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   304篇
  免费   14篇
  国内免费   20篇
耳鼻咽喉   1篇
儿科学   12篇
妇产科学   2篇
基础医学   24篇
口腔科学   11篇
临床医学   25篇
内科学   49篇
皮肤病学   5篇
神经病学   9篇
特种医学   155篇
外科学   6篇
综合类   3篇
预防医学   5篇
眼科学   1篇
药学   24篇
肿瘤学   6篇
  2020年   1篇
  2019年   2篇
  2018年   4篇
  2017年   1篇
  2016年   9篇
  2015年   12篇
  2014年   9篇
  2013年   4篇
  2012年   4篇
  2011年   3篇
  2010年   8篇
  2009年   14篇
  2008年   19篇
  2007年   29篇
  2006年   10篇
  2005年   11篇
  2004年   8篇
  2003年   5篇
  2002年   12篇
  2001年   14篇
  2000年   8篇
  1999年   11篇
  1998年   25篇
  1997年   15篇
  1996年   6篇
  1995年   10篇
  1994年   10篇
  1993年   9篇
  1991年   6篇
  1990年   1篇
  1989年   8篇
  1988年   9篇
  1987年   4篇
  1986年   7篇
  1985年   6篇
  1984年   4篇
  1983年   2篇
  1982年   3篇
  1981年   1篇
  1980年   4篇
  1977年   2篇
  1976年   4篇
  1975年   4篇
排序方式: 共有338条查询结果,搜索用时 15 毫秒
81.
AIM:To assess the current diagnostic and therapeutic management and the clinical implications of congenital single coronary artery(SCA) in adults.METHODS:We identified 15 patients with a SCA detected from four Dutch angiography centers in the period between 2010 and 2013.Symptomatic patients who underwent routine diagnostic coronary angiography(CAG) for suspected coronary artery disease and who incidentally were found to have isolated SCA were analyzed.RESULTS:Fifteen(7 females) with a mean age of 58.5 ± 13.78 years(range 43-86) had a SCA.ConventionalCAG demonstrated congenital isolated SCA originating as a single ostium from the right sinus of Valsalva in 6 patients and originating from the left in 9 patients.Minimal to moderate coronary atherosclerotic changes were found in 4,and severe stenotic lesions in another 4 patients.Seven patients were free of coronary atherosclerosis.Runs of non-sustained ventricular tachycardia were documented in 2 patients,one of whom demonstrated transmural ischemic changes on presentation.Myocardial perfusion scintigraphic evidence of transmural myocardial ischemia was found in 1 patient due to kinking and squeezing of the SCA with an interarterial course between the aorta and pulmonary artery.Multi-slice computed tomography(MSCT) was helpful to delineate the course of the anomalous artery relative to the aorta and pulmonary artery.Percutaneous coronary intervention was successfully performed in 3 patients.Eight patients were managed medically.Arterial bypass graft was performed in 4 patients with the squeezed SCA.CONCLUSION:SCA may be associated with transient transmural myocardial ischemia and aborted sudden death in the absence of coronary atherosclerosis.The availability and sophistication of MSCT facilitates the delineation of the course of a SCA.We present a Dutch case series and review of the literature.  相似文献   
82.
Broudy  VC; Kovach  NL; Bennett  LG; Lin  N; Jacobsen  FW; Kidd  PG 《Blood》1994,83(8):2145-2152
Stem cell factor (SCF) is a hematopoietic growth factor produced by fibroblasts and endothelial cells that stimulates the growth of primitive hematopoietic cells. SCF triggers cell growth by binding to the c-kit receptor. Because endothelial cells can respond to certain hematopoietic growth factors, we tested human umbilical vein endothelial cells for display of the c-kit receptor and examined the effect of SCF on endothelial cell proliferation, adhesion molecule expression, and production of tissue factor. Quantitative binding experiments with 125I-SCF showed both high-affinity (Kd = 42 pmol/L) and low-affinity (Kd = 1.7 nmol/L) c-kit receptors. There were approximately 1,100 high-affinity c-kit receptors, and 5,400 low- affinity c-kit receptors per endothelial cell. Enzyme immunoassays showed that endothelial cells released soluble c-kit receptor and SCF. The transmembrane form of SCF was detected by indirect immunofluorescence analysis using monoclonal or polyclonal anti-SCF receptor antibodies. The addition of SCF (100 ng/mL) did not alter endothelial cell proliferation over a 7-day period. Similarly, there was no change in the release of tissue factor or expression of inducible endothelial adhesion molecules (intercellular adhesion molecule-1, endothelial-leukocyte adhesion molecule-1, and vascular cell adhesion molecule-1) measured by enzyme-linked immunosorbant assay at 4 and 24 hours after SCF addition. The neutralizing anti-c-kit receptor monoclonal antibody SR-1 blocked binding of 125I-SCF to the c- kit receptor by 98% but did not alter endothelial cell proliferation or adhesion-molecule expression. c-kit receptors were also detected on adult endothelial cells lining small blood vessels in normal human lymph nodes. These data indicate that normal human endothelial cells produce SCF and show high-affinity c-kit receptors that have the capacity to dimerize. The lack of response to exogenous SCF may be because of intracellular activation of the c-kit receptor via autocrine production of SCF. Alternatively, SCF and c-kit may play a role other than stimulation of proliferation, adhesion-molecule display, or tissue factor production by endothelial cells. The production of soluble c-kit receptors by normal human endothelial cells may serve to regulate the bioactivity of SCF within the bone marrow microenvironment.  相似文献   
83.
Two human hemopoietic growth factors involved in monocytopoiesis, interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) were studied for their ability to stimulate blood monocytes and to bind to the monocyte membrane. Both cytokines maintained monocyte/macrophage numbers during long-term culture and increased cell size as compared with controls. Effects on cell numbers were present at low cytokine concentrations (6 to 20 pmol/L), whereas enhanced 3H-thymidine incorporation was observed only at higher concentrations (greater than or equal to 60 pmol/L). Autoradiographic studies showed only 1% to 3% of stimulated monocytes with nuclear grains. These results suggest that the primary mechanism for IL-3 and GM-CSF-induced maintenance of monocyte/macrophage numbers in humans is through an effect on cell survival. Surface receptors for both IL-3 and GM-CSF were studied by using 125I-labeled recombinant human (rh) cytokines and performing Scatchard analyses. Both cytokines showed curvilinear Scatchard plots, and computer analyses favored a two-site binding model. High-affinity binding data for 125I rhIL-3 (Kd 7.7 to 38.2 pmol/L; receptor number/cell 95 to 580) and for 125I rhGM-CSF (Kd 4.7 to 38.9 pmol/L; receptor number/cell 8 to 67) show similar binding affinities for the two cytokines but a lower receptor number/cell for 125I rhGM-CSF. Low-affinity binding characteristics for 125I rhIL-3 (Kd 513 to 939 pmol/L; receptor number/cell 179 to 5,274) and for 125I rhGM- CSF (Kd 576 to 1,120 pmol/L; receptor number/cell 130 to 657) show a similar pattern for the two cytokines. Specificity of 125I rhIL-3 and 125I rhGM-CSF binding to monocytes was established by the ability of the homologous cytokine to inhibit binding and the inability of a range of other cytokines to compete at 100-fold excess molar concentration. It is important, however, that binding of 125I rhIL-3 was partially inhibited by rhGM-CSF and that rhIL-3 partially inhibited binding of 125I rhGM-CSF to the monocyte membrane under conditions shown to prevent receptor internalization. The degree of inhibition varied between 25% and 80% in different experiments, and quantitative inhibition experiments showed that 1,000-fold excess concentrations of competitor failed to inhibit binding of the heterologous ligand completely. These results demonstrate that human IL-3 and GM-CSF have similar effects on growth and survival of human monocytes in vitro and suggest that these and other common biological effects may be mediated either through a common receptor or through distinct receptors associated on the monocyte membrane.  相似文献   
84.
Lum  LG; Munn  NA; Schanfield  MS; Storb  R 《Blood》1986,67(3):582-587
The results of this study show that donor-derived immunity can be detected and persists in long-term survivors with and without chronic graft-v-host disease (GVHD) after human marrow grafting. Seventy-one marrow recipients (60 long-term and 11 short-term survivors) were studied for the presence of specific serum IgG antibodies to tetanus toxoid (TT), and 46 marrow recipients (35 long-term and 11 short-term) were tested for antibodies to diphtheria toxoid (DT) and measles virus after marrow grafting using an enzyme-linked immunosorbent assay. Of the 60 long-term survivors, 31 were healthy and 29 had chronic GVHD. None of the recipients were immunized to the test antigens postgrafting. Most long-term healthy recipients exhibited antibody titers to the recall test antigens, whereas only a minority of those with chronic GVHD had antibody titers to recall antigens. In healthy long-term recipients (greater than or equal to one year postgrafting) whose donors were immune to the test antigens, 25 of 31 had titers to TT, 11 of 17 had titers to DT, and 12 of 20 had titers to measles. In recipients with C-GVHD, 13 of 29 had titers to TT, six of 15 had titers to DT, and six of 15 had titers to measles virus. Within 100 days postgrafting, 11 of 11 had anti-TT titers, ten of ten had anti-DT titers, and seven of eight had antimeasles virus titers.  相似文献   
85.
86.
短暂性脑缺血发作病因诊断的评估   总被引:7,自引:0,他引:7  
短暂性脑缺血发作病因诊断的评估魏岗之缺血性脑血管意外是中国老人致死和致残的主要原因,短暂性脑缺血发作(TIA)是脑血管意外的警告信号。其中约有1/3将发展为脑血管意外,一次TIA预示有罹患脑血管意外的危险,因而能使医生在发病前进行干预。TIA是由于血...  相似文献   
87.
88.
The stem cell inhibitor, macrophage inflammatory protein-1 alpha (MIP-1 alpha) or LD78, protects multipotent hematopoietic progenitors in murine models from the cytotoxic effects of chemotherapy. Clinical use of human MIP-1 alpha during chemotherapy could therefore lead to faster hematologic recovery and may allow dose intensification. We have also shown that human MIP-1 alpha causes the rapid mobilization of hematopoietic cells, suggesting an additional clinical use in peripheral blood stem cell transplantation. However, the clinical evaluation of human MIP-1 alpha is complicated by its tendency to associate and form high molecular weight polymers. We have produced a variant of rhMIP-1 alpha, BB-10010, carrying a single amino acid substitution of Asp26 > Ala, with a reduced tendency to form large polymers at physiologic pH and ionic strength. This greatly increases its solubility, facilitating its production and clinical formulation. We confirmed the potency of BB-10010 as a human MIP-1 alpha-like agonist in receptor binding, calcium mobilization, inhibition of colony formation, and thymidine suicide assays. The myeloprotective activity of BB-10010 was shown in a murine model of repeated chemotherapy using hydroxyurea. BB-10010 is therefore an ideal variant with which to evaluate the therapeutic potential of recombinant human MIP-1 alpha.  相似文献   
89.
Kaphingst KA, Facio FM, Cheng M‐R, Brooks S, Eidem H, Linn A, Biesecker BB, Biesecker LG. Effects of informed consent for individual genome sequencing on relevant knowledge. Increasing availability of individual genomic information suggests that patients will need knowledge about genome sequencing to make informed decisions, but prior research is limited. In this study, we examined genome sequencing knowledge before and after informed consent among 311 participants enrolled in the ClinSeq? sequencing study. An exploratory factor analysis of knowledge items yielded two factors (sequencing limitations knowledge; sequencing benefits knowledge). In multivariable analysis, high pre‐consent sequencing limitations knowledge scores were significantly related to education [odds ratio (OR): 8.7, 95% confidence interval (CI): 2.45–31.10 for post‐graduate education, and OR: 3.9; 95% CI: 1.05, 14.61 for college degree compared with less than college degree] and race/ethnicity (OR: 2.4, 95% CI: 1.09, 5.38 for non‐Hispanic Whites compared with other racial/ethnic groups). Mean values increased significantly between pre‐ and post‐consent for the sequencing limitations knowledge subscale (6.9–7.7, p < 0.0001) and sequencing benefits knowledge subscale (7.0–7.5, p < 0.0001); increase in knowledge did not differ by sociodemographic characteristics. This study highlights gaps in genome sequencing knowledge and underscores the need to target educational efforts toward participants with less education or from minority racial/ethnic groups. The informed consent process improved genome sequencing knowledge. Future studies could examine how genome sequencing knowledge influences informed decision making.  相似文献   
90.
The objective of this study was to assess the cost of caring for patients with psoriasis in Italy according to the AISP study (Associazione Italiana Studi Psoriasi or Italian Association for Studies on Psoriasis), involving 104 university and hospital centres and 7992 patients in 1994. The mean yearly cost of care for a single patient was calculated at 905 Euros. Hospitalization accounted for more than four-fifths of the costs, therapy for about one-eighth (systemic therapies were the most expensive) and office visits and day hospitals for the remainder. In our study series less than 20% of patients accounted for more than 90% of the total costs.  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