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   332篇
  免费   23篇
  国内免费   22篇
儿科学   28篇
妇产科学   6篇
基础医学   33篇
口腔科学   10篇
临床医学   42篇
内科学   110篇
皮肤病学   4篇
神经病学   6篇
特种医学   72篇
外科学   7篇
综合类   13篇
预防医学   12篇
药学   14篇
肿瘤学   20篇
  2021年   5篇
  2020年   2篇
  2018年   5篇
  2017年   4篇
  2016年   2篇
  2015年   6篇
  2014年   6篇
  2013年   9篇
  2012年   2篇
  2011年   8篇
  2010年   14篇
  2009年   9篇
  2008年   6篇
  2007年   27篇
  2006年   8篇
  2005年   5篇
  2004年   4篇
  2003年   6篇
  2002年   7篇
  2001年   6篇
  2000年   5篇
  1999年   9篇
  1998年   17篇
  1997年   21篇
  1996年   14篇
  1995年   14篇
  1994年   10篇
  1993年   13篇
  1992年   1篇
  1991年   3篇
  1990年   6篇
  1989年   15篇
  1988年   13篇
  1987年   7篇
  1986年   21篇
  1985年   7篇
  1984年   3篇
  1983年   6篇
  1982年   5篇
  1981年   1篇
  1980年   4篇
  1979年   4篇
  1978年   2篇
  1977年   10篇
  1976年   6篇
  1975年   3篇
  1974年   9篇
  1973年   3篇
  1972年   1篇
  1940年   1篇
排序方式: 共有377条查询结果,搜索用时 15 毫秒
371.
Whole exome sequencing and chromosomal microarrays are two powerful technologies that have transformed the ability of researchers to search for potentially causal variants in human disease. This study combines these tools to search for causal variants in a patient found to have maternal uniparental isodisomy of chromosome 2. This subject has a complex phenotype including skeletal and renal dysplasia, immune deficiencies, growth failure, retinal degeneration and ovarian insufficiency. Eighteen non‐synonymous, rare homozygous variants were identified on chromosome 2. Additionally, five genes with compound heterozygous mutations were detected on other chromosomes that could lead to a disease phenotype independent of the uniparental disomy found in this case. Several candidate genes with potential connection to the phenotype are described but none are definitively proven to be causal. This study highlights the potential for detection of a large number of candidate genes using whole exome sequencing complicating interpretation in both the research and clinical settings. Forums must be created for publication and sharing of detailed phenotypic and genotypic reports to facilitate further biological discoveries and clinical counseling.  相似文献   
372.
白木通多糖的研究   总被引:9,自引:1,他引:9  
张劲松  方积年 《药学学报》1997,32(6):438-441
用碱液从白木通(Akebia trifoliate)茎中提取所得的粗多糖ATB经DEAE-Celulose及SephadexG-200柱层析后得到一多糖纯品ATBB 2,其分子量为2.3×105。糖组分分析ATBB-2中各糖残基的摩尔比为Rha∶Ara∶Xyl∶Gal∶Glc∶GalA=1.22∶1.00∶1.10∶0.85∶0.24∶0.82。经甲基化,高碘酸氧化,Smith降解,部分酸水解,1H和13CNMR谱的分析揭示ATBB-2是一个结构复杂的杂多糖。  相似文献   
373.
The exact role of fibre-optic bronchoscopy (FOB) and CT of the chest in the diagnosis of patients presenting with haemoptysis and a normal or non-localizing chest radiograph has not been clearly defined. A study was designed to evaluate 50 patients presenting with haemoptysis and a normal or non-localizing chest radiograph using FOB and high-resolution computed tomography (HRCT). A definitive diagnosis was established in 17 (34%) patients. The aetiologies included bronchiectasis (24%), bronchial adenoma (6%), tuberculosis (2%) and bronchitis (2%). The diagnosis was made by HRCT in 15 (30%) patients, while FOB was diagnostic in five (10%) patients. The diagnosis was made by HRCT and FOB in all patients with focal airway abnormalities. Therefore, HRCT effectively delineated abnormalities of both the central and peripheral airways. It is concluded that CT should be obtained prior to FOB in all patients presenting with haemoptysis and a normal or non-localizing chest radiograph.  相似文献   
374.
蛇床子中一新的角型呋喃香豆素   总被引:6,自引:0,他引:6  
从辽宁新民产蛇床Cnidium monnieri 果实中分离鉴定8个化合物,分别为欧山芹素(oroselone,Ⅰ),β谷舀醇(Ⅱ),哥伦比亚内酯(columbianadin,Ⅲ),佛手柑内醋(bergapten,Ⅳ),O-乙酰哥伦比亚甙贰元(O-acetycolumbianetin,v),O-乙酰异蛇床素(cniforinA,Ⅵ),爱得尔庭(edultin,Ⅶ)和'-乙酰白芷素(2'-acetylangelicin,Ⅷ)。其中化合物Ⅷ为一新化合物,化合物Ⅰ系首次从该植物中分得。  相似文献   
375.

Background  

Because both public health surveillance and action are crucial, the authors initiated meetings at regional and national levels to assess and reform surveillance and action systems. These meetings emphasized improved epidemic preparedness, epidemic response, and highlighted standardized assessment and reform.  相似文献   
376.
Ikebuchi  K; Ihle  JN; Hirai  Y; Wong  GG; Clark  SC; Ogawa  M 《Blood》1988,72(6):2007-2014
Serial observations of blast cell colony development from spleen cells of mice treated with 5-fluorouracil (5-FU) four days earlier revealed that either form of human interleukin-1 (IL-1 alpha or IL-1 beta) hastens the emergence of interleukin-3 (IL-3)-dependent blast cell colonies. This activity was essentially indistinguishable from the effect of interleukin-6 (IL-6) or granulocyte colony-stimulating factor (G-CSF) in the same system, an effect that we have ascribed previously to a shortening of the G0 period of the dormant stem cells. We also analyzed the time courses of colony formation from cultures of day-2 post-5-FU marrow cells supported by IL-1 alpha, IL-6, or G-CSF alone or in combination with IL-3. In the presence of IL-3, G-CSF and IL-6 but not IL-1 alpha hastened the development of colonies and increased the numbers of multilineage colonies relative to cultures of IL-3 alone. This observation, together with our previous data from the human system, suggests that the synergistic effect of IL-1 is likely due to induction of secondary growth factors, including IL-6 and G-CSF, by accessory cells in culture. The effect of IL-6 on G0 was confirmed by analysis of the cycling status of progenitor cells in short-term culture. While neither IL-3 nor IL-6 alone had any effect on the cycling status, the combination of factors resulted in a rapid recruitment of quiescent cells into cell cycle (within 48 hours) as represented by a twofold increase in the numbers of multipotential progenitors and a significant increase in the sensitivity of these cells to 3H-thymidine with high specific activity. Combinational testing of all of these synergistic factors revealed that the target cell populations for the IL-1, IL-6, and G-CSF overlap considerably, suggesting that they all may act through a common mechanism. This is further supported by our finding that cells from blast cell colonies grown in the presence of a combination of any one of the synergistic factors with IL-3 replate with higher efficiency and yield more multilineage secondary colonies than those from colonies grown in IL-3 alone. These findings provide further evidence that IL-1, IL-6, and G- CSF serve to integrate the immediate host responses to infection through augmentation of effector cells and antibody production as well as the longer term host responses by recruitment of dormant hemopoietic stem cells into active cell cycling.  相似文献   
377.
The purpose of this in vitro study was to evaluate the ability of lateral compaction of gutta-percha and of five thermoplasticized gutta-percha filling techniques to obturate simulated lateral canals. Sixty extracted single-rooted human teeth were instrumented at the working length to a #35 file before creating three simulated lateral canals on the mesial and distal surfaces of the root, one in each third, using a #15 engine reamer. After enlarging root canals to a #45 file, the teeth were randomly divided into six equal groups of 10 and obturated according to the following techniques: lateral compaction of gutta-percha (group A), hybrid technique (group B), Ultrafil (group C), Obtura II (group D), System B + Obtura II (group E), and Thermafil (group F). AH26 was used as the sealer. A greater number of simulated lateral canals were obturated when Ultrafil, Thermafil, and System B + Obtura II were used, in comparison with canals obturated with the hybrid technique, Obtura II, or lateral compaction of gutta-percha. This difference was statistically significant (p < 0.05). No statistically significant differences were found between results obtained in the obturation of simulated lateral canals in the different thirds of the root (p > 0.05).  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