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   73491篇
  免费   7305篇
  国内免费   4416篇
耳鼻咽喉   654篇
儿科学   1550篇
妇产科学   430篇
基础医学   5341篇
口腔科学   1449篇
临床医学   8734篇
内科学   7797篇
皮肤病学   818篇
神经病学   2114篇
特种医学   2652篇
外国民族医学   5篇
外科学   7554篇
综合类   18717篇
现状与发展   15篇
一般理论   4篇
预防医学   7827篇
眼科学   964篇
药学   8610篇
  89篇
中国医学   6443篇
肿瘤学   3445篇
  2024年   313篇
  2023年   878篇
  2022年   2125篇
  2021年   2796篇
  2020年   2404篇
  2019年   1592篇
  2018年   1761篇
  2017年   2119篇
  2016年   1853篇
  2015年   2916篇
  2014年   3738篇
  2013年   4514篇
  2012年   6284篇
  2011年   6806篇
  2010年   6162篇
  2009年   5698篇
  2008年   5721篇
  2007年   5304篇
  2006年   4854篇
  2005年   3969篇
  2004年   3065篇
  2003年   2719篇
  2002年   2208篇
  2001年   1875篇
  2000年   1317篇
  1999年   647篇
  1998年   222篇
  1997年   239篇
  1996年   182篇
  1995年   105篇
  1994年   136篇
  1993年   53篇
  1992年   70篇
  1991年   65篇
  1990年   51篇
  1989年   59篇
  1988年   30篇
  1987年   47篇
  1986年   46篇
  1985年   24篇
  1984年   22篇
  1983年   19篇
  1982年   14篇
  1981年   9篇
  1979年   15篇
  1977年   10篇
  1975年   9篇
  1957年   15篇
  1956年   9篇
  1955年   12篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
金尔伦治疗急性颅脑损伤的剂量效应研究   总被引:2,自引:1,他引:1  
目的探讨金尔伦(盐酸纳洛酮)在治疗大鼠液压脑损伤后神经功能恢复和病理损害程度的剂量效应.方法将104只SD大鼠随机分为4组,伤后早期分别腹腔注射0.03 mg/Kg(小剂量组)、0.3 mg/Kg(中剂量组)、3 mg/Kg(大剂量组)金尔伦和等量生理盐水(对照组),连续7 d.结果中、大剂量组动物伤后脑神经功能恢复、脑水肿减轻程度及光、电镜检查显著优于对照组及小剂量组.结论伤后早期使用中剂量和大剂量金尔伦(盐酸纳洛酮)对大鼠液压颅脑损伤有明显的治疗效果.  相似文献   
12.
采用连续延伸PCR方法克隆到粗糙脉孢菌(Neurospora crassa)漆酶基因,并将其克隆到表达载体pPIC9k,重组质粒经线性化、电激转化Pichia pastoris KM71,部分阳性克隆的PCR结果表明:漆酶基因已整合到巴斯德毕赤酵母染色体上,重组菌经甲醇诱导后3~5d产漆酶量最高,为2-3U/mL。  相似文献   
13.
A 25-year-old female has had brown to erythematous telangiectatic patches and grouped papules on her face, neck, arm, and trunk since childhood following B.C.G. vaccination. Histopathologically, the lesions consisted of hyperkeratosis, slight acanthosis, tuberculoid granulomas with some Langerhans type giant cells in the mid-dermis. Although various forms of cutaneous tuberculosis after B.C.G. vaccination have been reported, it was difficult for us to assign the patient's skin lesion to any specific disease entity. Remission of her cutaneous lesions occurred clinically and histopathologically after treatment with isoniazid and rifampin.  相似文献   
14.
15.
复式脉冲低能量ESWL治疗肾结石769例报告   总被引:3,自引:0,他引:3  
目的探讨复式脉冲HB-V型低能量体外冲击波碎石机治疗肾结石的治疗效果.方法采用复式脉冲HB-ESWL-VG型低能量碎石机治疗直径<2.0 cm的各类肾结石769例,治疗工作电压3~9 kV,平均冲击次数2 300次.结果肾盏结石总粉碎率为97.4%,其中上中盏结石复打率为13.1%,术后3个月排净率为89.4%,下盏结石复打率为17.3%,排净率为81.5%;肾盂结石粉碎率为98.3%,复打率为6.1%,术后3个月排净率为93.0%.结论复式脉冲低能量ESWL治疗肾结石具有治疗成功率高、复打率低、无严重并发症、副作用少之优点.  相似文献   
16.
BACKGROUND: Surgery on digit and nail requires a clear bloodless field that is often achieved by a tourniquet. OBJECTIVE: The objective is to present a simple, effective, and safe tourniquet for digital surgery. MATERIALS AND METHODS: A latex glove and a nylon zip-tie were used. A long strip is cut from the little finger tube of a latex glove. This is used for wrapping around the digit for exsanguination. The pressure is then maintained with a household nylon zip-tie. The finger strip is then cut to expose the operative field ready for surgery. The tourniquet pressure can be adjusted by tightening or loosening of the nylon zip-tie. RESULTS: Exsanguination and a bloodless field can be effectively achieved. The long tail of the nylon zip-tie reminds the operator to remove it at end of the surgery. CONCLUSION: A latex strip and nylon zip-tie combo serves as a simple, effective, and safe tourniquet for digital surgery.  相似文献   
17.
造影剂到达腹主动脉的峰值大小与患者因素的关系   总被引:3,自引:0,他引:3  
目的探讨造影剂到达腹主动脉的峰值大小与患者因素之间的关系。方法108例患者以2.5ml/s注射欧乃派克(300mgI/ml)20ml,12s后采用testbolus技术在腹腔干水平同层动态扫描腹主动脉,用dynamic evaluation软件测得腹主动脉的峰值大小,采用单因素回归分析和多因素逐步回归分析法研究患者的性别、年龄、身高、体重、心率、血压、注射位点、达峰时间及是否有心脏病、糖尿病、或化疗史对造影剂到达腹主动脉峰值大小是否有影响及影响程度。结果造影剂到达腹主动脉峰值大小,在男性平均比女性低;其随年龄、身高、体重、达峰时间的增加而逐渐降低,注射位点在手背静脉其值平均比在肘部静脉低;其不受心率、血压、是否有心脏病、糖尿病或化疗史的影响。参考公式:峰值大小(HU)=383.8400-身高(cm)×1.0909-体重(kg)×0.6760 注射位点×16.7878-达峰时间(s)×1.6882。结论可根据患者的性别、年龄、身高、体重、注射位点和达峰时间来适当调整患者CT血管成像时造影剂用量。  相似文献   
18.
我院2003年6月~2006年10月应用电解可脱式铂金微弹簧圈对65例颅内动脉瘤病人进行血管内栓塞,配合术前术后有效的护理,取得良好的治疗效果,现就护理体会报告如下。1材料与方法本组65例,男29例,女36例,年龄26~67岁,平均年龄45岁。以自发性蛛网膜下腔出血(SAH)为首发症状61例,头痛头晕3例、肢体麻木无力1例。本组65例中,45例在神经麻醉下,20例在气管插管全身麻醉下实施栓塞术。全身肝素化抗凝下,采用Seldinger’s技术经股动脉穿刺插管行全脑血管造影术(DSA),沿微导管放入直径与动脉瘤体匹配的电解可脱式微弹簧圈,电解解脱后,复查脑血管造影,…  相似文献   
19.
Performance measurement of the microPET focus 120 scanner.   总被引:6,自引:0,他引:6  
The microPET Focus 120 scanner is a third-generation animal PET scanner dedicated to rodent imaging. Here, we report the results of scanner performance testing. METHODS: A (68)Ge point source was used to measure energy resolution, which was determined for each crystal and averaged. Spatial resolution was measured using a (22)Na point source with a nominal size of 0.25 mm at the system center and various off-center positions. Absolute sensitivity without attenuation was determined by extrapolating the data measured using an (18)F line source and multiple layers of absorbers. Scatter fraction and counting rate performance were measured using 2 different cylindric phantoms simulating rat and mouse bodies. Sensitivity, scatter fraction, and noise equivalent counting rate (NECR) experiments were repeated under 4 different conditions (energy window, 250 approximately 750 keV or 350 approximately 650 keV; coincidence window, 6 or 10 ns). A performance phantom with hot-rod inserts of various sizes was scanned, and several animal studies were also performed. RESULTS: Energy resolution at a 511-keV photopeak was 18.3% on average. Radial, tangential, and axial resolution of images reconstructed with the Fourier rebinning (FORE) and filtered backprojection (FBP) algorithms were 1.18 (radial), 1.13 (tangential), and 1.45 mm full width at half maximum (FWHM) (axial) at center and 2.35 (radial), 1.66 (tangential), and 2.00 mm FWHM (axial) at a radial offset of 2 cm. Absolute sensitivities at transaxial and axial centers were 7.0% (250 approximately 750 keV, 10 ns), 6.7% (250 approximately 750 keV, 6 ns), 4.0% (350 approximately 650 keV, 10 ns), and 3.8% (350 approximately 650 keV, 6 ns). Scatter fractions were 15.9% (mouse phantom) and 35.0% (rat phantom) for 250 approximately 750 keV and 6 ns. Peak NECR was 869 kcps at 3,242 kBq/mL (mouse phantom) and 228 kcps at 290 kBq/mL (rat phantom) at 250 approximately 750 keV and 6 ns. Hot-rod inserts of 1.6-mm diameter were clearly identified, and animal studies illustrated the feasibility of this system for studies of whole rodents and mid-sized animal brains. CONCLUSION: The results of this independent field test showed the improved physical characteristics of the F120 scanner over the previous microPET series systems. This system will be useful for imaging studies on small rodents and brains of larger animals.  相似文献   
20.
Two embryonal CNS tumors, atypical teratoid/rabdoid tumor (AT/RT) and primitive neuroectodermal tumor (PNET), may be confused with each other and misdiagnosed. Here we report an infant with a congenital supratentorial tumor, which was detected by fetal MRI at 37 weeks gestation. On routine histological examination, the tumor was composed mainly of small undifferentiated cells, among which many rhabdoid cells and occasional sickle‐shaped embracing cells were observed. No mesenchymal or epithelial areas were evident. Our impression was that the tumor was an atypical example of AT/RT. Immunohistochemically, almost all the tumor cells were strongly positive for vimentin. However, epithelial membrane antigen was notably negative, and most of the tumor cell nuclei were clearly positive for INI1. In addition, many tumor cells were positive for neurofilament protein. There were also occasional small areas containing many tumor cells positive for glial fibrillary acidic protein. Finally, a diagnosis of PNET, with a rhabdoid phenotype and expression of neuronal and glial markers, was made. In the present case, application of INI1 immunostaining was very helpful for distinguishing PNET from AT/RT.  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