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   18492篇
  免费   1094篇
  国内免费   262篇
耳鼻咽喉   218篇
儿科学   232篇
妇产科学   111篇
基础医学   2223篇
口腔科学   443篇
临床医学   1623篇
内科学   1528篇
皮肤病学   41篇
神经病学   3297篇
特种医学   1083篇
外科学   4728篇
综合类   2118篇
预防医学   446篇
眼科学   179篇
药学   949篇
  9篇
中国医学   311篇
肿瘤学   309篇
  2024年   44篇
  2023年   320篇
  2022年   468篇
  2021年   700篇
  2020年   593篇
  2019年   592篇
  2018年   597篇
  2017年   593篇
  2016年   597篇
  2015年   599篇
  2014年   1119篇
  2013年   1142篇
  2012年   1009篇
  2011年   1108篇
  2010年   866篇
  2009年   957篇
  2008年   821篇
  2007年   866篇
  2006年   764篇
  2005年   663篇
  2004年   624篇
  2003年   513篇
  2002年   407篇
  2001年   364篇
  2000年   301篇
  1999年   304篇
  1998年   252篇
  1997年   267篇
  1996年   195篇
  1995年   192篇
  1994年   166篇
  1993年   155篇
  1992年   151篇
  1991年   134篇
  1990年   98篇
  1989年   110篇
  1988年   90篇
  1987年   86篇
  1986年   130篇
  1985年   158篇
  1984年   143篇
  1983年   139篇
  1982年   108篇
  1981年   96篇
  1980年   91篇
  1979年   46篇
  1978年   32篇
  1977年   37篇
  1976年   22篇
  1973年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
目的:为了提高股骨颈骨折固定强度和愈合率,减少骨坏死及其它并发症.方法:应用中空双头加压螺纹钉加折断式螺钉治疗股骨颈骨折.结果:经35例临床应用及术后平均28个月随访,优良率为88.6%.结论:本手术切口小、创伤小、出血少、时间短、固定较可靠,便于功能锻炼,术后恢复良好.  相似文献   
52.
股骨干骨折--扩髓和不扩髓髓内钉比较   总被引:4,自引:0,他引:4  
治疗股骨干骨折,采用不扩髓髓内钉比扩髓髓内钉手术时间明显缩短,而且失血也少。但是,扩髓钉的骨愈合更快,延迟愈合更少。两者都没有显著增加包括肺损害等其它并发症的风险。功能结果不能确定。  相似文献   
53.
兔股骨干缺损模型的制备及在组织工程骨实验中的应用   总被引:21,自引:11,他引:10  
目的为组织工程骨修复负重骨缺损的研究提供标准化的实验动物模型.方法测量兔股骨干基本解剖数据,用于指导制备模型.在解剖学研究的基础上,取4~5个月龄成年新西兰大白兔18只,随机分为三组,每组6只,分别制备10、15、20mm的股骨干中段骨和骨膜缺损,并用普通钢板螺丝钉固定股骨.4、8、12周时分别摄X线侧位片进行定性分析,双能量X线骨密度测量仪(DXA)做骨密度扫描进行定量分析,并在每个时间点分别取2只动物取材做大体观察和组织学检查.结果兔股骨解剖数据:兔股骨长94.1 mm;股骨干中点横径7.4 mm,矢状径5.8 mm;骨皮质厚度:屈侧最厚,内、外两侧次之,伸侧最薄,平均1.2 mm;髓腔略呈椭圆形,其横径与矢状径相差约1mm,取其平均值,髓腔直径4.1 mm.骨缺损动物大体观察、X线片、骨密度检查和组织学检查显示:10 mm骨缺损组均于8~12周出现骨性愈合;15 mm和20 mm骨缺损组直至12周仍未见骨愈合.结论在不桥接和填充任何材料的情况下,钢板螺钉固定的兔股骨干15 mm以上的实验性骨缺损不能自行愈合,可用于组织工程骨修复负重骨缺损的实验研究.  相似文献   
54.
The component of a composite prosthesis, which makes contact with the visceral peritoneum, can be reabsorbable or non-reabsorbable, and laminar or reticular. This study was designed to determine whether the composition of this second, barrier component could improve its behavior at this interface. Abdominal wall defects in rabbits were repaired using a polypropylene prosthesis (PP), or the composites Sepramesh (PP+h) or Vicryl (PP+v). Fourteen days after surgery, the implants were evaluated by light and scanning electron microscopy, and immunohistochemistry. Prosthetic areas occupied by adhesions (PP: 71.08±5.09, PP+h: 18.55±4.96, P+v: 69.69±16.81%), neoperitoneal thickness (PP: 256.17±21.68, PP+h: 83.11±19.63, PP+v:213.72±35.90 μm) and macrophage counts (PP: 8.73±1.16, PP+h: 27.33±4.13, PP+v: 31.24±3.08%) showed significant differences (P<0.05). The tested biomaterials induced an optimal recipient tissue infiltration. Least adhesion formation was observed on the PP+h implants. This suggests that the second component, although reabsorbable, should be smooth in structure.  相似文献   
55.
提出了文题的计算模型,它采用非线性弹塑性蠕变有限元法,计算构件危险点在高温及周期保载的交变载荷谱作用下的应力应变响应,以应变范围区分法累积损伤,从而求出构件的疲劳寿命,并以带孔矩形薄板为例作了计算与验证,结果吻合较好,可供工程应用。  相似文献   
56.
Femoral attachment of the anterior cruciate ligament   总被引:3,自引:1,他引:2  
Endoscopic anterior cruciate ligament (ACL) reconstruction is one of the most popular orthopaedic procedures. Correct tunnel positioning is a prerequisite to success. Current surgical techniques are unable to duplicate the complex anatomy and function of the native ACL. Surgery mainly aims at restoring anteroposterior laxity. The ACL is not isometric and only a few fibers are nearly isometric over the full range of motion. However, a nearly isometric behaviour of the ACL graft is desirable. Isometry is mainly influenced by femoral attachment; thus the femoral tunnel position has a greater effect than the tibial on graft length changes. The purpose of this article is to describe the anatomy of the femoral ACL insertion and to discuss the surgical techniques used to replicate it.  相似文献   
57.
OBJECTIVES: Lateral biopsies are thought to have a better cancer detection rate compared with standard sextant biopsies. This study aimed to determine whether lateral peripheral zone biopsies in Japanese men who underwent transrectal ultrasound-guided prostate biopsies provided a significantly higher cancer detection rate than sextant biopsies. METHODS: Between 1999 and 2004, data were collected from 461 men who underwent prostate biopsy and had enough data regarding the performance of lateral biopsies for statistical analysis. There were two categories in this study: (i) patients who underwent sextant prostate biopsies; and (ii) patients who underwent sextant biopsies plus lateral biopsies. RESULTS: Prostate cancer was detected in 141 (30.6%) of 461 patients. It was detected in 24 (22.2%) of 108 patients who underwent sextant biopsies and 117 (33.1%) of 353 patients who underwent sextant plus lateral biopsies. Lateral biopsies were not associated with a statistically higher rate of positive biopsy findings; however, we found a significantly higher ratio of patients with positive findings in those with prostate specific antigen (PSA) levels 10 ng/mL (one of 71, 1.4%) among those who had positive cores only in lateral biopsy samples (P < 0.0001). CONCLUSIONS: Lateral biopsies did not show a significantly higher detection ratio of prostate cancer compared to sextant biopsies. However, lateral biopsies were more effective than sextant biopsies in patients with lower PSA levels. Our findings might be useful for the establishment of biopsy strategies to detect prostate cancer, especially in patients with lower PSA levels.  相似文献   
58.
59.
Purpose: It was investigated whether alterations in neuronal structure and function occasioned by strabismic amblyopia also may be reflected in alterations in the expression on Y type neurons of a Cat-301 antibody sensitive antigen in the lateral geniculate nucleus (LGN) and cortex of our cat model of strabismic amblyopia. Methods/Results: The percentage of positively labelled cells was reduced in LGN laminae that received input from the deviated eye in strabismic amblyopic cats compared with normal cats. In the strabismic cortex, the density of immunopositive neurons was significantly reduced compared with normal, the effect being most pronounced in layer IV Conclusions: Despite previous physiological recordings indicating a decrease in X-cell associated acuity in strabismic amblyopia, the present findings imply that the changes in the early visual experience occasioned by strabismus also produce specific molecular changes in theY neuronal class.  相似文献   
60.
Bertalanffy  H.  Kretzschmar  H.  Gilsbach  J. M.  Ott  D.  Mohadjer  M. 《Acta neurochirurgica》1990,104(3-4):151-155
Summary This case report describes a patient presenting with symptoms of increased intracranial pressure, whose computerized tomographic (CT) scan was highly suggestive of a large low-grade glioma invading the basal ganglia. Magnetic resonance imaging (MRI) revealed a well-demarcated space-occupying mass of increased intensity in the left lateral ventricle and adjacent white matter. Following stereotactic biopsy, which yielded a homogeneous jelly-like material, the mass was removed microsurgically and was found to be most like a colloid cyst on histological examination. Discussion focusses on the clinical and differential diagnostic implications of this very unusual combination of findings.  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