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   260912篇
  免费   6647篇
  国内免费   352篇
耳鼻咽喉   2440篇
儿科学   9025篇
妇产科学   4567篇
基础医学   26334篇
口腔科学   3224篇
临床医学   21023篇
内科学   49195篇
皮肤病学   1984篇
神经病学   24310篇
特种医学   11907篇
外国民族医学   5篇
外科学   43332篇
综合类   3396篇
一般理论   103篇
预防医学   24946篇
眼科学   4701篇
药学   14882篇
中国医学   783篇
肿瘤学   21754篇
  2023年   479篇
  2022年   774篇
  2021年   2035篇
  2020年   1107篇
  2019年   1893篇
  2018年   23735篇
  2017年   18706篇
  2016年   20866篇
  2015年   2652篇
  2014年   3500篇
  2013年   4641篇
  2012年   12661篇
  2011年   26649篇
  2010年   21864篇
  2009年   14397篇
  2008年   24648篇
  2007年   27149篇
  2006年   6139篇
  2005年   7635篇
  2004年   8560篇
  2003年   9118篇
  2002年   6976篇
  2001年   1105篇
  2000年   1164篇
  1999年   1028篇
  1998年   1127篇
  1997年   1043篇
  1996年   819篇
  1995年   798篇
  1994年   748篇
  1993年   601篇
  1992年   619篇
  1991年   625篇
  1990年   598篇
  1989年   523篇
  1988年   509篇
  1987年   467篇
  1986年   445篇
  1985年   520篇
  1984年   590篇
  1983年   525篇
  1982年   691篇
  1981年   615篇
  1980年   611篇
  1979年   312篇
  1978年   385篇
  1977年   378篇
  1976年   303篇
  1975年   288篇
  1974年   269篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
42.
To determine whether polymorphisms of platelet surface glycoprotein associated with arterial thrombosis are risk factors for branch retinal vein occlusion. A case-control study in which 69 patients with branch retinal vein occlusion and 147 controls who attended the eye clinic for nonvascular complications participated. DNA was extracted from whole blood and analyzed for genotyping of platelet glycoprotein polymorphisms by polymerase chain reactions and specific restricted enzymes. No relationship was found between the four platelet glycoprotein polymorphisms i.e. GPIa C807T, VNTR and Kozak of glycoprotein Ibalpha, the HPA-1 of glycoprotein IIIa and the occurrence of branch retinal vein occlusion. The HPA-2 polymorphism was found in 18 out 60 (30%) patients with branch retinal vein occlusion in comparison with 27 out 142 (19%) of controls, with an estimated odds ratio of 1.8 (95% confidence interval, 0.91-3.65). The four platelet glycoprotein polymorphisms are not risk factors for branch retinal vein occlusion and therefore it seems unnecessary to screen those patients for it. A larger study is required, however, to determine whether HPA-2 is a novel risk factor for branch retinal vein occlusion.  相似文献   
43.
44.
45.
46.

Background  

The fibromyalgia syndrome (FMS) is suggested to be a manifestation of depression or affective spectrum disorder. We measured the cognitive style of patients with FMS to assess personality styles in 44 patients with fibromyalgia syndrome (FMS) by comparing them with 43 patients with major depressive disorder (MDD) and 41 healthy controls (HC).  相似文献   
47.
BACKGROUND: The dopamine transporter (DAT) is known to be a key regulator of dopamine, and recent studies of genetics, treatment, and imaging have highlighted the role of DAT in attention-deficit/hyperactivity disorder (ADHD). The findings of in vivo neuroimaging of DAT in ADHD have been somewhat discrepant, however. METHOD: Dopamine transporter binding was measured using a highly selective ligand (C-11 altropane) and positron emission tomography (PET). The sample consisted of 47 well-characterized, treatment-na?ve, nonsmoking, non-comorbid adults with and without ADHD. Additionally, control subjects had few symptoms of ADHD. RESULTS: Results showed significantly increased DAT binding in the right caudate in adults with ADHD compared with matched control subjects without this disorder. CONCLUSIONS: These results confirm abnormal DAT binding in the striatum of adults with ADHD and provide further support that dysregulation of DAT may be an important component of the pathophysiology of ADHD.  相似文献   
48.
49.
Introduction Choroid plexus cysts can lead to isolation of the lateral ventricles and distension of the third ventricle. We present an ultrasonographic video documentation of an infant with variably shaped and localized choroid plexus cyst of the third ventricle. Case report An infant had periods of increased intracranial pressure with changing dilatation of the first to third ventricle. Cerebral ultrasonography of the not crying boy demonstrated a choroid plexus cyst limply hanging down from the roof of the third ventricle to the beginning of the aqueduct of Sylvius. During crying, the cyst prolapsed from the third into left lateral ventricle and was strangled by the foramen of Monro. Endoscopic cyst fenestration and third ventriculostomy continuously solved the problem of intermittent hydrocephalus occlusus. Conclusion Depending not only on localization and size but also on cyst form and cerebrospinal fluid pressure, a single choroid plexus cyst can cause various obstructions of cerebrospinal fluid pathways.  相似文献   
50.
Introduction Iniencephaly, a neural tube defect involving occiput and inion and combined with rachischisis of the cervical, thoracic spine, and retroflexion position of the head is a very rare congenital abnormality of the fetus–newborn with a 0.1–10 of 10,000 prevalence. This abnormality’s prognosis is thought to be dismal. This abnormality can be associated with other abnormalities such as anencephaly, encephalocele, hydrocephalus, cyclopia, absence of the mandible, cleft lip and palate, cardiovascular disorders, diaphragmatic hernia, renal abnormalities, overgrowth of the arms compared to the legs, and club food and gastrointestinal atresia. Discussion Most of the patients are dead born, and the others die in a few hours. There are only six previously documented long-term survivors. In our case, our patient with iniencephalic signs and findings is still living. She is 2 years old now. We think that this patient presents a mild form of iniencephaly.  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