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   126993篇
  免费   11551篇
  国内免费   7211篇
耳鼻咽喉   1172篇
儿科学   1440篇
妇产科学   1646篇
基础医学   15681篇
口腔科学   2600篇
临床医学   13746篇
内科学   19882篇
皮肤病学   1579篇
神经病学   7418篇
特种医学   4693篇
外国民族医学   45篇
外科学   15306篇
综合类   19523篇
现状与发展   15篇
一般理论   21篇
预防医学   8978篇
眼科学   2914篇
药学   13091篇
  82篇
中国医学   5773篇
肿瘤学   10150篇
  2024年   296篇
  2023年   1278篇
  2022年   3117篇
  2021年   4014篇
  2020年   3194篇
  2019年   2835篇
  2018年   3508篇
  2017年   3198篇
  2016年   2965篇
  2015年   4451篇
  2014年   5618篇
  2013年   5894篇
  2012年   8505篇
  2011年   9174篇
  2010年   6239篇
  2009年   5428篇
  2008年   6476篇
  2007年   6542篇
  2006年   6127篇
  2005年   5433篇
  2004年   4104篇
  2003年   3766篇
  2002年   3346篇
  2001年   6181篇
  2000年   5934篇
  1999年   4999篇
  1998年   2121篇
  1997年   1723篇
  1996年   1179篇
  1995年   1012篇
  1994年   832篇
  1993年   694篇
  1992年   2155篇
  1991年   1856篇
  1990年   1703篇
  1989年   1651篇
  1988年   1411篇
  1987年   1299篇
  1986年   1143篇
  1985年   978篇
  1984年   628篇
  1983年   493篇
  1982年   271篇
  1981年   200篇
  1980年   154篇
  1979年   295篇
  1978年   84篇
  1974年   78篇
  1973年   100篇
  1972年   77篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
961.
Biological effects of ionising radiation are dependent on the distribution of doses in tissue. In this article parameters influencing the distribution of dose in tissue are discussed with emphasis on intraoral and rotational panoramic radiography. For both examinations the probability to develop stochastic effects is estimated. For intraoral radiography the probability ranges from 0.1 to 0.3 per million exposures and for rotational panoramic radiography from 0.4 to 0.8 per million. For the whole Dutch population the probability to develop stochastic effects is 0-2 persons per year and 0-1 person per year respectively. Dental radiography is therefore justified if further diagnostic information is to be expected and exposure circumstances are optimal.  相似文献   
962.
The author used smear from Stensen's duct aspiration to observe exfoliated cytology in order to help diagnosis of early mumps.According to the smears from 100 cases of mumps and other 50 cases of bacteria parotitis and/or normal parotid as contro,the author revealed that if there are a lot of ductal epithelial cells,monocytes and polynuclear cells,monocytes and polynuclear phagocytes at same time,it could give diagnosis "Mumps" to that patient.In control group,it is unable to observe those three kind cells at same time.The author also discussed the mechanism of how would these three kind cells appear in mumps in accordance with references.  相似文献   
963.
964.
Summary An 8-month-old girl had an ependymoma in the clivus, 2x6 cm in size, connected with the fourth ventricle by a cord of tissue 0.5 cm thick. There were no indications to make us suspect the origin of the tumour in the fourth ventricle, or that it was a case of ependymoma.  相似文献   
965.
966.
This paper report,s the iodine metabolism and pituitary-thyroid axis function among the inhabitants of an untreated endemic goiter region in the southeast.ern part (Heba commune) of Guizhou province. The results of the investigation showed that the urine iodine excretion of the inhabi- tants in the untreated endemic goiter region was lower than that of those in the normal non- endemic region, a rural commune of Guiyang city and an iodized salt treated endemic region, Shilong commune. The urine iodine excretion was low not only among the goiter patients and cretins but also among the nongoitrous adults and children. Same was with the 24 hr thyroid .131I uptake figures which were higher than normal among the goiter patients and cretins as well as nongoitrous adults and children in Heba commune. It is concluded that in the endemic goiter region, the goiter patients and cretins as well as the nongoitrous adults and children are suffering from iodine deficiency. Studies of pituitary thyroid axis function of the inhabitants in the untreated endemic goiter region, Heba commune, showed basically normal values for serum T3, definitely low values for serum T4 and markedly elevated values for se- rum TSH. The relation_ship between low serum T4 and elevated serum TSH was frequently ob- served among the cretins and the goiter ;patients although myxedema was rarely manifested. Thus hormonal hypothyroidism was not un- common among the inhabitants of Heba com- mune and the term "euthyroidism" should be used with discretion.  相似文献   
967.
Ten monomeric indole alkaloids have been identified from the roots of KOPSIA OFFICINALIS. Four of them are known: (-)-kopsinine 1, (+)-5,22-dioxokopsane 2, (-)-tetrahydroalstonine 4, and (-)-quebrachamine 3; and six are new: (-)-isoeburnamine 5 (enantiomer of the known alkaloid (+)-isoeburnamine), (-)-N-methoxycarbonyl-12-methoxykopsinaline 7, (-)-N-methoxycarbonyl-11,12-methylenedioxy kopsinaline 8, (-)-N-methoxycarbonyl-11,12-dimethoxykopsinaline 9, (-)-11,12-methylenedioxykopsinaline 10, and (-)-12-methoxykopsinaline 11.  相似文献   
968.
A rare case of pulmonary infection caused by Emericella nidulans and Aspergillus flavus is reported for the first time in our country. "This diagnosis is of significance mycologically. :Direct microscopic examination and histopatho- logic cross section of expectorated mass show numerolus cleistoithecia of varying size, filled by asci and ascospores. Outside the cleistothecia 'were numerous thickwalled Hulle cells. The pa- tient was treated satisfactorily with antimyco- tics.  相似文献   
969.
双上斜肌麻痹的临床特征与治疗   总被引:2,自引:0,他引:2  
甘晓玲  郭静秋 《眼科学报》1991,7(4):190-195
双眼上斜肌同时麻痹称为双上斜肌麻痹,近年来受到国内外眼科学者的重视。本文报告13例,均是我科近年来手术治疗并在术后观察3个月以上者。13例病人都无明显外伤史,发病在出生时及出生后早期,为先天性病变。手术次数1~2次。临床特征:不对称病变以单眼上斜视,代偿头位为主要表现,其中有一部分病人为潜在型双侧病变。对称型以两侧同向注视时的反向上斜视为主要表现,双侧Bielschowsky征为阳性。不少病人同时有V型斜视。需要手术治疗的病人一般应做双眼手术。可根据病情决定是同时做双侧手术,还是分次做,以及术式、术量。术后大部分病人能获得满意的头位及眼位。  相似文献   
970.
红核的镇痛作用和加强电针镇痛的作用   总被引:3,自引:2,他引:1  
<正> 红核属锥体外系,其主要机能是调节躯体运动和肌紧张。但近年来的工作指出它与感觉的调制也有关。如电刺激红核可抑制大鼠的伤害性行为反应。刺激红核可兴奋中缝大核(NRM)神经元的电活动,而刺激NRM可加强电针在三叉神经脊束核尾侧  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