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   267050篇
  免费   10270篇
  国内免费   5356篇
耳鼻咽喉   2475篇
儿科学   7721篇
妇产科学   3947篇
基础医学   28811篇
口腔科学   3097篇
临床医学   23237篇
内科学   45744篇
皮肤病学   2657篇
神经病学   21936篇
特种医学   13525篇
外国民族医学   27篇
外科学   38484篇
综合类   13540篇
现状与发展   18篇
一般理论   10篇
预防医学   23479篇
眼科学   5028篇
药学   19115篇
  55篇
中国医学   5511篇
肿瘤学   24259篇
  2024年   299篇
  2023年   1355篇
  2022年   3201篇
  2021年   5115篇
  2020年   3534篇
  2019年   3448篇
  2018年   25112篇
  2017年   20291篇
  2016年   22665篇
  2015年   5778篇
  2014年   6386篇
  2013年   6287篇
  2012年   14615篇
  2011年   28727篇
  2010年   23659篇
  2009年   15374篇
  2008年   24338篇
  2007年   26390篇
  2006年   5087篇
  2005年   6455篇
  2004年   6527篇
  2003年   7399篇
  2002年   5056篇
  2001年   2286篇
  2000年   2220篇
  1999年   1857篇
  1998年   1174篇
  1997年   1138篇
  1996年   812篇
  1995年   738篇
  1994年   670篇
  1993年   408篇
  1992年   540篇
  1991年   508篇
  1990年   529篇
  1989年   424篇
  1988年   352篇
  1987年   292篇
  1986年   243篇
  1985年   191篇
  1984年   123篇
  1983年   96篇
  1982年   62篇
  1981年   55篇
  1980年   77篇
  1979年   58篇
  1974年   49篇
  1938年   60篇
  1932年   57篇
  1930年   46篇
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
991.
992.
993.
本实验用日本大耳白兔复制输精管结扎的长期动物模型,分为结扎25月组(VG25),同龄假手术25月组(SOG25);结扎6月组(VG6),同龄假手术6月组(SOG6)。记录各组家兔心功能,检测心肌及血清NE含量,称取心重(WH)。结果表明,左心室收缩期末压(LVSP),VG略高于SOG;左心室舒张末压(LVEDP),V625显著的低于SOG25P<0.05),VG6与5OG6比较虽无显著差异,也呈低值;±dp/dtmax,VG均明显高于SOG(P<0.01)。相关检验表明,+dp/dtmax与血清及心肌NE含量无相关性;心重与+dp/dtmax呈明显正相关,P<0.05;在25月组,LVSP与+dp/dtmax呈正相关,P<0.05。提示输精管结扎可提高心肌收缩功能。  相似文献   
994.
Summary A patient undergoing regular haemodialysis for chronic renal insufficiency developed neck pain followed by progressive spinal cord compression due to subluxation at the level C3-4. Decompression, laminectomy and osteosynthesis led to an almost complete recovery. A review of all the histological specimens suggested that hyperparathyroidism and not amyloidosis caused the vertebral destruction.  相似文献   
995.
目的:探讨肺良恶性病变中角蛋白和核仁组织区的表达意义。方法:采用免疫组化ABC法和AgNOR染色,对54例肺良恶性病变进行检测。结果:角蛋白表达在低分化腺癌最高,AgNOR表达以未分化癌最高。结论:角蛋白对判定肺癌类型有一定帮助,AgNOR颗粒数目对判定肺癌的分化程度和预后有重要意义。角蛋白和AgNOR对肺癌的类型鉴别及预后判定有重要作用。  相似文献   
996.
急性胰腺炎CT、B超、手术及临床对照研究   总被引:5,自引:0,他引:5  
笔者分析了24例急性胰腺炎的CT所见,并同B超、临床化验和剖腹探查结果进行了对照研究。表明:(1)急性胰腺炎的CT诊断优于B超,对胆源性胰腺炎B超对诊断有明确帮助。(2)急性胰腺炎时,CT表现与血淀粉酶浓度不一定成正比。(3)急性胰腺炎可累及门脉系统引起血管并发症。  相似文献   
997.
Radiographs are ordered and interpreted for immediate clinical decisions 24 hours a day by emergency physicians (EP’s). The Joint Commission for Accreditation of Health Care Organizations requires that all these images be reviewed by radiologists and that there be some mechanism for quality improvement (QI) for discrepant readings. There must be a log of discrepancies and documentation of follow up activities, but this alone does not guarantee effective Q.I. Radiologists reviewing images from the previous day and night often must guess at the preliminary interpretation of the EP and whether follow up action is necessary. EP’s may remain ignorant of the final reading and falsely assume the initial diagnosis and treatment were correct. Some hospitals use a paper system in which the EP writes a preliminary interpretation on the requisition slip, which will be available when the radiologist dictates the final reading. Some hospitals use a classification of discrepancies based on clinical import and urgency, and communicated to the EP on duty at the time of the official reading, but may not communicate discrepancies to the EP’s who initial read the images. Our computerized radiology department and picture archiving and communications system have increased technologist and radiologist productivity, and decreased retakes and lost films. There are fewer face-to-face consultations of radiologists and clinicians, but more communication by telephone and electronic annotation of PACS images. We have integrated the QI process for emergency department (ED) images into the PACS, and gained advantages over the traditional discrepancy log. Requisitions including clinical indications are entered into the Hospital information System and then appear on the PACS along with images and readings. The initial impression, time of review, and the initials of the EP are available to the radiologist dictating the official report. The radiologist decides if there is a discrepancy, and whether it is category I (potentially serious, needs immediate follow-up), category II (moderate risk, follow-up in one day), or category III (low risk, follow-up in several days). During the working day, the radiologist calls immediately for category I discrepancies. Those noted from the evening, night, or weekend before are called to the EP the next morning. All discrepancies with the preliminary interpretation are communicated to the EP and are kept in a computerized log for review by a radiologist at a weekly ED teaching conference. This system has reduced the need for the radiologist to ask or guess what the impression was in the ED the night before. It has reduced the variability in recording of impressions by EP’s, in communication back from radiologists, in the clinical follow-up made, and in the documentation of the whole QI process. This system ensures that EP’s receive notification of their discrepant readings, and provides continuing education to all the EP’s on interpreting images on their patients.  相似文献   
998.
目的:为了解食管癌患者和非食管癌患者体内维生素A的水平及其与食管癌发病的关系.方法:采用微量荧光法对32例食管癌患者(实验组)和32例非食管癌患者(对照组)血清中维生素A含量进行了测定.结果:显示实验组与对照组血清维生素A均值分别为1.55μmol/L,1.69μmol/L.经统计学处理两组血清维生素A水平有显著性差异(P<0.01).结论:提示食管癌的发生可能与机体维生素A水平有关,这种关系需进一步探讨.  相似文献   
999.
从东亚钳蝎粗毒中分离纯化出蝎毒素Ⅳ,经套管注入侧脑室,用辐射热测痛和屈肌反射检测两种方法,观察蝎毒素Ⅳ的中枢镇痛作用,结果蝎毒索Ⅳ可以明显延长大鼠缩腿潜伏期,并可显著抑制C纤维诱发的屈肌反射。提示蝎毒素Ⅳ具有显著的中枢镇痛作用。  相似文献   
1000.
Syringolides are water-soluble, low-molecular-weight elicitors that trigger defense responses in soybean cultivars carrying the Rpg4 disease-resistance gene but not in rpg4 cultivars. 125I-syringolide 1 previously was shown to bind to a soluble protein(s) in extracts from soybean leaves. A 34-kDa protein that accounted for 125I-syringolide 1 binding activity was isolated with a syringolide affinity-gel column. Partial sequences of internal peptides of the 34-kDa protein were identical to P34, a previously described soybean seed allergen. In soybean seeds, P34 is processed from a 46-kDa precursor protein and was shown to have homology with thiol proteases. P34 is a moderately abundant protein in soybean seeds and cotyledons but its level in leaves is low. cDNAs encoding 46-, 34-, and 32-kDa forms of the soybean protein were cloned into the baculovirus vector, pVL1392, and expressed in insect cells. The resulting 32- and 34-kDa proteins, but not the 46-kDa protein, exhibited ligand-specific 125I-syringolide binding activity. These results suggest that P34 may be the receptor that mediates syringolide signaling.  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