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   9259篇
  免费   815篇
  国内免费   656篇
耳鼻咽喉   87篇
儿科学   220篇
妇产科学   134篇
基础医学   918篇
口腔科学   203篇
临床医学   1021篇
内科学   1363篇
皮肤病学   132篇
神经病学   417篇
特种医学   304篇
外国民族医学   1篇
外科学   913篇
综合类   1867篇
现状与发展   1篇
一般理论   2篇
预防医学   762篇
眼科学   208篇
药学   982篇
  10篇
中国医学   580篇
肿瘤学   605篇
  2024年   29篇
  2023年   98篇
  2022年   283篇
  2021年   336篇
  2020年   330篇
  2019年   274篇
  2018年   283篇
  2017年   266篇
  2016年   254篇
  2015年   353篇
  2014年   474篇
  2013年   466篇
  2012年   622篇
  2011年   683篇
  2010年   536篇
  2009年   438篇
  2008年   556篇
  2007年   575篇
  2006年   487篇
  2005年   493篇
  2004年   384篇
  2003年   430篇
  2002年   378篇
  2001年   340篇
  2000年   242篇
  1999年   182篇
  1998年   116篇
  1997年   117篇
  1996年   94篇
  1995年   80篇
  1994年   66篇
  1993年   63篇
  1992年   54篇
  1991年   69篇
  1990年   50篇
  1989年   43篇
  1988年   32篇
  1987年   37篇
  1986年   32篇
  1985年   16篇
  1984年   10篇
  1983年   12篇
  1982年   10篇
  1981年   5篇
  1980年   6篇
  1979年   5篇
  1978年   5篇
  1977年   3篇
  1976年   4篇
  1968年   3篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
目的 探讨经尿道膀胱肿瘤低功率电切术的适应症、手术方法及其疗效评估. 方法分析65例经尿道膀胱肿瘤切除术.手术时间10~90 min,平均时间41 min;膀胱穿孔1例,术后冲洗时间1~3 d,平均2 d;导尿管留置时间1~5 d,平均4 d.结果 随访0.5~3 a,48例中肿瘤复发15例,其中原位复发2例,异位多位复发13例.结论 经尿道膀胱肿瘤低功率电切可防止并明显减少闭孔神经反射的发生,具有操作简单,损伤小,出血少、恢复快等优点.  相似文献   
62.
Background: People with abnormal colour vision often report difficulty seeing coloured berries and flowers in foliage, which suggests they will have a diminished capacity for visual search when target objects are marked out by colour. There is very little experimental evidence of the effect of abnormal colour vision on visual search and none relating to search for objects in natural foliage. Method: We showed 79 subjects with abnormal colour vision (seven protanopes, 10 deuteranopes, 16 protanomals and 46 deuteranomals) and 20 subjects with normal colour vision photographs of natural scenes and asked them to locate clumps of red berries, to trace the length of a red string on grass and to name the season depicted in a photograph taken in the Autumn and the same scene photographed in the Summer. Colour vision was assessed using the Ishihara, the Medmont C100, the Farnsworth D15, the Richmond HRR and the Nagel anomaloscope. Results: All the subjects with abnormal colour vision located fewer clumps of red berries than those with normal colour vision. The subjects who failed the Farnsworth D15 performed significantly worse than those who passed but the distribution of scores in the two groups overlaps. The majority of subjects with abnormal colour vision could not trace the full length of the string: only 38 per cent of anomalous trichromats who passed the Farnsworth D15 test and three per cent of those who failed it were able to trace the full length of the string. Fifty‐five per cent of those classed as having a mild deficiency by the HRR test could trace the whole string. Most dichromats were unable to identify the Autumn season and those who did may have been assisted by guessing. Most (94 per cent) of those who passed the Farnsworth D15 test and all those classified as having a ‘mild’ deficiency by the HRR test could identify the season. Conclusions: All people with abnormal colour vision, even those with a very mild deficiency, have some degree of impairment of their ability to see coloured objects in natural surroundings. A pass at the Farnsworth D15 test or a ‘mild’ classification with the Richmond HRR test identifies those likely to have the least problems with visual search and identification tasks. The results have practical implications for the selection of personnel in occupations that involve visual search in natural terrain.  相似文献   
63.
隐动脉筋膜蒂的交腿皮瓣修复小腿严重软组织缺损   总被引:7,自引:2,他引:5  
目的探讨一种小腿严重软组织缺损的修复方法。方法以健侧隐动脉为蒂的顺行或逆行交腿皮瓣修复患侧小腿软组织缺损。结果本组8例均有效地覆盖受区创面,随访三个月,皮瓣全部成活。结论该皮瓣不牺牲小腿的重要血管,质地与受区相似,方法简单易行,血运可靠,血管蒂长,是修复小腿严重软组织缺损的较好方法。  相似文献   
64.
自1990年以来收治直径在2-5.6cm的大、巨型垂体腺瘤33例。依肿瘤生长形态与扩展范围将其简略分为三种类型。A型:瘤体位于鞍内或侵入蝶窦;B型;瘤体呈椭圆形或哑铃向鞍上扩展,三脑室明显移位抬高;C型:瘤体巨大侵入三脑室阻塞室间孔或明显的鞍周扩展。  相似文献   
65.
bcl-2反义寡核苷酸对膀胱癌BIU87细胞株的影响   总被引:2,自引:0,他引:2  
目的:探讨bcl-2反义寡核苷酸对培养的膀胱癌BIU87细胞株的影响.方法:采用bcl-2基因第1外显子的反义寡核苷酸,以硫代磷酸修饰(PS-ASON),序列为5′-TCTCCCAGCGTGCGCCAT-3′,与膀胱癌细胞株BIU87共同孵育作为实验组.加入正义的bcl-2寡核苷酸,序列为5′-TACCGCGTGCGACCCTCT-3′(PS-SON)作为对照组,用流式细胞仪检测细胞凋亡和坏死率,电镜观察细胞形态变化.结果:与对照组相比,实验组的细胞坏死率明显上调,电镜下细胞形态呈坏死改变.结论:bcl-2的反义寡核苷酸引起膀胱癌细胞大量坏死,可能成为膀胱癌的治疗方法之一.  相似文献   
66.
新型重组人肿瘤坏死因子药代动力学的实验方法   总被引:2,自引:0,他引:2  
目的 为探讨新型重组人肿瘤坏死因子(nrTNF α)药代动力学而建立生物样品中nrhTNFα的检测方法。方法 (1)方法Ⅰ(RA):动物肌注^125 Ⅰ标记的nrhTNFα后,测定各生物样品中的总放射活性;(2)方法Ⅱ(HPLC-RA);上述生物样品无经HPLC分离后,收集并测定其中^125Ⅰ-nrhTNFα部分的放射活性;(3)方法 ⅢELISA法。结果 RA,HPLC-RA法检测的nrhTNFα质量浓度与放射性呈直线相关(RA,r=0.999HPLC-RA,r=0.999)。ELISA法证明nrhTNFα的酶联免疫检测药盒适用于nrhTNFα的检测,nrhTNFα的标准曲线与nrhTNFα的标准曲线显正相关,r=0.994,这一检测系统与其他细胞因子包括IFNα,TNFβ,IL-2和IL-6无交叉反应。结论 RA,HPLC-RA和ELISA法均可作为nrhTNFα的药代动力学实验方法。  相似文献   
67.
We have previously reported the purification of a 37 kDa platelet agglutinating protein (PAP p37) from the plasma of a patient with thrombotic thrombocytopenic purpura (TTP) that was shown to be present in a subset of TTP patients. To gain further insight into the interaction between PAP p37 and platelets, we have studied the properties of PAP p37 binding to platelets. Washed human platelets from two normal donors and two TTP patients after recovery were used for the experiments. The PAP p37 binding to platelets was specific, concentration dependent and saturable. Scatchard analysis demonstrated about 20,564-27,090 PAP p37 binding sites per platelet. Stimulation of platelets with thrombin or ADP did not have any significant effect on its binding. Thiol- and serine-specific protease inhibitors did not inhibit PAP p37 binding to the platelets. Sugars such as glucose, fructose, mannose, and sialic acid, at 40 mM, inhibited its binding to platelets by 44%, 73%, 79%, and 91% respectively, but galactose and amino sugars did not have any significant effect. At 250 micrograms/ml, Concanavalin-A inhibited 42% of binding, but other lectins, such as phytohemagglutinin-P, potato lectin and helix pomatia lectin (snail), did not. Pre-incubation of 125I-PAP p37 with the adult human IgG, decreased its binding to the platelets. The monoclonal antibodies to GP Ib (6D1) and GP IIb-IIIa complex (10E5) did not inhibit the binding of 125I-PAP p37 to platelets. Fibrinogen and von Willebrand factor did not affect the binding either. These results suggest that PAP p37 binds to platelets on the sites other than GP Ib or GP IIb-IIIa complex.  相似文献   
68.
STUDY OBJECTIVE--The aim was to examine if there is an effect of fathers' age and of birth order on the occurrence of congenital heart disease. DESIGN--This was a hospital based case-referent study including use of birth defects surveillance data. SUBJECTS--Subjects were 497 cases of congenital heart disease aged between 3 months and 5 years, born in Beijing and Hebei Province, China; 6222 children without congenital heart disease serve as reference baseline. MEASUREMENTS AND MAIN RESULTS--With stratified analysis and logistic regression analyses, congenital heart disease was found to be associated with fathers' age less than 25 years (odds ratio 2.63), independent of mothers' age and of birth order. There was also evidence to show a higher birth order effect on the occurrence of congenital heart disease independent of parental ages. CONCLUSION--Higher birth order and fathers aged less than 25 years were both independently associated with some categories of congenital heart disease and with congenital heart disease overall.  相似文献   
69.
目的 探讨垂体生长激素腺瘤并发重型糖尿病的临床治疗方法和效果。方法 收治6例大型垂体生长激素腺瘤合并重型糖尿病病人,首先给予大剂量胰岛素控制血糖,待血糖降至10mmol/L左右时手术行肿瘤次全切除,术后常规放疗,DT:50Gy。结果 本组6例病人术后胰岛素所需剂量即明显下降。其中5例获随访0.6~6年,平均随访时间4.5年,均已恢复正常工作,停用任何降糖药物。血糖尿糖复查正常。结论 对大型生长激素腺瘤合并重型糖尿病的病人,积极手术切除肿瘤并辅以放疗是一种迅速有效的治疗选择。  相似文献   
70.
目的探讨乌蛇败毒胶囊治疗湿疹的机理。方法采用变应性接触性皮炎小鼠模型,分为模型组,对照组及大、中、小剂量组和空白组,观察各组治疗前后血清IL-2、TNF-α的变化。结果中药组能明显降低模型小鼠血清中IL-2、TNF-α的含量(P<0.01),降低诱发后鼠耳的肿胀度,减少真皮内单一核及多形核白细胞数目(P<0.01)。结论乌蛇败毒胶囊治疗湿疹的部分机理是抑制小鼠Ⅳ型变态反应、降低血清IL-2,TNF-α含量,减轻炎症损伤。  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