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   7583篇
  免费   633篇
  国内免费   26篇
耳鼻咽喉   106篇
儿科学   190篇
妇产科学   261篇
基础医学   1029篇
口腔科学   154篇
临床医学   940篇
内科学   1613篇
皮肤病学   140篇
神经病学   725篇
特种医学   615篇
外科学   933篇
综合类   66篇
一般理论   1篇
预防医学   558篇
眼科学   129篇
药学   304篇
中国医学   12篇
肿瘤学   466篇
  2023年   62篇
  2022年   59篇
  2021年   96篇
  2020年   93篇
  2019年   98篇
  2018年   136篇
  2017年   97篇
  2016年   134篇
  2015年   186篇
  2014年   268篇
  2013年   345篇
  2012年   338篇
  2011年   354篇
  2010年   281篇
  2009年   246篇
  2008年   328篇
  2007年   369篇
  2006年   360篇
  2005年   314篇
  2004年   289篇
  2003年   251篇
  2002年   224篇
  2001年   253篇
  2000年   238篇
  1999年   195篇
  1998年   137篇
  1997年   133篇
  1996年   139篇
  1995年   111篇
  1994年   99篇
  1993年   101篇
  1992年   127篇
  1991年   131篇
  1990年   137篇
  1989年   139篇
  1988年   122篇
  1987年   112篇
  1986年   95篇
  1985年   103篇
  1984年   67篇
  1983年   52篇
  1982年   55篇
  1981年   52篇
  1980年   41篇
  1979年   67篇
  1977年   53篇
  1975年   42篇
  1974年   41篇
  1973年   43篇
  1972年   45篇
排序方式: 共有8242条查询结果,搜索用时 0 毫秒
1.
A rotating contact lens holder for the three-mirror Goldmann lens permits circular examination of the fundus or chamber angle without having to change the position of the fingers on the edge of the lens. The contact lens holder consists of an outer polygonal ring hold by the thumber and index finger. An inner rotating ring holds the contact lens. Continuous rotation of the contact lens is performed with the free middle Finger. This device permits circular examination of the retina without interruption of fixation. The instrument improves not only the speed but also the reliability of the examination.  相似文献   
2.
Cerebral infarction is rare in premature newborns and is most commonly the result of arterial embolization from the placenta. A focal echodense area was identified on prenatal cranial ultrasonography (US) in a premature infant (34 weeks of gestation). After birth, cerebral infarction was confirmed by magnetic resonance imaging (MRI). The clinical findings, imaging findings and pathogenesis are discussed. New diagnostic methods such as MRI show to be a useful approach in the neonatal period facilitating recognition of cerebrovascular accidents also in low-birth-weight infants.  相似文献   
3.
Benign intracranial hypertension (BIH) is reported in three children from Australia and one from New Zealand, who were being treated with recombinant human growth hormone (rhGH). Three males and one female, aged between 10.5 and 14.2 y, developed intracranial hypertension within 2 weeks to 3 months of starting treatment. A national database, OZGROW, has been prospectively collecting data on all 3332 children treated with rhGH in Australia and New Zealand from January 1986 to 1996. The incidence of BIH in children treated with growth hormone (GH) is small, 1.2 per 1000 cases overall, but appears to be greater with biochemical GHD (<10IUml -1), i.e. 6.5/1000 (3 in 465 cases), relative risk 18.4, 95% confidence interval 1.9-176.1, than in all other children on the database. The incidence in patients with Turner's syndrome was 2.3/1000 (1 in 428 cases). No cases in patients with partial GHD (10–20 IUml -1) or chronic renal failure were identified. Possible causative mechanisms are discussed. The authors'practice is now to start GH replacement at less than the usual recommended dose of 14IUm-2 week-1 in those children considered to be at high risk of developing BIH. Ophthalmological evaluation is recommended for children before and during the first few months following commencement of rhGH therapy and is mandatory in the event of peripheral or facial oedema, persistent headaches, vomiting or visual symptoms. The absence of papilledema does not exclude the diagnosis.  相似文献   
4.
AD  Giannoukas  N  Labropoulos  FCT  Smith  GS  Venables  JD  Beard  武婕 《中华脑血管病论坛》2005,3(5):555-560
目的由于卒中风险随着狭窄严重程度的增加而升高,因此认为颈内动脉(ICA)接近闭塞患者的卒中风险很高。在现有的随机试验中,还没有专门针对这种情况进行探讨,因此其处理尚存在争汶。方法:对相关文献进行系统评价。结果:对ICA接近闭塞患者的处理还存在争议:一些学者支持进行干预,而另一些学者则认为存在风险或没有益处而反对进行干预。在ICA接近闭塞的有症状患者中进行一项比较外科治疗与最佳内科治疗的多中心前瞻性随机试验似乎非常困难,因为这类研究需要大量的患者。尽管如此,基于目前的证据,似乎很难拒绝手术治疗。结论:由于目前对ICA接近闭塞患者的最佳处理方案仍存在着争议,因此需要前瞻性观察性研究以证实其在有症状和无症状人群中的患病率以及相关的卒中风险。基于目前的证据,大多数医疗中心选择手术治疗,但它相对干内科治疗的特粱尚右待证章.  相似文献   
5.
Although intellectual impairment is common in patients with myotonic dystrophy, this aspect of the disease has received relatively little research attention. We examined 41 patients with myotonic dystrophy using objective neuropsychological procedures and magnetic resonance imaging. Ten patients (24%) had severe and generalized intellectual dysfunction, while lesser or no cognitive impairment characterized the remaining patients. Degree of intellectual impairment was not related to neuromuscular status or sex. Patients with severe intellectual disturbance had significantly earlier onset of both myotonia and weakness and were more likely to inherit the disease from their mother. Magnetic resonance imaging findings indicated that while degree of cerebral atrophy was not related to severity of intellectual impairment, skull thickness, focal white matter lesions, and anterior temporal lobe abnormalities were significantly more common in patients with severely disturbed intellect. This study reports a number of previously unreported cerebral magnetic resonance imaging findings associated with intellectual impairment in myotonic dystrophy, but the etiology of these changes awaits neuropathologic examination.  相似文献   
6.
7.
The murine Mls antigens were originally discovered because they have an enormous T cell stimulatory capacity, exceeding in strength any other antigen. The finding that Mls interacts directly with the V beta segment of the T cell receptor, leading to in vivo deletion and in vitro stimulation of T cells expressing particular V beta genes, provided an explanation for this phenomenon and led to the formulation of the new term of superantigen. Recently it was discovered by several groups that these superantigens are encoded by type B retroviruses, the mammary tumor viruses which are transmitted vertically as infectious particles or exist as proviruses in the murine genome.  相似文献   
8.
An approach to differentiating tissues by means of local texture analysis is described and its diagnostic power is evaluated using various diseases of the liver, kidney and the prostate.  相似文献   
9.
Murine cytomegalovirus causes diffuse myocardial lesions in immunologically intact young adult male BALB/cBy mice. The cardiac changes develop in and around the small penetrating blood vessels of the heart where perivascular and interstitial infiltrates of macrophages and lymphocytes accumulate. Focal lesions of the coronary vessels and the endocardium also appear. When infected mice are depleted of CD4+ T lymphocytes, myocardial lesions fail to develop even though virus replication in the heart is enhanced. Contrary wise, when CD4+ cells are adoptively transferred into infected, thymectomized, irradiated, bone marrow-repleted mice, focal perivascular necrotizing lesions of the heart develop. Depletion of CD8+ T lymphocytes fails to influence virus replication and the development of cardiac lesions. Endothelial and endocardial cells appear to be major sites of virus replication in the heart. Delayed hypersensitivity is hypothesized to be the mechanism of cardiac injury in this model system.  相似文献   
10.
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