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   1066篇
  免费   79篇
耳鼻咽喉   20篇
儿科学   38篇
妇产科学   65篇
基础医学   191篇
口腔科学   23篇
临床医学   103篇
内科学   207篇
皮肤病学   24篇
神经病学   91篇
特种医学   23篇
外国民族医学   1篇
外科学   125篇
综合类   4篇
预防医学   104篇
眼科学   15篇
药学   81篇
中国医学   1篇
肿瘤学   29篇
  2023年   5篇
  2022年   9篇
  2021年   25篇
  2020年   15篇
  2019年   35篇
  2018年   23篇
  2017年   27篇
  2016年   19篇
  2015年   28篇
  2014年   27篇
  2013年   46篇
  2012年   57篇
  2011年   56篇
  2010年   26篇
  2009年   31篇
  2008年   74篇
  2007年   54篇
  2006年   65篇
  2005年   50篇
  2004年   41篇
  2003年   53篇
  2002年   52篇
  2001年   33篇
  2000年   40篇
  1999年   33篇
  1998年   10篇
  1997年   11篇
  1996年   9篇
  1995年   9篇
  1994年   6篇
  1993年   5篇
  1992年   19篇
  1991年   18篇
  1990年   11篇
  1989年   19篇
  1988年   8篇
  1987年   15篇
  1986年   8篇
  1985年   9篇
  1984年   11篇
  1983年   4篇
  1982年   6篇
  1981年   4篇
  1979年   6篇
  1978年   4篇
  1977年   5篇
  1976年   4篇
  1973年   4篇
  1971年   3篇
  1970年   3篇
排序方式: 共有1145条查询结果,搜索用时 31 毫秒
1.
Two pregnancies in a patient with a fixed-rate pacemaker are reported. The first pregnancy was uneventful. The second had no maternal complications either. A moderate tachysystolia was detected during the second period. The newborn was delivered with forceps applied under spinal anesthesia. Newborn infant evolution presented no hazards, but umbilical cord analysis revealed a severe acidosis, in spite of a normal scalp analysis 45 min earlier. Epidural anesthesia is recommended for such patients.  相似文献   
2.
Three dimensional computed tomography was performed in 150 children suffering from a bone lesion of the base of the skull and face. These lesions were either malformative, neoplastic, infectious or traumatic. 3D CT provided an essential anatomical approach to the lesions facilitating the choice of the most appropriate treatment. 3D CT is also indicated in the follow-up of these operated children, particularly of the growth of the operated bone segment and its relations with adjacent structures.  相似文献   
3.
Localised agenesis of the scalp is the most frequent patern in aplasia cutis congenita (ACC), a congenital absence of the skin and occasionally of deeper layers. Several clinical groups are characterised by the location and pattern of skin defects, associated malformations and the mode of inheritance. Death occurs in 20% of cases, secondary to the associated anomalies, to infections or to haemorrhage from ulceration of the sagittal sinus when there is also a defect of the underlying skull. In this latter case, we close the defect by two rotational scalp flaps (Orticochea technique) at birth. A three-dimensional CT study is useful for showing the extent of the skull defect and the deformity of the craniofacial complex and the changes in the bone after treatment.  相似文献   
4.
Surveillance methods that measure St. Louis encephalitis (SLE) virus activity in nature may provide forewarning of its epidemic occurrence in humans. An antigen capture enzyme immunoassay was developed to detect SLE virus in infected mosquitoes. The assay detected purified SLE viral antigen at a concentration of 62 pg/0.1 ml when antigen was incubated overnight; 250 pg/0.1 ml was detected in a single-day assay (antigen incubated for 3 h). The assay detected 67.9 and 70.8% of laboratory-prepared pools of infected mosquitoes after 3 h and overnight incubation, respectively. The sensitivity of the procedure was 90.5% in identifying pools with infectious titers greater than dex 3.0. The specificity of the assay was controlled by retesting positive pools preincubated with SLE virus and normal antibodies, which led to a diminution of signal in the pools containing viral antigen. The procedure was suitably specific in discriminating between SLE and related flaviviruses, detecting only high infectious doses of heterologous antigens.  相似文献   
5.
6.
Summary The content of the mitochondrial poly(A)-RNA fraction of human heart has been analyzed by electrophoresis through agarose slab gels in the presence of methyl mercury hydroxide and staining with ethidium bromide. It is possible to identify all the heavy strand coded mRNAs in the electrophoretic pattern. This pattern is qualitatively similar to that obtained from the mitochondria of cells cultured in vitro (HeLa cells), although differences in the relative amount of some components have been detected.  相似文献   
7.
Human immunodeficiency virus type 1 (HIV-1) proviral DNA from peripheral blood mononuclear cells (PBMCs) was quantitated in 61 HIV-1-seropositive individuals by a nonisotopic polymerase chain reaction assay. Primers from the gag region (SK38, SK39) were used to determine the log10 HIV-1 proviral copy number per 10(6) CD4+ T lymphocytes (peripheral blood proviral load). A standard curve was generated for each assay by using ACH-2 cell DNA. The peripheral blood proviral load was followed in 15 individuals in a longitudinal study and was measured in 45 individuals in a cross-sectional analysis. Three of four untreated patients who were followed for 14 months had stable PBMC proviral loads and CD4+ T lymphocyte counts; one untreated patient had a sustained increase in PBMC proviral load followed 5 months later by a significant decline in the CD4+ T lymphocyte count. Eleven previously untreated individuals were monitored for 1 year following initiation of zidovudine and/or 2',3'-dideoxyinosine therapy. The mean log10 number of proviral HIV-1 copies per 10(6) CD4+ T cells decreased from 4.3 +/- 0.4 at the baseline to 3.5 +/- 0.6 after 2 to 4 months of therapy (P < 0.01). This initial 0.8 log10 fall in the PBMC proviral load after the initiation of therapy was followed by a rise in the PBMC proviral load by the sixth month of therapy. The PBMC proviral load in 45 subjects, both treated (n = 25) and untreated (n = 20), correlated inversely with the CD4+ T lymphocyte count (P < 0.01, R = 0.49). PBMC proviral DNA quantification by a nonisotopic polymerase chain reaction assay correlates with HIV-1 disease progression and could be used to monitor the effect of antiretroviral therapy.  相似文献   
8.
HIV cross-sectional studies were conducted among high-risk populations in 9 countries of South America. Enzyme-linked immunosorbent assay screening and Western blot confirmatory testing were performed, and env heteroduplex mobility assay genotyping and DNA sequencing were performed on a subset of HIV-positive subjects. HIV prevalences were highest among men who have sex with men (MSM; 2.0%-27.8%) and were found to be associated with multiple partners, noninjection drug use (non-IDU), and sexually transmitted infections (STIs). By comparison, much lower prevalences were noted among female commercial sex workers (FCSWs; 0%-6.3%) and were associated mainly with a prior IDU and STI history. Env subtype B predominated among MSM throughout the region (more than 90% of strains), whereas env subtype F predominated among FCSWs in Argentina and male commercial sex workers in Uruguay (more than 50% of strains). A renewed effort in controlling STIs, especially among MSM groups, could significantly lessen the impact of the HIV epidemic in South America.  相似文献   
9.

Background  

Using a rat model we have found that the bioflavonoid silymarin (SY) ameliorates some of the negative consequences of in utero exposure to ethanol (EtOH). In the current study our aim was to determine if laterality preference and corpus callosum development were altered in rat offspring whose mothers were provided with a concomitant administration of SY with EtOH throughout gestation.  相似文献   
10.
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