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   2132篇
  免费   117篇
  国内免费   12篇
耳鼻咽喉   9篇
儿科学   26篇
妇产科学   23篇
基础医学   200篇
口腔科学   42篇
临床医学   227篇
内科学   622篇
皮肤病学   33篇
神经病学   209篇
特种医学   82篇
外科学   190篇
综合类   22篇
预防医学   113篇
眼科学   39篇
药学   70篇
中国医学   2篇
肿瘤学   352篇
  2022年   11篇
  2021年   26篇
  2020年   18篇
  2019年   25篇
  2018年   36篇
  2017年   29篇
  2016年   23篇
  2015年   31篇
  2014年   43篇
  2013年   71篇
  2012年   84篇
  2011年   115篇
  2010年   68篇
  2009年   55篇
  2008年   96篇
  2007年   97篇
  2006年   98篇
  2005年   130篇
  2004年   94篇
  2003年   99篇
  2002年   86篇
  2001年   89篇
  2000年   98篇
  1999年   83篇
  1998年   38篇
  1997年   26篇
  1996年   18篇
  1995年   22篇
  1994年   22篇
  1993年   19篇
  1992年   40篇
  1991年   45篇
  1990年   41篇
  1989年   41篇
  1988年   43篇
  1987年   31篇
  1986年   39篇
  1985年   22篇
  1984年   17篇
  1983年   21篇
  1982年   11篇
  1981年   8篇
  1979年   15篇
  1976年   12篇
  1975年   14篇
  1974年   10篇
  1972年   8篇
  1970年   8篇
  1968年   8篇
  1967年   8篇
排序方式: 共有2261条查询结果,搜索用时 10 毫秒
1.
Lymphocyte-predominant Hodgkin’s lymphoma (LPHL) differs in histologic and clinical presentation from classical Hodgkin’s lymphoma (cHL). Treatment of LPHL patients using standard Hodgkin’s lymphoma protocols leads to complete remission in more than 95% of patients. Survival and freedom from treatment failure are substantially worse in advanced-stage patients than for early-stage patients. Thus, patients in advanced stages and those in early stages with unfavorable risk factors should be treated similar to those with cHL. In contrast, patients with early-stage LPHL without risk factors might be sufficiently treated with reduced-intensity programs having less severe adverse effects. As a result, treatment of early LPHL is rather heterogeneous, including radiotherapy using extended-fleld technique, involved-fleld radiotherapy (IF-RT), combined-modality treatment, and, more recently, monoclonal antibodies. Watch-and-wait strategy plays an important role in pediatric oncology, to avoid adverse effects associated with therapy. IF-RT seems to be emerging as a treatment of choice for patients with stage IA LPHL; most larger study groups, such as the German Hodgkin Study Group and the European Organisation for Research and Treatment of Cancer, have adopted IF-RT as the treatment of choice for these patients.  相似文献   
2.
3.
4.
OBJECTIVE: Although the clinical course of Alzheimer disease (AD) is gradual, it is useful for a number of reasons to distinguish between different levels of severity. The Clinical Dementia Rating (CDR) has demonstrated high validity and reliability for this purpose, but it requires a considerable amount of data to be collected both from the patient and from an informant. In the present study, the authors mapped Mini-Mental State Examination (MMSE) scores onto CDR categories to determine how well the MMSE performs as a surrogate of the CDR as a timesaving method of staging dementia. METHOD: Eight hundred sixty-three probands, including 524 patients with probable AD, 92 patients with questionable dementia, and 247 with memory complaints but no objective cognitive impairment, were included. Cutoff scores were identified on one-half of the sample using a receiver operating characteristic analysis. The cutoff values were then applied to the other half of the sample, and the agreement between MMSE score ranges and CDR stages was determined by calculating Cohen's kappa. RESULTS: The MMSE discriminated well between CDR stages 0.5, 1, 2, and 3 but performed poorly in the separation between CDR stages zero and 0.5. The MMSE ranges were 30 for no, 26-29 for questionable, 21-25 for mild, 11-20 for moderate, and 0-10 for severe dementia. Substantial agreement between the two instruments was obtained for the categories mild (kappa=0.62, p<0.001, N=115), moderate (kappa=0.69, p<0.001, N=114), and severe dementia (kappa=0.76, p<0.001, N=39), whereas the agreement was moderate for no (kappa=0.44, p<0.001, N=120) and only fair for questionable dementia (kappa=0.28, p<0.001, N=42). CONCLUSION: The MMSE can be used as a surrogate measure for the CDR for the staging of dementia in AD.  相似文献   
5.
Hematologic profiles of 462 persons, mostly active-duty service members, were studied to determine whether hematologic differences between blacks and whites exist in a healthy population. Whites had significantly greater mean concentrations of leukocytes (6.73 vs 5.95 x 10(9)/L), neutrophils (3.96 vs 3.16 x 10(9)/L), and hemoglobin (153 vs 135 g/L for men, 147 vs 125 g/L for women). The mean differences were largely due to relatively symmetric shifts in the frequency distributions for these cell concentrations. No significant correlation was found between neutrophil count and morbidity from infection as measured by a standardized questionnaire. The use of separate hematologic reference values for blacks and whites should be considered.  相似文献   
6.
 In order to determine the dynamics of hematopoietic cell turnover, proliferative activity and incidence of apoptosis (programmed cell death) were evaluated in bone marrow trephine biopsies. Selection of patients (20 in each group) included in addition to a control group, idiopathic thrombocytopenia (ITP), reactive thrombocytosis (TH), secondary polycythemia-smokers' polyglobuly (PG), primary (essential-hemorrhagic) thrombocythemia (PTH), polycythemia vera (PV), and finally acute myeloid leukemia (AML). Apoptosis was demonstrated by the in situ end-labeling technique (ISEL) and proliferative activity by applying the monoclonal antibody PC10 raised against proliferating cell nuclear antigen (PCNA). To assess dynamic features of hematopoiesis, an index was calculated consisting of the ratio between PCNA-positive nuclei and the apoptotic cell fraction. This factor was termed the hematopoietic turnover index (HTI). Morphometric analysis revealed that the HTI was significantly increased in AML and PV. According to cell culture studies both disorders are characterized by either a prevalent proliferation of the myeloid or erythroid cell mass. On the other hand, PG, PTH, and TH showed no relevant enhancement of this index in comparison to the control specimen. In vitro experiment results are in keeping with the finding that PG and PTH are not associated with a significant expansion of the erythroid lineage (CFU-E). Similar to ITP and TH, in PTH megakaryocyte proliferation (CFU-MEG) is the predominant feature of cell turnover. Differences between PTH and TH are in line with the reduced in vitro formation of CFU-MEG in the latter disorder. In conclusion, our in situ study on turnover rates of the bone marrow in various neoplastic and reactive lesions extends previous experimental data on hematopoietic cell kinetics. Received: 10 March 1997 / Accepted: 18 May 1997  相似文献   
7.
8.
9.
10.
Reducing waste of intravenous solutions.   总被引:1,自引:0,他引:1  
A program to minimize the waste of i.v. drug solutions is outlined, and the results of audits to determine the effectiveness of the program are presented. The program for reducing i.v. solution waste at a 500-bed acute-care center involves measures to compound admixtures for individual shifts, recycle solutions, remove unused solutions from nursing units, use a standardized administration schedule and automatic stop orders, standardize total parenteral nutrient (TPN) solutions, use commercially prepared products when possible, verify telephone orders, and prepare labile products just before use. From January 1987 to January 1990, six 30-day audits were performed to determine the number of i.v. admixtures discarded. The audits showed the hospital's average rate of waste to be 3.27%, well below other published values. The medical and surgical intensive-care units, pediatrics wards, and general medicine units accounted for most of the waste, which was largely attributable to dosage changes and stat-type drugs ordered but never used. Poor communication between the pharmacy and the nursing units also contributed to sterile product waste. Although the audits showed that waste was already at a low level, they pointed out areas for further improvement. A computer linkup that gives physicians the formulas for i.v. solutions is being set up, the list of standardized TPN solution formulas is being expanded to include condition-specific solutions, and clinical pharmacists are establishing better communication with the nursing units. By using several methods to reduce the waste of i.v. solutions, a pharmacy department has limited the rate of waste to only 3.27%.  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