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   280篇
  免费   38篇
  国内免费   12篇
耳鼻咽喉   1篇
儿科学   21篇
基础医学   10篇
口腔科学   12篇
临床医学   40篇
内科学   49篇
皮肤病学   2篇
神经病学   12篇
特种医学   41篇
外科学   14篇
综合类   5篇
预防医学   99篇
眼科学   4篇
药学   11篇
肿瘤学   9篇
  2023年   2篇
  2022年   5篇
  2021年   6篇
  2020年   5篇
  2019年   2篇
  2018年   8篇
  2017年   18篇
  2016年   9篇
  2015年   8篇
  2014年   10篇
  2013年   25篇
  2012年   6篇
  2011年   10篇
  2010年   12篇
  2009年   13篇
  2008年   5篇
  2007年   11篇
  2006年   9篇
  2005年   6篇
  2004年   8篇
  2003年   3篇
  2002年   3篇
  2001年   8篇
  1999年   7篇
  1998年   8篇
  1997年   12篇
  1996年   11篇
  1995年   12篇
  1994年   15篇
  1993年   6篇
  1992年   6篇
  1991年   2篇
  1989年   7篇
  1988年   6篇
  1987年   6篇
  1986年   4篇
  1985年   2篇
  1984年   6篇
  1983年   4篇
  1982年   4篇
  1980年   2篇
  1975年   1篇
  1969年   2篇
  1968年   1篇
  1965年   1篇
  1963年   1篇
  1957年   1篇
  1943年   2篇
  1939年   1篇
  1937年   1篇
排序方式: 共有330条查询结果,搜索用时 17 毫秒
71.
Background. Delivery of home parenteral nutrition (PN) is typically cycled over 12 hours. Discharge to home on PN is often delayed due to potential adverse events (AEs) associated with cycling PN. The purpose was to determine whether patients requiring long‐term PN can be cycled from 24 hours to 12 hours in 1 day instead of 2 days without increasing the risk of PN‐related AEs. Methods. Hospitalized patients receiving PN at goal calories infused over 24 hours without severe electrolyte or blood glucose abnormalities were eligible. Patients were randomly assigned to a 1‐step “fast‐track” protocol or 2‐step “standard” protocol. AEs were defined as hypoglycemia or hyperglycemia, new‐onset or worsening dyspnea, tachycardia, tachypnea, lower extremity or sacral edema, pulmonary edema, or abdominal ascites and were graded as minor or major. Results. In the 63 patients studied, the most prevalent PN‐related AE was hyperglycemia, occurring in 24.2% and 30.0% of patients in the fast‐track and standard groups, respectively. Overall, there was no significant difference in the prevalence of PN‐related minor AEs between fast‐track and standard groups (33.3% and 53.3%, P = .5). No major PN‐related AEs occurred in the fast‐track group, while 1 major PN‐related AE (pulmonary edema) occurred in the standard group. Conclusions. Fast‐track cycling is as safe as standard cycling in patients without diabetes mellitus or major organ dysfunction requiring long‐term PN. Fast‐track cycling could potentially expedite hospital discharge, resulting in decreased healthcare costs and improved patient satisfaction.  相似文献   
72.
73.
ObjectiveThe objective of this study was to learn about the experiences of principals and school food service directors with the Texas Public School Nutrition Policy.DesignSemistructured qualitative interviews were conducted to gain first hand reactions to the new nutrition policy.SettingData were gathered from Texas middle schools.ParticipantsPrincipals and food service directors from 24 schools randomly selected from 10 Texas Education regions were interviewed.Phenomenon of InterestParticipants were interviewed about their reactions to the implementation of the Texas School Nutrition Policy.AnalysisTwo researchers, using thematic analysis, independently analyzed each interview. Differences in coding were reconciled and themes were generated.ResultsThe themes that surfaced included resistance to the policy, policy development process, communication, government role, parental role, food rewards, fund raising, and leadership.Conclusions and implicationsResistance to the policy was not extreme. In the future a wider array of school personnel who are affected by school food regulations should be included in the development of new policies. It is critical to communicate with all concerned parties about the policy.  相似文献   
74.
75.
76.
A multi-site clinical study compared platelets chosen for refractory patients by prospective platelet crossmatching using stored donor platelets and HLA-based selection. Seventy-three patients who were refractory to random-donor platelets received two plateletpheresis components, one chosen by HLA-based criteria and the other by crossmatching. Patients were carefully evaluated to exclude nonimmune factors that could adversely affect transfusion results. Each of the five study sites used a crossmatch procedure with which it had experience. Results from this study indicate the following: 1) The overall rate of successful transfusion was similar when an HLA-based method of donor selection that includes all grades of matching and mismatching was compared to a crossmatch-based method of donor selection. 2) HLA-based selection that restricts recipients to grade A and BU matches was superior to a selection method based upon crossmatching alone. Donor selection based on HLA matching (grades A or BU) was also superior to selection based on any degree of HLA mismatching (grades BX, C, or D). 3) Selection of donors based on HLA-cross-reactive groups (defined by in vitro serologic crossreactivity) was no more successful than that based on grade C and D mismatches and was no more successful than selection by crossmatching alone. 4) Lymphocytotoxic and platelet antibodies were not detected in many of the enrolled patients, even though patients demonstrating nonimmune factors were eliminated from the study. It can be concluded that HLA-compatible (grades A and BU) platelets provide optimal support for refractory patients, but that crossmatch-selected platelets are acceptable as an alternative component.  相似文献   
77.
Six cases of immune hemolytic anemia attributed to donor-derived red cell antibodies after allogeneic bone marrow transplantation (BMT) are reported. In 2/6 cases, severe intravascular hemolysis was seen, 6/6 required increased red cell transfusion, and 1/6 was treated by plasma exchange. All recipients were receiving cyclosporine to prevent graft-v- host disease. Investigations showed that in each case, the donor lacked ABO or Rho(D) red cell antigens present in the recipient. The direct antiglobulin test was positive in 6/6. Relevant serum antibody (anti-A, four cases; anti-B, one case; anti-D, one case) was first detected one to three weeks after BMT. Eluates made from recipient red cells showed the same specificity as serum antibody. Maximum hemolysis occurred nine to 16 days after BMT, suggesting that active production of antibody by "passenger" donor lymphocytes was the likely mechanism of hemolysis, rather than passive transfer of antibody in the marrow infusion. Retrospective analysis of 21 consecutive cyclosporine-treated BMT patients receiving marrow lacking ABO or D antigens present in the recipient showed that (1) 15/18 patients tested had red cell antibody production against recipient red cell antigens; (2) despite the frequent presence of antibody specific for recipient red cell antigens, only 3/21 patients developed clinically significant hemolysis; (3) clinical hemolysis could not be predicted by donor or recipient red cell antibody titers. We conclude that although red cell antibody against recipient antigens is frequently produced after minor ABO and D mismatched BMT in cyclosporine-treated recipients, only 10% to 15% of cases develop clinically significant immune hemolysis. The data presented show that the most likely source of antibody is "passenger" donor lymphoid cells.  相似文献   
78.
We treated 93 patients with myelodysplastic syndrome using cyclophosphamide and either total body irradiation (n = 88) or busulfan (n = 5) followed by marrow transplantation. Sixty-five marrow donors were genotypically HLA-identical siblings and 28 were other family members or unrelated donors. Before transplantation all patients had either severe neutropenia or thrombocytopenia or had greater than 5% blasts in the marrow or peripheral blood. The probabilities of disease- free survival, relapse, and non-relapse mortality at 4 years were 41%, 28%, and 43%, respectively. Multivariate analysis revealed that younger age and shorter disease duration were significantly associated with improved disease-free survival and decreased non-relapse mortality. Relapse was seen only in patients with excess blasts at the time of transplantation (51% at 4 years). Patients younger than age 40 and without excess blasts had a 4-year disease-free survival of 62%. This study confirms that allogeneic marrow transplantation can cure some patients with myelodysplasia. Because of the favorable outcome in younger patients without excess blasts, we recommend that transplantation be considered early for patients younger than age 40, before disease progression or development of life-threatening cytopenias. For older patients and those with excess blasts, changes in the transplant procedure will be necessary to improve outcome.  相似文献   
79.
Wiskott-Aldrich syndrome (WAS) is a fully penetrant X-linked recessive disorder characterized by immunodeficiency, thrombocytopenia, and severe eczema. WAS is a life-threatening disease, with a poor quality of life and high mortality rate in childhood. The gene responsible for the disease has been localized to the proximal short arm of the X- chromosome and recently isolated through positional cloning and named WAS protein (WASP). We have characterized 17 WAS families. We have developed a rapid, nonradioactive screening protocol for identifying WASP gene alterations in genomic DNA. Our method allows simultaneous evaluation of single strand confirmation polymorphism and heteroduplex formation. We have identified 15 novel mutations that involve single basepair changes, or small insertions or deletions, all of which result in premature stop cordon, frame shift with secondary premature stop codon, or splice site defect. These studies document the considerable heterogeneity of the location of mutations in the WASP gene causing full-blown WAS and show the efficiency and rapidity of a screening approach for mutation identification in WAS that will be useful for carrier detection and prenatal diagnosis.  相似文献   
80.
Background: Compared with early enteral feeds, the delayed introduction and slow advancement of enteral feedings to reduce the incidence of necrotizing enterocolitis (NEC) are not well studied in extremely low birth weight (ELBW) infants. Objective: To study the effects of a standardized slow enteral feeding (SSEF) protocol in ELBW infants. Methods: ELBW infants who followed an SSEF protocol (September 2009 to December 2012) were compared with a similar group of historical controls (January 2003 to July 2009). Short‐term outcomes between the 2 groups were compared by propensity score (PS) analysis. Results: One hundred twenty‐five infants in the SSEF group were compared with 294 historical controls. Compared with the controls, feeding initiation day, full enteral feeding day, parenteral nutrition (PN) days, and total central line days were longer in the SSEF group. There was no significant difference in overall NEC (5.6% vs 11.2%, respectively; P = .10) or surgical NEC (1.6% vs 4.8%, respectively; P = .17) between the SSEF group and controls. However, in infants with birth weight <750 g, NEC (2.1% vs 16.2%, respectively; P < .01) or combined NEC/death (12.8% vs 29.5%, respectively; P = .03) was significantly less in the SSEF group compared with controls. In infants who survived to discharge, there was no significant difference in the discharge weight or length of stay in PS‐adjusted analysis. Conclusions: An SSEF protocol significantly reduces the incidence of NEC and combined NEC/death in infants with birth weight <750 g. Despite taking longer to achieve full enteral feeding on this protocol, surviving ELBW infants demonstrated comparable weight gain at discharge without prolonging their hospital stay.  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