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   508篇
  免费   28篇
  国内免费   3篇
耳鼻咽喉   5篇
儿科学   14篇
妇产科学   20篇
基础医学   46篇
口腔科学   35篇
临床医学   29篇
内科学   131篇
皮肤病学   34篇
神经病学   31篇
特种医学   20篇
外国民族医学   1篇
外科学   71篇
综合类   12篇
预防医学   9篇
眼科学   12篇
药学   39篇
中国医学   4篇
肿瘤学   26篇
  2024年   1篇
  2023年   10篇
  2022年   20篇
  2021年   27篇
  2020年   21篇
  2019年   23篇
  2018年   20篇
  2017年   18篇
  2016年   21篇
  2015年   26篇
  2014年   23篇
  2013年   28篇
  2012年   30篇
  2011年   31篇
  2010年   17篇
  2009年   18篇
  2008年   16篇
  2007年   18篇
  2006年   12篇
  2005年   19篇
  2004年   13篇
  2003年   5篇
  2002年   3篇
  2001年   8篇
  2000年   7篇
  1999年   12篇
  1998年   4篇
  1997年   5篇
  1996年   2篇
  1995年   3篇
  1993年   1篇
  1992年   6篇
  1991年   10篇
  1990年   7篇
  1989年   3篇
  1988年   8篇
  1987年   8篇
  1986年   8篇
  1985年   6篇
  1984年   2篇
  1983年   7篇
  1982年   2篇
  1980年   1篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1976年   3篇
  1972年   1篇
  1971年   1篇
  1967年   1篇
排序方式: 共有539条查询结果,搜索用时 15 毫秒
61.

Background

Significant tricuspid regurgitation (TR) is occasionally associated with severe mitral stenosis and has an adverse impact on morbidity and mortality in patients undergoing mitral valve surgery. However, the effect of successful mitral balloon valvotomy (MBV) on significant TR is not fully elucidated. The aim of this study was to investigate TR after MBV in patients with severe mitral stenosis.

Methods

We analyzed the data of 53 patients with significant TR (grade ≥2, on a 1 to 3 scale) from the mitral balloon valvotomy database at our hospital. Patients were evaluated by Doppler echocardiography before valvotomy and at follow-up 1 to 13 years after MBV. Patients were divided into group A (27 patients), in whom TR regressed by ≥1 scale, and group B (26 patients), in whom TR did not regress.

Results

The Doppler-determined pulmonary artery systolic pressure was initially higher and decreased at follow-up more in group A (from 70.7 ± 23.8 to 36.5 ± 8.3 mm Hg; P < .0001) than in group B (from 48.7 ± 17.8 to 41.6 ± 13.1 mm Hg; P = NS). Compared with patients in group B, patients in group A were younger (25 ±10 vs 35 ± 11 years; P < .005), had higher prevalence of functional TR (85% vs 8%; P < .0001), and had lower incidence of atrial fibrillation (7% vs 38%; P < .005). Significant decrease in right ventricular end-diastolic dimension after MBV was noted in group A but not in group B. The mitral valve area at late follow-up was larger in group A than in group B (1.8 ± 0.3 vs 1.6 ± 0.3 cm2; P < .05).

Conclusions

Regression of significant TR after successful MBV in patients with severe mitral stenosis was observed in patients who had severe pulmonary hypertension. This improvement in TR occurred even in the presence of organic tricuspid valve disease.  相似文献   
62.
Type 2 diabetes is a polygenic disease characterized by interaction of environmental and genetic factors. The paraoxonase 1 gene (PON1) 55 and 192 polymorphisms have been reported to be associated with type 2 diabetes and its complications. Our aim is to study the PON1 55, 192 gene polymorphisms and enzyme activity in type 2 diabetic Egyptian population with complications. 100 type 2 diabetic patients with complications (34 with cardiac and 66 with microvascular complications (neuropathy, retinopathy and/or nephropathy)). This was in addition to 100 healthy control subjects of matched age and sex were taken. PON1 55 L?M and 192 Q?R gene polymorphisms and PON1 enzyme activity serum levels were detected. The LL genotype of PON1 55 polymorphism and QR and QQ genotypes of PON1 192 polymorphism were more frequent among the patients with diabetic complications. The PON1 enzyme activity levels were lower among the diabetic patients than in control subjects. PON1 55 and 192 polymorphisms and enzyme activity seems to be related to diabetic complications in this population.  相似文献   
63.
Adaptation of adult bone marrow transplant recipient long-term survivors   总被引:1,自引:0,他引:1  
Although there is a small literature on psychosocial and psychiatric aspects of bone marrow transplants (BMT) in adult recipients during the BMT hospitalization phase, adaptation of long-term adult BMT recipient survivors has received little study. This study surveyed the adaptation of BMT recipient survivors over age 17 who were an average of 42 months posttransplant. Study variables included the recipients' current self-reported health status, mood state, social role function, self esteem, life satisfaction, and relationships with their BMT donors and other family members. A companion study of those who donated BMT to the recipients eligible for this study was also performed. The study participants were preponderantly young adults who currently were in an intimate relationship and vocationally active. About 1/4 of the subjects reported ongoing medical problems. Also, 15-25% reported significant emotional distress, low self-esteem, and less-than-optimal life satisfaction. The subjects' current quality of relationship with their donors was highly correlated with many measures of their psychosocial status. The findings indicate that about 75% of BMT recipient long-term survivors are doing well from a psychosocial as well as a medical standpoint, that the recipient-donor relationship may be sensitive to any changes in the recipient's status, and that 15-20% of BMT recipient survivors report a degree of psychological distress that might benefit from specific psychological/psychiatric intervention.  相似文献   
64.
Surgical treatment of severe discrete supravalvular aortic stenosis by placement of a patch graft across the narrowed area of aorta at one point has been associated with a substantial incidence of residual stenosis. Successful relief of a severe stenosis was achieved by a modification of a previously reported technique in which the stenotic area is expanded at two points. Use of this technique should be considered in cases of severe discrete supravalvular aortic stenosis.  相似文献   
65.
To assess how often psychiatric consultants omit written data from their consultation notes, the authors reviewed 78 initial consultation notes written by second-year psychiatric residents. Data considered essential for an adequate psychiatric evaluation were typically omitted. Categories that were observed to have the highest frequencies of missing data included family history of psychiatric illness (60.3%), history of substance abuse (44.9%), marital status (37.2%), previous psychotropic drug use (35.9%), previous psychiatric treatment (26.9%), and patient history of psychiatric illness (24.4%). The frequencies of omissions were significantly (p less than .001, except for the last item, p less than .01) higher than those from the consultation notes written by a second cohort of psychiatric residents who used a worksheet that listed data categories. The authors' findings argue for the use of worksheets delineating data categories to ensure that clinicians write adequate consultation notes.  相似文献   
66.
The interaction of retinoids and flavonoids with phospholipases A2 (PLA2) was studied to assess the mechanism of inhibition. Retinoids, such as retinal, retinol, retinoic acid and retinol acetate, and flavonoids, such as quercetin, rutin, morin and sciadopitysin, inhibit Ca2+-dependent PLA2 activity of human synovial fluid (HSF) in vitro in a dose-dependent fashion; ID20S ranged from 2-8 microM. Retinal inhibited neutral active Ca2+-dependent PLA2S from human platelets, human plasma, human polymorphonuclear leukocytes and Naja mossambica mossambica venom in a dose-dependent manner while quercetin inhibits extracellular PLA2 activities of human plasma, HSF and N. m. mossambica venom in a dose-dependent manner but not PLA2 activity derived from human platelets and polymorphomonuclear leukocytes. Inhibition of PLA2 activity by both flavonoid and retinoids were independent of Ca2+ or Na+. Increasing substrate concentration (9-144 nmols) relieved the inhibition of HSF-PLA2 activity by quercetin indicating probable interaction with the substrate. The inhibition by retinal is independent of substrate concentration suggesting that inhibition by retinal is probably due to direct interaction with the enzyme. both retinal and quercetin quenched the relative fluorescent intensity of N. m. mossambica PLA2 and in a dose-dependent manner in the same concentration range at which they inhibit in vitro PLA2 activity. Retinal and quercetin shift the thermotropic phase transition of distearoylphosphatidylethanolamine (DSPE) liposomes. Both compounds broadened the transition peak, shifted the Tm to lower temperature, and decreased enthalpy significantly. These findings indicate that inhibition of non-pancreatic human PLA2S by retinoids and flavonoids can be mediated by interaction with enzyme and/or substrate.  相似文献   
67.
Two hundred sixty-two adolescents, ages 13 through 17, and one of the parents of each, interviewed separately, are compared with regard to their use of substances. Youthful subjects in each comparison group are similar in age, sex, ethnicity and socioeconomic status. Results show a variety of relationships between parental use of coffee, cigarettes, beer and wine, hard liquor and marijuana/hashish and adolescent use of such substances. Generally, parental use of these substances is moderately to strongly related to use by their children. The strongest relationships are found for coffee, mother's use of cigarettes, and father's use of hard liquor. All of these relationships are not linear. For example, fathers who are moderate drinkers of hard liquor are more likely to have adolescent children who are substance users. Two theories of intergenerational substance use are discussed.  相似文献   
68.
69.
Psychological problem frequencies of very ill, homebound cancer patients were studied using an instrument entitled "Psychosocial Problem Categories for Homebound Cancer Patients." This instrument contains thirteen major categories of problems and fifty individual problems. A total of 570 patient records were obtained from two visiting nurse agencies in two different counties. Records were rated by a pair of trained raters, with level of interrater reliability being r = 0.96. Intervention frequencies by visiting health care professionals were also assessed. Percentages are based on at least one mention of problem or intervention. The five most frequent problem categories included: 1) Somatic side effects, 30% of total problems, of which pain involved 13% of total problems, 2) Patient mood disturbance, 15% of total problems, 3) Equipment problems, 8% of total problems, 4) Family relationship impairment, 7% of total problems, and 5) Cognitive impairment, 6% of total problems. The three most frequent interventions included: 1) Instructor/reinforcement to patient/family, 22% of total interventions, 2) No intervention for problem, 17% of total interventions, and 3) Counseling/emotional support, 17% of total interventions. Because the assessment instrument showed high interrater reliabilities for the two demographically dissimilar patient populations, it may be adaptable to heterogeneous populations.  相似文献   
70.
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