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   309篇
  免费   19篇
耳鼻咽喉   3篇
儿科学   10篇
妇产科学   6篇
基础医学   37篇
口腔科学   5篇
临床医学   42篇
内科学   54篇
皮肤病学   14篇
神经病学   16篇
特种医学   4篇
外科学   29篇
综合类   1篇
一般理论   1篇
预防医学   41篇
眼科学   14篇
药学   21篇
中国医学   2篇
肿瘤学   28篇
  2023年   3篇
  2021年   13篇
  2020年   9篇
  2019年   5篇
  2018年   21篇
  2017年   5篇
  2016年   8篇
  2015年   12篇
  2014年   13篇
  2013年   17篇
  2012年   26篇
  2011年   33篇
  2010年   17篇
  2009年   12篇
  2008年   19篇
  2007年   22篇
  2006年   10篇
  2005年   7篇
  2004年   12篇
  2003年   8篇
  2002年   12篇
  1996年   1篇
  1995年   3篇
  1994年   1篇
  1993年   1篇
  1988年   1篇
  1985年   1篇
  1982年   1篇
  1978年   1篇
  1962年   1篇
  1961年   1篇
  1949年   1篇
  1948年   2篇
  1947年   1篇
  1945年   1篇
  1942年   3篇
  1941年   1篇
  1940年   3篇
  1939年   1篇
  1938年   2篇
  1937年   1篇
  1934年   1篇
  1933年   1篇
  1932年   1篇
  1931年   3篇
  1930年   1篇
  1929年   1篇
  1924年   2篇
  1922年   1篇
  1914年   1篇
排序方式: 共有328条查询结果,搜索用时 125 毫秒
41.
OBJECTIVE: Nowadays, registration of patient data on paper is gradually being replaced by registration using an intensive care information system (ICIS). The aim of this study was to evaluate the effect of the use of an ICIS on nursing activity. DESIGN: Randomized controlled trial with a crossover design. SETTING: An 18-bed medical-surgical ICU in a teaching hospital. PATIENTS, NURSES AND INTERVENTIONS: During a 6week period 145 consecutive adult patients admitted to the ICU after uncomplicated cardiothoracic surgery were randomized into two groups: for one group the documentation was carried out using a paper-based registration (Paper), in the second group an ICIS was used for documentation. MEASUREMENTS AND RESULTS: The nursing activities for these patients were studied during two separate periods: the admission period and the registration phase (the period directly following the admission procedure). The duration of the admission procedure was measured by time-motion analysis and the nursing activities in the registration phase were studied by work sampling methodology. All nursing activities during the registration phase were grouped in four main categories: patient care, documentation, unit-related and personal time. The duration of the admission procedure was longer in the ICIS group (18.1+/-4.1 versus 16.8+/-3.1 min, p<0.05). In the registration phase, a 30% reduction in documentation time (Paper 20.5% of total nursing time versus ICIS 14.4%, p<0.001), corresponding to 29 min (per 8h nursing shift) was achieved. This time was completely re-allocated to patient care. CONCLUSIONS: The use of the present ICIS in patients after cardiothoracic surgery alters nursing activity; it reduces the time for documentation and increases the time devoted to patient care. Electronic supplementary material: is available if you access this article at http://dx.org/10.1007/s00134-002-1542-9. On that page (frame on the left side), a link takes you directly to the supplementary material.  相似文献   
42.
The role of p53 in suppression of KSHV cyclin-induced lymphomagenesis   总被引:3,自引:0,他引:3  
Kaposi's sarcoma-associated herpesvirus (KSHV) encodes a cyclin D homolog, K cyclin, that is thought to promote viral oncogenesis. However, expression of K cyclin in cultured cells not only triggers cell cycle progression but also engages the p53 tumor suppressor pathway, which probably restricts the oncogenic potential of K cyclin. Therefore, to assess the tumorigenic properties of K cyclin in vivo, we transgenically targeted expression of K cyclin to the B and T lymphocyte compartments via the E micro promoter/enhancer. Around 17% of E micro -K cyclin animals develop lymphoma by 9 months of age, and all such lymphomas exhibit loss of p53. A critical role of p53 in suppressing K cyclin-induced lymphomagenesis was confirmed by the greatly accelerated onset of B and T lymphomagenesis in all E micro -K cyclin/p53(-/-) mice. However, absence of p53 did not appear to accelerate K cyclin-induced lymphomagenesis by averting apoptosis: E micro -K cyclin/p53(-/-) end-stage lymphomas contained abundant apoptotic cells, and transgenic E micro -K cyclin/p53(-/-) lymphocytes in vitro were not measurably protected from DNA damage-induced apoptosis compared with E micro -K cyclin/p53(wt) cells. Notably, whereas aneuploidy was frequently evident in pre-lymphomatous tissues, end-stage E micro -K cyclin/p53(-/-) tumors showed a near-diploid DNA content with no aberrant centrosome numbers. Nonetheless, such tumor cells did harbor more restricted genomic alterations, such as single-copy chromosome losses or gains or high-level amplifications. Together, our data support a model in which K cyclin-induced genome instability arises early in the pre-tumorigenic lymphocyte population and that loss of p53 licenses subsequent expansion of tumorigenic clones.  相似文献   
43.
44.
45.

Background

The industrial uses of indium, a rare metal with no known physiological role in humans, have increased dramatically over the past 15 years.The results of animal toxicity studies showing pulmonary and systemic effects as well as some reports in workers have created a growing concern about the possible occurrence of toxic effects in exposed workers. Validated biomarkers to assess exposure to indium are not available.

Objectives

This work aimed at investigating the kinetics of indium in urine (In-U) and plasma (In-Pl) in workers manufacturing In ingots and mainly exposed to hardly water-soluble In compounds. All nine workers from the In department of a large metallurgical concern participated in the study as well as 5 retired workers and 20 controls.

Methods

Personal breathing zone air was collected throughout the work shift on Monday and Friday. Blood and urine samples were collected, before and after the shift, on the same day as the air sampling and on preshift the next Monday after a non-working week-end. Moreover, rats were given either InCl3 by intraperitoneal injection or In2O3 by pharyngeal aspiration, In was followed in plasma during 120 days and measured in tissues 120 days after exposure.

Results

Higher In-Pl and In-U concentrations were found in both current (range 0.32–12.61 μg/L plasma; 0.22–3.50 μg/g creat) and former (0.03–4.38 μg/L plasma; 0.02–0.69 μg/g creat) workers compared with controls (<0.03 μg/L plasma; <0.02 μg/g creat). Both biological parameters were highly correlated but no correlation was found between In-air (10–1030 μg/m3) and In-Pl or In-U. Normalizing In-U by the urinary creatinine concentration reduced the inter- (from 90% to 70%) and intra-individual variability (from 54% to 35%). In-Pl remained remarkably stable along the working week (inter- and intra-individual variability: 89% and 10%, respectively). Neither In-U nor In-Pl significantly increased during the day or the week. A week-end without occupational exposure was not sufficient to reach the background In-Pl and In-U levels measured in controls. The results of the experimental investigations confirmed the hypothesis that inhalation of hardly soluble In compounds may cause accumulation of In in the body leading to a prolonged “endogenous exposure” from both a lung depot of “insoluble” particles that are progressively absorbed and from a retention depot in other internal organs.

Conclusion

This study shows that in workers exposed to hardly soluble In compounds, In-U and In-Pl are very sensitive to detect exposure and mainly reflect long-term exposure. In-Pl levels are particularly stable for a given individual. In-U might be more influenced than In-Pl by recent exposure. Both parameters remained high years after withdrawal from exposure, indicating a possible endogenous exposure and a prolonged risk of pulmonary and systemic diseases even after work exposure has ceased.  相似文献   
46.
47.
Survival from pancreatic adenocarcinoma remains extremely poor, approximately 5% at 5 years. Risk factors include smoking, high body mass index (BMI), family history of pancreatic cancer, and long‐standing diabetes; in contrast, allergies are associated with reduced risk. Little is known about associations between these factors and survival. We analyzed overall survival in relation to risk factors for 475 incident cases who took part in a hospital based case–control study. Analyses were conducted separately for those who did (160) and did not (315) undergo tumor resection. Kaplan‐Meier methods were used to describe survival according to smoking, BMI, family history, diabetes, and presence of allergies. Cox proportional hazards models were used to adjust for covariates. There was no association with survival based on smoking, family history, or history of diabetes in either group. Among patients with resection, those with allergies showed nonstatistically significant longer survival, a median of 33.1 months (95% CI: 19.0–52.5) vs. 21.8 months (95% CI: 18.0–33.1), p = 0.25. The adjusted hazard ratio (HR) was 0.72 (95% CI: 0.43–1.23), p = 0.23. Among patients without resection, those with self‐reported allergies survived significantly longer than those without allergies: 13.3 months (95% CI: 10.6–16.9) compared to 10.4 months (95% CI: 8.8–11.0), p = 0.04, with an adjusted HR of 0.68 (95% CI: 0.49–0.95), p = 0.02. Obesity was nonsignificantly associated with poorer survival, particularly in the resected group (HR = 1.62, 95% CI: 0.76–3.44). The mechanisms underlying the association between history of allergies and improved survival are unknown. These novel results need to be confirmed in other studies.  相似文献   
48.
49.
50.
A 76-year-old male was admitted with Braunwald IIIB unstable angina and treated with intravenous heparin. Coronary angiography 20 days later revealed a severe stenosis in the left circumflex artery. During coronary angioplasty thrombus developed in the circumflex artery, extended in the left main and lead to its occlusion. Normal left coronary artery patency and flow were achieved after intracoronary and intravenous administration of abciximab, and multiple stenting. Platelet-count decrease and an ELISA assay documented the presence of heparin-induced thrombocytopenia with thrombosis syndrome (HITTS). HITTS should be suspected after acute thrombus formation during coronary angioplasty.  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