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   916篇
  免费   78篇
  国内免费   9篇
耳鼻咽喉   4篇
儿科学   43篇
妇产科学   13篇
基础医学   80篇
口腔科学   26篇
临床医学   141篇
内科学   246篇
皮肤病学   44篇
神经病学   26篇
特种医学   123篇
外科学   102篇
综合类   13篇
预防医学   42篇
眼科学   3篇
药学   22篇
肿瘤学   75篇
  2023年   8篇
  2021年   8篇
  2020年   6篇
  2019年   12篇
  2018年   20篇
  2017年   18篇
  2016年   27篇
  2015年   23篇
  2014年   37篇
  2013年   35篇
  2012年   37篇
  2011年   35篇
  2010年   32篇
  2009年   58篇
  2008年   24篇
  2007年   30篇
  2006年   37篇
  2005年   34篇
  2004年   23篇
  2003年   21篇
  2002年   27篇
  2001年   11篇
  2000年   14篇
  1999年   28篇
  1998年   35篇
  1997年   39篇
  1996年   37篇
  1995年   28篇
  1994年   26篇
  1993年   32篇
  1992年   14篇
  1991年   18篇
  1990年   12篇
  1989年   21篇
  1988年   19篇
  1987年   23篇
  1986年   12篇
  1985年   13篇
  1984年   10篇
  1983年   10篇
  1982年   3篇
  1981年   10篇
  1980年   5篇
  1978年   3篇
  1977年   3篇
  1976年   5篇
  1973年   2篇
  1971年   3篇
  1965年   2篇
  1963年   2篇
排序方式: 共有1003条查询结果,搜索用时 0 毫秒
111.
Potential effectiveness of stored cord blood (non-frozen) for emergency use   总被引:1,自引:0,他引:1  
Bone marrow has been used for a number of years to assist patients who have accidentally received potentially lethal levels of irradiation. The intent of the transplant is to replace the victim's own bone marrow that has been injured from the irradiation or to act as temporary support to allow the patient's own marrow to recover. Following the Chernobyl disaster, some victims received bone marrow that was HLA matched or partially matched. However, donor marrows were difficult to obtain in adequate numbers; as a substitute for bone marrow, frozen fetal liver cells were used as a source of hematopoietic stem cells. The use of fetal livers, however, was unsuccessful. Human umbilical cord blood, currently considered an excellent source of hematopoietic stem cells, was not used at Chernobyl. For several years, we have been able experimentally to keep SJL/J mice alive with the use of human umbilical cord blood after the animals received lethal levels of irradiation. This finding suggests that under certain conditions human cord blood does not have to be HLA matched to facilitate rescue from irradiation. In addition, there are reports of unmatched HLA cord blood being used successfully for marrow transplantation. If human cord blood does not have to be matched for HLA, there may be emergency cataclysmic circumstances where the availability of umbilical cord blood may be of considerable value. To simulate a clinical situation such as a nuclear accident, in which human cord blood might serve as a source of stem cells for marrow transplantation, we attempted to rescue immunocompetent mice after 900 cGY of irradiation with the use of (nonfrozen) human cord blood stored in a blood bank. The blood was stored under routine conditions (3–6 °C) for 5 and 7 days in special bags that allow transmission of oxygen. Following lethal levels of irradiation, the cord blood was administered to the animals and a significant survival rate was obtained.  相似文献   
112.
Oxidative stress can generate a mass of oxygen free radicals (OFR) in the cells, and these OFRs can induce several acute and chronic symptoms and diseases. If the amount of the generated OFRs overwhelms the antioxidant capacity of the cells, the pathophysiological changes may lead to the death of the cell or the development of chronic degenerative diseases.  相似文献   
113.
114.
Background  Pemphigus is an autoimmune disease characterized by the formation of intra-epidermal blisters. Patients develop auto-antibodies against desmoglein 1 and 3 proteins and induce acantholysis.
Objective  This work addresses the issue of whether the Fas pathway mediates acantholysis. Furthermore, the possible suppliers of the Fas pathway were investigated.
Methods  Seventeen biopsies of pemphigus patients were studied by haematoxylin and eosin staining, and apoptosis was defined by TUNEL. The expression of Fas, FasL and caspase 3 was studied by in situ hybridization and immunohistochemistry. Cell infiltrates were studied by immunofluorescence with monoclonal anti-CD3, CD4, CD8, CD19 and CD69.
Results  All of the biopsies showed intra-epidermal blisters, acantholytic cells and inflammatory infiltrates. The blisters expressed Fas, FasL and caspase 3. Cell infiltrates were composed of CD8 and a few CD4+CD69+ cells. Additionally, CD19+ cells were detected. Interestingly, the Fas expression was increased in acantholytic cells and perilesional keratinocytes. Incidentally, these cells exhibited apoptotic features. Interestingly, the CD8 cells expressed FasL.
Conclusion  This paper presents the morphological evidence that apoptosis and acantholysis are linked. Therefore, the Fas pathway is associated with CD8 cells in pemphigus lesions.

Conflicts of interest


None declared.  相似文献   
115.
116.
Due to progress in lung transplantation, post-transplantation osteoporosis becomes an important problem. We determined bone mineral density (BMD) in 74 lung transplantation candidates, among them 24 patients with cysticfibrosis, 16 with chronic obstructive pulmonary disease, 14 with pulmonary fibrosis, and 11 with pulmonary hypertension. The mean T score (+/- SD) was -2.6 +/- 1.3 at femoral neck (FN), -2.2 +/- 1.6 at Ward's triangle (WT) and -2.3 +/- 1.5 at lumbar spine (LS). Osteoporosis was found in 61% of the patients at FN, 45% at WT and 50% at LS. Patients with different underlying lung diseases were similarly affected, not only those with cystic fibrosis but also others, including patients with pulmonary hypertension. No association was found between BMD and age, gender, menstrual condition in women and testosterone level in men. A negative correlation was found between chronic glucocorticoid use and T scores. Body mass index correlated positively (p < 0.01) with T scores at any site and the correlation was also significant for the 2 largest subgroups. Loss of lung function (FEV1) also was associated with lower T scores. No correlation was found between BMD and biochemical indices of bone turnover. Multivariate analysis revealed BMI and glucocorticoid use as independent risk factors. We conclude that osteoporosis is a very common condition in patients with end-stage pulmonary disease, independent of the underlying diagnosis. In view of additional bone loss under immunosuppressive treatment after lung transplantation, early diagnosis and prevention of osteoporosis in the pretransplant period should receive high priority.  相似文献   
117.
Summary A limited cortical resection including the rolandic fissure and the pre-and postcentral cortical regions was carried out in a patient suffering from epilepsia partialis continua resistant to antiepileptic drugs. The histological examination revealed several foci of very large neurons distributed with no laminar organization in the depth of the rolandic fissure and in the crown of the primary motor and primary somatosensory areas; these lesions were consistent with focal cortical dysplasia. In addition, decreased numbers of neurons, astrocytosis and proliferation of capillaries, compatible with chronic tissue necrosis, were found in the inferior regions of the banks of the rolandic fissure. Subpopulations of local-circuit neurons were examined with parvalbumin, calbindin D-28k and somatostatin immunocytochemistry. Focal areas of cortical dysplasia contained abnormal immunoreactive neurons. Huge parvalbumin-immunoreactive cells were distributed at random and resembled axo-axonic (chandelier) and basket neurons. Abnormal calbindin D-28k-immunoreactive cells were reminiscent of double-bouquet neurons and multipolar cells. Very large somatostatin-immunoreactive cells were seldom observed in the dysplastic foci. On the other hand, areas of tissue necrosis displayed massive reduction of immunoreactive cells and fibers. Abnormalities in the morphology and distribution of local-circuit (inhibitory) neurons observed here for the first time in focal cortical dysplasia may have a pivotal role in the appearance and prolongation of electrical discharges and continuous motor signs in human focal epilepsy.Supported in part by a grant FIS 90E1263  相似文献   
118.
119.
120.
OBJECTIVES: To evaluate simultaneously several possible risk factors for blood bank specimen hemolysis. METHODS: This was a prospective cohort study of emergency department and labor and delivery patients to estimate the effect of various factors on the risk of blood bank specimen hemolysis. Study variables included patient demographics, type and gauge of needle or catheter, anatomic location of venipuncture, and patient care area. Hemolysis was determined by blood bank laboratory technicians. Cox proportional hazards multivariate regression modeling was performed to estimate the adjusted relative risks for hemolysis. RESULTS: Of the 605 subjects with complete data, 194 (32.1%) subjects had blood specimens drawn directly with a steel needle, and 411 (69.1%) had specimens drawn through a Vialon (BD Medical Systems, Inc., Sandy, UT) intravenous (IV) angiocatheter. The overall risk of hemolysis for all was 7%, 10% for Vialon IV angiocatheters and 1.5% for steel needles. In the multivariate analysis, the factors most closely associated with hemolysis were the use of Vialon IV catheters and sampling from an anatomic site other than the antecubital area. CONCLUSIONS: Blood bank specimens drawn from Vialon IV catheters (particularly smaller gauge catheters) and from veins outside the antecubital area are at significantly increased risk to hemolyze.  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