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   807820篇
  免费   62836篇
  国内免费   21917篇
耳鼻咽喉   8782篇
儿科学   17710篇
妇产科学   12331篇
基础医学   72995篇
口腔科学   19064篇
临床医学   86708篇
内科学   97354篇
皮肤病学   10443篇
神经病学   41176篇
特种医学   21028篇
外国民族医学   103篇
外科学   78015篇
综合类   127393篇
现状与发展   63篇
一般理论   92篇
预防医学   77081篇
眼科学   12317篇
药学   77770篇
  878篇
中国医学   76253篇
肿瘤学   55017篇
  2024年   2752篇
  2023年   13504篇
  2022年   25031篇
  2021年   33439篇
  2020年   31685篇
  2019年   34223篇
  2018年   31639篇
  2017年   29475篇
  2016年   27795篇
  2015年   26764篇
  2014年   51075篇
  2013年   55473篇
  2012年   45967篇
  2011年   50152篇
  2010年   41098篇
  2009年   37755篇
  2008年   36276篇
  2007年   37988篇
  2006年   33330篇
  2005年   29748篇
  2004年   24822篇
  2003年   21746篇
  2002年   17043篇
  2001年   15483篇
  2000年   12870篇
  1999年   11067篇
  1998年   8730篇
  1997年   7971篇
  1996年   7213篇
  1995年   6781篇
  1994年   6123篇
  1993年   5025篇
  1992年   4667篇
  1991年   4097篇
  1990年   3603篇
  1989年   3283篇
  1988年   3106篇
  1987年   2619篇
  1986年   2242篇
  1985年   5512篇
  1984年   6478篇
  1983年   4485篇
  1982年   5307篇
  1981年   4617篇
  1980年   4087篇
  1979年   3723篇
  1978年   3149篇
  1977年   2398篇
  1976年   2716篇
  1975年   1982篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
中药生产过程质量控制关键技术研究进展   总被引:10,自引:8,他引:2  
中医药发展已上升到国家战略层面,在医药行业贯彻实施"中国制造2025"战略的新形势下,中药生产过程质量控制是中药工业需要加快突破的关键领域之一。对中药生产过程质量控制领域在工艺设计、分析检测、过程建模、制造装备等方面的关键共性问题进行解析,综述了中药生产过程质量控制体系中工艺过程理解、生产过程实时分析方法开发、过程控制策略建立3个方面的研究进展;并结合企业研究实践,介绍了质量源于设计(quality by design,Qb D)、过程分析技术(process analytical technology,PAT)、实验设计(design of experiment,DOE)、多变量统计分析等关键技术在上述3个研究方向中的应用进展,分析了实际工业应用的难点问题并对其应用前景进行展望,旨在为中药企业应用和提升生产过程质量控制技术提供参考。  相似文献   
2.
3.
4.
Potential for widespread transmission of HIV/AIDS among American Indian (AI) adolescents exists, yet no evidence-based interventions (EBIs) have been adapted and evaluated with this population. Intensive psychoeducation may improve knowledge and decision-making which could potentially translate to reductions in HIV risk behaviors. A peer group randomized controlled comparison of an adapted EBI vs. control was delivered over an eight-day summer basketball camp in one reservation-based tribal community to adolescents ages 13–19. Outcome data were gathered immediately post-camp and at 6 and 12 months follow-up. Self-selected peer groups were randomized to intervention (n = 138) or control (n = 129) conditions for a total sample of 267 participants (56.2% female), mean age 15.1 years (SD = 1.7). Intervention participants had better condom use self-efficacy post-camp (Adjusted Mean Difference [AMD] = ?0.75, p < 0.005) and at 6 (AMD = ?0.44, p < 0.005) and 12 months (AMD = ?0.23, p < 0.05) follow-up. Intervention participants also had higher HIV prevention and transmission knowledge (post-camp: AMD = 0.07, p < 0.01; 6 months: AMD = 0.06, p < 0.01) were more likely to believe condoms prevent sexually transmitted infections (post-camp: RR = 1.41, p < 0.005; 6 months: RR = 1.34, p < 0.05), to talk with an adult about HIV/AIDS (post-camp: RR=1.78, p < 0.005; 6 months: RR = 1.14, p < 0.005), had higher partner negotiation efficacy related to substance use during sex (post-camp: AMD = 0.37, p < 0.01), and were more likely to intend to use a condom (post-camp: RR = 1.39, p < 0.01). The adapted intervention had short- and medium-term impacts on AI adolescent risk for HIV/AIDS, but attenuated at 12 months. Intervention delivery through a community-based camp is feasible and acceptable with strong retention. Additional study is needed to evaluate the adapted intervention's impact on sexual risk behaviors and if booster sessions and parent involvement translate to long-term impacts.  相似文献   
5.
Sinus venosus atrial septal defect (SV‐ASD) usually coexists with partial anomalous pulmonary vein connection (PAPVC). It is a difficult diagnosis in transthoracic echocardiography (TTE) due to eccentric position of defects. We present a rare case of atypical anatomical variation in PAPVC, which was never described before. Two right pulmonary veins drained into superior vena cava, which overrode SV‐ASD and interatrial septum, a third pulmonary vein into the right atrium. Complete diagnosis could not be set after TTE, nor transesophageal echocardiography, whereas angio‐CT was finally conclusive. This diagnostic approach allowed the surgical planning.  相似文献   
6.
<正>我国结核患者在2011年统计已达500万例,仅次于印度位居世界第二[1]。临床多见抗结核药物引起肝损害及过敏反应,对眼部的副反应关注较少[2]。笔者临床中发现部分结核患者在抗结核治疗早期可出现视物模糊、异物感、干涩及视物不持久等类似干眼的主诉,眼科常规检查未发现明显视神经病变,更多为眼表的改变。笔者观察抗结核药物对眼表的毒副反应,报道如下。1资料与方法1.1研究对象收集2012年1月—2014年10月  相似文献   
7.
《Vaccine》2020,38(3):570-577
IntroductionPediatric pneumococcal pneumonia complicated by parapneumonic pleural effusion/empyema (PPE/PE) remains a major concern despite general immunization with pneumococcal conjugate vaccines (PCVs).MethodsIn a nationwide pediatric hospital surveillance study in Germany we identified 584 children <18 years of age with bacteriologically confirmed PPE/PE from October 2010 to June 2018. Streptococcus pneumoniae was identified by culture and/or PCR of blood samples and/or pleural fluid and serotyped.ResultsS. pneumoniae was identified in 256 of 584 (43.8%) children by culture (n = 122) and/or PCR (n = 207). The following pneumococcal serotypes were detected in 114 children: serotype 3 (42.1%), 1 (25.4%), 7F (12.3%), 19A (7.9%), other PCV13 serotypes (4.4%) and non-PCV13 serotypes (7.9%). Between October 2010 and June 2014 serotype 1 (38.1%) and serotype 3 (25.4%) were most prevalent, whereas between July 2014 and June 2018 serotype 3 (62.7%) and non-PCV13 serotypes (15.7%) were dominant. Compared to children with other pneumococcal serotypes, children with serotype 3 associated PPE/PE were younger (median 3.2 years [IQR 2.1–4.3 years] vs. median 5.6 years [IQR 3.8–8.2 years]; p < 0.001) and more frequently admitted to intensive care (43 [89.6%] vs. 48 [73.8%]; p = 0.04). Seventy-six of 114 (66.7%) children with pneumococcal PPE/PE had been vaccinated with pneumococcal vaccines. Thirty-nine of 76 (51.3%) had received a vaccine covering the serotype detected. Thirty of these 39 breakthrough cases were age-appropriately vaccinated with PCV13 and considered vaccine failures, including 26 children with serotype 3, three children with serotype 19A and one child with serotype 1.ConclusionFollowing the introduction of PCV13 in general childhood vaccination we observed a strong emergence of serotype 3 associated PPE/PE in the German pediatric population, including a considerable number of younger children with serotype 3 vaccine breakthrough cases and failures. Future PCVs should not only cover newly emerging serotypes, but also include a more effective component against serotype 3.  相似文献   
8.
Central illustration: cumulative major adverse cardiac events (MACE) and bioresorbable vascular scaffold (BVS) thrombosis rates after 1, 2, 3, 4 and 5 years.
  相似文献   
9.
10.
目的:探讨健康干预应用于肥胖中学生的效果。方法:抽取张掖市第一中学肥胖中学生180例,随机分为观察组与对照组,观察组实施健康干预,对照组仅予以常规健康教育,比较两组肥胖改善情况。结果:观察组干预效果显著优于对照组(P<0.05);干预后观察组的 BMI、腰围、胸围及皮脂厚度均较对照组显著降低(P<0.05)。结论:在肥胖中学生中实施健康干预有利于促进学生身体形态生长水平的改善,控制和降低学生 BMI和肥胖增长速度。  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