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   2356篇
  免费   295篇
  国内免费   62篇
耳鼻咽喉   24篇
儿科学   80篇
妇产科学   49篇
基础医学   374篇
口腔科学   34篇
临床医学   255篇
内科学   607篇
皮肤病学   44篇
神经病学   127篇
特种医学   124篇
外科学   203篇
综合类   58篇
预防医学   382篇
眼科学   51篇
药学   190篇
中国医学   4篇
肿瘤学   107篇
  2021年   25篇
  2019年   24篇
  2018年   30篇
  2016年   28篇
  2015年   31篇
  2014年   55篇
  2013年   73篇
  2012年   98篇
  2011年   94篇
  2010年   67篇
  2009年   78篇
  2008年   97篇
  2007年   153篇
  2006年   124篇
  2005年   127篇
  2004年   113篇
  2003年   93篇
  2002年   80篇
  2001年   75篇
  2000年   55篇
  1999年   82篇
  1998年   59篇
  1997年   59篇
  1996年   44篇
  1995年   43篇
  1994年   45篇
  1993年   38篇
  1992年   53篇
  1991年   41篇
  1990年   30篇
  1989年   44篇
  1988年   47篇
  1987年   40篇
  1986年   34篇
  1985年   41篇
  1984年   25篇
  1983年   29篇
  1982年   24篇
  1981年   34篇
  1980年   24篇
  1979年   33篇
  1978年   24篇
  1977年   26篇
  1976年   31篇
  1975年   23篇
  1974年   23篇
  1973年   20篇
  1972年   15篇
  1971年   19篇
  1968年   15篇
排序方式: 共有2713条查询结果,搜索用时 15 毫秒
61.
N A Black  E Thompson    C F Sanderson 《Gut》1994,35(9):1301-1305
The impact of open cholecystectomy on patients' symptoms and health status and their level of satisfaction has been examined to provide a basis for comparison with newer rival treatments. A prospective cohort study using patient and surgeon completed questionnaires before and six weeks after surgery was carried out in 14 general hospitals in eight European countries. Five hundred and eighty three patients were recruited consecutively in 1990 to 1991. Information on their symptoms, general health status, activities of daily living, and satisfaction with their care were collected. After surgery 42.8% of patients reported that they were free of symptoms. Symptoms varied in their responsiveness to surgery--six weeks after surgery 89% of those who had complained of vomiting had improved, 81% of nausea, 69% of loss of appetite, 65% of abdominal pain, and 51% of flatulence. In contrast 28.1% of patients still suffered from flatulence and 23.5% continued to complain of abdominal pain. Most patients' (62.7%) general health improved, 28% were unchanged, and 9.3% were worse. After surgery most patients reported no restrictions in their normal social activities (75-90% depending on the activity) and most (89.5%) felt the results of their operation had been as expected or better than expected. Most patients undergoing open cholecystectomy reported an improvement in their symptoms, health status, and social functioning. This was reflected in their high level of satisfaction. Some patients, however, gained no benefit and a small proportion were worse than before surgery.  相似文献   
62.
Epstein-Barr virus lymphoproliferation after bone marrow transplantation   总被引:16,自引:7,他引:16  
We review 15 cases of secondary B-cell lymphoproliferative disorders that occurred among 2,475 patients who received allogeneic bone marrow transplants (BMTs) at the Fred Hutchinson Cancer Research Center (Seattle) between 1969 and 1987. The histopathologic findings in 14 of the 15 patients spanned a wide spectrum of lymphoproliferative lesions. One patient had features characteristic of angioimmunoblastic lymphadenopathy. Epstein-Barr virus (EBV) genomic sequences were identified by Southern blot analysis in each of the 13 patients evaluated. Ten of the 12 lesions evaluated originated in donor cells. In two patients, who had mixed chimerism after transplantation, the lesions originated in host cells. The combined evidence from immunoglobulin light chain staining and the analysis of immunoglobulin heavy chain gene rearrangement indicated that the lesions in most patients represented polyclonal proliferations that gave rise to clonal subpopulations. The results indicate an overall actuarial incidence of 0.6% for this complication in BMT recipients. Anti-CD3 monoclonal antibody (MoAb) treatment of acute graft-v-host disease (GVHD) and T cell depletion of the donor marrow were statistically significant risk factors, and GVHD appeared to play a contributing role, particularly in the setting of human leukocyte antigen (HLA) disparity. Two patients had no identifiable risk factors. Prophylaxis or treatment with acyclovir had no detectable effect in the patients; all but two died with uncontrolled lymphoproliferation.  相似文献   
63.
Interactions between astrocytes and endothelial cells are believed to play an important role in the control of blood-brain barrier permeability and transport. Astrocytes and endothelial cells respond to a variety of stimuli with an increase of intracellular free calcium ([Ca2+]i) that is propagated to adjacent cells as an intercellular Ca2+ wave. We hypothesized that intercellular Ca2+ signaling also occurs between astrocytes and endothelial cells, and we investigated this possibility in co-cultures of primary astrocytes and an endothelial cell line using caged messengers. Intercellular Ca2+ waves, induced by mechanical stimulation of a single cell, propagated from astrocytes to endothelial cells and vice versa. Intercellular Ca2+ waves could also be induced by flash photolysis of pressure-injected caged inositol trisphosphate (IP3) and also by applying the flash to remote noninjected cells. Ca2+ waves induced by flash photolysis propagated from endothelial cells to astrocytes but not from astrocytes to endothelial cells even though caged IP3 diffused between the two cell types. Flash photolysis of caged Ca2+ (NP-EGTA) resulted in an increase of [Ca2+]i but did not initiate an intercellular Ca2+ wave. We conclude that an increase of IP3 in a single cell is sufficient to initiate an intercellular Ca2+ wave that is propagated by the diffusion of IP3 to neighboring cells and that can be communicated between astrocytes and endothelial cells in co-culture. By contrast, Ca2+ diffusion via gap junctions does not appear to be sufficient to propagate an intercellular Ca2+ wave. We suggest that intercellular Ca2+ waves may play a role in astrocyte-endothelial interactions at the blood-brain barrier. GLIA 24:398–407, 1998. © 1998 Wiley-Liss, Inc.  相似文献   
64.
Background The National Health Strategy envisages a health system incorporating patient views; and providing accessible, consultant-led dialysis services with patient choice of dialysis modality, in all regions. Aims To describe patients’ experiences of renal services against National Health Strategy objectives. Methods Telephone interviews with 192 dialysis patients from three hospitals in the Eastern region. Results One-quarter of participants (16% of haemodialysis [HD] and 46% of peritoneal dialysis patients) lived outside the Eastern region, and travelled there because dialysis was not available locally. Two-thirds (65%) had a choice of dialysis modality. High satisfaction with interpersonal care was observed (83–98% satisfaction). Dissatisfaction with physical environment included parking (39–56%), waiting areas (62–69%), HD unit space (74%). Regarding support services, dietary services were satisfactory (92–95%), with lower satisfaction ratings for social and financial support services (62%). Conclusions Structural and management issues must be addressed to advance a quality agenda for renal care in Ireland.  相似文献   
65.
66.
67.
When the entire body of dogs was exposed to 450 units of Roentgen irradiation a hemorrhagic syndrome developed which was characterized by thrombo-cytopenia, prolonged clotting and bleeding times, and neutropenia. The prothrombin time remained normal until about 24 hours before death. The calcium, phosphorus, and magnesium levels were not altered. Fibrinogen was present but syneresis was poor. Toluidine blue and protamine sulfate, substances which can inhibit the biologic action of heparin, restored the clotting time to normal. The hemorrhagic state was not materially altered by transfusions, vitamin K, or vitamin C. Toluidine blue and protamine sulfate were ineffective in the control of hemorrhage produced by dicumarol. The defect responsible for bleeding after irradiation appeared to be the presence in the circulation of an anticoagulant whose properties, so far as tested, were indistinguishable from those of heparin.  相似文献   
68.
Aspirin is currently the most cost-effective drug for the secondary prevention of cardiovascular disease, but treatment failures are relatively common. Several factors have been linked to these recurrent vascular events in patients prescribed aspirin, including smoking, drug interactions, nonadherence, comorbid conditions, and aspirin resistance. The term aspirin resistance has been used to describe not only an absence of the expected pharmacologic effects of aspirin on platelets but also poor clinical outcomes, such as recurrent vascular events, in patients treated with aspirin. Aspirin resistance is perhaps more precisely understood as the phenomenon of measurable, persisting platelet activation that occurs in patients prescribed a therapeutic dose of aspirin and may underlie an unknown proportion of aspirin treatment failures. Key challenges for future research are to standardize a definition of aspirin resistance and to compare whether different measures of platelet activation, either alone or in combination, independently predict cardiovascular events. These challenges must be met before researchers conduct studies to assess the clinical utility of testing on patient outcomes and cost-effective prescribing.  相似文献   
69.
This paper reports the findings of a study which was carried out to evaluate the educational preparation of cancer and palliative care nurses in England. The study was carried out in three stages and covered the following areas; documentary analysis of curriculae, assessment of practice, patients and professionals views of threshold and expert practice. The findings suggested that although there was widespread compliance with a national standard for cancer nursing, this was not the case for palliative care nursing. There was uncertainty about what should be assessed in practice and ambiguity about what was actually assessed. Partnership with children and their parents, clinical skills, multi-disciplinary working, and personal attributes were the main foci for expectations of threshold practice but an expert panel had difficulty in describing the attributes of higher level practice. The paper also describes how some of recommendations from the study are being taken forward in current policy and practice.  相似文献   
70.
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