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   1423篇
  免费   108篇
  国内免费   4篇
耳鼻咽喉   4篇
儿科学   27篇
妇产科学   6篇
基础医学   128篇
口腔科学   22篇
临床医学   180篇
内科学   285篇
皮肤病学   353篇
神经病学   21篇
特种医学   99篇
外科学   125篇
综合类   66篇
预防医学   72篇
眼科学   16篇
药学   51篇
  1篇
中国医学   19篇
肿瘤学   60篇
  2022年   11篇
  2021年   17篇
  2020年   16篇
  2019年   23篇
  2018年   23篇
  2017年   21篇
  2016年   23篇
  2015年   50篇
  2014年   49篇
  2013年   46篇
  2012年   81篇
  2011年   73篇
  2010年   58篇
  2009年   61篇
  2008年   66篇
  2007年   61篇
  2006年   53篇
  2005年   41篇
  2004年   50篇
  2003年   55篇
  2002年   34篇
  2001年   44篇
  2000年   32篇
  1999年   34篇
  1998年   39篇
  1997年   37篇
  1996年   45篇
  1995年   34篇
  1994年   30篇
  1993年   21篇
  1992年   24篇
  1991年   12篇
  1990年   17篇
  1989年   18篇
  1988年   28篇
  1987年   23篇
  1986年   17篇
  1985年   20篇
  1984年   15篇
  1983年   17篇
  1982年   14篇
  1981年   11篇
  1980年   9篇
  1979年   9篇
  1978年   8篇
  1977年   5篇
  1976年   10篇
  1973年   4篇
  1972年   5篇
  1971年   6篇
排序方式: 共有1535条查询结果,搜索用时 31 毫秒
51.
To determine if antibodies to Borrelia burgdorferi persist after antibiotic treatment, we recalled 32 patients with Lyme disease from a primary care practice a mean of 16 months after treatment and analyzed initial and follow-up serum samples by ELISA and immunoblot assays. Of the eight patients whose initial serum specimens were positive for IgM antibody by ELISA, three had positive titers of IgM antibody at follow-up; of the 23 patients whose initial serum specimens were positive for IgG antibody by ELISA, 19 had positive titers of IgG at follow-up. Of the five patients whose initial serum specimens were positive for IgM antibody by immunoblot, two had positive titers of IgM antibody at follow-up; of the 30 patients whose initial serum specimens were positive for IgG antibody by immunoblot, 29 had positive titers of IgG antibody at follow-up. The bands on the IgG immunoblot remained remarkably constant during the period from analysis of the initial specimen to that of the follow-up specimen. Nine of the 32 patients had persistent or recurrent symptoms, and ELISA and immunoblot were not helpful for identifying these nine patients.  相似文献   
52.
目的 :了解我国卫生应急人员对突发公共卫生事件风险评估的认知状况,从文化程度、职称情况、单位性质、单位级别等方面进行比较,为提高卫生应急人员风险评估的认识和能力提供依据。方法 :采用问卷调查的方法,对全国(大陆地区)31个省(自治区、直辖市)承担突发公共卫生事件应急处置的卫生应急工作人员进行调查。采用描述性分析和χ2检验对调查数据进行分析。结果 :我国卫生应急人员对风险评估概念熟悉程度较低,且不同学历、不同职称、不同工作年限、不同机构、不同层级之间的认知存在一定差异;对风险评估工作内容的认知也存在分歧。结论 :应加强风险评估培训,健全风险评估制度,以全面提高卫生应急人员对风险评估的认知水平。  相似文献   
53.
54.
Human T-cell lymphotropic virus I (HTLV-I)-induced adult T-cell leukemia (ATL) cells constitutively express interleukin-2 (IL-2) receptors identified by the anti-Tac monoclonal antibody (MoAb), whereas normal resting cells do not. This observation provided the scientific basis for a trial of intravenous anti-Tac in the treatment of nine patients with ATL. The patients did not suffer untoward reactions and did not have a reduction in the normal formed elements of the blood, and only one of the nine produced antibodies to the anti-Tac MoAb. Three patients had transient mixed, partial, or complete remissions lasting from 1 to more than 8 months after anti-Tac therapy, as assessed by routine hematologic tests, immunofluorescence analysis of circulating cells, and molecular genetic analysis of HTLV-I provirus integration and of the T-cell receptor gene rearrangement. The precise mechanism of the antitumor effects is unclear; however, the use of a MoAb that prevents the interaction of IL-2 with its receptor on ATL cells provides a rational approach for the treatment of this malignancy.  相似文献   
55.
We explored the feasibility and toxicity of administering escalating doses of anti-CD3/CD28 ex vivo costimulated T cells as a therapeutic adjunct for patients with relapsed, refractory, or chemotherapy-resistant, aggressive non-Hodgkin lymphoma (NHL) following high-dose chemotherapy and CD34+-selected hematopoietic cell transplantation (HCT). Sixteen patients had infusions on day 14 after HCT of autologous T cells that had been stimulated using beads coated with anti-CD3 and anti-CD28 monoclonal antibodies. At baseline, the subjects had severe quantitative and functional T-cell impairments. The culture procedure partially reversed impaired cytokine responsiveness in T cells in vitro and in vivo. Transient dose-dependent infusion toxicities were observed. There was a rapid reconstitution of lymphocytes; however, there were persistent defects in CD4 T cells. Most interestingly, 5 patients had a delayed lymphocytosis between day 30 and day 120 after HCT. Maximal clinical responses included 5 patients with a complete response (CR), 7 patients with a partial response (PR), and 4 patients with stable disease. At a median follow-up of 33 months (range, 26-60 months), 5 patients are alive with stable or relapsed disease and 3 patients remain in CR. In conclusion, this phase 1 trial demonstrates that adoptive transfer of autologous costimulated T cells (1) is feasible in heavily pretreated patients with advanced NHL, (2) is associated with a rapid recovery of lymphocyte counts, (3) reverses cytokine activation deficits in vitro, and (4) is associated with delayed lymphocytosis in a subset of patients.  相似文献   
56.
Blood donors reactive by enzyme-linked immunosorbent assay for antibody to the human immunodeficiency virus (HIV) who showed atypical patterns of viral core protein reactivity on Western blot were monitored for several months. Characterization of their antibodies was performed by 1) use of recombinant HIV proteins; 2) determination of cross-reactivity to HTLV-I, HTLV-II, and HTLV-IV: 3) assessment of immune status; and 4) identification of potentially interfering autoantibodies. Nineteen of 20 donors maintained the same HIV antibody reactivity throughout the follow-up period; the other donor became fully antibody-positive. Eighteen of 20 donors' sera showed clear reactivity with HIV recombinant core proteins. Ten of 19 donor samples demonstrated cross-reactivity to HTLV-IV; 3 of these 10 also cross-reacted with HTLV-I. The immune status of all donors was normal, although the medical histories and HLA antibody screens suggested possible autoimmune reactivity in 9 of 18 donors. During follow-up interviews, three donors reported possible risk factors for HIV infection that had not been acknowledged at the time of blood donation. We conclude that exclusion of donors with these atypical serologic test results is warranted while further studies to determine significance are being conducted.  相似文献   
57.
58.
目的 探讨用改进的倒谱方法估计平均骨小梁间距(mean trabecular bone spacing,MTBS)的可行性.方法 提出了一种基于反向滤波器的改进的倒谱分析方法用于估计MTBS,并将该方法应用于仿真及离体牛胫骨松质骨中的实验信号.结果 改进的倒谱方法能有效减少超声换能器脉冲响应和组织散射特性对倒谱的干扰,而且实现简单,计算量小.结论 相比于传统的倒谱方法,改进的倒谱方法在估计MTBS时, 对弥散散射和噪声有更强的鲁棒性,因此估计MTBS的精度更高.  相似文献   
59.
60.
目的探讨α-珠蛋白生成障碍性贫血产前诊断在降低出生缺陷中的效果。方法选择2003年1月至2012年7月进行α-珠蛋白生成障碍性贫血产前诊断的妊娠1 037例,采用聚合酶链反应结合琼脂糖凝胶电泳和反向点杂交技术对脐带血和原位培养后的羊水或绒毛组织检测α珠蛋白基因,同时对合并β-珠蛋白生成障碍贫血者进行β-珠蛋白基因检测。结果 1 037例妊娠中α-珠蛋白生成障碍性贫血检出率为79.27%,其中血红蛋白H(Hb Bart′s)胎儿水肿综合征292例,HbH病45例;同时检出中间型、重型β-珠蛋白生成障碍贫血5例,β-珠蛋白生成障碍贫血杂合子28例,包括α复合β-珠蛋白生成障碍贫血26例,终止妊娠339例。结论α-珠蛋白生成障碍性贫血产前干预是防止该类患儿出生的有效措施,同时应加强复合型珠蛋白生成障碍贫血的干预。  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