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   61236篇
  免费   5349篇
  国内免费   4124篇
耳鼻咽喉   527篇
儿科学   817篇
妇产科学   1069篇
基础医学   7798篇
口腔科学   971篇
临床医学   7825篇
内科学   9592篇
皮肤病学   702篇
神经病学   3661篇
特种医学   2268篇
外国民族医学   52篇
外科学   6189篇
综合类   8187篇
现状与发展   19篇
一般理论   3篇
预防医学   4095篇
眼科学   1751篇
药学   6431篇
  63篇
中国医学   3086篇
肿瘤学   5603篇
  2024年   278篇
  2023年   959篇
  2022年   2406篇
  2021年   3145篇
  2020年   2315篇
  2019年   2163篇
  2018年   2263篇
  2017年   1905篇
  2016年   1904篇
  2015年   2711篇
  2014年   3360篇
  2013年   2837篇
  2012年   4490篇
  2011年   4958篇
  2010年   2975篇
  2009年   2282篇
  2008年   3150篇
  2007年   3176篇
  2006年   3175篇
  2005年   3136篇
  2004年   2145篇
  2003年   2074篇
  2002年   1791篇
  2001年   1253篇
  2000年   1315篇
  1999年   1412篇
  1998年   936篇
  1997年   882篇
  1996年   675篇
  1995年   617篇
  1994年   510篇
  1993年   334篇
  1992年   419篇
  1991年   370篇
  1990年   328篇
  1989年   284篇
  1988年   294篇
  1987年   241篇
  1986年   232篇
  1985年   182篇
  1984年   127篇
  1983年   98篇
  1982年   54篇
  1981年   52篇
  1980年   40篇
  1979年   97篇
  1978年   41篇
  1975年   40篇
  1974年   52篇
  1973年   30篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
ObjectiveTo report our experience in the reconstruction of soft tissue defects in the hand with a free anterolateral thigh deep fascia flap and describe the clinical outcomes.MethodsThis study was a retrospective trial. From November 2016 to January 2020, six patients (four men and two women) with soft tissue defects in the hand were included in this study. The average age of the patients was 33.7 ± 12.7 years (range, 20 to 50 years). All patients underwent reconstructions with free anterolateral thigh deep fascia flaps. Relevant clinical characteristics were recorded prior to surgery. The size and thickness of the deep fascia flap and the thickness of the skin were measured intraoperatively. The survival of the flaps and skin grafts and the occurrence of infection were recorded after the operation. At follow‐up, donor site complications and postoperative effects were evaluated according to the outcome satisfaction scale. The pain in the injured hand was assessed using the visual analog scale.ResultsThe average body mass index (BMI) was 26.6 ± 1.7 kg/m2 (range, 23.9 to 28.7 kg/m2). The defect sizes ranged from 5 cm × 5 cm to 13 cm × 8 cm (average, 53.1 ± 27.9 cm2). The six anterolateral thigh deep fascia flaps ranged from 7 cm × 6 cm to 14 cm × 9 cm in size (average, 71.8 ± 29.1 cm2). The thicknesses of skin ranged from 25 mm to 40 mm (average, 32.5 ± 4.8 mm), and the thicknesses of the deep fascia flaps ranged from 2 mm to 3 mm (average, 2.5 ± 0.5 mm). After the operation, the blood supply of the deep fascia flap was normal in all cases. The second‐stage skin grafts of most patients survived completely. The skin graft in one case was partially necrotic and healed after a dressing change. No infection occurred. At follow‐up (average, 16.3 ± 6.9 months), there was only a linear scar and no loss of sensation at the donor site of each patient. According to the outcome satisfaction scale, the outcome satisfaction score ranged from 6 to 8 (average, 7.2 ± 0.9), all of which were satisfactory. Apart from one patient who reported mild pain, all the other patients reported no pain. Three typical cases are presented in this article.ConclusionsThe free anterolateral thigh deep fascia flap, which is suitable for reconstruction of soft tissue defects in the hand, can provide very good outcomes both functionally and aesthetically.  相似文献   
122.
Penile fracture is described as a traumatic rupture of the tunica albuginea caused by blunt injury to the erect penis. It usually occurs as a single rupture of the tunica albuginea in one of two corpora cavernosa; a rupture with urethral injury is an extremely rare condition. Although its diagnosis is usually clinical, ultrasound plays an important role in confirming diagnosis and identifying the site of the injury. Here, we presented a case of penile fracture with complete urethral injury. A 43-year-old male was admitted to the hospital because of trauma to the genital and dysuria following sexual intercourse. After admission, the patient was diagnosed with double penile fracture and complete urethral injury after the physical and B-ultrasound examinations. Emergency surgery to remove the hematoma and repair the urethra was performed. The patient recovered smoothly and was discharged on the third day after operation. After two months’ follow-up, the patient urinated smoothly and achieved an adequate erection without other complications. In this case, consistent with previous studies, emergency surgery for penile fracture is necessary and can preserve the urethral function and sexual function. In addition, there are two lesions in tunica albuginea in this case, so careful search for the penile shaft during the surgery is important to avoid the missed injuries. This report provides evidence of an uncommon and underreported clinical case.  相似文献   
123.
利用二氧化硅特异地吸附核素的特性,建立了从琼脂糖凝胶中回收DNA的方法。结果表明本方法对1300 ̄3500bp的DNA回收效果较好,回收效率达60% ̄70%,100 ̄1500bp,3500 ̄5000bp的DNA亦能被有效地回收。通过对回收DNA的酶切,连接等实验,证实了所回收的DNA片段能够满足进一步的实验要求。该方法简单,快捷,经济,适用,值得推广。  相似文献   
124.
125.
单片微机化微弱发光测量仪及其在肿瘤研究中的初步应用   总被引:2,自引:0,他引:2  
单片微机化微弱发光测量仪由中科院生物物理所和北京科龙生物医学技术开发公司研制成功。该仪器适用于肿瘤研究中生物医学样品的微弱发光的测量。测量样品的重复性优于0.8%,稳定性优于0.5%,线性相关系数达0.9997,不仅可以进行样品的发光强度测量,还可以进行动力学曲线的测量以及样品发射光谱的测量。光谱在400nm-750nm范围内。测量方式可选择手动、半自动和自动计时三种。测量结果表明,荷瘤裸鼠血液微  相似文献   
126.
PHA对人扁桃体T细胞CD4和CD8抗原复合表达的研究   总被引:3,自引:0,他引:3  
  相似文献   
127.
利用旋转壁式生物反应器(Rotating wall vessel,RWV)体外培养脐带血干细胞,使其大量扩增,以满足临床应用对造血干/祖细胞的数量与质量要求。从脐带血分离得到的单个核细胞(Mononuclear cells,MNC)在T-flask中培养24h,之后接种到RWV反应器中,培养200h。每24h细胞计数,测量培养基的pH和渗透压变化;在144h和197h测CD34 细胞含量并做CFU-GM半固体培养。有核细胞(Nucleated cells,NC)与CD34 细胞在第197h,分别扩增了435.5±87.6倍和32.7±15.6倍,CFU-GM(Colony-forming unit-granulocyte/macrophage)细胞扩增了21.7±4.9倍。整个培养过程中,RWV反应器中的pH和渗透压都保持在造血细胞最佳的扩增条件内,pH基本保持在7.2~7.4之间,渗透压基本保持在290~310mmol/kg之间。由于旋转壁式生物反应器(RWV)结构上的特殊性,可以保证细胞在悬浮流动的状态下生长,很好地模拟了脐带中的造血微环境,使脐带血造血干细胞在该反应器中短期内得到大量扩增。  相似文献   
128.
本工作应用激光多普勒电泳技术对MA737小鼠乳腺癌细胞膜表面电荷特性及高温(42.5℃)对癌细胞的热效应进行了深入的研究。结果发现,MA737癌细胞的电泳迁移率(EPM)明显高于相应正常细胞的EPM(约20%),表明癌细胞表面负电荷增高;实验发现唾液酸可能是MA737癌细胞膜表主要负电基团的来源之一。研究还发现,MA737癌细胞的热敏性比相应的正常细胞强,随高温受热时间的延长,癌细胞的EPM呈下降趋势。  相似文献   
129.
W Mao  L Zeng  Q Ma  Y Chen  Z Dai  P Tang  X Guo  D Li  W Su 《眼科学报》1990,6(3-4):88-90
We report here the preliminary effects of zinc iontophoresis in treatment of 26 Rp patients who had decreased zinc serum level or abnormal ratio of serum copper to zinc. Through more than 20 to 30 times of therapy, the vision of 15.38% eyes increased more than "3 lines", 4% eyes increased more than 5 degrees in the visual field, 13.46% eyes improved in dark adaptation threshold (greater than 1.0), the visual functions of the rest eyes were slightly improved or unimproved. The fundus didn't change before & after treatment. There were no changes of ERG in 8 eyes of 4 cases. In addition, the advantages and disadvantages between Zn iontophoresis and Zn compound taken orally, the improvement of vision by direct electric current therapy, the relationship between the metabolism of Zn element and Vit A and influence of Zn over the mechanism of dark adaptation were also briefly discussed.  相似文献   
130.
球囊导管损伤后早期动脉平滑肌细胞的增殖   总被引:4,自引:0,他引:4  
目的:研究动脉硬化早期中膜与内膜平滑肌细胞的增殖。方法:球囊导管损伤大鼠的颈总动脉后在电镜和光镜下观察其形态和生化指标变化。结果:术后24h 5-溴脱氧尿嘧啶尿苷阳性平滑肌细胞出现,阳性细胞率分别于术后第2,5d出现高峰。术后第2,3d迁移细胞的出现率最高。术后第3d,88.8%迁移细胞增殖细胞核抗原阳性。透射电子显微镜下,术后第3d中膜平滑肌细胞特别是内层的为合成型,并且与细胞外基质连接稀疏,基底膜、胶原纤维和弹性纤维被消失。结论:动脉损伤后,中膜平滑肌细胞呈高增殖性,由收缩型转变为合成型,与细胞外基质的结合性降低,中膜弹性纤维、胶原纤维被消化,增生活跃的细胞向内膜的迁移性增高。迁移至内膜的平滑肌细胞呈高增殖性。  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