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   1530篇
  免费   88篇
  国内免费   78篇
耳鼻咽喉   10篇
儿科学   83篇
妇产科学   11篇
基础医学   215篇
口腔科学   28篇
临床医学   228篇
内科学   269篇
皮肤病学   57篇
神经病学   86篇
特种医学   353篇
外科学   94篇
综合类   29篇
预防医学   63篇
眼科学   11篇
药学   91篇
中国医学   1篇
肿瘤学   67篇
  2022年   7篇
  2021年   11篇
  2020年   8篇
  2019年   10篇
  2018年   19篇
  2017年   10篇
  2016年   13篇
  2015年   20篇
  2014年   28篇
  2013年   31篇
  2012年   39篇
  2011年   31篇
  2010年   34篇
  2009年   53篇
  2008年   37篇
  2007年   78篇
  2006年   21篇
  2005年   47篇
  2004年   35篇
  2003年   33篇
  2002年   46篇
  2001年   39篇
  2000年   35篇
  1999年   48篇
  1998年   73篇
  1997年   82篇
  1996年   51篇
  1995年   64篇
  1994年   46篇
  1993年   43篇
  1992年   34篇
  1991年   40篇
  1990年   31篇
  1989年   57篇
  1988年   45篇
  1987年   41篇
  1986年   40篇
  1985年   63篇
  1984年   27篇
  1983年   22篇
  1982年   33篇
  1981年   27篇
  1980年   33篇
  1979年   10篇
  1978年   5篇
  1977年   17篇
  1976年   20篇
  1975年   13篇
  1973年   7篇
  1967年   6篇
排序方式: 共有1696条查询结果,搜索用时 15 毫秒
61.
62.
PURPOSE: To evaluate a modified algorithm in the diagnostic management of polytraumatized patients by using whole body multislice CT (MSCT) as primary diagnostic tool. MATERIAL AND METHODS: Between June 1999 and October 2000 532 polytraumatized patients were referred to the emergency department. 336 polytraumatized patients were primarily evaluated using whole body MSCT according to the "Innsbruck Emergency Algorithm." MSCT is performed immediately after cardiovascular stabilization of the patient. During the initial stabilization period free intraabdominal fluid is excluded or demonstrated by abdominal ultrasound. Time-consuming conventional radiographs are omitted with exception of an optimal chest X-ray. In patients with suspected or obvious arterial injuries or fractures the multislice-CT-dataset is used to perform 2D and 3D reconstructions in order to optimize visualization of additional skeletal and vascular injuries. RESULTS: By means of whole body MSCT it was possible to detect all injuries. The diagnostic advantage of whole body MSCT as compared to conventional X-ray was analyzed in 111 consecutive polytraumatized patients with an injury severity score (ISS) of 34.77. The early use of MSCT shortened the time for diagnostic work-up substantially (approximately 50%). CONCLUSION: Whole body multislice-CT used as primary diagnostic tool in the management of polytraumatized patients allows for a fast, accurate and comprehensive diagnostic work-up.  相似文献   
63.
Deliberate self-harm (DSH) has been one of the major health problems of adolescents in the U.K. for many years. Any changes in rates of DSH or the demographic characteristics of the patient population are likely to have important implications for clinical services and for future suicidal behaviour. Following a decline in rates in the late 1970s and mid 1980s, there were signs in the late 1980s that rates were beginning to increase again. We have used data collected by the Oxford Monitoring System for Attempted Suicide on the basis of patients presenting to the general hospital in Oxford to review trends in DSH in under 20-year-olds between 1985 and 1995. There was a substantial increase in the numbers of teenage DSH patients during the 11-year study period, with an increase between 1985-1986 and 1994-1995 of 27.7% in males, 28.3% in females, and 28.1% overall. There were no demographic changes within the catchment area to explain a change of this size. As rates of repetition of DSH also increased in both sexes during the study period the overall number of episodes of DSH rose even more between 1985-1986 and 1994-1995 (+56.9% in males, +46.3% in females, and +49.4% overall). As in previous studies the majority of adolescents had interpersonal problems and/or difficulties with studying or employment. Self-poisoning with paracetamol and paracetamol compounds became increasingly common such that by 1995 these were used in almost two-thirds of overdoses. The recent increase in DSH in adolescents has important implications for general hospital and adolescent psychiatric services. The greater frequency of repetition of DSH may herald increased future suicide rates. The case for restricting the amount of paracetamol available is overwhelming. Evaluative trials of specific interventions following adolescent DSH are urgently required.  相似文献   
64.
OBJECTIVE: To clinically characterize affected individuals in families with paroxysmal kinesigenic dyskinesia (PKD), examine the association with infantile convulsions, and confirm linkage to a pericentromeric chromosome 16 locus. BACKGROUND: PKD is characterized by frequent, recurrent attacks of involuntary movement or posturing in response to sudden movement, stress, or excitement. Recently, an autosomal dominant PKD locus on chromosome 16 was identified. METHODS: The authors studied 11 previously unreported families of diverse ethnic background with PKD with or without infantile convulsions and performed linkage analysis with markers spanning the chromosome 16 locus. Detailed clinical questionnaires and interviews were conducted with affected and unaffected family members. RESULTS: Clinical characterization and sampling of 95 individuals in 11 families revealed 44 individuals with paroxysmal dyskinesia, infantile convulsions, or both. Infantile convulsions were surprisingly common, occurring in 9 of 11 families. In only two individuals did generalized seizures occur in later childhood or adulthood. The authors defined a 26-cM region using linkage data in 11 families (maximum lod score 6.63 at theta = 0). Affected individuals in one family showed no evidence for a shared haplotype in this region, implying locus heterogeneity. CONCLUSIONS: Identification and characterization of the PKD/infantile convulsions gene will provide new insight into the pathophysiology of this disorder, which spans the phenotypic spectrum between epilepsy and movement disorder.  相似文献   
65.
PGR +331 A/G and increased risk of epithelial ovarian cancer.   总被引:2,自引:0,他引:2  
Childbearing and use of oral contraceptives are known to lower the risk of ovarian cancer, and it has been suggested that progesterone or progestin exposures play a role in these associations. The effects of progesterone may be mediated in part through the progesterone receptor, which exists in two functionally distinct protein isoforms, hPR-A and hPR-B. It is known that individuals carrying the A allele of the progesterone receptor gene (PGR) polymorphism, +331 A/G (rs10895068), have greater production of the hPR-B receptor isoform. We therefore examined the association between PGR +331 A/G genotype and risk of ovarian cancer in a population-based study of 490 cases and 534 controls in the state of Connecticut. Adjusted for various reproductive and other factors, a statistically significant increased risk was seen for carriage of the A allele compared with GG genotype [odds ratio (OR), 1.68; 95% confidence interval (95% CI), 1.09-2.59]. When subjects were considered separately according to menopausal status, no increased risk with the A allele was seen for premenopausal women (OR, 0.96; 95% CI, 0.46-2.02) but significantly increased risk was found for postmenopausal women (OR, 2.31; 95% CI, 1.31-4.06). Similar increased risks particularly among postmenopausal women were seen for all histologic tumor types. These findings have been observed before for breast and endometrial cancer, although not for ovary, but still suggest that an hPR-B mechanism may be involved in ovarian neoplasia.  相似文献   
66.
The use of heat in wound healing has been demonstrated to aid oxygen flow and hence healing in acute wounds. However, the situation in chronic wounds is less clear. This study was designed to investigate the benefits of using a radiant heat therapy system in the treatment of Stage 3 and 4 pressure ulcers. Despite randomisation, patients receiving radiant heat therapy were more infirm than those receiving standard treatment. This prospective, single-centre, randomised trial resulted in an accelerated rate of healing for those receiving heat therapy compared to a standard treatment: time difference to 75% of original area = 6.4 days (p = 0.057), to 50% of original area = 9.6 days (p = 0.039), time to 25% = 7.2 days (p = 0.01). This new development warrants further investigation to fully assess the role of a thermoregulation system in chronic wound healing.  相似文献   
67.
68.
High mobility group proteins 1 and 2 recognize chromium-damaged DNA   总被引:2,自引:0,他引:2  
Chromium (Cr) is a human carcinogen and a potent DNA damaging agent. Incubation of DNA with CrCl3 resulted in dose-dependent binding of Cr to DNA and, at concentrations >20 microM, altered the electrophoretic mobility of a 100 bp oligonucleotide. We also demonstrate that high mobility group (HMG) proteins 1 and 2 bind Cr-damaged DNA (Cr-DNA). Protein binding was lesion density-dependent, with maximal binding to DNA treated with 100 microM CrCl3. HMG2 binds to Cr-DNA with a calculated Kd of approximately 10(-9) M. These proteins also bound DNA obtained from chromate-treated cells. These results suggest that the covalent attachment of Cr to DNA induces alterations in DNA structure which are recognized by HMG1 and HMG2. Therefore, these proteins may function as Cr-damaged DNA recognition proteins in vivo and as a consequence of binding, may play a role in directing the cellular response to Cr-DNA adduct formation.   相似文献   
69.
It is postulated that a vigorous host inflammatory response in the cystic fibrosis lung contributes to lung injury. Tumour necrosis factor-alpha (TNF-alpha) may play a part in that process and in the generation of leukotrienes. Therefore, the relationships between sputum TNF-alpha, leukotriene concentration, and lung function abnormalities in 16 children with cystic fibrosis were investigated. Each subject provided sputum samples and performed spirometry. TNF-alpha was measured by enzyme linked immunosorbent assay; individual leukotrienes were separated using high performance liquid chromatography and quantified by radioimmunoassay. The geometric mean concentration of TNF-alpha was 129.7 pg/ml and 95% confidence interval 48.2 to 348.3. Mean (SEM) leukotriene B4 (LTB4) was 97.8 (22.9) pmol/g and total cysteinyl leukotrienes were 60.9 (14.8) pmol/g. Mean (SD) forced expiratory volume in one second (FEV1) of the group was 53 (15)% of predicted and forced vital capacity (FVC) was 65 (14)% of predicted. There was a significant positive correlation between TNF-alpha and both LTB4 and the total cysteinyl leukotriene sputum content. An inverse relationship existed between TNF-alpha and FEV1 and FVC. Moreover, a negative correlation was observed between sputum LTB4 and FEV1 and FVC. These results suggest that TNF-alpha and the leukotrienes may participate in the airways inflammation and airflow obstruction observed in cystic fibrosis subjects and support the hypothesis that TNF-alpha upregulates the 5-lipoxygenase pathway in vivo.  相似文献   
70.
The cytokines interleukin-1 and interleukin-2 participate in the inflammatory response, and may contribute to hypergammaglobulinaemia G and the development of lung injury in cystic fibrosis. Anti-inflammatory treatment with corticosteroids may attenuate this response. The effect of a 12 week course of oral prednisolone on spirometry and serum concentrations of interleukin-1 alpha (IL-1 alpha), soluble interleukin-2 receptor (sIL-2R), and IgG was investigated in 24 children with cystic fibrosis. Prednisolone was administered, in a double blind and placebo controlled manner, at an initial dose of 2 mg/kg daily for 14 days and tapered to 1 mg/kg on alternate days for 10 weeks. The treated group (n = 12) experienced an increase in forced expiratory volume in one second and forced vital capacity at 14 days, however, these changes were smaller at 12 weeks. In the treated group, change in pulmonary function was associated with decreased serum IgG and cytokine concentrations. Prednisolone suppresses serum concentrations of these cytokines, which may participate in the inflammatory response, the excessive synthesis of IgG, and airflow obstruction observed in cystic fibrosis patients.  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