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   908篇
  免费   54篇
  国内免费   1篇
耳鼻咽喉   1篇
儿科学   32篇
妇产科学   11篇
基础医学   126篇
口腔科学   7篇
临床医学   74篇
内科学   278篇
皮肤病学   11篇
神经病学   64篇
特种医学   7篇
外科学   126篇
综合类   2篇
预防医学   57篇
眼科学   46篇
药学   44篇
中国医学   1篇
肿瘤学   76篇
  2024年   1篇
  2023年   14篇
  2022年   3篇
  2021年   40篇
  2020年   16篇
  2019年   40篇
  2018年   38篇
  2017年   25篇
  2016年   34篇
  2015年   33篇
  2014年   40篇
  2013年   53篇
  2012年   91篇
  2011年   91篇
  2010年   41篇
  2009年   49篇
  2008年   62篇
  2007年   66篇
  2006年   52篇
  2005年   50篇
  2004年   36篇
  2003年   33篇
  2002年   39篇
  2001年   3篇
  2000年   2篇
  1999年   2篇
  1998年   4篇
  1997年   1篇
  1996年   1篇
  1995年   2篇
  1993年   1篇
排序方式: 共有963条查询结果,搜索用时 343 毫秒
1.
2.
This study aimed to determine whether a weight-adjusted dose of subcutaneous enoxaparin is as effective and safe as oral acenocoumarol for the secondary prophylaxis of pulmonary embolism. Three hundred and eighty consecutive noncancer outpatients hospitalized with an episode of symptomatic pulmonary embolism selected treatment with acenocoumarol or enoxaparin at a dose of 1 mg/kg once daily after being informed of the type of administration and expected frequency of laboratory monitoring for both medicinal products. Endpoints were symptomatic recurrent thromboembolic events evaluated by standard objective testing, and a composite endpoint of recurrent venous thromboembolism, major bleeding, and death from any cause. One hundred and ninety-nine patients (52%) chose acenocoumarol therapy and 181 chose enoxaparin monotherapy. Four patients in the enoxaparin group (2.2%) and six patients in the acenocoumarol group (3%) had an objective thromboembolic recurrence (hazard ratio, 1.35; 95% confidence interval, 0.38-4.79; P = 0.64). Nine patients in the enoxaparin group (5.0%) had a hemorrhagic complication compared with 11 in the acenocoumarol group (5.5%) (P = 0.81). The hospital length of stay was shorter with enoxaparin compared with acenocoumarol (11 versus 16 days, P = 0.0001). Enoxaparin is as effective and safe as acenocoumarol in the secondary prevention of recurrent thromboembolic disease and is associated with shorter hospitalization.  相似文献   
3.
Pituitary metastases of solid tumours are infrequent, specially as a first manifestation. When they happen, they are usually due to breast or lung cancer and are asymptomatic or produce diabetes insipidus. It is very strange that they produce hormonal deficiency. We present a case report of a bronchogenic adenocarcinoma in a 65-year-old man which began with panhypopituitarism, diabetes insipidus and visual alterations. Magnetic resonance imaging revealed a large sellar mass, with clivus infiltration and invading the right cavernous sinus. The biopsy result was adenocarcinoma metastases from lung cancer.  相似文献   
4.
5.
Susceptibility testing of Eikenella corrodens is usually performed by a Mueller-Hinton sheep blood agar dilution (AD) method. However, this method is impractical for testing only a few strains. We compared AD with the broth microdilution method using Haemophilus test medium (HTM) in order to determine the susceptibility of 36 clinical isolates of E. corrodens to eight antimicrobial agents. MICs obtained by the HTM method yielded 95.5 and 84% agreement (within 2 and 1 log2 dilutions, respectively) with those obtained by AD. The HTM method with incubation in CO2 for 48 h was highly reproducible and constitutes an easy alternative for antimicrobial susceptibility testing of E. corrodens.  相似文献   
6.
Alterations in the mismatch repair genes (hMLH1 and hMSH2) play an important role in the development of microsatellite instability in sporadic endometrial cancer. Tissue microarray technology allows molecular profiling of tumor samples at the DNA, RNA, and protein levels. We analyzed hMLH1 and hMSH2 expression by immunohistochemistry in a group of atypical endometrial hyperplasias (n = 10), endometrioid endometrial carcinomas (n = 58), and nonendometrioid endometrial carcinomas (n = 27) on tissue microarray. The results were correlated with microsatellite instability status as evaluated by BAT-25 and BAT-26. Overall, 29.4% of lesions showed microsatellite instability. Loss of nuclear hMLH1 and hMSH2 protein expression was seen in 22.3% and 6.5% of cases, respectively. Immunohistochemistry for hMLH1 and hMSH2 showed lack of protein expression in 64% and 16.6% of microsatellite instability-positive endometrial lesions, respectively. Taken together, hMLH1 or hMSH2 protein expression was absent in 18 of 24 microsatellite instability-positive cases (75% sensitivity). A high level of concordance was found between immunohistochemistry for hMLH1 and hMSH2 and microsatellite instability status evaluated by BAT-25 and BAT-26 (kappa value of 0.7). Of the 57 cases found to be microsatellite instability negative, 53 showed normal expression of both proteins (93% specificity). The observed predictive value of absence of expression of hMLH1 for predicting microsatellite instability-positive status was 82%. The predictive value of normal expression of both proteins for predicting microsatellite instability-negative status was 90%. These results are consistent with those previously reported in whole tissue sections. Therefore, immunohistochemical analysis of hMLH1 and hMSH2 expression on tissue microarray provides an accurate technique for screening for tumors with microsatellite instability. Tissue microarrays represent an ideal approach for comparing different diagnostic or predictive markers with one another in consecutive tissue microarray sections.  相似文献   
7.
目的 分析2015—2020年四川省手足口病流行病学及病原学特征,为手足口病的防控提供科学依据。 方法 利用描述流行病学方法对2015—2020年四川省手足口病监测资料进行统计分析。 结果 2015—2020年四川省累计报告手足口病520 147例,重症1 759例,死亡38例,2015—2020年四川省手足口病发病率呈波动状,年均发病率为104.82/10万,2015—2017和2019年呈现明显的双峰(4—7月和10—12月),2018、2020年呈单峰,发病高峰分别在7—11月和10—12月;年龄以 5 岁及以下儿童为主,男女性别比为1.38∶1;发病率居前五位的地区是成都市(221.25/10万)、眉山市(145.51/10万)、德阳市(115.52/10万)、雅安市(108.02/10万)和遂宁市(100.56/10);共报告实验室确诊病例44 410例,其中其他肠道病毒、CoxA16、EV71分别占65.53%、22.35%、12.12% 。 结论 2015—2020年四川省手足口病发病水平呈上升趋势,防控压力逐渐加大。四川省手足口病发病以5岁以下儿童为主,成都及周边,川东北发病率较高,优势病原分型构成发生变化,其他肠道病毒比重逐渐提高,病原学监测工作需要调整。  相似文献   
8.
Aránzazu Caballero-Marcos  Magdalena Salcedo  Roberto Alonso-Fernández  Manuel Rodríguez-Perálvarez  María Olmedo  Javier Graus Morales  Valentín Cuervas-Mons  Alba Cachero  Carmelo Loinaz-Segurola  Mercedes Iñarrairaegui  Lluís Castells  Sonia Pascual  Carmen Vinaixa-Aunés  Rocío González-Grande  Alejandra Otero  Santiago Tomé  Javier Tejedor-Tejada  José María Álamo-Martínez  Luisa González-Diéguez  Flor Nogueras-Lopez  Gerardo Blanco-Fernández  Gema Muñoz-Bartolo  Francisco Javier Bustamante  Emilio Fábrega  Mario Romero-Cristóbal  Rosa Martin-Mateos  Julia Del Rio-Izquierdo  Ana Arias-Milla  Laura Calatayud  Alberto A. Marcacuzco-Quinto  Víctor Fernández-Alonso  Concepción Gómez-Gavara  Jordi Colmenero  Patricia Muñoz  José A. Pons  the Spanish Society of Liver Transplantation 《American journal of transplantation》2021,21(8):2876-2884
The protective capacity and duration of humoral immunity after SARS-CoV-2 infection are not yet understood in solid organ transplant recipients. A prospective multicenter study was performed to evaluate the persistence of anti-nucleocapsid IgG antibodies in liver transplant recipients 6 months after coronavirus disease 2019 (COVID-19) resolution. A total of 71 liver transplant recipients were matched with 71 immunocompetent controls by a propensity score including variables with a well-known prognostic impact in COVID-19. Paired case–control serological data were also available in 62 liver transplant patients and 62 controls at month 3 after COVID-19. Liver transplant recipients showed a lower incidence of anti-nucleocapsid IgG antibodies at 3 months (77.4% vs. 100%, < .001) and at 6 months (63.4% vs. 90.1%, < .001). Lower levels of antibodies were also observed in liver transplant patients at 3 (= .001) and 6 months (< .001) after COVID-19. In transplant patients, female gender (OR = 13.49, 95% CI: 2.17–83.8), a longer interval since transplantation (OR = 1.19, 95% CI: 1.03–1.36), and therapy with renin–angiotensin–aldosterone system inhibitors (OR = 7.11, 95% CI: 1.47–34.50) were independently associated with persistence of antibodies beyond 6 months after COVID-19. Therefore, as compared with immunocompetent patients, liver transplant recipients show a lower prevalence of anti-SARS-CoV-2 antibodies and more pronounced antibody levels decline.  相似文献   
9.
RNA viruses replicate as complex distributions of non-identical but closely related variant genomes termed viral quasispecies. When the error rate during genome replication exceeds a threshold value, the genetic information cannot be maintained and the system enters error catastrophe. This violation of the error threshold results in virus extinction and it is currently being investigated as a new antiviral strategy, based on antiviral activity of some mutagenic agents. Previous studies with the important animal pathogen foot-and-mouth disease virus (FMDV) have shown that FMDV entry into error catastrophe is associated with an increase of complexity (mutation frequency and Shannon entropy) of the mutant spectrum of the quasispecies and that mutated, pre-extinction RNA interferes with the infectivity of standard RNA. Here, we report that despite the increase of complexity, the genomic consensus nucleotide sequence of pre-extinction FMDV RNA remains invariant, and that the fitness of pre-extinction FMDV is at least six-fold lower than the fitness of the parental viral clone, prior to mutagenic treatments. Thus, a low fitness genome ensemble can suppress replication of high fitness virus. Furthermore, the results show that profound genetic modifications associated with fitness decrease of a virus population can take place without any manifestation in the consensus genomic sequence. Thus, increase in mutant spectrum complexity and invariance of the consensus sequence characterizes FMDV extinction through error catastrophe.  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