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   416篇
  免费   10篇
儿科学   41篇
妇产科学   9篇
基础医学   36篇
口腔科学   26篇
临床医学   45篇
内科学   61篇
皮肤病学   10篇
神经病学   6篇
特种医学   8篇
外科学   68篇
综合类   25篇
预防医学   29篇
眼科学   4篇
药学   53篇
肿瘤学   5篇
  2014年   2篇
  2013年   5篇
  2012年   2篇
  2010年   17篇
  2009年   10篇
  2006年   3篇
  2004年   2篇
  2003年   6篇
  2001年   5篇
  1999年   5篇
  1998年   15篇
  1997年   17篇
  1996年   10篇
  1995年   13篇
  1994年   7篇
  1993年   13篇
  1992年   9篇
  1991年   8篇
  1990年   11篇
  1989年   9篇
  1988年   9篇
  1987年   6篇
  1986年   7篇
  1985年   6篇
  1984年   4篇
  1983年   5篇
  1982年   6篇
  1981年   4篇
  1980年   4篇
  1979年   5篇
  1978年   2篇
  1977年   1篇
  1976年   2篇
  1975年   1篇
  1974年   3篇
  1973年   2篇
  1969年   1篇
  1965年   3篇
  1964年   2篇
  1963年   1篇
  1962年   1篇
  1961年   2篇
  1959年   12篇
  1958年   21篇
  1957年   33篇
  1956年   25篇
  1955年   21篇
  1954年   21篇
  1949年   19篇
  1948年   22篇
排序方式: 共有426条查询结果,搜索用时 15 毫秒
71.
72.
73.
74.
75.

Objectives

To determine sex bias in the selection of strategies to evaluate patients with acute myocardial infarction (AMI), and determine if the choice of strategy influences survival.

Background

Controversy exists regarding the role of female sex in the use of invasive evaluation for AMI and its possible effect on adverse outcomes.

Methods

Electronic health record data from the Geisinger Acute Myocardial Infarction Cohort (GAMIC) was analyzed which included 1,968 men and 1,047 women admitted to the Geisinger Medical Center between January 2001 and December 2006 with acute myocardial infarction (AMI).Multivariate logistic regression analyses were used to determine independent correlates of an invasive evaluation. Multivariate logistic regression modeling stratified on sex was used to determine when invasive evaluation was done and whether there was a correlation with mortality.

Results

In unadjusted analyses, male sex was a significant predictor for the use of invasive evaluation (odds ratio = 1.71, 95% CI = [1.46, 2.00]). Adjusted for baseline differences (like age, renal function, co‐morbid conditions) multivariate analyses found no significant relationship between male sex and invasive evaluation (OR = 1.02, 95% CI = [0.82, 1.23]). Females in the STEMI group were found to be less revascularized. No difference was observed in the one‐year mortality between women and men regardless of invasive evaluation or revascularization.

Conclusions

Sex was not independently associated with the occurrence of an invasive evaluation of a MI. Females in the STEMI group were less revascularized. There was no strong gender effect on survival irrespective of the performance on an invasive evaluation or revascularization. (J Interven Cardiol 2013;26:14–21)
  相似文献   
76.
77.

Purpose

Teratomas with malignant transformation comprise up to 6% of metastatic teratomas. The prognosis of patients with these tumors can vary considerably. We delineate factors that may be related to prognosis in a cohort of men with teratoma with malignant transformation.

Materials and Methods

We analyzed pathological features, treatment, response, recurrence, time to recurrence, subsequent followup and survival for 21 patients (median age 28 years) diagnosed with teratoma with malignant transformation during a 7-year period at our institution.

Results

Malignant nongerm cell elements were present in the primary tumor in 11 cases (52%). Of 18 patients with testicular primaries 17 (94%) presented with metastatic disease. Despite aggressive treatment with surgery and chemotherapy 17 of 21 cases (81%) recurred (median time 6 months). Overall, 5 patients (24%) died of disease (median survival 23 months), 5 (24%) are alive with metastases (median followup 41 months) and 11 (52%) have no evidence of disease (median followup 50 months). Progression/recurrence was substantially greater for 2 of 2 cases with a mediastinal origin, 3 of 4 with rhabdomyosarcomatous differentiation and 5 of 6 with neural differentiation compared with the remainder of the cohort (p <0.05).

Conclusions

Teratomas with malignant transformation are usually metastatic at presentation, have a high recurrence rate and are more aggressive than teratomas without malignant transformation. Prognosis is especially poor for mediastinal teratomas with malignant transformation and for those with neural or rhabdomyosarcomatous differentiation. Complete surgical resection of residual or recurrent disease appears to offer the best chance for prolonged survival.  相似文献   
78.
ABSTRACT: Oocytes obtained from superstimulated rhesus monkeys are needed for in vitro fertilization experiments. The animals become refractory to repeated ovarian stimulation by pregnant mare serum gonadotropin (PMSG). Production of antibodies against PMSG was suspected. Antibodies were not detected by gel-diffusion tests, but were found using ELISA procedures in sera from all monkeys that had been treated with PMSG. Sera from seven of nine treated monkeys had antibodies that cross-reacted with FSH-P. An ovarian stimulation test using golden hamsters showed that sera from PMSG-treated rhesus monkeys completely blocked superstimulation of follicle development and ovarian weight gain by PMSG. This study demonstrates that the refractoriness of rhesus monkeys to repeated ovarian stimulation by PMSG is due to the production of nonprecipitating antibodies to PMSG that effectively block the activity of PMSG on the ovary. Formation of these antibodies may preclude use of other gonadotropin preparations in refractory monkeys. Alternative ovarian stimulation procedures avoiding use of gonadotropin preparations need to be developed to permit repeated treatment of rhesus monkeys for multiple oocyte collection.  相似文献   
79.
Finite element analysis of three- and four-unit bridges   总被引:2,自引:0,他引:2  
A two-dimensional finite element model of a mandibular quadrant was used to examine differences in magnitude of the principal stresses from the placement of three- and four-unit bridges. The area of interest spanned the first premolar to the second molar. Loading conditions were (i) vertical and distributed and (ii) 30 degrees to the vertical and concentrated. The principal stresses were calculated and compared for: (i) the first molar removed with the remaining bone either cancellous or cancellous surrounded by a cortical shell; (ii) as in (i) but with the second premolar and first molar removed; (iii) a three-unit bridge spanning the second premolar to the second molar; and (iv) a four-unit bridge spanning the first premolar to the second molar. Each tooth was supported by periodontal ligaments, cortical and cancellous bone with each assigned the appropriate physical constants. Removal of the first molar resulted in considerable variation of the stresses especially when the cortical shell was replaced by cancellous bone. Because of the lower modulus of cancellous bone and its lower load-bearing capabilities the stresses were three to ten times lower and more uniform within the cancellous bone. Generally, the addition of a bridge resulted in lower and better distributed sigma min stresses. The bridge also resulted in higher tensile stresses distal to the abutment teeth which theoretically could result in bone deposition. No significant differences in magnitude were observed between the three- and four-unit bridge. From a stress standpoint the bridges resulted in more uniform stress distribution around the abutments and an increase in the tensile stress distal to the abutments. Such findings support the placement of a fixed bridge to maintain bone in an edentulous area.  相似文献   
80.
Neural crest patterning and the evolution of the jaw   总被引:4,自引:2,他引:2  
Here we present ideas connecting the behaviour of the cranial neural crest during development with the venerable, perhaps incorrect, view that gill-supporting cartilages of an ancient agnathan evolved into the skeleton of an early gnathostome's jaw. We discuss the pattern of migration of the cranial neural crest ectomesenchyme in zebrafish, along with the subsequent arrangement of postmigratory crest and head mesoderm in the nascent pharyngeal segments (branchiomeres), in diverse gnathostomes and in lampreys. These characteristics provide for a plausible von Baerian explanation for the problematic inside-outside change in topology of the gills and their supports between these 2 major groups of vertebrates. We consider it likely that the jaw supports did indeed arise from branchiomeric cartilages.  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