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   76361篇
  免费   7163篇
  国内免费   4592篇
耳鼻咽喉   666篇
儿科学   1048篇
妇产科学   1130篇
基础医学   9063篇
口腔科学   1325篇
临床医学   9141篇
内科学   12246篇
皮肤病学   845篇
神经病学   3843篇
特种医学   3057篇
外国民族医学   49篇
外科学   8897篇
综合类   11548篇
现状与发展   16篇
一般理论   18篇
预防医学   5064篇
眼科学   1996篇
药学   7971篇
  74篇
中国医学   3770篇
肿瘤学   6349篇
  2024年   218篇
  2023年   1082篇
  2022年   2637篇
  2021年   3651篇
  2020年   2635篇
  2019年   2370篇
  2018年   2554篇
  2017年   2301篇
  2016年   2245篇
  2015年   3223篇
  2014年   3941篇
  2013年   3882篇
  2012年   5514篇
  2011年   5971篇
  2010年   3766篇
  2009年   3132篇
  2008年   4230篇
  2007年   4300篇
  2006年   3979篇
  2005年   3879篇
  2004年   2931篇
  2003年   2691篇
  2002年   2434篇
  2001年   2015篇
  2000年   2008篇
  1999年   1836篇
  1998年   1042篇
  1997年   1008篇
  1996年   803篇
  1995年   704篇
  1994年   614篇
  1993年   445篇
  1992年   628篇
  1991年   533篇
  1990年   473篇
  1989年   426篇
  1988年   339篇
  1987年   323篇
  1986年   255篇
  1985年   199篇
  1984年   132篇
  1983年   96篇
  1982年   69篇
  1981年   81篇
  1980年   42篇
  1979年   81篇
  1978年   38篇
  1974年   38篇
  1973年   37篇
  1972年   43篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
The toxic effects of nitroquine-dapsone compound(NQD)in mice and dogs were studied.The therapeutic index of NQDin mice is 1911,the greatest among the 6 antimalarials tested.Thetoxic effects of NQD(50 mg/kg/day for 3 days per os)and nitro-quine in dogs were manifested by injuries on the adrenal cortexand intestinal epithelium.When folic acid(4 mg/kg/day for 4 days)or calcium leucovorinum(0.3 mg/kg/day for 4 days)were usedconcomitantly with NQD,the death rate and the incidence of dia-rrhea in the toxicated dogs were greatly reduced,the injury on theintestinal epithelium was much milder,and the goblet cells weremuch more numerous than those without treatment.The results suggestthat folic acid and calcium leucovorinum can protect the undifferen-tiated cells in the intestinal crypts from being injured by NQD.  相似文献   
92.
Delta hepatitis virus infection in China   总被引:1,自引:0,他引:1  
To assess the prevalence, epidemiological features and prognostic implications of hepatitis D (Delta) in Sichuan Province, The People's Republic of China, 649 sera (515 from HBsAg positive patients and 134 from HBsAg negative subjects) were tested by radioimmunoassay (RIA) for antibody to the hepatitis D virus (anti-HD). Forty-seven sera (7.2%) showed some degree of reactivity. Serial dilutions of these sera indicated that prozoning was not responsible for the equivocal results. Thirty-four of the 47 sera were submitted under code to a second laboratory for independent analysis. According to those results anti-HD antibodies were detected in four of these sera. The overall prevalence of anti-HD in the HBsAg positive patients therefore was 0.8% (4/515). On the basis of clinical, biochemical and histological data 427 HBsAg positive sera were further divided into acute Type B hepatitis, chronic Type B hepatitis, healthy carrier state and hepatocellular carcinoma (HCC) subgroups. Two of 65 (3.1%) anti-HD positive sera belonged to the acute Type B hepatitis group; one of 104 (0.9%), the chronic Type B hepatitis group and one of 246 (0.4%), the healthy carrier group. No antibody was detected in sera from 12 HBsAg positive HCC patients. All HBsAg negative patients were negative for anti-HD antibody. The results of this study indicate that despite a high prevalence of hepatitis B virus infection, positive serology for delta virus is uncommon in Sichuan Province, The People's Republic of China.  相似文献   
93.
纤维支气管镜床边治疗肺不张的疗效观察   总被引:2,自引:0,他引:2  
程美婷 《护理研究》2006,20(8):2187-2188
肺不张不是一种独立的疾病,一旦发生可加重原发病,甚至危及病人生命。因此,应迅速消除支气管、肺泡分泌物和阻塞物。经纤维支气管镜(简称纤支镜)吸引治疗由痰栓引起的肺不张可起到立竿见影的效果。纤支镜在直视下进入段支气管甚至亚段支气管,准确清除呼吸道炎性分泌物,解除气道阻塞,促使肺复张,改善肺通气和换气功能,迅速提高氧分压,降低二氧化碳分压,有利于感染的控制及黏膜水肿的消除,目标性强、效率高、损伤少。这种直视下操作最大限度地减少盲目吸引所致的支气管黏膜损伤。我科2003年1月-2005年6月进行床边纤支镜介导治疗急性肺不张病人23例,效果良好。现报告如下。  相似文献   
94.
脊柱复合性损伤的救治风险与早期治疗   总被引:3,自引:1,他引:2  
目的评估脊柱复合性损伤的特点和救治风险,探讨风险控制与最佳治疗的方法。方法采用AIS、ISS、TRISS及APACHEⅡ等评分方法对273例脊柱复合性损伤患者进行定量评价与救治分类,并依据伤后的损伤分级、参数评定及计量评分等指标进行量化分析和统计处理。结果颈椎合并伤115例,胸椎合并伤141例,胸腰椎合并伤294例,腰骶椎合并伤181例;患者的救治风险和脊椎伤的治疗选择或手术时机与其合并伤的解剖伤势及由此所构成的整体伤情密切相关(P<0.01或<0.05);高风险性伤员往往综合伤势严重,生存概率(Ps)趋低,并发症和死亡率高(P<0.01或<0.05)。结论脊柱脊髓损伤常合并有严重的多发伤,高危伤情不仅可增加其救治风险和脊柱伤的处理难度,且还易于丧失手术最佳时机。分类救治对伤员的风险控制和脊柱伤的专科治疗是有益的。  相似文献   
95.
The antiparasitic drug, suramin, has antiproliferative effects in human carcinoma cells. It has been suggested that this occurs through blockade of growth factor-receptor interactions. Three types of evidence that suramin rapidly inhibits cellular respiration or disrupts cellular energy balance in intact cells of the human prostate carcinoma cell line, DU145, are presented. Beginning at approximately 10(-4) M, suramin rapidly causes dose-dependent inhibition of tetrazolium conversion by mitochondrial dehydrogenases in intact cells, demonstrating an inhibition of respiration. This effect is reversed by exchange with suramin-free media but not by pretreatment with serum, epidermal growth factor, insulin-like growth factor I, acidic and basic fibroblast growth factors, or calcium. Rhodamine 123 (10 micrograms/ml) uptake by mitochondria in intact DU145 cells is inhibited in the presence of 10(-3) M suramin. Treatment with 10(-4)-10(-3) M suramin causes the loss of rhodamine 123 from cells with mitochondria prestained with rhodamine 123, indicating that suramin is acting as an ionophore or respiratory poison. Also shown by electron microscopy are progressive toxic changes in mitochondria of DU145 cells within 1 h after treatment with 10(-4) M suramin. These data indicate that in intact DU145 cells 10(-4) M suramin rapidly disrupts cellular energy balance or respiration as seen by three studies of mitochondrial state. Disruption of energy balance or respiration represents a likely antiproliferative mechanism, as is thought to be a primary mechanism for the action of suramin in parasitic diseases. This proposed mechanism of action for suramin can explain the most prominent observed clinical toxicities of nephrotoxicity, adrenal toxicity, coagulopathy, and demyelinating neuropathy.  相似文献   
96.
胰岛素瘤的超声诊断:与其他诊断方法比较   总被引:1,自引:0,他引:1  
目的:探讨超声等方法对胰岛素瘤的定位诊断价值。材料和方法:对42例经过手术和病理证实的胰岛素瘤患者术前定位诊断的各种方法进行回顾性分析,并与其他诊断方法对比分析其各自的定位符合率。结果:定位诊断符合率分别为B超31%(13/42)、EUS55.6%(5/9)、IOUS100%(10/10)、超声引导下PTPC100%(3/3)、CT59.5%(25/42)、MRI50%(6/12)、选择性DSA27.3%(3/11)及ASVS90%(9/10)。彩超(CDUS)对胰岛素瘤良、恶性有鉴别作用。结论:遵循循序渐进原则,先后选用B超(含CDUS)、EUS、CT等已可解决80%以上的定位诊断,然后再做MRI及ASVS;对仍未作出定位者,只要定性诊断明确即有手术探查指征,因为IOUS能提供可靠的定位信息。  相似文献   
97.
98.
larangea ltubus喉罩插管(LTS)和气管内插管(ETI)均是保持气道通畅和改善通气的方式,我们设计了以下研究对两种方法在急诊情况下的应用进行了研究。将内科医生根据其插管经验分为3组(1组插管经验〈50次;2组〉50次但〈500次;3~n〉500次),分别在人体气道模型上进行模拟LTS和ETI,统计改善气道所需时间杀Ⅱ成功率。结果显示:LTS的成功率为99.39%(n=325),高于ETI(92.35%,n=302);  相似文献   
99.
100.
The first universal hepatitis B vaccination program for newborns in the world was launched in Taiwan in July 1984. Most studies on the effectiveness of hepatitis B vaccination focused on the seroprevalence of HBs Ag among children under 14 years old. Only few studies focused on the seropositivity of anti-HBs among adolescents aged 15–18 years old. The present study aimed to evaluate the impact of the nationwide hepatitis B vaccination program on the immunity to HBV infection and the necessity of boost among adolescents. In this study including eight annual seroprevalence surveys from 2000 to 2007, 2342 college entrants (1589 15-year-olds in group I and 753 18-year-olds in group II) and 1851 university freshmen (18-year-olds in group III) participated. Subjects identified anti-HBs, HBs Ag and anti-HBc negative were given boost three doses of HBV vaccine. The HBs Ag seroprevalence was 11.6%, 3.5% and 1.0% for participants who were born before 1984, 1984–1986 and after 1986. The anti-HBs-seropositive rates were significantly higher in group II (83.1%) than in group I (53.0%) and group III (53.5%). All 572 participants who were seronegative for anti-HBs, HBs Ag and anti-HBc became anti-HBs-seropositive after catch-up vaccination. It is concluded that the anti-HBs-seropositive rate decreased to 50% in 15 years after vaccination, and boost vaccination was 100% effective. The necessity and age for boost among anti-HBs negative adolescents and the timing of the first immunization should be further evaluated.  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