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   11738篇
  免费   840篇
  国内免费   30篇
耳鼻咽喉   122篇
儿科学   390篇
妇产科学   218篇
基础医学   1909篇
口腔科学   262篇
临床医学   1093篇
内科学   2190篇
皮肤病学   332篇
神经病学   1563篇
特种医学   467篇
外科学   966篇
综合类   61篇
一般理论   4篇
预防医学   818篇
眼科学   354篇
药学   792篇
中国医学   16篇
肿瘤学   1051篇
  2023年   101篇
  2022年   81篇
  2021年   276篇
  2020年   225篇
  2019年   256篇
  2018年   308篇
  2017年   277篇
  2016年   379篇
  2015年   412篇
  2014年   492篇
  2013年   652篇
  2012年   926篇
  2011年   938篇
  2010年   533篇
  2009年   522篇
  2008年   828篇
  2007年   803篇
  2006年   760篇
  2005年   731篇
  2004年   632篇
  2003年   586篇
  2002年   544篇
  2001年   100篇
  2000年   86篇
  1999年   99篇
  1998年   117篇
  1997年   109篇
  1996年   64篇
  1995年   68篇
  1994年   48篇
  1993年   43篇
  1992年   44篇
  1991年   39篇
  1990年   24篇
  1989年   20篇
  1988年   24篇
  1987年   31篇
  1986年   35篇
  1985年   23篇
  1984年   28篇
  1983年   23篇
  1982年   20篇
  1981年   16篇
  1979年   26篇
  1978年   29篇
  1977年   20篇
  1976年   26篇
  1975年   16篇
  1974年   20篇
  1973年   15篇
排序方式: 共有10000条查询结果,搜索用时 39 毫秒
41.
OBJECTIVE: We investigated outcomes after surgical therapy in patients with active infective endocarditis (AIE) with regard to survival in relation to surgical urgency, valve position, number of valves implanted and abscess formation. We aimed to identify independent risk factors for early mortality. METHODS AND RESULTS: Two hundred and fifty-five patients received Shelhigh bioprostheses between February 2000 and March 2007. A total of 74.1% had native and 25.9% prosthetic AIE. Surgery was regarded as urgent in 57.3% and as an emergency procedure in 38.4%. There was a highly significant difference in survival rate between patients who were operated on urgently versus in an emergency (p<0.0001), between single and double valve replacement (p=0.0206) and between patients with and without abscess formation (p=0.0245). There were two cases of early reinfection (0.78%) and six of late reinfection (2.35%) leading to re-operation. CONCLUSIONS: The survival of patients differs significantly in dependence on their surgical urgency. Better outcome could have been achieved if patients had been referred earlier for surgery and operated upon before heart failure or septic shock developed. Long-term survival was better in patients without abscess formation. The low reinfection rate of Shelhigh bioprostheses in AIE is promising and the early and mid-term results achieved need to be verified in the long-term course.  相似文献   
42.
43.
Immune defense capacity differs between men and women. Whereas men are more prone to infection and sepsis, women more commonly develop autoimmune diseases. We investigated the difference in cytokine secretion between males and females in response to different immune stimuli. Whole blood from 154 healthy volunteers (age 24 +/- 5.2; 82 females, 72 males) was collected within 2 h on 2 consecutive days. Blood from males produced significantly more tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-6, and IL-8 than blood from females in response to a high concentration of either lipopolysaccharide (LPS) or lipoteichoic acid (LTA), whereas IL-10 and interferon-gamma (IFN-gamma) secretion did not differ. Normalization of cytokine measurement to individual monocyte counts cancelled these differences for all parameters except TNF-alpha. Stimulation with a lower concentration of LPS (100 pg/mL) produced even stronger differences in cytokine release, which were not cancelled by normalization to the producing cells. The coefficients of variation (CV) of the LPS-induced and LTA-induced cytokine responses were higher in blood from women than men for all parameters and stimuli measured. Thus, the stronger innate immune response of males in comparison to females appears to stem not only from a difference in monocyte counts but also from the steepness of the response curve.  相似文献   
44.
Introduction Postoperative treatment for colorectal cancer depends on tumor stage as defined by the International Union Against Cancer (UICC). Adjuvant chemotherapy is not recommended in patients without lymph node involvement (UICC stages I and II). As many as 20–30% of these patients, however, will develop recurrence. Aims and objectives We conducted this study to determine the presence of disseminated tumor cells in the lymph nodes by quantitative real-time polymerase chain reaction (QRT-PCR) for cytokeratin 20 (CK20) in an attempt to provide supplementary information compared to histopathological findings. Materials and methods Using a standard QRT-PCR assay, we examined primary tumors and 391 lymph nodes from 31 patients with completely resected colorectal cancer. Results Of the 31 primary tumors, 29 were positive for CK20 by QRT-PCR. Discussion An examination of the lymph nodes from the 29 patients with CK20-positive primary tumors revealed that 35 (92.1% sensitivity) of the 38 histopathologically positive lymph nodes and 54 (16.7%) of the 324 histopathologically negative lymph nodes were positive by molecular analysis. CK20 expression was detected in 10 (100%) of 10 patients with a histopathologically positive lymph node status (pN1). In 9 (47.4%) of 19 patients with negative histopathological results (pN0), we detected a CK20 mRNA signal in at least one lymph node. Whereas eight patients with histopathologically negative lymph nodes could be upstaged on the basis of the molecular findings, no patient would be downstaged. Conclusion Our results suggest that QRT-PCR for CK20 is a useful tool for the quantitative detection of micrometastases in the regional lymph nodes. We introduce a standardized procedure that integrates a molecular diagnostic technique in the clinical staging.  相似文献   
45.
Editorial     
Ohne Zusammenfassung  相似文献   
46.
The acrocephalosyndactylies (ACS) are a group of inherited disorders characterized by premature fusion of cranial sutures in association with abnormalities of the hands and feet. Based on their clinical features, different types of ACS have been described. We here report on a family with 9 individuals affected with ACS III (Saethre-Chotzen syndrome), 5 of them severely. Clinical features of the patients are presented with regard to differential diagnostic delineations.  相似文献   
47.
Eight commercially available HPD-photosensitizers intended for photodynamic therapy were tested in a murine tumour model with regard to their therapeutic efficacy. The regrowth delay of the fibrosarcoma SSK-2 on the mouse C3H, Neuherberg-line, was determined 3, 24, 48 and 72 h after injection of the drugs (dose: 9 mg kg–1 body weight). The corresponding pharmacodynamics, as measured by regrowth delay, were approximated by an exponential function and the characterizing coefficients derived. These coefficients served to quantify the photodynamic properties of the drugs.The pharmacodynamics of five substances were compared with those obtained fluorometrically. The latter showed shorter decay constants than the therapy-correlated substances which indicates different metabolic behaviour of the therapeutic and diagnostically useful fluorescent components of haematoporphyrin-derived photosensitizers.  相似文献   
48.
Based on experimental data from animal studies different theories regarding the size of an epileptic focus have been postulated which range from single pacemaker cells to extended neuronal networks. We report a case which gives further information about the size of a human epileptic focus which can trigger manifest epileptic seizures. We report a 22-year-old man with medically refractory temporal lobe epilepsy. This patient suffered from brief complex partial seizures and frequent epigastric auras. To differentiate a mesiotemporal from a temporolateral seizure origin the patient was implanted with a 10 contact depth electrode from a posterior approach into the right hippocampus, and additional temporobasal/temporolateral subdural strip electrodes. Depth recordings revealed an electrographic status with continuous rhythmic sharp wave activity (1 Hz), the field of which was confined to a diameter of less than 1 cm in the anterior hippocampus, whereas temporobasal subdural strip electrodes did not display this activity. Periodically, spread of this activity occurred to the amygdala, to the posterior part of the hippocampus, and less often to the temporobasal cortex. Most seizure patterns remained subclinical, few of them became symptomatic as partial seizures. This case demonstrates that a hippocampal epileptic focus causing electrographic focal status epilepticus may be limited to a volume of less than 1 cm in diameter. This observation is discussed with regard to implantation strategies and to possible superselective resective or modulatory approaches in the treatment of such limited epileptogenic areas.  相似文献   
49.
PURPOSE. To propose a new NANDA diagnosis, self‐neglect. DATA SOURCES. Research studies and literature published from a variety of disciplines including nursing as well as primary research. DATA SYNTHESES. This diagnosis can be used to describe a constellation of self‐care problems of varying severity and impact on the health and well‐being of people who self‐neglect. Included are two subtypes of self‐neglect based on the degree of intentionality. Clarification of self‐neglect is long overdue because self‐neglect presents conceptual, identification, and intervention problems for nurses, healthcare workers, and for medicolegal systems across settings and in many countries. CONCLUSION. The proposed diagnosis, self‐neglect, fills a gap in current standardized terminology. This diagnosis will contribute significantly to nurses leading the way in the explication of an interdisciplinary and international health concern. PRACTICE AND POLICY IMPLICATIONS. Developing self‐neglect as a recognized nursing label is vital to clinicians and policy makers within and across countries. Appreciating less serious/non‐life‐threatening presentations will give nurses a care perspective to improve the health and well‐being of those in earlier stages of self‐neglect. Definitions for this phenomenon will contribute to care planning and interventions, leading to consistency in practice and research.  相似文献   
50.
Summary Carbetimer, a new synthetic low molecular weight polyelectrolyte with a novel structure displayed antitumor activiy in a number of animal tumor model systems and in vitro investigations. Based on these findings it was brought to a phase I clinical trial in patients with advanced malignant disease after failure of conventional treatment or with no conventional treatment available. Forty-eight patients received 98 courses. The schedule was a one hour i.v. infusion every four weeks. The starting dose was 180 mg/m2 and dose escalation was performed according to a modified Fibonacci formula up to 16,690 mg/m2. At least three patients were treated at each dose level and each patient was eligible to receive repeat courses at the same dose, until progressive disease or dose-limiting toxicity intervened. No hematological toxicity was encountered. Some adverse effects such as reversible proteinuria, hypercalcaemia, pain at infusion site, nausea and vomiting and fatigue were seen partly in a dose-related manner but did not represent the maximum tolerated dose (MTD). The limiting toxicity at the highest dose level of 16,690 mg/m2 consisted of ocular symptoms (light flashes) accompanied by a modest decrease of blood pressure and nausea or vomiting during a one hour infusion. 16,690 mg/m2/1 hour was considered the MTD. There were four deaths on study, all considered diseaserelated. Fourteen patients had stable disease for more than two courses, which, however, could also be explained by the natural course of disease. No clear-cut antitumor responses were noted in our study center.The recommended dose for phase II trials derived from our results is 12,550 mg/m2/2 hours. However, with regard to experiences in other phase I studies, the subsequent phase II studies will be performed with a dose of 6,500 mg/m2.  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