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   74438篇
  免费   6546篇
  国内免费   4922篇
耳鼻咽喉   484篇
儿科学   879篇
妇产科学   898篇
基础医学   8411篇
口腔科学   1253篇
临床医学   9979篇
内科学   10848篇
皮肤病学   778篇
神经病学   3725篇
特种医学   2312篇
外国民族医学   42篇
外科学   7108篇
综合类   13311篇
现状与发展   18篇
一般理论   7篇
预防医学   5268篇
眼科学   1808篇
药学   8037篇
  59篇
中国医学   3970篇
肿瘤学   6711篇
  2024年   210篇
  2023年   1018篇
  2022年   2588篇
  2021年   3399篇
  2020年   2773篇
  2019年   2221篇
  2018年   2330篇
  2017年   2282篇
  2016年   2096篇
  2015年   3365篇
  2014年   4223篇
  2013年   3918篇
  2012年   5856篇
  2011年   6243篇
  2010年   4234篇
  2009年   3447篇
  2008年   4297篇
  2007年   4245篇
  2006年   3984篇
  2005年   3733篇
  2004年   2462篇
  2003年   2302篇
  2002年   1924篇
  2001年   1536篇
  2000年   1655篇
  1999年   1693篇
  1998年   999篇
  1997年   1095篇
  1996年   773篇
  1995年   733篇
  1994年   660篇
  1993年   417篇
  1992年   461篇
  1991年   454篇
  1990年   405篇
  1989年   322篇
  1988年   301篇
  1987年   293篇
  1986年   239篇
  1985年   185篇
  1984年   134篇
  1983年   99篇
  1982年   46篇
  1981年   58篇
  1980年   33篇
  1979年   41篇
  1978年   25篇
  1977年   19篇
  1976年   18篇
  1973年   10篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
On genetic studies of bone loss.   总被引:3,自引:0,他引:3  
  相似文献   
102.
慢性肝炎(简称慢肝)属中医学“胁痛”、“黄疽”、“瘾积”等范畴。其病程长,疗效慢,且易反复发作。目前尚无特殊疗法。笔者通过研习有关文献,回顾长期临床验案,对慢性肝炎之证治略有心得,兹介绍如下。  相似文献   
103.
目的探讨超声引导下活体犬肝注射不同剂量的醋酸高渗氯化钠液(acetic acid hypertonic saline solution,AHS)后行射频消融(RFA),观察犬肝一次性毁损体积的变化。方法使用LDRF-120S多极RFA系统联合AHS对活体犬肝行RFA。健康成年杂种犬30只,随机分为5组(n=6)。A组:注射2ml AHS后立即行RFA;B组:注射2ml AHS后延时5min行RFA;C组:注射4ml AHS后立即行RFA;D组:注射4ml AHS后延时5min行RFA;E组:注射6ml AHS后立即行RFA。结果5组间平均起始阻抗差异无统计学意义(P>0.05);5组间平均消融时间差异有统计学意义(F=83.831,P<0.001),LSD-t检验分析各组间两两比较差异有统计学意义(P<0.001),在观察范围内E组平均消融时间最长;5组间平均毁损直径差异有统计学意义(F=53.488,P<0.001),在观察范围内E组平均毁损直径最大,LSD-t检验分析除D与E组间差异无统计学意义(P>0.05)外,其余各组间两两比较差异有统计学意义(P<0.001);网状纤维染色显示凝固坏死区及其邻近的正常肝组织均可见血管内血栓形成;E组在AHS注射过程中出现不同程度的外溢;A、B、C及D组14d内无动物死亡,E组死亡4只。结论活体犬肝局部注射AHS4ml后延时5min行RFA即可达到较理想的毁损体积。  相似文献   
104.
BACKGROUND CONTEXT: Retrolisthesis is relatively rare but when present has been associated with increased back pain and impaired back function. Neither the prevalence of this condition in individuals with lumbar disc herniations nor its possible relation to preoperative back pain and dysfunction has been well studied. PURPOSE: The purposes of this study were as follows: (1) to determine the prevalence of retrolisthesis (alone or in combination with other degenerative conditions) in individuals with confirmed L5-S1 disc herniation who later underwent lumbar discectomy; (2) to determine if there is any association between retrolisthesis and degenerative changes within the same vertebral motion segment; and (3) to determine the relation between retrolisthesis (alone or in combination with other degenerative conditions) and preoperative low back pain, physical function, and quality of life. STUDY DESIGN/SETTING: Cross-sectional study. PATIENT SAMPLE: A total of 125 individuals were identified for incorporation into this study. All patients had confirmed L5-S1 disc herniation on magnetic resonance imaging (MRI) and later underwent L5-S1 discectomy. All patients were enrolled in the Spine Patient Outcomes Research Trial (SPORT) study; data were obtained from the multi-institutional database comprised of SPORT patients from across the United States. OUTCOME MEASURES: Retrolisthesis, degenerative change on MRI, and Modic changes. METHODS: MRI scans of the lumbar spine were assessed at spinal level L5-S1 for all 125 patients. Retrolisthesis was defined as posterior subluxation of 8% or more. Disc degeneration was defined as any loss of disc signal on T2 imaging. Modic changes were graded 1 to 3 and collectively classified as vertebral endplate degenerative changes. The presence of facet arthropathy and ligamentum flavum hypertrophy was classified jointly as posterior degenerative changes. RESULTS: The overall incidence of retrolisthesis at L5-S1 in our study was 23.2%. Retrolisthesis combined with posterior degenerative changes, degenerative disc disease, or vertebral endplate changes had incidences of 4.8%, 16%, and 4.8% respectively. The prevalence of retrolisthesis did not vary by sex, age, race, smoking status, or education level when compared with individuals with normal sagittal alignment. However, individuals with retrolisthesis were more likely to be receiving workers' compensation than those without retrolisthesis. Increased age was found to be associated with individuals having vertebral endplate degenerative changes (both alone and in conjunction with retrolisthesis) and degenerative disc disease. Individuals who had retrolisthesis with concomitant vertebral endplate degenerative changes were more often smokers and had no insurance. The presence of retrolisthesis was not associated with an increased incidence of having degenerative disc disease, posterior degenerative changes, or vertebral endplate changes. No statistical significance was found between the presence of retrolisthesis on the degree of patient preoperative low back pain and physical function. Patients with degenerative disc disease were found to have increased leg pain compared with those patients without degenerative disc changes. CONCLUSIONS: We found no significant relationship between retrolisthesis in patients with L5-S1 disc herniation and worse baseline pain or function. It is possible that the contribution of pain or dysfunction related to retrolisthesis was far overshadowed by the presence of symptoms caused by the concomitant disc herniation. It remains to be seen whether retrolisthesis will affect outcome after discectomy in these patients.  相似文献   
105.
目的 探讨血红素对人脐静脉内皮细胞氧化应激损伤的保护作用。方法 将培养的人脐静脉内皮细胞进行分组:对照组、损伤组、血红素组。观察各组细胞在光、电镜下形态学的改变。结果 在光镜下,血红素组细胞的生长状态明显优于损伤组;在电镜下,损伤组细胞核固缩,而血红素组细胞核幼稚,核仁明显。结论 在人脐静脉内皮细胞中,血红素对过氧化氢所造成的氧化应激损伤有明显的保护作用。  相似文献   
106.
小切口股骨近端解剖钢板治疗股骨转子间骨折   总被引:5,自引:4,他引:1  
目的 探讨股骨转子间骨折的治疗方法和疗效。方法小切口微创股骨近端解剖钢板内固定治疗股骨转子间骨折17例。结果 随访时间8个月~3年,平均1.6年,优良16例,占94%(16/17)。结论 小切口微创股骨近端解剖钢板内固定治疗股骨转子间骨折具有切口小、出血少等优点,是一种微创手术。  相似文献   
107.
目的探讨利用球囊导管加压注射泛影葡胺行子宫输卵管造影的应用价值。方法对219例不孕症用76%泛影葡胺采用球囊导管加压注射法作子宫输卵管造影检查,并在透视下实时点片。结果普通注射时双侧输卵管显示185例(84.47%),单侧显示24例;加压注射后203例(92.69%)双侧输卵管显示,单侧显示14例,成功率100%。子宫畸形见于9例,输卵管异常131例,造影剂弥散与吸收异常104例。结论利用球囊导管加压注射水溶性造影剂,可以明显提高子宫输卵管造影质量及输卵管再通效果,有重要的临床价值。  相似文献   
108.
目的 评估单纯行玻璃体切除术对外因性细菌性眼内炎的疗效。方法 外因性细菌性眼内炎21例(21只眼),其中白内障摘除联合人工晶状体植入术后1只眼,眼球穿通伤后20只眼。均作睫状体平部三切口玻璃体切除术,晶状体混浊者一并切除,若有球内异物一并取出,伴视网膜脱离者,重水或气/液交换复位视网膜后行眼内炎光凝、长效气体或硅油填充以及巩膜环扎,术中灌注液内不加入庆大霉素,术毕不作玻璃体腔注药,术后联合抗生索和激素静脉用药。结果 炎症控制20只眼,术后矫正视力提高20只眼,有效率为80.95%。结论 玻璃体切除术对严重细菌性眼内炎而言是最重要的治疗手段。  相似文献   
109.
The levels and temporal variations of surface ozone at a coastal site in East China during summer and autumn were analyzed and the influences of meteorological parameters on ozone were investigated. An inland city was chosen as a comparison site. The main results and conclusions of this study are: (1) ozone pollution, with a maximum 1 h concentration of 150.98 ppbv, was severe during summer and autumn at the coastal site; (2) the ozone level was obviously higher at the coastal site than that at the inland site in September; (3) besides temperature and solar radiation, sea-land breeze circulation is an important factor influencing the ozone level at the coastal site, and sea breeze often induce high ozone levels (the average ozone concentration for sea breeze was about 13 ppbv higher than that for land breeze).  相似文献   
110.
人工股骨头置换术治疗高龄非稳定性股骨转子间骨折   总被引:14,自引:3,他引:11  
目的探讨高龄患者非稳定性股骨转子间骨折行人工股骨头置换术的临床疗效。方法本组74例,年龄75~89岁,平均80.3岁;骨折类型按Evans分类:ⅢA型31例,ⅢB型24例,Ⅳ型19例。其中3例为经内固定治疗失败病例,合并内科疾病者69例,在相关内科协同治疗后行双极骨水泥型人工股骨头置换术,术后早期进行康复锻炼。结果74例都顺利通过手术,住院期间无死亡病例;72例获得随访,随访时间3~16个月,平均9.2个月;无一例出现畸形,髋关节功能接近或恢复到受伤前水平,生活可自理;2例于出院后5个月、11个月死于其他疾病。结论人工股骨头置换术治疗高龄非稳定性股骨转子间骨折是一种效果确切的治疗方法,操作简单、创伤小、卧床时间短、并发症低、死亡率低,提高了高龄患者的生活质量。  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