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   266458篇
  免费   26422篇
  国内免费   16188篇
耳鼻咽喉   2221篇
儿科学   3653篇
妇产科学   2294篇
基础医学   28584篇
口腔科学   4868篇
临床医学   31425篇
内科学   30205篇
皮肤病学   2705篇
神经病学   10011篇
特种医学   10469篇
外国民族医学   65篇
外科学   23776篇
综合类   58537篇
现状与发展   57篇
一般理论   12篇
预防医学   24219篇
眼科学   5137篇
药学   32030篇
  324篇
中国医学   21501篇
肿瘤学   16975篇
  2024年   1264篇
  2023年   3917篇
  2022年   9942篇
  2021年   12550篇
  2020年   9875篇
  2019年   7191篇
  2018年   7504篇
  2017年   8081篇
  2016年   7070篇
  2015年   11381篇
  2014年   14195篇
  2013年   15755篇
  2012年   21998篇
  2011年   23540篇
  2010年   19164篇
  2009年   16184篇
  2008年   17687篇
  2007年   17146篇
  2006年   15510篇
  2005年   12871篇
  2004年   9413篇
  2003年   8377篇
  2002年   6946篇
  2001年   5966篇
  2000年   4731篇
  1999年   3200篇
  1998年   1800篇
  1997年   1915篇
  1996年   1383篇
  1995年   1292篇
  1994年   1166篇
  1993年   810篇
  1992年   1016篇
  1991年   919篇
  1990年   809篇
  1989年   747篇
  1988年   660篇
  1987年   591篇
  1986年   554篇
  1985年   439篇
  1984年   378篇
  1983年   308篇
  1982年   280篇
  1981年   229篇
  1980年   196篇
  1979年   198篇
  1978年   192篇
  1977年   211篇
  1976年   191篇
  1974年   156篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
人肿瘤特异抗原MAGE-3基因疫苗的构建和表达   总被引:8,自引:1,他引:7  
目的:克隆肿瘤特异性共享抗原mage-3基因,制备基于α-病毒复制酶的高效黑色素瘤特异性基因疫苗。方法:用RT-PCR方法从黑色素瘤细胞系LB373中制备mage-3基因,以含α-病毒复制酶的哺乳细胞高效表达质粒pSMART2a为载体,构建重组DNA疫苗。重组子用载体中的T7和T3启动子序列为测序引物进行自动测序。再将鉴定过的重组质粒用脂质体法转化293细胞,用免疫印迹法和免疫组化法鉴定转化细胞中mage-3蛋白的表达。结果:正确构建了mage-3/pSMART2a重组质粒,并且在转化此质粒的293细胞中检测出了mage-3蛋白的表达。结论:此重组mage-3/pSMART2a质粒可以作为肿瘤特异的DNA疫苗,可进行下一步的肿瘤动物模型的疫苗接种及相关免疫学效应研究。  相似文献   
42.
在人们印象中“公共卫生”是一个很模糊的领域,它比较形象的载体可能就是爱国卫生运动或预防接种。美国1932年提出的公共卫生的定义,对现在依然有指导意义:公共卫生就是预防疾病,延长寿命,通过有组织的社会共同努力来改变环境卫生,从而促进身体的健康,提高工作效率,控制社区传染病的流行,教育个人形成良好的卫生习惯,组织医护人员对疾病进行早期的诊断和预防性治疗。简而言之,“公共卫生”就是关注公众健康的科学。公共卫生学不能脱离临床医学,后是对某种疾病的个体的治疗,而前则着眼对某种疾病做群体防护。  相似文献   
43.
异位妊娠的腹腔镜手术临床分析   总被引:4,自引:0,他引:4  
目的探讨电视腹腔镜手术治疗内出血异位妊娠的安全性和可行性。方法回顾分析2000年8月 ̄2004年8月该院电视腹腔镜手术治疗的15例伴有内出血的异位妊娠(出血量大于800mL,观察组)及同期30例无明显内出血异位妊娠病人的临床资料(对照组)。结果15例病人均手术成功,无中转开腹及并发症发生,两组手术时间及手术后住院时间均无明显差异。结论随着腹腔镜手术操作技巧、麻醉和监护技术的提高,腹腔镜手术治疗内出血甚至休克型异位妊娠在一定条件下是安全可行的。  相似文献   
44.
氟尿嘧啶化放疗的现状与未来   总被引:1,自引:0,他引:1  
赵明 《药品评价》2006,3(4):252-263,270
20世纪60年代在肿瘤的根治和辅助治疗中就使用了氟尿嘧啶(Fluorouracil,FU)化放疗(外放疗同时进行化疗)。2002年.全世界约200万肿瘤患者接受了FU治疗.其中很大一部分是以FU为基础的化放疗。FU是许多肿瘤患者的基础治疗药物。总之,FU化放疗显著改善了肿瘤的局部控制.并提高了部分肿瘤患者的生存率:也提高了部分具有重要功能的器官的保留。  相似文献   
45.
目的:探讨腰椎形态结构变化对峡部裂性滑脱及小关节退变的作用和意义。方法:采用改良的“非种子区域分割方法”及非平行“最佳切割平面”等一系列新型计算机辅助设计(CAD)方法精确建立包括椎间盘高度、腰椎小关节角、椎间盘前凸角改变的L4~L5活动节段有限元模型;在2700N轴向压缩载荷条件下,分别对各有限元模型的峡部、小关节应力、小关节接触力以及椎间盘负载进行测试。结果:压缩载荷下,腰椎活动节段峡部、小关节等效应力及小关节接触力随椎间盘高度的减小而减小,随小关节角的增大而增加,随椎间盘前凸角的增加而减小。结论:椎间盘高度、腰椎小关节角、椎间盘前凸角等形态结构变化对腰椎节段有限元模型的峡部、小关节应力及小关节接触力有明显的影响。提示腰椎峡部应力性骨折及小关节退变的发生与椎间盘高度、腰椎小关节角、椎间盘前凸角等解剖形态因素有关。  相似文献   
46.
The sympathetic nervous system of the heart plays a key role in the pathophysiology of various cardiac diseases. Small-animal models are valuable for obtaining further insight into mechanisms of cardiac disease and therapy. To determine the translational potential of cardiac neuronal imaging from rodents to humans, we characterized the rat sympathetic nervous system using 3 radiotracers that reflect different subcellular mechanisms: (11)C-meta-hydroxyephedrine (HED), a tracer of neuronal transport showing stable uptake and no washout in healthy humans; (11)C-phenylephrine (PHEN), a tracer of vesicular leakage and intraneuronal metabolic degradation with initial uptake and subsequent washout in humans; and (11)C-epinephrine (EPI), a tracer of vesicular storage with stable uptake and no washout in humans. METHODS: We used a small-animal PET system to study healthy male Wistar rats at baseline, after desipramine (DMI) pretreatment (DMI block), and with DMI injection 15 min after tracer delivery (DMI chase). The rats were kept under general isoflurane anesthesia while dynamic emission scans of the heart were recorded for 60 min after radiotracer injection. A myocardial retention index was determined by normalizing uptake at 40 min to the integral under the arterial input curve. Washout rates were determined by monoexponential fitting of myocardial time-activity curves. RESULTS: At baseline, HED showed high myocardial uptake and sustained retention, EPI showed moderate uptake and significant biphasic washout, and PHEN showed moderate uptake and monoexponential washout. The average (+/- SD) left ventricular retention index for HED, PHEN, and EPI was 7.38% +/- 0.82%/min, 3.43% +/- 0.45%/min, and 4.24% +/- 0.59%/min, respectively; the washout rate for HED, PHEN, and EPI was 0.13% +/- 0.23%/min, 1.13% +/- 0.35%/min, and 0.50% +/- 0.24%/min, respectively. The DMI chase resulted in increased washout only for HED. DMI block decreased myocardial uptake of all tracers by less than 90%. CONCLUSION: Kinetic profiles of HED in the rat myocardium were similar to those of HED in humans, suggesting comparable neuronal transport density. Unlike in humans, however, significant washout of EPI and faster washout of PHEN were encountered, consistent with high intraneuronal metabolic activity, high catecholamine turnover, and reduced vesicular storage. This evidence of increased neuronal activity in rodents has implications for translational studies of cardiac neuronal biology in humans.  相似文献   
47.
中西医结合治疗急性冠脉综合征临床疗效观察   总被引:3,自引:0,他引:3  
目的观察中西医结合治疗急性冠脉综合征(ACS)的临床疗效。方法将60例ACS患者随机分为两组。治疗组在抗血小板、抗凝、降脂、扩张冠状动脉、降压、保护血管内皮功能等常规治疗基础上服用中药复方苏欣康颗粒;对照组在常规治疗基础上加用复方丹参滴丸。2周为1个疗程,1个疗程结束后观察治疗前后临床症状、心电图、24h动态心电图变化,并判定疗效。结果经2周治疗后,治疗组总有效率(90.O%,27/30)显著高于对照组(83.3%,25/30),差异有统计学意义(P〈0.05)。治疗组临床症状的改善程度高于对照组,其中以对心悸、自汗及心肾阳虚的改善最显著(P均〈0.05)。治疗组心律失常发生率(36.7%)低于对照组(50.0%),但差异无统计学意义(P〉O.05)。结论中药复方苏欣康结合常规手段治疗ACS疗效确切,可作为治疗ACS的有效方剂。  相似文献   
48.
Changes in T .lymphocyte subsets after severe traumatic brain inJury   总被引:2,自引:0,他引:2  
BACKGROUND: Besides local changes of cranial parenchymal cells, hemorrhage, etc., severe traumatic brain injuries also cause the changes of total body fluid and various functions, and the changes of lymphocytes and T lymphocyte subsets should be paid more attention to. OBJECTIVE: To reveal the changing laws of T lymphocyte subsets after severe traumatic brain injury, and compare with mild to moderate brain injury. DESIGN: A comparative observation. SETTINGS: Department of Neurosurgery, Longgang District Buji People's Hospital of Shenzhen City; Central Laboratory of Shenzhen Hospital of Prevention and Cure for Chronic Disease. PARTICIPANTS: All the subjects were selected from the Department of Neurosurgery, Longgang District Buji People's Hospital of Shenzhen City from August 2002 to August 2005. Thirty patients with severe brain injury, whose Glasgow coma score (GCS) was ≤ 8 points, were taken as the experimental group, including 21 males and 9 females, aging 16 - 62 years. Meanwhile, 30 patients with mild traumatic brain injury were taken as the control group (GCS ranged 14- 15 points), including 18 males and 12 females, aging 15 -58 years. All the subjects were in admission at 6 hours after injury, without disease of major organs before injury Informed consents were obtained from all the patients or their relatives. METHODS: (1) The T lymphocytes and the subsets in peripheral blood were detected with immunofluorescent tricolor flow cytometry at l, 3, 7 and 14 days after injury in both groups. (2) The conditions of pulmonary infections were observed at 4 days after injury. The differences of measurement data were compared with the t test. MAIN OUTCOME MEASURES: Changes of T lymphocytes subsets at 1 - 14 days after severe and mild or moderate traumatic injury. RESULTS: Finally, 28 and 25 patients with mild to moderate traumatic brain injury, whereas 25 and 21 patients with severe traumatic brain injury were analyzed at 7 and 14 days respectively, and the missed ones died due to the development of disease. (1) Changes of T lymphocyte subsets: At 1 and 3 days after injury, CD3, CD4, CD8, CD4/CD8 began to decrease, whereas CD8 increased in the experimental group, which were very significantly different from those in the control group (t =2.77 - 3.26, P 〈 0.01), and began to recover at 7 days, which were significantly different from those in the control group (t = 2.06 - 2.24, P 〈 0.05), and generally recovered to the normal levels at 14 days (P 〉 0.05). (2) Conditions of pulmonary infections: At 4 days after injury, the rate of pulmonary infection was significantly different between the experimental group and control group [73% (22/30), 0, x2=37.29, P 〈 0.01]. CONCLUSION: Patients with severe traumatic brain injury suffer from damages of cellular immune function at early period (within 7 days), and they are easily to be accompanied by pulmonary infections.  相似文献   
49.
目的:对我院收治的克罗恩病诊治效果分析。方法:依据我院1988年~2004年间收治克罗恩病39例的临床表现、肠镜及病理切片检查结果进行诊断和治疗。结果:非手术24例中,17例3年内肠检查见粘膜网状疤痕,13例完全恢复,7例失访。手术组12例,其中9例痊愈,1例复发死于机械性肠梗阻伴穿孔伴发腹膜炎。结论:要针对病人的具体情况,既要防止复发,还要尽量保证病人的生活质量,特别对青年病人选择造口术要慎重,同时应注重防止复发的措施。  相似文献   
50.
老年人隐裂牙综合治疗的临床分析   总被引:3,自引:0,他引:3  
目的:评价老年人隐裂牙综合治疗的临床效果。方法:对114例隐裂牙进行综合治疗,1年后随访观察。结果:114颗隐裂牙中,根管治疗全冠修复的有效率为92.86%,充填治疗组有效率为87.5%。结论:综合治疗可以保留牙体组织并恢复咬合力,是老年人隐裂牙治疗较理想的方法。  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