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   22644篇
  免费   2003篇
  国内免费   1505篇
耳鼻咽喉   135篇
儿科学   218篇
妇产科学   209篇
基础医学   2769篇
口腔科学   393篇
临床医学   3184篇
内科学   3207篇
皮肤病学   245篇
神经病学   1172篇
特种医学   778篇
外国民族医学   13篇
外科学   2169篇
综合类   4224篇
现状与发展   5篇
一般理论   1篇
预防医学   1167篇
眼科学   578篇
药学   2458篇
  22篇
中国医学   1294篇
肿瘤学   1911篇
  2024年   95篇
  2023年   428篇
  2022年   1003篇
  2021年   1218篇
  2020年   944篇
  2019年   743篇
  2018年   843篇
  2017年   722篇
  2016年   723篇
  2015年   1115篇
  2014年   1329篇
  2013年   1129篇
  2012年   1666篇
  2011年   1829篇
  2010年   1077篇
  2009年   856篇
  2008年   1138篇
  2007年   1105篇
  2006年   1157篇
  2005年   1125篇
  2004年   740篇
  2003年   660篇
  2002年   566篇
  2001年   506篇
  2000年   536篇
  1999年   545篇
  1998年   334篇
  1997年   330篇
  1996年   227篇
  1995年   230篇
  1994年   226篇
  1993年   125篇
  1992年   135篇
  1991年   132篇
  1990年   131篇
  1989年   95篇
  1988年   90篇
  1987年   78篇
  1986年   65篇
  1985年   62篇
  1984年   22篇
  1983年   13篇
  1982年   15篇
  1981年   14篇
  1980年   3篇
  1979年   15篇
  1978年   2篇
  1977年   2篇
  1976年   3篇
  1974年   3篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
Twenty five cases, including 26 eyes with retinal vein occlusion (RVO) were examined by means of the electro-oculogram. The results showed that 23 of the 26 eyes suffering from RVO exhibited abnormalities of the electro-oculogram (EOG). The potential difference and Arden ratio in the RVO eyes were lower than those in the normal eyes (P<0.01). The more the visual acuity of ill eyes was decreased, the higher the abnormal rate of EOG in ill eyes was. 14 eyes had the visual acuity less than 0.1, whose EOGs were abnortmal. Six eyes had the visual acuity from 0. 2 to 0. 4, in which the EOGs of 5 eyes were abnormal. Six eyes had the visual acuity more than 0. 5, a-mong which the EOGs of 4 eyes were abnormal. Based on the above observations, it may be considered that the circulatory disturbance resulting from RVO damages not only the internal layer but also the external layer of the retina. We suggest that EOG is a useful method for distingquishing lesions caused by RVO and may reflect the functional condition  相似文献   
22.
Objective. To study the characteristics of changes of LDH enzyme patterns of mice under slight hypoxia.Methods. Mice treated with artificial hypoxia, various tissues were made for the test of LDH enzymatic activity by the specific staining technique. LDH (1 -5) relative percentage enzymatic activity (RPEA) were measured with CS-910 dual-wavelength thin layer chromatography scanner.Results. The RPEA of LDH isozymes of various tissues after slight hypoxia shifted to the isozymes LDH1 and LDH2, whose principal subunits are H subunits, and the RPEA of LDH,(H4), LDH2(H3M) increased, while RPEA of LDH5(M4) in various tissues decreased prominently except the cardiac muscle, and that of LDH4(HM3) decreased as well. After polyacrylamide gel electrophoresis (PAGE) of the hypoxia treated cardiac muscle specimen was made, activity subbands originated regularly in the isozyme patterns of LDH, with the regularity of LDH1 (0 subband), LDH2 (0-1 subbands), LDH3 (0-2 subbands), LDH4 (1-3 subbands), LDH5 (2-4 subbands).  相似文献   
23.
丙型肝炎病毒感染对肾移植术后影响的临床研究   总被引:3,自引:0,他引:3  
OBJECTIVE: To study the influence of hepatitis C virus (HCV) infection on the clinical outcome of kidney transplantation. METHODS: The recipient/graft survival, the incidence of acute/chronic rejection and cause of death in 86 HCV-infected recipients of renal transplantation were compared with those in another 86 recipients without HCV infection. RESULTS: HCV-infected recipients had significantly shorter 5-year survival (74.4%) than those without HCV infection (87.2%, P<0.01). The 1-year (94.2%/90.7% vs 96.8%/96.0%) and 3-year recipient/graft survival rates (88.4%/79.1% vs 90.7%/87.2%), the incidence of acute/chronic rejection (31.3% vs 21.2%, and 12.5% vs 6.5%) and the 5-year graft survival (73.3%/81.4%) were comparable between the two groups (P>0.05). Hepatic disease was identified as the primary cause of mortality. CONCLUSIONS: HCV infection may affect the long-term survival of the recipients with kidney transplantation, and therefore should be considered as a relative contraindication of kidney transplantation.  相似文献   
24.
针刺对偏头痛大鼠脑内一氧化痰、5-羟色胺的影响   总被引:12,自引:2,他引:10  
目的 :观察针刺对偏头痛大鼠脑内一氧化氮 (NitricOxide,NO)和 5 -羟色胺 (Sereotonin ,5 -HT)的影响 ,并探讨其防治偏头痛的作用机制。方法 :将 4 0只大鼠随机分为正常对照组、模型组、针刺预防组和针刺治疗组 ;采用硝酸还原法和反相高效液相色谱法分别测定颈静脉 (ExternalJugularVein ,EJV)中NO和 5 -HT含量。结果 :与正常对照组比较 ,模型组NO显著升高 ,5 -HT显著降低 (P <0 .0 1) ;与模型组比较 ,针刺预防组和针刺治疗组NO显著降低 (P <0 .0 1) ,5 -HT明显升高 (P <0 .0 1)。结论 :针刺不仅能治疗偏头痛 ,而且能减慢 5 -HT的降解 ,抑制NO的释放。推测针刺偏头痛可能是通过调节 5 -HT和NO的含量而实现的。  相似文献   
25.
微波干燥法对腊叶标本压制的实验研究   总被引:2,自引:1,他引:1  
目的:寻求一种不受气候条件影响而能成功制作腊叶标本的新技术。方法:采用微波干燥法,即用微波炉,由创制的直径31cm瓦楞纸板、吸水纸与玻璃皿组成的压制程序进行微波干燥。结果:微波干燥法可用于腊叶标本压制,且优于传统的常规腊叶标本压制方法。结论:本研究为腊叶标本的制作提供了一个新方法,收到了便捷、高效、且保色的理想效果。  相似文献   
26.
北京农村居民健康状况及卫生服务需求调查   总被引:17,自引:5,他引:12  
目的了解北京农村居民健康状况及卫生服务需求特点。方法从昌平区、顺义区、大兴区、房山区随机抽取25~64岁农民1605人进行统一问卷调查。结果农民高血压自报患病率为22.4%,超重和肥胖率为56.1%;现在吸烟率为34.4%,缺乏运动率为41.6%;家庭主要经济支出为学生上学(35.3%),建房(25.4%)和疾病(21.2%);54.9%家庭医疗费用支出占总收入的10%以上;最关心的健康问题主要是慢性疾病防治(70.2%);最希望获得的健康知识是慢性病预防知识(72%);希望获得健康知识的途径是广播和电视(81%);家庭最希望获得的医疗保健服务是方便看病和获得药物(73.8%)。结论慢性病给农民带来沉重负担,并成为农民关心的主要健康问题。  相似文献   
27.
目的 通过研究枸橼酸能否减轻一水草酸钙(calcium oxalate monohydrate,COM)晶体对体外培养的Wistar大鼠肾小管上皮细胞造成的损伤,以探讨枸橼酸在尿路结石防治中的作用及其机制。方法分离、培养正常雄性Wistar大鼠的肾小管上皮细胞,在原代培养第5天时,将细胞分成3组(空白对照组、COM组及枸橼酸组),分别于各组培养液中培养2h后用比色法测定各组细胞培养基中丙二醛(malonaldehyde,MDA)的含量及细胞的钙镁ATP酶(Ca`2+-Mg`2+-ATPase)和钠钾ATP酶(Na`2+K`+-ATPase)的活性。结果①COM组和枸橼酸组细胞Ca2+-Mg`2+ATPase和Na`++K`+-ATPase活性均明显低于对照组(P〈0.05);②与枸橼酸组相比,COM组细胞Ca`2+-Mg`2+-ATPase和a`++K`+-ATPase活性下降更加明显(P〈O.05);③COM组和枸橼酸组细胞培养基中MDA的含量均明显高于对照组(P〈O.05);④与枸橼酸组相比,COM组细胞培养基中MDA的含量更高(P〈O.05)。结论外源性枸橼酸能够减轻一水草酸钙晶体对体外培养的Wistar大鼠肾小管上皮细胞造成的脂质过氧化损伤。  相似文献   
28.
清燥救肺汤加减治疗依那普利所致咳嗽临床研究   总被引:1,自引:0,他引:1  
目的 :观察清燥救肺汤加减治疗依那普利所致咳嗽疗效。方法 :设清燥救肺汤组与复方甘草片组对照观察疗效及对血压的影响。结果 :与对照组比较 ,疗效有显著差异 ,P <0 .0 1;血压有明显改善 ,P <0 .0 5。结论 :清燥救肺汤用于治疗依那普利所致咳嗽疗效肯定。  相似文献   
29.
Objective: To summarize the clinical outcomes of 117 human vitrified blastocyst transfer cycles and to determine the impact factors.Methods: In IVF-ET cycles, supernumerary embryos were cultured to 5-Day(D5) or 6-Day(D6), blastocysts of various stages were cryopreserved by vitrification using cryoloops. Survival rate and clinical pregnancy rate were observed.Results: A total of 312 blastocysts were thawed in 117 frozen embryo transfer cycles, the survival rate was 90.7% (283/312) after thawing. After the transfer of 230 blastocysts in 115 cycles, 69.6% (80/115) of the women got clinically pregnant, and 17.5% (14/80) of them suffered from miscarriage, 39 healthy babies were born in 28 deliveries, and the other 38 pregnancies are ongoing. The implantation rate was 47.4% (109/230). In 107 transfer cycles with 2 hatched blastocysts transferred in each cycle, 72.9% (78/107) got clinically pregnant, while in 8 cycles with 1 or no hatched blastocysts in the two transferred blastocysts, the clinical pregnancy rate is 25%(2/8). The clinical pregnancy rates were not statistically different between natural (77.4%, 24/31) or artificial endometrium preparation (66.7%, 56/84) cycles. Conclusions: These findings suggest that blastocyst vitrification is effective in terms of implantation rate and pregnancy outcome. Transferring of two hatched blastocyst can achieve a higher pregnancy rate.  相似文献   
30.
桥本氏病手术治疗45例临床分析   总被引:2,自引:1,他引:1  
本文分析45例桥本氏病诊断和手术治疗的经验教训。本病合并其它甲状腺外科疾病 诊断困难,手术方式要慎重选择。术中常规冰冻快速活检,可帮助鉴别诊断和指导术式选择。  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