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   175篇
  免费   16篇
  国内免费   5篇
耳鼻咽喉   1篇
儿科学   7篇
妇产科学   2篇
基础医学   9篇
口腔科学   21篇
临床医学   27篇
内科学   38篇
皮肤病学   8篇
神经病学   2篇
特种医学   65篇
外科学   3篇
综合类   2篇
预防医学   5篇
眼科学   1篇
药学   5篇
  2022年   1篇
  2021年   1篇
  2020年   1篇
  2019年   2篇
  2018年   8篇
  2017年   4篇
  2016年   2篇
  2015年   1篇
  2014年   3篇
  2013年   4篇
  2010年   6篇
  2009年   6篇
  2008年   3篇
  2007年   5篇
  2006年   2篇
  2005年   6篇
  2004年   1篇
  2003年   3篇
  2002年   1篇
  2000年   2篇
  1999年   1篇
  1998年   7篇
  1997年   12篇
  1996年   11篇
  1995年   11篇
  1994年   13篇
  1993年   14篇
  1992年   2篇
  1991年   4篇
  1990年   6篇
  1989年   11篇
  1988年   10篇
  1987年   5篇
  1986年   1篇
  1985年   6篇
  1983年   4篇
  1982年   4篇
  1981年   1篇
  1980年   3篇
  1978年   2篇
  1976年   5篇
  1975年   1篇
排序方式: 共有196条查询结果,搜索用时 15 毫秒
121.
122.
In modern obstetrics, the role of internal podalic version (IPV) is limited to delivery of the second twin. A retrospective study was conducted to assess the efficacy of IPV in singleton neglected shoulder presentation with fetal demise. Women with live fetuses, previous CS or contracted pelvis were excluded. The procedure involved repositioning the prolapsed hand under anaesthetic followed by breech extraction. 12 women were identified over a 19 month period and all underwent successful IPV. One woman had a postpartum haemorrhage. We conclude that, in singleton pregnancies with a transverse lie, IPV has a role to play in the delivery of dead fetuses.  相似文献   
123.
124.
125.
126.
127.
Broudy  VC; Lin  NL; Kaushansky  K 《Blood》1995,85(7):1719-1726
Thrombopoietin (Tpo), the ligand for the c-mpl receptor, is a major regulator of platelet production in vivo. Treatment of mice with purified recombinant Tpo increases platelet count fourfold and expands colony-forming unit-megakaryocyte (CFU-Meg) numbers. Other cytokines including interleukin-3 (IL-3), IL-6, IL-11, erythropoietin (Epo), and stem cell factor (SCF) can stimulate megakaryopoiesis. Therefore, we examined the effects of recombinant murine Tpo in combination with these cytokines on megakaryopoiesis in vitro. Murine marrow cells were cultured in agar in Iscove's modified Dulbecco's medium (IMDM) supplemented with 10% horse serum and beta-mercaptoethanol in the presence of recombinant growth factors, and CFU-Meg colonies were counted on day 5. Megakaryocyte ploidy was analyzed using murine marrow cells cultured for 5 days in IMDM supplemented with 1% nutridoma-SP and recombinant growth factors. Megakaryocytes were identified by labeling with the 4A5 antibody and ploidy was analyzed by flow cytometry. Tpo supported the growth of CFU-Meg in a dose-dependent manner. Although the addition of SCF (50 ng/mL), Epo (2 U/mL), or IL-11 (50 ng/mL) alone exerted only a modest effect on CFU-Meg growth, the combination of SCF plus Tpo, Epo plus Tpo, or IL-11 plus Tpo resulted in a synergistic enhancement of the number of CFU-Meg colonies. IL-3 alone supported CFU- Meg colony growth, and the effects of IL-3 plus Tpo or IL-6 plus Tpo on colony growth appeared to be approximately additive. Fifty percent of megakaryocytes generated in cultures containing IL-3 or Epo displayed < or = 16 N ploidy. In contrast, cultures containing Tpo uniquely generated large numbers (30% to 35% of the total) of megakaryocytes with > or = 64N ploidy. These results show that Tpo stimulates both proliferation of committed megakaryocytic progenitor cells and maturation of megakaryocytes, and that two multipotent cytokines, SCF and IL-11, as well as a late-acting erythroid cytokine, Epo, can synergize with Tpo to stimulate proliferation of CFU-Meg.  相似文献   
128.
129.
The structural abnormalities and functional characteristics of dysfunctional prothrombin variants in two new kindreds have been determined. Prothrombin Corpus Christi (family 1) was purified and found to have markedly reduced fibrinogen clotting activity, yet normal amidolytic and near-normal platelet aggregating activity. A transition (C to T) at nucleotide position 8885, present in the heterozygous form in affected family members, resulted in the substitution of Cys for Arg 382. This substitution results in the loss of a positive charge within the fibrinogen-binding exosite of thrombin, thus accounting for the observed functional defect. A heterozygous C to T transition was also present at position 19994 in other family members with a hypoprothrombinemic phenotype. This mutation results in the replacement of Gln 541 (CAA) by a premature stop codon (TAA). Prothrombin Dhahran (family 2) was found to have markedly reduced fibrinogen clotting activity, but normal amidolytic activity. Affected family members were found to have a G to A transition at nucleotide position 7312 resulting in the substitution of His for Arg 271. This substitution results in the abolition of a factor Xa cleavage site, yielding meizothrombin rather than thrombin, on activation of prothrombin Dhahran by factor Xa. All but one of the above mutations occur at CpG dinucleotides, thus further supporting the observation of a high incidence of CpG transitions in hereditary dysprothrombinemia. The significant bleeding tendencies of individuals homozygous for prothrombin Dhahran (prothrombin clotting activity 5% to 7%) contrast sharply with the absence of significant chronic bleeding in the proband expressing prothrombin Corpus Christi (prothrombin clotting activity 2%). Our findings underscore the capacity of thrombin to contribute to clinical hemostasis by mechanisms other than its fibrinogen clotting activity.  相似文献   
130.
Women with melanoma and its precursor lesions, dysplastic naevi, have a higher prevalence of reproductive disorders than women without melanotic lesions. This association appears strongest among young women with dysplastic naevi and endometriosis. The purpose of this study was to evaluate patients with laparoscopy-confirmed endometriosis for the presence of dysplastic naevi. A total of 66 endometriosis patients and 35 controls completed a detailed questionnaire and underwent an extensive dermatological examination for the presence of dysplastic naevi. In all, 41% of patients aged < or = 32 years had dysplastic naevi, compared with 8% of controls (P = 0.038). In addition, 29% of patients with endometriosis reported a family history of melanoma compared with 10% of controls (P = 0.039). This study demonstrated an association between endometriosis and dysplastic naevi in younger women of reproductive age and found an associated family history of melanoma among endometriosis patients. These observations may be useful in the evaluation and care of young women by both gynaecologists and dermatologists.   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