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   126992篇
  免费   12330篇
  国内免费   9787篇
耳鼻咽喉   1042篇
儿科学   1275篇
妇产科学   1223篇
基础医学   14867篇
口腔科学   2189篇
临床医学   17065篇
内科学   18726篇
皮肤病学   1294篇
神经病学   6647篇
特种医学   4590篇
外国民族医学   79篇
外科学   12696篇
综合类   22922篇
现状与发展   41篇
一般理论   6篇
预防医学   8796篇
眼科学   3656篇
药学   13544篇
  117篇
中国医学   7978篇
肿瘤学   10356篇
  2024年   516篇
  2023年   2217篇
  2022年   5568篇
  2021年   7048篇
  2020年   5276篇
  2019年   4436篇
  2018年   4568篇
  2017年   4109篇
  2016年   3866篇
  2015年   5931篇
  2014年   7260篇
  2013年   6501篇
  2012年   9431篇
  2011年   10282篇
  2010年   6585篇
  2009年   5224篇
  2008年   6681篇
  2007年   6542篇
  2006年   6261篇
  2005年   6290篇
  2004年   4048篇
  2003年   3737篇
  2002年   3206篇
  2001年   2808篇
  2000年   2941篇
  1999年   3087篇
  1998年   2059篇
  1997年   2084篇
  1996年   1589篇
  1995年   1496篇
  1994年   1297篇
  1993年   812篇
  1992年   1004篇
  1991年   809篇
  1990年   688篇
  1989年   640篇
  1988年   536篇
  1987年   465篇
  1986年   402篇
  1985年   301篇
  1984年   137篇
  1983年   119篇
  1982年   73篇
  1981年   72篇
  1980年   48篇
  1979年   54篇
  1974年   1篇
  1972年   1篇
  1965年   2篇
  1964年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
We have previously shown that neuregulin-1 (NRG-1) protects neurons from ischemic brain injury if administered before focal stroke. Here, we examined the therapeutic window and functional recovery after NRG-1 treatment in rats subjected to 90 mins of middle cerebral artery occlusion (MCAO) and 24 h of reperfusion. Neuregulin-1 (2.5 ng/kg bolus, 1.25 ng/kg/min infusion) reduced infarct volume by 89.2%+/-41.9% (mean+/-s.d.; n=8; P<0.01) if administered immediately after the onset of reperfusion. Neuroprotection was also evident if NRG-1 was administered 4 h (66.4%+/-52.6%; n=7; P<0.01) and 12 h (57.0%+/-20.8%; n=8; P<0.01) after reperfusion. Neuregulin-1 administration also resulted in a significant improvement of functional neurologic outcome compared with vehicle-treated animals (32.1%+/-5.7%; n=9; P<0.01). The neuroprotective effect of the single administration of NRG-1 was seen as long as 2 weeks after treatment. Neurons labeled with the neurodegeneration marker dye Fluoro-JadeB were observed after MCAO in the cortex, but the numbers were significantly reduced after NRG-1 treatment. These results indicate that NRG-1 is a potent neuroprotective compound with an extended therapeutic window that has practical therapeutic potential in treating individuals after ischemic brain injury.  相似文献   
62.
病理性近视眼的研究进展   总被引:5,自引:4,他引:1  
通过复习近年来相关文献,对近视眼发生发展机制与形觉剥夺之间的关系进行综合评述。认为近视眼的发生及眼轴延长与形觉剥夺有一定关系,深入研究其相关机制,对近视眼的早期防治具有重要意义。  相似文献   
63.
内脏高敏感与功能性胃肠病   总被引:3,自引:0,他引:3  
功能性胃肠病(functional gastrointestinal disorders,FGIDs)是指一组以慢性或反复发作的消化道症状就诊,但无明确胃肠黏膜结构改变或生化异常可查的症候群。心理、社会因素可加重FGIDs患者症状,患者可同时伴有躯体症状[1]。其发病机制目前尚不明确,最初该类疾病被认为是胃肠神经官能症,大量的流行病学资料表明,尽管精神压力与患者症状发作有关,但主要还是决定于患者的就医行为。此后,FGIDs发病机制的研究又集中在胃肠动力改变方面,肠易激综合征患者(IBS)、功能性消化不良患者(FD)、非心源性胸痛患者(NCCP)均发现了各种胃肠动力异…  相似文献   
64.
S D Xu 《中华外科杂志》1990,28(10):588-91, 636
108 pigs were shot at the level of lumbar 1 to investigate the changes of spinal cord in relation to the speed of shooting and the trajectory through which the bullet passed. The cord lesions of the specimens could be divided, according to its severity, into 4 grades: (1) transection in 41; (2) complete destruction in 43; both lesion 1&2 resulted in permanent paraplegia; (3) incomplete destruction in 13, those resulted in incomplete paraplegia eventually recovered; (4) mild damage, that was concussion in 11, resumed perfectly. Through a transducer sealed into the spinal canal, the intracanal pressure was recorded: (1) Shooting through spinal canal with a pressure over 5 kg caused cord transection. (2) shooting through canal wall with a pressure of 2.5 to 5; 0 kg caused complete cord destruction. (3) shooting nearby the outer margin of vertebra with a pressure less than 1.0 kg caused mild cord damage. It was found that the speed of bullet, the trajectory with relation to cord and the grade of cord lesion are in agreement with each other. The mutual effects among them would make one think it reasonable to classify cord injury as follows: 1. Injury from bullet through spinal canal or vertebral body usually causes cord transaction; 2. Injury from bullet through canal wall at high speed would make a chance of complete destruction in 94%; at low speed, a chance of either complete or incomplete lesion in 50% each. 3. Injury nearby vertebra, high speed bullet would cause a chance of complete cord lesion in 86%; low speed one would make a chance of incomplete lesion in 1/3 and mild lesion in 2/3.  相似文献   
65.
H T Xu  S L Chen  L S Li 《中西医结合杂志》1990,10(12):737-9, 710
In 24 open-chest mongrel dogs, coronary artery critical stenosis were produced by a micrometer constriction on left circumflex coronary artery. It was reduction about 87% in lumen area. CBF, -Vce, -dp/dt max were decreased, T was increased (P less than 0.01). 15 minutes after stenosis, the Salvia miltiorrhiza injection was injected into left atrium. CBF, -dp/dt max, -Vce were increased and T was decreased after the injection of Salvia miltiorrhiza. Moreover, the change of CBF was the earliest. The results proved that the Salvia miltiorrhiza could improve the left ventricular diastolic function in coronary artery stenosis.  相似文献   
66.
67.
68.
In this paper,250 cases of headache,shoulder pain,lumbago and leg pain weretreated with 20%Angelicae Sinensis mixed with Vitamine B_(12) point-injection therapy.The total effective rate was 95.2%and in which the cure rate was 53.6%.Authors have found a close correlation between the effectiveness and the duration of disease.  相似文献   
69.
护理服务质量的感知与期望分析   总被引:1,自引:0,他引:1  
护理服务质量是一个多维的评价指标。它即有质量部分(技术性、定量),又有非质量部分(功能性、定性),前者是指护理专业的技术水平以及护理工作结果的服务质量,后者是指服务过程的质量,因此护理服务质量不仅取决于医院护理者提供的技术性、定量的技术质量,而且还取决于病人在护理服务过程中感知与期望之间的对比。病人在住院之前对医院护理服务的质量有一个期望,接受了护理服务之后就有了感知,如果病人感知到的护理服务符合期望的护理服务,就会感到满意,如果病人感知到的护理服务高于期望的护理服务,就会感到欣喜,这就是优质护理服务,如果感知…  相似文献   
70.
The tumor microenvironment consists of tumor, immune, stromal, and inflammatory cells which produce cytokines, growth factors, and adhesion molecules that promote tumor progression and metastasis. Of particular interest in this setting is interleukin-1 (IL-1), a pleiotropic cytokine with numerous roles in both physiological and pathological states. It is known to be up regulated in many tumor types and has been implicated as a factor in tumor progression via the expression of metastatic and angiogenic genes and growth factors. A number of studies have reported that high IL-1 concentrations within the tumor microenvironment are associated with a more virulent tumor phenotype. Solid tumors in which IL-1 has been shown to be up regulated include breast, colon, lung, head and neck cancers, and melanomas, and patients with IL-1 producing tumors have generally bad prognoses. The exact mechanisms by which IL-1 promotes tumor growth remain unclear, though the protein is believed to act via induction of pro-metastatic genes such as matrix metalloproteinases and through the stimulation of adjacent cells to produce angiogenic proteins and growth factors such as VEGF, IL-8, IL-6, TNFα, and TGFβ. The IL-1 receptor antagonist (IL-1ra) is a naturally occurring inhibitor to IL-1 and acts by binding to the IL-1 receptor without activating it. The protein has been shown to decrease tumor growth, angiogenesis, and metastases in murine xenograft models. Our focus in this review is to summarize the known data on the role of IL-1 in tumor progression and metastasis and the use of IL-1 inhibition as a novel therapeutic approach in the treatment of solid organ malignancies.  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