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   162639篇
  免费   13177篇
  国内免费   5017篇
耳鼻咽喉   1219篇
儿科学   3847篇
妇产科学   1582篇
基础医学   25129篇
口腔科学   3096篇
临床医学   15963篇
内科学   22658篇
皮肤病学   1529篇
神经病学   7559篇
特种医学   3216篇
外国民族医学   22篇
外科学   12820篇
综合类   26060篇
现状与发展   12篇
一般理论   25篇
预防医学   11417篇
眼科学   4279篇
药学   17210篇
  21篇
中国医学   8677篇
肿瘤学   14492篇
  2024年   207篇
  2023年   1837篇
  2022年   2948篇
  2021年   5676篇
  2020年   4977篇
  2019年   5232篇
  2018年   5110篇
  2017年   5152篇
  2016年   5316篇
  2015年   5355篇
  2014年   8575篇
  2013年   9767篇
  2012年   7997篇
  2011年   9265篇
  2010年   7942篇
  2009年   7752篇
  2008年   7701篇
  2007年   8897篇
  2006年   8155篇
  2005年   8180篇
  2004年   7118篇
  2003年   6318篇
  2002年   4691篇
  2001年   4634篇
  2000年   3789篇
  1999年   3539篇
  1998年   2491篇
  1997年   2209篇
  1996年   2288篇
  1995年   2196篇
  1994年   1909篇
  1993年   1734篇
  1992年   1485篇
  1991年   1296篇
  1990年   1099篇
  1989年   1024篇
  1988年   952篇
  1987年   736篇
  1986年   565篇
  1985年   640篇
  1984年   652篇
  1983年   410篇
  1982年   504篇
  1981年   429篇
  1980年   369篇
  1979年   311篇
  1978年   253篇
  1977年   222篇
  1976年   252篇
  1975年   158篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
[目的]评价羟苯磺酸钙治疗糖尿病性皮肤溃疡的疗效和安全性.[方法]采用双盲临床随机对照试验.76例糖尿病性皮肤溃疡患者,随机分为试验组和对照组.试验组38例服用羟苯磺酸钙;对照组38例服用安慰剂维生素C;疗程8周.[结果]试验组溃疡愈合的速度与程度均明显优于对照组.总有效率试验组为94.74%,对照组为52.63%,两者之间有显著差异(P<0.01).服药期间肝肾功能无异常改变.[结论]羟苯磺酸钙是治疗糖尿病性皮肤溃疡有效安全的药物.  相似文献   
992.
In this study, the anti-tumour activity of selenium-protein polysaccharide (SPP), a water extract of the rich selenium Agaricus blazei, was tested both in vivo and in vitro. The results of in vivo experiments show that SPP at doses of 50 and 100 mg/kg inhibits proliferation of implanted Sarcoma 180 by 22 and 37.69%, respectively, and promotes lymphocyte transformation and natural killer (NK) cells activity in tumour bearing mice. During the in vitro experiment, we treated the tumour and non-tumour bearing mice with SPP, and prepared serum treated with SPP (SerumSPP). The results show that SerumSPP, whether from tumour or non-tumour bearing mice, significantly inhibits K562 cells proliferation and induces their apoptosis, and also significantly increases caspase-3 activity of K562 cells. However, the difference in anti-tumour activity of SerumSPP between tumour and non-tumour bearing mice is significantly different (p<0.01). The results, according to the studies both in vivo and in vitro, imply that SPP extracted from rich selenium A. blazei can inhibit growth of implanted Sarcoma 180 and promote lymphocyte transformation and NK cells activity in vivo. Additionally, SerumSPP can inhibit proliferation and cause apoptotic morphological changes and the fragmentation of internucleosomal DNA, and increase caspase-3 activity of K562 cells in vitro, which indicates that apoptosis of K562 cells induced by SerumSPP may be related to up-regulation of caspase-3.  相似文献   
993.
本文收集了我省十年(1974—1983)来诊断为恶性淋巴瘤的病例,按免疫功能分类复查了全部切片,最后确诊为非何杰金氏恶性淋巴瘤(NHL)528例,进行了分析。本组NHL在首发部位、类型分布等方面与国内外有所不同。本组NHL首发于淋巴结外的占64.02%,明显高于国内其它省、市,而滤泡型淋巴瘤则低于国内多数地区。T细胞淋巴瘤占14.84%,较国内、外均低。并提出提高制片质量和广泛开展及应用免疫学技术的重要性。  相似文献   
994.
A BASIC computer program is described which is useful for calculating filling concentrations for ALZET osmotic mini-pumps employed in studies of chronic drug and hormone administration. After the user has entered the required daily dose, the pump parameters and the animals' weights, the program gives the following information: The total quantity of the drug or hormone required for the experiment; the minimum volume and concentration of solution, allowing a 10% margin for error, to serve as a standard that, when diluted, will fill all pumps in the experiment; individual volumes of this solution that, when diluted to a constant volume will yield the required concentrations to fill each of the respective pumps. Use of this program will ensure reliably accurate and very rapid preparations of solutions for mini-pump use.  相似文献   
995.
29例复发性甲状舌管囊肿和瘘中.男性20例,女性9例。复发次数1~4次,以2年或2年以内复发居多。作者对复发的有关因素进行了讨论,并且提出术中注射亚甲蓝显示瘘管,以利完全切除。  相似文献   
996.
使用胶质银染色技术,对28例良性腹水和26例恶性腹水进行核仁组成区(AgNORs)形态定量研究。结果表明:良性腹水间皮细胞与恶性腹水癌细胞二者在AgNORs数目、形态、大小及核内分布方面均存在显著差异。另外,对5例临床上疑诊恶性腹水而常规脱落细胞学(HE)染色阴性或未肯定者进行上述定量分析,确定腹水良恶性质,结果与组织病理学诊断相一致。提示该技术在一定程度上可弥补常规脱落细胞形态学之不足。  相似文献   
997.
采用无抗凝作用剂量肝素皮下注射治疗小儿肾病综合征25例,观察了近期疗效与12~24月后对皮质激素或环磷酰胺(CTX)治疗反应的关系.结果表明,近期对肝素治疗显效但复发以及有效者,今后用激素或CTX治疗均可达完全缓解,无效者则效果较差.本文结果表明,肝素治疗的近期疗效可用于预测肾病患儿的远期预后.  相似文献   
998.
The surface of the ovary has been found to be composed of two types of epithelial cells called A and B cells which are found in their own respective zones, the A and B zones. A quantitative study was undertaken to determine the mean cell volumes and cell ultrastructure. Ovarian biopsies were taken from six women and A and B zones, having been identified by scanning electron microscopy, were re-embedded for transmission electron microscopy. Stereological measurements using point sampled intercepts were made on vertical sections and showed that B cells are significantly larger than A cells. The volume weighted mean cell volumes of the A and B cells were 237.3 microns 3 and 676.8 microns 3 respectively. The volume fractions of the nucleus and mitochondria were similar in the two cell types. Although the vesicle content of each type was similar, a large variation between cases made the interpretation difficult. The stereological tools used in this study proved to be easy and efficient estimators of surface cell ultrastructure and give an important direction for ultrastructural research.  相似文献   
999.
The objective of this study was to establish to what extent muscle, cutaneous, and joint afferents alter the excitability of spinal and cortical motor neurons. This question was examined by studying the impact of electrical stimulation of the second and third digits, the median nerve at the wrist, and the recurrent thenar motor branch on the F/H and magneto-electrical cortical motor responses (MEPs) of the thenar muscles. The firing frequencies of single F/H motor unit action potentials were unaltered by the foregoing conditioning peripheral stimuli. MEPs conditioned by motor threshold stimulation of the median nerve at the wrist or the recurrent motor branch were significantly increased in size at conditioning to test intervals of 50 to 80 milliseconds. No significant change in MEP size resulted from conditioning stimulation of the digital nerves. We conclude that muscle afferents were primarily responsible for the increase in MEP size. Conditioning stimuli may allow examiners to assess central motor conduction where it would otherwise be impossible.  相似文献   
1000.
以食管癌“109”细胞株免疫 BALB/C 小鼠,取其脾细胞与小鼠骨髓瘤细胞株SP2/0 融合,经三次克隆化,获得稳定分泌抗食管癌“109”细胞株单克隆抗体的杂交瘤细胞系2GF3。其分泌的单克隆2GF3抗体与外周血淋巴组胞、ABO 型红细胞、癌胚抗原以及3/5胃癌细胞株无反应,与2/5胃癌细胞株有弱(+)反应。与2GF3抗体对应的抗原为2GF3抗原,荧光标记检测表明后者主要表达在细胞膜上。用去污剂提取膜抗原进行电泳后转移至硝酸纤维素膜上进行酶标分析,2GF3抗原是分子量53KD 的糖蛋白,在还原及非还原条件下均显示相同的区带。它与抗癌胚抗原抗体及抗甲胎蛋白抗体均无反应,表明它不同于癌胚抗原和甲胎蛋白。  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