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   19篇
  国内免费   9篇
耳鼻咽喉   1篇
儿科学   3篇
基础医学   31篇
口腔科学   4篇
临床医学   24篇
内科学   67篇
皮肤病学   1篇
神经病学   5篇
特种医学   7篇
外科学   12篇
综合类   8篇
预防医学   5篇
眼科学   1篇
药学   3篇
中国医学   4篇
肿瘤学   27篇
  2023年   1篇
  2022年   4篇
  2021年   6篇
  2020年   4篇
  2019年   6篇
  2018年   13篇
  2017年   9篇
  2016年   4篇
  2015年   8篇
  2014年   11篇
  2013年   8篇
  2012年   10篇
  2011年   14篇
  2010年   15篇
  2009年   6篇
  2008年   11篇
  2007年   3篇
  2006年   8篇
  2005年   6篇
  2004年   7篇
  2003年   2篇
  2002年   5篇
  2001年   2篇
  1996年   1篇
  1995年   2篇
  1994年   2篇
  1993年   1篇
  1992年   3篇
  1990年   1篇
  1987年   1篇
  1984年   1篇
  1982年   1篇
  1980年   1篇
  1979年   1篇
  1978年   2篇
  1977年   3篇
  1976年   4篇
  1975年   2篇
  1974年   1篇
  1973年   4篇
  1972年   3篇
  1971年   2篇
  1970年   2篇
  1968年   1篇
  1967年   1篇
排序方式: 共有203条查询结果,搜索用时 31 毫秒
51.
BACKGROUND: Xerostomia is one of the disturbing side-effects of radiotherapy to the head and neck region. Pilocarpine has been approved for the treatment of this condition in the chronic phase, but its use concurrent with radiation could also be beneficial for prevention or reduction of the subsequent radiation-induced xerostomia. We undertook to test this hypothesis in a clinical trial. METHODS: At the start of radiotherapy, randomization was performed to either pilocarpine 5 mg three times daily or placebo in a double-blind setting. The drug was started with irradiation and continued until 3 months after the end of radiotherapy. Xerostomia was evaluated 6 months after the end of radiation by a subjective visual analog scale questionnaire. Also the objective grade of xerostomia was recorded by two separate observers. RESULTS: A total number of 60 patients were randomized into the trial, but unfortunately only 39 patients were finally evaluated for xerostomia, 18 in the pilocarpine and 21 in the placebo group. Mean age was 42 years, and mean parotid dose was 58 Gy. Mean subjective xerostomia was 40.3 mm in the pilocarpine group and 57 mm in the placebo group (P = 0.02). Also mean objective xerostomia grade was 2.2 in the pilocarpine group and 2.6 in the placebo group (P = 0.01). Subjective and objective xerostomia results were positively correlated (P = 0.01). Age and the parotid dose did not have a significant effect on xerostomia. CONCLUSIONS: Compared to placebo, pilocarpine used with radiotherapy could lead to a significant diminishment of subsequent radiation-induced xerostomia.  相似文献   
52.
A transient expression assay for fowlpox virus (FPV) was developed to assess the feasibility of using heterologous promoters in FPV and to qualitatively determine relative promoter strength. A transient expression system for FPV has not been reported, and various methods used for transient expression in vaccinia-virus-infected cells produced negative results when used with FPV. Here a successful method for transient expression of E. coli beta-galactosidase in FPV-infected chick embryo fibroblasts is reported. This transient expression assay has been developed to qualitatively assess promoter recognition and gene expression by FPV. It should also prove useful in the identification of promoters from the FPV genomic library and in testing the accuracy of chimeric promoter-gene constructs.  相似文献   
53.
The kinetics of phytohemagglutinin (PHA) response of peripheral blood lymphocytes from chickens infected with oncogenic Marek's disease (MD) virus (MDV) or nononcogenic herpesvirus of turkeys (HVT) was studied with a whole blood microassay. At about 7 days after inoculation, a depression in PHA response was observed in MDV-inoculated resistant line N or susceptible line 7(2) chickens and in HVT-inoculated line 7(2) chickens. All chickens initially regained their PHA responsiveness. Susceptible chickens that died of MD or developed MD lymphoma in later stages of virus infection showed a second severe depression in PHA response. No depression was observed in HVT-vaccinated chickens when challenged with MDV. The PHA response of MDV-inoculated chickens that survived MD, HVT-inoculated chickens, and HVT-vaccinated MDV-challenged chickens showed evidence of enhancement. The depression of PHA response was studied and was attributed to the suppressive effect of macrophages on T-cell response, a finding consistent with our previous studies on MDV suppression of PHA response.  相似文献   
54.
目的:观察局灶性脑缺血损伤后大鼠脑组织中Semaphorin 3A(Sema 3A)蛋白表达水平,以及通络救脑注射液对该因子表达的影响.方法:以线拴法制作大鼠大脑中动脉缺血模型(MCAO),设正常组、模型组及通络救脑注射液组,分别在造模后12h、24h、3d、7d,共4个时间点采取动物脑组织,测定脑梗死体积及脑组织中GAP43的表达水平,及Sema 3A的表达部位和蛋白表达水平.结果:通络救脑注射液能够减少脑缺血动物脑梗死体积,与模型组相比均有显著差异.结论:大鼠脑缺血损伤后Sema 3A表达增加与神经元的坏死有相关性,通络救脑注射液能够降低其表达水平,对缺血损伤的脑组织发挥保护作用.  相似文献   
55.
为筛选新型杀菌抑霉药物,本文报道了标题化合物对7种细菌和4种真菌的杀菌抑霉活性。18~64%的受试菌株对配体Ⅰ_2~Ⅰ_(11)和配合物Ⅱ_2~Ⅱ_(11)表现敏感;多数化合物对大肠杆菌有抑制作用;串珠镰刀菌、毛霉菌、黄曲霉菌、青霉菌对化合物Ⅰ_2高度敏感,抑菌圈直径为15~25mm;化合物Ⅰ_(11)和Ⅱ_(11)分别对73%和64%的菌株有抑菌作用。  相似文献   
56.
PURPOSE: To evaluate the impact of computed tomographic (CT) planning in comparison to clinical mark-up (CM) for palliative radiation of chest wall metastases. METHODS AND MATERIALS: In patients treated with CM for chest wall bone metastases (without conventional simulation/fluoroscopy), two consecutive planning CT scans were acquired with and without an external marker to delineate the CM treatment field. The two sets of scans were fused for evaluation of clinical tumor volume (CTV) coverage by the CM technique. Under-coverage was defined as the proportion of CTV not covered by the CM 80% isodose. RESULTS: Twenty-one treatments (ribs 17, sternum 2, and scapula 2) formed the basis of our study. Due to technical reasons, comparable data between CM and CT plans were available for 19 treatments only. CM resulted in a mean CTV under-coverage of 36%. Eleven sites (58%) had an under-coverage of >20%. Mean volume of normal tissues receiving >/=80% of the dose was 5.4% in CM and 9.3% in CT plans (p = 0.017). Based on dose-volume histogram comparisons, CT planning resulted in a change of treatment technique from direct apposition to a tangential pair in 7 of 19 cases. CONCLUSIONS: CT planning demonstrated a 36% under-coverage of CTV with CM of ribs and chest wall metastases.  相似文献   
57.
58.
Phosphonoacetate (PA), but not any of its analogues tested, effectively inhibited avian herpesvirus replication and viral DNA synthesis in cell cultures. At 100 mug/ml culture medium, PA completely inhibited the replication of Marek's disease virus (MDV), herpesvirus of turkeys, and owl herpesvirus, but had no measurable effect on normal cell growth. PA also inhibited DNA polymerases induced by these avian viruses. Enzyme inhibition was 50% at a PA concentration of 0.2 mug/ml. At a concentration of 3-6 mug/ml, the compound also effected a 50% inhibition of alpha (maxi) enzyme of the host DNA polymerase. It had no effect on the host beta (mini) enzyme. When administered to chickens, PA did not inhibit the replication of MDV, nor did it prevent the development of lymphoma.  相似文献   
59.
60.
Structural proteins of Marek's disease virus   总被引:3,自引:0,他引:3  
Marek's disease virus (MDV) was propagated in roller-bottle cultures of duck embryo fibroblasts and partially purified by sucrose gradient centrifugation. Analysis of viral protein by polyacrylamide gel electrophoresis revealed that at least eight proteins (designated VPI-VPVIII) were present in MDV. The VPI is the major viral protein. At least two viral proteins, VPII and VPIV, with glucosamine label could be detected. These two peaks may represent viral glycoprotein and may be associated with the viral envelope. No host cell proteins coelectrophoresed with any viral proteins. Similar electropherograms were obtained by coelectrophoresis of MDV and herpes simplex virus proteins and of MDV and pseudorabies virus proteins.  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