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   209篇
  免费   12篇
  国内免费   13篇
儿科学   13篇
基础医学   12篇
口腔科学   1篇
临床医学   26篇
内科学   56篇
皮肤病学   1篇
神经病学   5篇
特种医学   53篇
外科学   10篇
综合类   6篇
预防医学   10篇
眼科学   2篇
药学   32篇
肿瘤学   7篇
  2022年   1篇
  2021年   1篇
  2020年   1篇
  2019年   2篇
  2018年   6篇
  2017年   3篇
  2016年   3篇
  2015年   1篇
  2014年   2篇
  2013年   3篇
  2012年   3篇
  2010年   5篇
  2009年   5篇
  2008年   5篇
  2007年   4篇
  2006年   7篇
  2005年   4篇
  2004年   2篇
  2003年   6篇
  2001年   1篇
  2000年   3篇
  1999年   3篇
  1998年   17篇
  1997年   12篇
  1996年   22篇
  1995年   9篇
  1994年   10篇
  1993年   13篇
  1992年   5篇
  1991年   4篇
  1990年   7篇
  1989年   12篇
  1988年   16篇
  1987年   9篇
  1986年   2篇
  1985年   5篇
  1984年   3篇
  1983年   3篇
  1982年   6篇
  1981年   2篇
  1980年   1篇
  1977年   2篇
  1975年   3篇
排序方式: 共有234条查询结果,搜索用时 15 毫秒
151.
We investigated hematopoietic growth factor (HGF) and cytokine gene expression in the bone marrow (BM) and peripheral blood (PB) of healthy individuals as a starting point for delineating the physiologic role of cytokines in steady state hematopoiesis. BM biopsy specimens and PB samples from 7 healthy individuals were analyzed by polymerase chain reaction amplification of reverse-transcribed RNA using gene-specific primer sets. Consistent gene expression in the BM of all 7 individuals was detected for macrophage colony-stimulating factor (CSF), stem cell factor, interleukin-6 (IL-6), IL-7, erythroid-potentiating factor, erythroid-differentiating factor, and insulinlike growth factor 1, all cytokines with reported direct stimulatory effects on in vitro hematopoiesis. Of these, erythroid-potentiating factor and erythroid- differentiating factor appeared to be the only stimulating factors that were also expressed in the PB. Among the cytokines with inhibitory effects on in vitro hematopoiesis IL-4, tumor necrosis factor-alpha (TNF-alpha), TNF-beta, transforming growth factor-beta, and macrophage inflammatory protein-1 alpha were expressed in the BM of the 7 individuals. Except for TNF-alpha, the latter cytokines were also expressed in the PB. Consistent expression in the BM and PB of all tested individuals was also observed for IL-1 beta, IL-1 receptor antagonist, and IL-1 beta converting enzyme, which are all members of the IL-1 family with a possible indirect effect on hematopoiesis. Remarkably, no expression of granulocyte CSF, granulocyte-macrophage CSF, and IL-3 was found in the BM or PB of all investigated individuals (n = 15). This was also the case for IL-1 alpha, IL-2, IL-5, IL-9, IL- 12, IL-13, leukemia-inhibiting factor, interferon-gamma, and inhibin. Weak IL-8 and IL-10 expression was found in the BM and/or PB of a minority of investigated individuals. These findings provide insight into which cytokines or HGFs potentially are involved in the autocrine or paracrine regulation of in vivo steady state hematopoiesis. The absence of expression of granulocyte CSF, granulocyte-macrophage CSF, and IL-3 in the BM of healthy individuals implicates that it is highly unlikely that these HGFs are involved in the autocrine or paracrine regulation of constitutive hematopoiesis.  相似文献   
152.
Samuels  BL; Golomb  HM; Brownstein  BH 《Blood》1987,69(6):1570-1573
The mechanism of the antineoplastic effect of interferon (IFN) is not known and may result from direct effects on the neoplastic cells themselves, activation of intermediary effector cells, or a combination of these effects. The synthesis of specific proteins is induced in hairy cells when they are exposed to alpha-IFN in vitro. In particular, the called p80, is markedly induced. We investigated this effect in the hairy cells of seven patients in the leukemic phase of hairy cell leukemia who were being treated with subcutaneous (SC) IFN alpha 2b (r- Hu-IFN-alpha 2). Polyacrylamide gel electrophoresis (PAGE) was carried out on [35S]methionine-labeled whole cell lysates visualized by autoradiography and silver staining. Within 2 days of starting IFN therapy, induction of specific protein synthesis, including p80 was seen by [35S]methionine labeling in freshly isolated circulating hairy cells from 6 of 6 patients tested. Therefore, alpha-IFN has a direct biochemical effect on hairy cells in vivo that is similar to in vitro effects, at least with regard to p80 synthesis, although the kinetics of this effect may vary in the two situations.  相似文献   
153.
154.
Nitrogen mustard (NH2) and Nor-nitrogen mustard (Nor-HN2) both inhibit the polymerization of deoxyhemoglobin S in solution and in intact erythrocytes. Metabolic studies were undertaken to determine the feasability of an extracorporeal treatment with these or related agents. Glucose utilization, hexose monophosphate shunt activity, methemoglobin reduction, and incubation with acetylphenylhydrazine for Heinz body formation were performed, as well as specific assays for hexokinase, pyruvate kinase, glucose-6-phosphate dehydrogenase, glutathione reductase, ATP, reduced glutathione (GSH), and survival of autologous mustard-treated cells in rabbits. HN2 was found to enter red cells rapidly and bind to intracellular contents. Metabolic studies revealed no significant inhibition or alteration of function by Nor-HN2 at 10 mg/ml of whole blood. Rabbit red cell survival was also normal. HN2, however, inhibited glutathione reductase and blocked the free sulfhydryl group of GSH by forming serveral addition products of alkylated GSH. Heinz body test with acetylphenylhydrazine became positive in HN2-treated cells, and rabbit red cell survival was shortened considerably in the concentration range used to inhibit sickling. Ascorbic acid stimulation of the hexose shunt pathway was inhibited by HN2, but methylene blue stimulation remained unaffected. 14-C-HN2 remains bound to red cells in vivo, and the disappearance of radioactivity is similar to that found with 14-C-DFP (disopropylfluorophosphate). Oxygen affinity of both HN2 and Nor-HN2 treated human red cells remains virtually the same as that found in control samples. It is concluded that Nor-HN2 may be a suitable agent for an extracorporeal therapy, and that each mustard needs to be evaluated individually for its antisickling effects and its suitability for extracorporeal use.  相似文献   
155.
The diagnosis of idiopathic immune thrombocytopenia remains a clinical diagnosis based on the exclusion of other causes of immune and nonimmune thrombocytopenia. Measurement of platelet-associated Ig (PAIg), while sensitive, is nonspecific for the diagnosis of immune thrombocytopenia. Published experience of antigen capture assays (including monoclonal antibody immobilization of platelet antigens or MAIPA) suggest a high sensitivity and specificity (70% to 80%) in selected groups of patients. In a prospective evaluation of 158 patients with thrombocytopenia from all causes, we report a sensitivity of 51% and specificity of 80% for direct MAIPA assays. MAIPA was considerably better in discriminating immune from nonimmune thrombocytopenia than two assays of PAIgG. Antiplatelet antibodies detected by MAIPA were more frequently directed against the glycoprotein (GP) IIb/IIIa than the GP Ib/IX complex. Our experience suggests that MAIPA assays are useful in the laboratory assessment of thrombocytopenia, should be performed before therapy, and that some patients with 'nonimmune' thrombocytopenia may have genuine antiplatelet antibodies.  相似文献   
156.

Background

This study aimed at determining the prevalence of malaria and anemia among children in rural community of Okada, Edo State Nigeria, as well as to assess the level of use of Insecticide treated bed nets and its impact on prevalence of malaria and anemia among study population.

Methods

Thick blood films from 226 children with signs and symptoms of malaria in Okada community were stained and examined for presence of malaria parasites. Hemoglobin concentration of all children was also determined using standard method.

Result

A total of 185 (81.9%) children were infected with malaria parasite. Malaria parasitaemia was significantly affected by age (P =0.003). A significantly higher number of positive cases of malaria and anemia was observed in rainy season as compared to dry season (P<0.05). The prevalence of anemia in children was 47.3%. Malaria was a risk factor for development of anemia in children (OR=2.551; 95% CI=1.227, 5.305; P=0.015). Use of insecticide treated bed nets was recorded in 11(4.9%) of children studied, and did not significantly reduce the prevalence of malaria and anemia. However among malaria parasite infected children, its use significantly reduced the prevalence of anemia (OR=0.126; 95%CI=0.015, 1.047; P=0.031).

Conclusion

Malaria and anemia among children was high malaria intervention progammes by relevant agencies is strongly advocated.  相似文献   
157.
158.
Kuypers  FA; Lewis  RA; Hua  M; Schott  MA; Discher  D; Ernst  JD; Lubin  BH 《Blood》1996,87(3):1179-1187
The phospholipids of the human red cell are distributed asymmetrically in the bilayer of the red cell membrane. In certain pathologic states, such as sickle cell anemia, phospholipid asymmetry is altered. Although several methods can be used to measure phospholipid organization, small organizational changes have been very difficult to assess. Moreover, these methods fail to identify subpopulations of cells that have lost their normal phospholipid asymmetry. Using fluorescently labeled annexin V in flow cytometry and fluorescent microscopy, we were able to identify and quantify red cells that had lost their phospholipid asymmetry in populations as small as 1 million cells. Moreover, loss of phospholipid organization in subpopulations as small as 0.1% of the total population could be identified, and individual cells could be studied by fluorescent microscopy. An excellent correlation was found between fluorescence-activated cell sorter (FACS) analysis results using annexin V to detect red cells with phosphatidylserine (PS) on their surface and a PS-requiring prothrombinase assay using similar red cells. Cells that bound fluorescein isothiocyanate (FITC)-labeled annexin V could be isolated from the population using magnetic beads covered with an anti-FITC antibody. Evaluation of blood samples from patients with sickle cell anemia under oxygenated conditions demonstrated the presence of subpopulations of cells that had lost phospholipid asymmetry. While only a few red cells were labeled in normal control samples (0.21% +/- 0.12%, n = 8), significantly increased (P < .001) annexin V labeling was observed in samples from patients with sickle cell anemia (2.18% +/- 1.21%, n = 13). We conclude that loss of phospholipid asymmetry may occur in small subpopulations of red cells and that fluorescently labeled annexin V can be used to quantify and isolate these cells.  相似文献   
159.
Patient death in Intensive Care Units (ICU) can be sudden and unexpected, leading to emotionally charged situations and life changing circumstances for family members. Supporting families during and after this critical period is particularly challenging for ICU nurses who often feel dissatisfied with the way they deal with the situation. Bereavement programs in various areas of nursing have been reported to be beneficial in promoting normal grief patterns. There is, however, a lack of research in the area of evaluation of bereavement programs in adult ICUs. This paper presents the results of an Australia-wide audit on current practices in the area of bereavement programs within adult ICUs.

Surveys were sent to 117 adult Australian ICUs; 99 surveys were returned completed (84.6% response rate). It was identified that most surveyed units offer minimal components of bereavement programs, such as viewing of the deceased and communicating with family members. Less than one third (n=26) provide additional follow-up services in the form of telephone calls and sympathy cards or referral to additional services. Ten units employ some form of program evaluation. Verbal feedback from staff and families is the primary assessment method. Over half of responding ICUs indicated they are considering or interested in providing a bereavement program in their unit.

This study highlights the need for research-based data to support the introduction or deletion of strategies for bereavement programs using family-centred outcome measures. ICU nurses are interested in this area of clinical practice and require considerable support. It is recommended that this support can come via postgraduate and on-going education, hospital policies and procedures.  相似文献   

160.
碘杂环化合物(IHC-64,IHC-65,IHC-66)有抗心律失常、降血压,并表现钙拮抗效应。4,4′-二(二甲氨基)-二苯甲烷[4,4′-bis(dimethyl amino)-diphenyl methane,BDDM]是合成碘杂环化合物的前体物,与抗心律失常药利多卡因、安博律定(aprindine)等在化学结构上有相近之处,如苯环和碱性氨基。本实验观察了碘杂环前体物BDDM的抗实验性心律失常作用。并进一步探讨本系列合成物的构效关系。  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