全文获取类型
收费全文 | 193篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
儿科学 | 3篇 |
基础医学 | 22篇 |
临床医学 | 2篇 |
内科学 | 20篇 |
皮肤病学 | 27篇 |
神经病学 | 3篇 |
特种医学 | 72篇 |
外科学 | 42篇 |
预防医学 | 3篇 |
眼科学 | 1篇 |
出版年
2015年 | 2篇 |
2013年 | 4篇 |
2010年 | 2篇 |
2008年 | 2篇 |
2007年 | 3篇 |
2006年 | 5篇 |
2005年 | 4篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 7篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1981年 | 3篇 |
1978年 | 4篇 |
1932年 | 4篇 |
1931年 | 3篇 |
1930年 | 9篇 |
1929年 | 6篇 |
1928年 | 7篇 |
1927年 | 2篇 |
1926年 | 3篇 |
1922年 | 4篇 |
1921年 | 2篇 |
1920年 | 3篇 |
1911年 | 1篇 |
1910年 | 1篇 |
1909年 | 2篇 |
1908年 | 1篇 |
1907年 | 3篇 |
1906年 | 1篇 |
1905年 | 3篇 |
1904年 | 3篇 |
1903年 | 7篇 |
1902年 | 1篇 |
1901年 | 1篇 |
1900年 | 2篇 |
1899年 | 1篇 |
1897年 | 1篇 |
排序方式: 共有195条查询结果,搜索用时 15 毫秒
1.
Madan M. Rehani Emily R. Melick Raza M. Alvi Ruhani Doda Khera Salma Batool-Anwar Tomas G. Neilan Michael Bettmann 《European radiology》2020,30(4):1839-1846
To determine percent of patients without malignancy and ≤ 40 years of age with high cumulative radiation doses through recurrent CT exams and assess imaging appropriateness. From the cohort of patients who received cumulative effective dose (CED) of ≥ 100 mSv over a 5-year period, a sub-set was identified with non-malignant disease. The top 50 clinical indications leading to multiple CTs were determined. Clinical decision support (CDS) system scores were analyzed using a widely adopted standard of 1–3 (red) as “not usually appropriate,” 4–6 (yellow) “may or may not be appropriate,” and 7–9 (green) “usually appropriate.” Clinicians reviewed patient records to assess compliance with appropriate use criteria (AUC). 9.6% of patients in our series were with non-malignant conditions and 1.4% with age ≤ 40 years. CDS scores (rounded) were 2% red, 38% yellow, 27% green, and 33% unscored CTs. Clinical society guidelines for CT exams, wherever available, were followed in 87.5 to 100% of cases. AUCs were not available for several clinical indications as also referral guidelines for serial CT imaging. More than half of CT exams were unrelated to follow-up of a primary chronic disease. We are faced with a situation wherein patients in age ≤ 40 years require or are thought to require many CT exams over the course of a few years but the radiation risk creates concern. There is a fair number of conditions for which AUC are not available. Suggested solutions include development of CT scanners with lesser radiation dose and further development of appropriateness criteria. 相似文献
2.
The suppressive activity of two bovine serum albumin-specific class II-restricted T suppressor cell clones (BVI/5 and 83/2-D11) was compared to that of a feeder cell-independent, IL 2-dependent subline (HF1.IL-2) of an originally antigen-dependent class II-restricted Ts cell clone (HF1). No soluble suppressor factors can be found in BVI/5 and 83/2-D11 Ts cell extracts or culture supernatants under conditions where an unspecific factor can be derived from HF1.IL-2 cells. This factor, when isolated from cell extracts in the presence of n-octyl-beta-D-glycopyranoside, has a molecular weight of 70-80 kD. In absence of this non-ionic detergent, it has a high affinity to membrane fragments and is associated with a molecular weight of 300 kD or more. The data are discussed in connection with recent findings of direct T suppressor to T helper interaction by cell-cell contact. 相似文献
3.
The effects of various indwelling ureteral catheter materials on the normal canine ureter 总被引:5,自引:0,他引:5
M Marx M A Bettmann S Bridge G Brodsky L M Boxt J P Richie 《The Journal of urology》1988,139(1):180-185
In an attempt to objectively evaluate the biocompatibility of materials commonly used for ureteral stenting, stent-catheters made of four different materials were placed randomly in 31 ureters of 19 mongrel dogs. Animals underwent urography at four weeks and were sacrificed at six weeks. Mild hydronephrosis was noted in eight instances, essentially unrelated to specific material. Silicone, C-flex and polyurethane stents caused a similar, mild degree of ureteral edema, but ureters stented with Silitek demonstrated fairly marked edema. Epithelial ulceration and erosion, often severe, occurred with all polyurethane stents, and rarely with the three other materials. All materials differed statistically from controls, and C-flex caused less reaction overall than polyurethane, indicating differences in biocompatibility of the various materials which may be relevant to their use in patients undergoing long-term ureteral stenting. In practical terms, these suggest that certain materials, notably silicone and C-flex, are more suitable for ureteral stenting than others. 相似文献
4.
5.
David M. L. Morgan Michael A. Bettmann 《Cardiovascular and interventional radiology》1989,12(3):154-160
We have used cell culture techniques to study the effects of 16 contrast agents on human vascular endothelial cells (HUVEC)in vitro, where both the dose and duration of exposure are precisely known. Our results demonstrate that 1) exposure of HUVEC to radiographic
contrast media can produce dose and time-dependent inhibition of the incorporation of [3H]leucine, [3H]thymidine, or [3H] uridine into marcromolecules; 2) thymidine incorporation is the most affected; 3) the inhibition is not primarily due to
osmotic effects; and 4) concomitant exposure to X-irradiation does not sensitize HUVEC to contrast agents. Where marked inhibition
occurred, it was accompanied by changes in cell morphology and later, by loss of the cytoplasmic marker lactate dehydrogenase,
indicating that under the conditions of our experiments the effects were cytotoxic, and not merely cytostatic. 相似文献
6.
Interventional angiographic techniques are of increasing importance in the management of arteriosclerosis and its complications. Two areas of particular interest are the treatment of focal arterial stenoses by percutaneous transluminal angioplasty and the treatment of arterial thromboemboli with selective infusion of thrombolytic agents. The administration of multiple drugs, in various combinations, is a critical factor in the success of these interventions. To effectively use this new pharmacoangiography, it is important to understand both the pathophysiology of the atherosclerotic or thrombotic process being treated and the actions of the drugs used. Preserving the effect of angioplasty relies on preventing thrombus formation and preventing recurrence of the atherosclerotic obstruction. Heparin during the procedure is clearly useful for the former, and aspirin in small doses and other antiplatelet medications are indicated for the latter. The precise utility of long-term anticoagulation, of low molecular weight dextran, and of various antiplatelet regimens remains to be proven. The theoretical importance of these medications in improving long-term patency rests on the effects they have on platelet and vessel wall prostaglandins, on intimal smooth muscle cell proliferation, and on the thrombogenicity of injured arterial intima. Fibrinolytic therapy, with streptokinase and urokinase, has been used for many years. Selective intraarterial use, however, is a new and promising application. Intracoronary streptokinase infusion during acute myocardial ischemia appears to prevent or limit infarction in certain patients. Peripheral use for acute arterial occlusion, either in native vessels or in grafts, is an area of great promise. Key considerations are thrombus age, size, and location, and the status of the arterial flow proximal and distal to the obstruction. 相似文献
7.
RATIONALE: The goal of this investigation was to understand clinicians' perceptions of the probability of pulmonary embolism as a function of V/Q scan results of normal, low, intermediate, and high probability. METHODS: A questionnaire was developed and distributed to 429 clinicians at a single academic medical center. The response rate was 44% (188 of 429). The questions included level of training, specialty, probability of PE given 1 of the 4 V/Q scan results, and estimations of the charges for V/Q scanning and pulmonary angiography, and estimations of the risks of pulmonary angiography. RESULTS: The medians and ranges for the probability of pulmonary embolism given a normal, low, intermediate, and high probability V/Q scan result were 2.5% (0-30), 12.5% (0.5-52.5), 41.25% (5-75), and 85% (5-100), respectively. Eleven percent (21 of 188) of the respondents listed the probability of PE in patients with a low probability V/Q scan as being 5% or less, and 33% (62 of 188) listed the probability of PE given an intermediate probability scan as 50% or greater. The majority correctly identified the rate of serious complications of pulmonary arteriography, but many respondents underestimated the charge for V/Q scans and pulmonary arteriography. CONCLUSIONS: A substantial minority of clinicians do not understand the probability of pulmonary embolism in patients with low and intermediate probability ventilation-perfusion scans. More quantitative reporting of results is recommended. This could be particularly important because VQ scans are used less frequently but are still needed in certain clinical situations. 相似文献
8.
Professor Dr. Bettmann 《Archives of dermatological research》1921,129(1):101-120
Ohne ZusammenfassungMit 2 Textabbildungen. 相似文献
9.
Professor Dr. Bettmann 《Archives of dermatological research》1904,70(1):67-96
Ohne ZusammenfassungMit 3 Abbildungen im Text. 相似文献
10.
Prof. Dr. S. Bettmann 《Archives of dermatological research》1923,142(2):235-251
Ohne ZusammenfassungMit 4 Textabbildungen. 相似文献