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   380篇
  免费   9篇
  国内免费   8篇
儿科学   12篇
妇产科学   7篇
基础医学   48篇
口腔科学   14篇
临床医学   55篇
内科学   50篇
皮肤病学   8篇
神经病学   8篇
特种医学   93篇
外科学   23篇
综合类   5篇
预防医学   17篇
眼科学   1篇
药学   48篇
肿瘤学   8篇
  2023年   3篇
  2021年   12篇
  2020年   6篇
  2019年   8篇
  2018年   7篇
  2017年   3篇
  2016年   3篇
  2015年   5篇
  2014年   13篇
  2013年   6篇
  2012年   11篇
  2011年   13篇
  2010年   25篇
  2009年   16篇
  2008年   10篇
  2007年   12篇
  2006年   13篇
  2005年   7篇
  2004年   3篇
  2003年   5篇
  2001年   3篇
  2000年   3篇
  1998年   18篇
  1997年   19篇
  1996年   13篇
  1995年   11篇
  1994年   13篇
  1993年   13篇
  1992年   3篇
  1991年   4篇
  1990年   3篇
  1989年   9篇
  1988年   8篇
  1987年   6篇
  1986年   10篇
  1985年   6篇
  1984年   3篇
  1982年   7篇
  1981年   3篇
  1980年   8篇
  1979年   5篇
  1978年   3篇
  1977年   7篇
  1976年   7篇
  1975年   9篇
  1972年   2篇
  1971年   2篇
  1970年   2篇
  1969年   2篇
  1967年   3篇
排序方式: 共有397条查询结果,搜索用时 15 毫秒
91.
92.
93.
Automatic implantable cardioverter defibrillators (AICDs) were studied in three groups: (a) Serial radiographs were reviewed in 51 clinic patients. Twenty of 96 (21%) AICD patches distorted with time. (b) Thirty-six postoperative computed tomographic (CT) scans of asymptomatic patients revealed that pericardial fluid collections were frequent during the month after surgery but rare beyond that. Echocardiography was insensitive for these collections. CT also demonstrated dense fibrosis around some distorted patches, months after surgery. (c) Five other patients with pericardial infection had distorted patches, and the four studied with CT had fluid beneath their patches. (d) A case of constrictive pericarditis had distorted patches but was not diagnosed with CT. The authors conclude that distorted patches may indicate postoperative complications and that CT is the imaging modality of choice.  相似文献   
94.
Computed equalization radiography: preliminary clinical evaluation   总被引:1,自引:0,他引:1  
Goodman  LR; Wilson  CR; Kim  CS 《Radiology》1993,186(2):399
  相似文献   
95.
We report the first clinical experience with a new method for projective imaging of blood vessels (angiography) using magnetic resonance. Vascular contrast is produced noninvasively by the phase response of moving protons. Diastolic and systolic gated images produce, respectively, flow signal and flow void; the difference image is a map of the pulsatile flow: an arteriogram. Preliminary studies are presented of the lower extremities of one healthy volunteer and four patients (one each with occlusive disease, soft-tissue tumor, arteriovenous malformation, and venous femoral-popliteal graft). Patient data are compared with accompanying conventional arteriograms, and the new method is discussed.  相似文献   
96.
OBJECTIVE: The objective of this study was to compare the cost (measured as resource utilization by the institution) and clinical effectiveness of transcatheter coil occlusion and surgical patent ductus arteriosus (PDA) closure. Similar comparisons have been made previously with other devices no longer in use in the United States. No such comparison has been made for coil occlusion, which has been performed increasingly since 1992. METHODS: All patients who underwent either coil or surgical closure of uncomplicated PDA at our institution between August 1993 and June 1996 were retrospectively identified. Patients were included in the study if they were eligible for either closure technique. Thus, they had a restrictive PDA (not associated with pulmonary hypertension) and no overt evidence of congestive heart failure. Patients were excluded if they had other significant cardiac or noncardiac problems. Total procedural and recovery costs (including labor, material, equipment, and overhead) incurred by the provider were determined using a cost accounting system called Transition Systems, Inc. To define further how costs differed for the two techniques, total costs were subdivided into the categories of professional, technical, inpatient hospital stay, postprocedure testing, and supplies and other miscellaneous costs. PDA closure rates and associated complications also were compared. Follow-up information was sought from outpatient visits to our institution or by contacting the referring physicians. RESULTS: A total of 39 patients were identified, 3 of whom were excluded because of coexisting medical problems. The study group consisted of 36 patients; 24 underwent PDA coil occlusion and 12 surgical closure. Mean age and weight were 8.8 years and 28.5 kg for the coil patients, and 7.3 years and 32.8 kg for the surgical patients. Median procedural duration was 150 minutes for the coil group and 165 minutes for the surgical group. The total cost to the institution of coil occlusion was significantly lower than that of surgical closure ($5273 vs $8509). The largest difference lay in the cost of hospital stay ($398 vs $2566) and in the professional costs ($1506 vs $2782). Technical costs were similar ($2156 for coil, $2151 for surgery), although use of the catheterization laboratory per unit of time was more expensive than use of the operating room ($800 vs $400 per hour). Additional technical costs of the surgical procedure related to general anesthesia and postoperative care made up the difference. No patient in either group had a residual PDA murmur at hospital discharge or thereafter. Follow-up echocardiography was performed in all coil occlusion patients, and tiny residual leaks were detected in 17%. Only 42% of the surgical patients had postoperative echocardiography; none had residual leaks. There were no deaths or major complications in either group. CONCLUSIONS: Transcatheter coil occlusion is as effective and less costly than surgical closure if silent residual leaks are not considered clinically significant. This information may be used increasingly in patient care decisions in the current era of managed medical care.  相似文献   
97.
Traumatic brain stem injury: MR imaging   总被引:9,自引:0,他引:9  
Gentry  LR; Godersky  JC; Thompson  BH 《Radiology》1989,171(1):177-187
Eighty-seven patients with acute (n = 70) or chronic (n = 17) head injuries were prospectively studied with magnetic resonance (MR) imaging and computed tomography (CT) to characterize the frequency and nature of traumatic brain stem injury (BSI). Forty-eight traumatic lesions were identified in 36 patients. Of 36 patients, 35 had neurologic findings that corroborated the radiographic impression of BSI. T1- and T2-weighted MR images demonstrated a significantly higher number of lesions than did CT. Patients with BSI had a significantly higher frequency of corpus callosum and diffuse axonal "shear" lesions. The number of cortical contusions and extraaxial hematomas was similar in both groups. The mean Glasgow Coma Scale (GCS) scores at admission were significantly lower in patients with evidence of BSI on MR images. Patients with primary BSI had lower initial GCS scores, a longer duration of coma, more diffuse axonal "shear" lesions, and a higher frequency of corpus callosum injury than patients with secondary BSI. The location of primary and secondary lesions was significantly different. Overall, MR imaging was more helpful than CT in detecting, localizing, and characterizing BSI.  相似文献   
98.
The increasing presence of aquatic contaminants, such as the pharmaceutical fluoxetine, has raised concerns over potentially disrupting effects on several aspects of fish reproduction. However, the effects of fluoxetine on reproductive and paternal behavior in fish remain understudied, particularly at environmentally relevant concentrations. In the current study, we therefore tested the hypothesis that waterborne fluoxetine at an environmentally relevant concentration (540 ng/l), disrupts specific reproductive and paternal behaviors in male Siamese fighting fish at distinct reproductive phases. A pre-post test design was adopted to investigate specific behavioral responses at the individual fish level in response to male conspecific intruders at two different distances from the nest across four distinct reproductive phases (before bubblenest construction, following bubblenest construction, after spawning and after hatching of the larvae). In the control specimens, the measured behaviours were not different between the spawning times and among the interactions in either distance to nest at the different reproduction phases. Our results indicate that fluoxetine specifically disrupts characteristic paternal territorial aggression behaviour only after spawning and hatching of the larvae, while male behaviour in previous reproductive phases is unaffected by fluoxetine exposure. Results of comparison between males at 1st spawning and specimens exposed to fluoxetine at 2nd spawning showed that the first reaction of the nest-holding males to the intruders, duration of fin spreading, number of bites, and 90° turn, and the frequency of sweeps were different between the spawning times after spawning or hatching of embryos. However, interaction of spawning time and reproduction phase was significant on biting behaviour. These results demonstrate that fluoxetine exposure at environmental concentrations negatively affects territorial defense behaviour in fighting fish during parental care after larval hatching, which may have possible implications on reproductive success and population dynamics.  相似文献   
99.
BACKGROUND: Sitosterolaemia is a lipid disorder in which plasma plant sterol levels are extremely elevated. Sitosterolaemia is clinically characterized by tuberous and tendon xanthomas, premature vascular disease and arthritis. OBJECTIVE: To report a case of sitosterolaemia diagnosed by cutaneous manifestations and to review this rare disease. METHODS: We report the case of a 60-year-old woman who presented with cutaneous xanthomas, arterial hypertension and polyarthralgias. The patient had had hypercholesterolaemia for many years without reduction of serum cholesterol, despite treatment with fenofibrate. RESULTS: Ezetimibe therapy was started, decreasing sitosterol plasmatic levels and tuberous xanthomas after 3 months of treatment. CONCLUSION: It is important to detect levels of sitosterol in plasma in patients with premature vascular disease, presence of xanthomas, and uncontrolled hypercholesterolaemia. Ezetimibe therapy is effective.  相似文献   
100.
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