlike the radiolabeled amines, 99mTc-HM-PAO localizes in primary tumors, probably indicating that its uptake mechanism is independent of non specific amine receptors. 99mTc-HM-PAO may be useful in the study of brain tumor physiology and response to therapy.  相似文献   
6.
Previous estimates of the prevalence of fatigue and chronic fatigue have derived largely from treated populations and have been biased by differential access to health-care treatment linked with gender, racial/ethnic and social class status. This study involves a community-based prevalence study of prolonged fatigue and chronic fatigue. It addresses: (1) the rate of prolonged fatigue and chronic fatigue in a socioeconomically and ethnically diverse sample of 28,673 adults in Chicago; and (2) establishes the relative prevalence of prolonged fatigue and chronic fatigue across race/ethnicity, socio-economic status and gender. Univariate and multivariate statistical techniques were utilized to delineate the overall rate of prolonged fatigue and chronic fatigue in the Chicago population and its relative prevalence by gender, race/ethnicity, and social class. Findings indicated that fatigue is common in urban populations, but that prolonged fatigue and chronic fatigue occur in about 5.00 to 7.68 percent and 2.72 to 4.17 percent, respectively, of the sample of the population. Highest levels of fatigue were consistently found among women and those with lower levels of education and occupational status.  相似文献   
7.

Background  

The Internet has been increasingly utilized in biomedical research. From online searching for literature to data sharing, the Internet has emerged as a primary means of research for many physicians and scientists. As a result, Web-based surveys have been employed as an alternative to traditional, paper-based surveys. We describe DADOS-Survey, an open-source Web-survey application developed at our institution that, to the best of our knowledge, is the first to be compliant with the Checklist for Reporting Results of Internet E-Surveys (CHERRIES). DADOS-Survey was designed with usability as a priority, allowing investigators to design and execute their own studies with minimal technical difficulties in doing so.  相似文献   
8.

Background  

Although regulatory compliance in academic research is enforced by law to ensure high quality and safety to participants, its implementation is frequently hindered by cost and logistical barriers. In order to decrease these barriers, we have developed a Web-based application, Duke Surgery Research Central (DSRC), to monitor and streamline the regulatory research process.  相似文献   
9.
Sciatic artery aneurysms (SAAs) develop in a persistent sciatic artery, which is a congenital anomalous continuation of the internal iliac artery and may be the major blood supply to the lower extremity. SAAs may appear clinically with rupture, thrombosis, distal embolization, or compression of the sciatic nerve. We have reviewed our three cases and the literature to delineate those factors that permit correct preoperative diagnosis and appropriate surgical intervention. Our three patients (aged 54 to 82 years) appeared with severe ischemia that resulted in above-knee amputations. The literature reveals 21 patients ranging in age from 35 to 84 years (58% were women). Twenty of those patients had operations, one of which resulted in death, and five in above-knee amputations. Unexplained sciatic or buttock pain, or a palpable "pulsating" buttock mass, suggests an SAA. The diagnosis is confirmed by angiography. The recommended treatment is femoropopliteal bypass grafting followed by ligature or percutaneous endovascular thrombosis of the aneurysm. Early diagnosis and correct surgical therapy are the keys to successful management of SAA.  相似文献   
10.
Benign myocardial uptake of technetium-99m labelled phosphates, not related to cardiac or metabolic disorders, has been documented except in the case of99mTc-methylene diphosphonate (MDP). The aim of this study was to assess the frequency of myocardial uptake and its possible association with malignant tumours in general and prostatic carcinoma in particular. We reviewed bone scintigrams performed with either99mTc-hydroxydiphosphonate (HDP) or99mTc-MDP over a period of more than 2 years for all patients with prostatic carcinoma and a matching group of patients suffering from other malignant and non-malignant disorders. A total of 965 scintigrams of 812 patients (males=559, females=253; age range 50–91 years, average age 69.2 years) were reviewed. Increased myocardial uptake was detected in 19 scintigrams (MDP=13, HDP=6) of 18 patients (17 males, one female). Most of the male patients with increased myocardial uptake had prostatic carcinoma (13/17) and were over 80 years of age (12/17). All patients were free of any cardiac or noncardiac disorder that might account for such uptake. When scintigraphy was repeated in the same patient, the uptake of99mTc-HDP was more diffuse and of higher grade than that of99mTc-MDP Benign myocardial uptake of99mTc-MDP is more common than previously thought. Although uptake of radiophosphates is attributed to asymptomatic atherosclerotic changes associated with old age, a strong association with prostatic carcinoma exists which may indicate variations in the bone: soft tissue affinity of different MDP complexes.  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