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   6518篇
  免费   747篇
  国内免费   42篇
耳鼻咽喉   31篇
儿科学   229篇
妇产科学   133篇
基础医学   968篇
口腔科学   293篇
临床医学   736篇
内科学   1715篇
皮肤病学   174篇
神经病学   407篇
特种医学   539篇
外科学   717篇
综合类   112篇
一般理论   4篇
预防医学   434篇
眼科学   151篇
药学   386篇
中国医学   2篇
肿瘤学   276篇
  2021年   84篇
  2020年   56篇
  2019年   72篇
  2018年   98篇
  2017年   73篇
  2016年   83篇
  2015年   96篇
  2014年   134篇
  2013年   189篇
  2012年   218篇
  2011年   274篇
  2010年   190篇
  2009年   152篇
  2008年   233篇
  2007年   260篇
  2006年   278篇
  2005年   250篇
  2004年   229篇
  2003年   215篇
  2002年   227篇
  2001年   232篇
  2000年   249篇
  1999年   195篇
  1998年   153篇
  1997年   126篇
  1996年   150篇
  1995年   102篇
  1994年   96篇
  1993年   90篇
  1992年   198篇
  1991年   149篇
  1990年   160篇
  1989年   163篇
  1988年   159篇
  1987年   152篇
  1986年   146篇
  1985年   153篇
  1984年   96篇
  1983年   101篇
  1982年   78篇
  1981年   74篇
  1980年   53篇
  1979年   96篇
  1978年   67篇
  1977年   61篇
  1976年   67篇
  1975年   49篇
  1972年   59篇
  1971年   56篇
  1970年   56篇
排序方式: 共有7307条查询结果,搜索用时 15 毫秒
1.
Isolated patellofemoral arthritis is an increasingly recognized entity, and is usually associated with previous patellofemoral dysplasia or instability. Patellofemoral arthroplasty (PFA) has evolved significantly in recent years, both in terms of implant design and importantly in the understanding of appropriate patient selection. This review outlines the indications and investigations for PFA, provides a brief history of the development of contemporary implants, and presents the clinical outcomes for the prostheses most commonly used in the UK. In addition, it provides a detailed surgical technique for implantation of an onlay implant, with tips on how to optimize patellofemoral biomechanics and thus achieve a consistently good outcome.  相似文献   
2.
3.

Background

Resistin is an immunometabolic mediator that is elevated in several inflammatory disorders. A ligand for Toll-like receptor 4, resistin modulates the recruitment and activation of myeloid cells, notably neutrophils. Neutrophils are major drivers of cystic fibrosis (CF) lung disease, in part due to the release of human neutrophil elastase- and myeloperoxidase-rich primary granules, leading to tissue damage. Here we assessed the relationship of resistin to CF lung disease.

Methods

Resistin levels were measured in plasma and sputum from three retrospective CF cohorts spanning a wide range of disease. We also assessed the ability of neutrophils to secrete resistin upon activation in vitro. Finally, we constructed a multivariate model assessing the relationship between resistin levels and lung function.

Results

Plasma resistin levels were only marginally higher in CF than in healthy control subjects. By contrast, sputum resistin levels were very high in CF, reaching 50–100 fold higher levels than in plasma. Among CF patients, higher plasma resistin levels were associated with allergic bronchopulmonary aspergillosis, and higher sputum resistin levels were associated with CF-related diabetes. Mechanistically, in vitro release of neutrophil primary granules was concomitant with resistin secretion. Overall, sputum resistin levels were negatively correlated with CF lung function, independently of other variables (age, sex, and genotype).

Conclusions

Our data establish relationships between resistin levels in the plasma and sputum of CF patients that correlate with disease status, and identify resistin as a novel mechanistic link between neutrophilic inflammation and lung disease in CF.  相似文献   
4.
BACKGROUND: Previous research has demonstrated that academic and neuropsychological functions are compromised in pediatric bipolar disorder (PBD). Investigation of the degree to which neuropsychological deficits might contribute to those academic problems is needed to aid in the recognition and intervention for school achievement difficulties in PBD. METHODS: A sample of 55 children and adolescents with PBD with and without attention-deficit/hyperactivity disorder (ADHD) (PBD group, n = 28; PBD+ADHD group, n = 27) were tested with a computerized neurocognitive battery and standardized neuropsychological tests. Age range of subjects was 7-17 years, with the mean age of 11.97 (3.18) years. Parents completed a structured questionnaire on school and academic functioning. RESULTS: Logistic regression analyses indicated that executive function, attention, working memory, and verbal memory scores were poorer in those with a history of reading/writing difficulties. A separate logistic regression analysis found that attentional dysfunction predicted math difficulties. These relationships between neuropsychological function and academic difficulties were not different in those with PBD+ADHD than in those with PBD alone. CONCLUSIONS: In PBD neuropsychological deficits in the areas of attention, working memory, and organization/problem solving skills all contribute to academic difficulties. Early identification and intervention for these difficulties might help prevent lower academic achievement in PBD.  相似文献   
5.
6.
7.
Sonoelasticity imaging of prostate cancer: in vitro results   总被引:2,自引:0,他引:2  
  相似文献   
8.
9.
Incisional hernias occur in up to 17% of patients after liver transplantation. Laparoscopic ventral hernia repair is associated with fewer wound complications and a decreased incidence of recurrence when compared to open hernia repair in nontransplant patients. This is a retrospective review of 13 patients who underwent laparoscopic incisional hernia repair (LAP group) after liver transplantation compared to 14 patients who had open repairs (OP group; all but one with mesh). Primary immunosuppression in both groups at the time of transplantation was tacrolimus, but more patients in the LAP group were on sirolimus at the time of hernia, while more patients in the OP group were on prednisone at the time of hernia repair. All operations were completed with a laparoscopic approach; there were no conversions to open. Length of stay differed significantly between the 2 groups, with a mean of 5.4 days for the LAP group compared to 2.7 days in the OP group (0.0059). Complications occurred in 2 (15%) of the patients in the LAP group and 5 (36%) in the OP group. One patient in the LAP group required mesh removal to exclude causes of recurrent ascites, and 1 in the OP group for mesh infection. One (7.6%) of the patients in the LAP group developed a recurrence, compared to 29% (4) of the OP group (P =0.3259). In conclusion, laparoscopic incisional hernia repair is safe in patients after liver transplantation, with a low risk of infection or recurrence.  相似文献   
10.
This paper investigates differences in the nature and frequency of psychiatric symptoms reported by patients with learning disability and by key informants. The study involved psychiatric assessment of 100 patients with learning disabilities and key informants using the Psychiatric Assessment Schedule for Adults with a Developmental Disability (PAS-ADD), a semi-structured psychiatric interview developed specifically for people who have a learning disability. There was considerable disagreement between respondent and informant interviews; only 40.7% of cases were detected by both interviews. Respondents were more likely to report on autonomic symptoms and certain psychotic phenomena. Other anxiety and depression symptoms were more frequently reported by infcrnnants. The results indicate that it is crucial for sensitive case detection to complete both interviews where possible. If the respondent cannot be interviewed, panic disorder or phobias may be particularly difficult to detect.  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