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   308980篇
  免费   18906篇
  国内免费   8254篇
耳鼻咽喉   3470篇
儿科学   10201篇
妇产科学   4050篇
基础医学   20051篇
口腔科学   8610篇
临床医学   35536篇
内科学   51006篇
皮肤病学   4522篇
神经病学   16306篇
特种医学   14395篇
外国民族医学   46篇
外科学   41819篇
综合类   34722篇
现状与发展   32篇
一般理论   5篇
预防医学   21337篇
眼科学   6002篇
药学   32376篇
  253篇
中国医学   13985篇
肿瘤学   17416篇
  2024年   801篇
  2023年   3842篇
  2022年   10838篇
  2021年   13682篇
  2020年   9045篇
  2019年   13888篇
  2018年   8360篇
  2017年   7880篇
  2016年   10061篇
  2015年   12715篇
  2014年   23506篇
  2013年   23339篇
  2012年   24447篇
  2011年   21561篇
  2010年   19405篇
  2009年   18250篇
  2008年   16324篇
  2007年   16612篇
  2006年   14178篇
  2005年   9978篇
  2004年   5955篇
  2003年   5182篇
  2002年   4240篇
  2001年   3386篇
  2000年   2980篇
  1999年   2050篇
  1998年   2335篇
  1997年   2130篇
  1996年   1762篇
  1995年   1723篇
  1994年   1646篇
  1993年   1315篇
  1992年   1457篇
  1991年   1304篇
  1990年   1266篇
  1989年   1241篇
  1988年   1146篇
  1987年   1024篇
  1986年   848篇
  1985年   1802篇
  1984年   1911篇
  1983年   1375篇
  1982年   1496篇
  1981年   1446篇
  1980年   1249篇
  1979年   1086篇
  1978年   813篇
  1977年   809篇
  1976年   706篇
  1974年   470篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
[(1R)‐endo]‐(+)‐3‐bromocamphor was dehalogenated with tritium gas to [3‐3H]camphor and via [3‐3H]phenylborneol converted to [3‐3H]deramciclane isolated as the fumarate salt (specific activity 51.8 GBq/mmol). This three step synthesis from [3‐3H]camphor gave an overall yield of 22%. Benzyloxy‐acetic acid methyl ester was reduced with sodium‐borotritide to 2‐benzyloxy‐ethanol‐[1‐3H], and through a four step procedure was converted to 2‐dimethylaminoethyl‐[2‐3H] chloride. The latter was condensed with the sodium derivative of 2‐phenylborneol giving rise to [2‐dimethylamino‐[2‐3H]ethoxy]deramciclane isolated as the fumarate (specific activity 8.177 GBq/mmol). This six step synthesis from [3H]NaBH4 gave an overall yield of 6%. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
92.
目的探讨Reiter综合征的病因、临床特点、治疗方法. 方法报告2例并检索收集国内文献171例,共计173例Reiter综合征,对其临床资料进行分析讨论. 结果 173例Reiter综合征的男女之比为5.41,平均发病年龄为27±10岁.完全型126例,不完全型67例.继发干感染106例,HLA-B27阳性59/72例.控制感染后经消炎痛、泼昆松、甲氨蝶呤等治疗后,均能达到临床完全缓解. 结论 Reiter综合征是病原体感染诱发的自身免疫性疾病,预后良好.  相似文献   
93.
94.
张钧  李鸣  李平 《西南国防医药》2007,17(4):420-422
目的:探讨甲状腺全切除术在治疗分化性甲状腺癌中的临床应用价值。方法:采用我院1988年1月~2001年5月甲状腺全切除术或甲状腺侧叶切除加峡部切除术治疗分化性甲状腺癌125例,对其手术并发症发生、局部复发、转移情况及术后5年生存率进行回顾性对比分析。结果:甲状腺全切除术术后并发症发生率高于甲状腺侧叶切除加峡部切除术组;局部复发、转移率低于侧叶切除加峡部切除术组;5年生存率两组无显著性差异。结论:甲状腺全切除术是治疗甲状腺癌有效的手术方式,但应掌握手术指征,改进、提高手术技术,减少并发症。  相似文献   
95.
神经外科麻醉对体感诱发电位的影响   总被引:1,自引:0,他引:1  
目的探讨神经外科手术麻醉对体感诱发电位(SEP)的影响,以期为麻醉和手术处理提供依据。方法随机抽取我科17例全麻手术病人,分成颅内疾病手术组(A组)与脊柱、脊髓疾病手术组(B组),于术前、麻醉(诱导完成)、术始、术中、术毕和术后6个时程连续监测SEP的潜伏期、波幅及波形并记录。结果麻醉后SEP潜伏期延长5.96%,波幅下降24.00%,未出现波形消失的情况。结论麻醉抑制SEP,表现为潜伏期延长和波幅下降,但未出现波形消失的情况。  相似文献   
96.
The specific characteristics of genetic data lead to ethical-legal conflicts in the framework of genetic diagnosis. Several international organisations, including UNESCO and the Council of Europe, have enacted rules referring to the use of genetic information. This paper discusses possible legal and ethical criteria that could be used in genetic testing.  相似文献   
97.
血糖水平对18F-FDG PET/CT图像质量的影响   总被引:1,自引:0,他引:1  
目的 研究血糖水平对18F-脱氧葡萄糖(FDG) PET/CT图像质量的影响.方法 80例行体格检查或评价肿瘤性质的受检者,按空腹血糖水平分为9组(组间距为1mmol/L),第1组为血糖正常组,即血糖<6.0mmol/L(10例);第2~9组血糖水平高于正常,分别为6.0~6.9mmol/L(11例),7.0~7.9mmol/L(13例),8.0~8.9mmol/L(11例),9.0~9.9mmol/L(11例),10.0~10.9mmol/L(8例),11.0~11.9mmol/L(6例),12.0~12.9mmol/L(5例),≥13.0mmol/L(5例).受检者做完PET/CT检查后,图像质量由2位有经验的医师独立判断.同时根据肝不同层面的标准摄取值(SUV)最大值(SUVmax)及SUV平均值(SUVavg)分别计算肝图像噪声.采用SPSS 12.0软件进行统计学处理.结果 (1)9组之间图像质量评分、肝噪声差异有统计学意义(P均<0.05).将第2~9组图像质量评分、肝噪声分别与第1组进行比较,第2~7组与第1组差异无统计学意义(P均>0.05);第8,9组与第1组比较差异有统计学意义(P均<0.05),且评分低于第1组.(2)血糖水平与图像质量评分呈负相关(r=-0.52,P<0.05);血糖水平与肝噪声呈正相关(SUVmax、SUVavgr值分别为0.33和0.60,P均<0.05);SUVavg所算噪声与血糖水平的相关性优于SUVmax.结论 图像质量随血糖水平的升高而下降,血糖<12.0mmol/L时与血糖正常者PET/CT图像质量差异无统计学意义,但当血糖水平≥12.0mmol/L时图像质量将显著下降.  相似文献   
98.
目的探讨继发性肝癌的手术适应证和方法。方法对52例继发性肝癌的临床病例资料进行回顾性分析。结果分别采用了左半肝切除、右半肝切除、左外叶切除、右前叶切除、右后叶切除和肝楔形切除术。术后1、3、5年的生存率分别为28.3%、19.4%和11.9%。结论对适合手术的继发性肝癌,行肝切除术可以获得满意的效果。  相似文献   
99.
Background contextLarge, prominent osteophytes along the anterior aspect of the cervical spine have been reported as a cause of dysphagia. Improvement of swallowing after surgical resection has been reported in a few case reports with short-term follow-up. The current report describes outcomes of a series of five patients with surgical treatment for this rare disorder, with a long-term follow-up.PurposeTo study the clinical and radiographic outcomes of a case series of patients surgically treated for dysphagia secondary to cervical diffuse idiopathic skeletal hyperostosis (DISH).Study designRetrospective review of a case series.Patient sampleFive cases from a University Hospital.Outcome measuresClinical and imagenological follow-up.MethodsThe records of five patients with dysphagia who had undergone anterior surgical resection of prominent osteophytes secondary to DISH were reviewed. Extrinsic esophageal compression secondary to anterior cervical osteophytes was radiographically confirmed via preoperative barium esophagogram swallowing study. All patients underwent anterior cervical osteophytes resection without fusion. Postoperatively, patients were followed-up clinically and radiographically with routine lateral cervical radiographs.ResultsPreoperative esophagogram showed that the esophageal obstruction was present at one level in three cases and two levels in two cases. The C3–C4 level was involved in three cases, C4–C5 in three cases, and C5–C6 in one case. There were no postoperative complications, including recurrent laryngeal nerve palsy, wound infection, or hematomas. All patients had resolution of dyphagia soon after surgery (within 2 weeks). Postoperative radiographs demonstrated complete removal of osteophytes. At final follow-up, ranging from 1 to 9 years (average 59.8 months, median 53 months), no patients reported recurrence of dysphagia. Final radiographic examination demonstrated minimal regrowth of the osteophytes.ConclusionsAlthough rarely indicated, surgical resection of anterior cervical osteophytes from DISH causing dyphagia produces good clinical and radiographical outcomes. After thorough evaluation to rule out other intrinsic or extrinsic causes of swallowing difficulty, surgical treatment of this uncommon condition might be considered.  相似文献   
100.
Abstract:  The identification of tumor-specific proteins located at the plasma membrane is hampered by numerous methodological pitfalls many of which are associated with the post-translational modification of such proteins. Here, we present a new combination of detergent fractionation of cells and of subtractive suppression hybridization (SSH) to gain overexpressed genes coding for membrane-associated or secreted proteins. Fractionation of subcellular components by digitonin allowed sequestering mRNA of the rough Endoplasmatic reticulum and thereby increasing the percentage of sequences coding for membrane-bound proteins. Fractionated mRNAs from the cutaneous T-cell lymphoma (CTCL) cell line HuT78 and from normal peripheral blood monocytes were used for SSH leading to the enrichment of sequences overexpressed in the tumor cells. We identified some 21 overexpressed genes, among them are GPR137B, FAM62A, NOMO1, HSP90, SLIT1, IBP2, CLIF, IRAK and ARC. mRNA expression was tested for selected genes in CTCL cell lines, skin specimens and peripheral blood samples from CTCL patients and healthy donors. Several of the detected sequences are clearly related to cancer, but have not yet been associated with CTCL. qPCR confirmed an enrichment of these mRNAs in the rough endoplasmic reticulum fraction. RT-PCR confirmed the expression of these genes in skin specimens and peripheral blood of CTCL patients. Western blotting verified protein expression of HSP90 and IBP2 in HuT78. GPR137B could be detected by immunohistology in HuT78 and in keratinocytes of dysplastic epidermis, but also in sweat glands of healthy skin. In summary, we developed a new technique, which allows identifying overexpressed genes coding preferentially for membrane-associated proteins.  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