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   39347篇
  免费   3426篇
  国内免费   1417篇
耳鼻咽喉   378篇
儿科学   671篇
妇产科学   629篇
基础医学   5806篇
口腔科学   1034篇
临床医学   3770篇
内科学   7182篇
皮肤病学   666篇
神经病学   3132篇
特种医学   1414篇
外国民族医学   3篇
外科学   4890篇
综合类   3351篇
现状与发展   4篇
一般理论   9篇
预防医学   2411篇
眼科学   1089篇
药学   3870篇
  6篇
中国医学   772篇
肿瘤学   3103篇
  2023年   237篇
  2022年   541篇
  2021年   802篇
  2020年   552篇
  2019年   643篇
  2018年   903篇
  2017年   764篇
  2016年   744篇
  2015年   994篇
  2014年   1172篇
  2013年   1422篇
  2012年   1933篇
  2011年   1956篇
  2010年   1247篇
  2009年   966篇
  2008年   1630篇
  2007年   1678篇
  2006年   1585篇
  2005年   1384篇
  2004年   1202篇
  2003年   1093篇
  2002年   950篇
  2001年   2516篇
  2000年   2398篇
  1999年   2034篇
  1998年   761篇
  1997年   556篇
  1996年   415篇
  1995年   383篇
  1994年   301篇
  1993年   282篇
  1992年   1111篇
  1991年   988篇
  1990年   884篇
  1989年   977篇
  1988年   867篇
  1987年   805篇
  1986年   740篇
  1985年   651篇
  1984年   418篇
  1983年   345篇
  1982年   197篇
  1981年   166篇
  1980年   140篇
  1979年   230篇
  1978年   105篇
  1977年   96篇
  1974年   97篇
  1973年   101篇
  1971年   95篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
This paper is a summary of our observations on 105 cases of infantile spasms. The age of onset was around six months after birth, but the patients came for treatment mainly about one year after onset. Fever of unknown cause, asphyxia, birth injury, infection of the central nervous system, tuberous sclerosis, phenylketonuria and recent immunization etc. were complained. Clinically, it is characterized by head nodding, mental retardation, myoclonic jerks and various neurologic deficits. EEG findings showed classical or modified arrythmia or other epileptiform patterns. About one third of 22 cases examined had abnormal brain stem auditory evoked potentials. Among 42 patients who underwent CT scanning before ACTH treatment, 18 were normal and 7 abnormal; during ACTH treatment 3 normal and 4 abnormal; after completion of treatment, 4 normal and 6 abnormal, suggesting no further atrophy of the brain. Examination of trace elements of the hair by particle-induced X-ray emission (PIXE) method in 23 patients revealed a significant difference in lead, calcium and zinc contents between patients and 101 controls, but no statistical difference in iron and copper contents between the two groups. Sodium valproate, prednisone and ACTH appear to be effective in the treatment of infantile spasms. Eight patients fully recovered, and they can go to school without difficulty. Many patients derived various degrees of improvement to the satisfaction of their parents. Two patients were still amented and often attacked by myoclonus. The effects, side effects of these drugs, and the possible pathogenesis were discussed.
  相似文献   
32.
33.
OBJECTIVE: The C2A domain of Synaptotagmin I is a molecular probe for the specific imaging of cell death. Here we test the hypothesis that the uptake of 99mTc-C2A in the acute phase of an infarction is associated with cardiac dysfunction in follow-ups. METHODS: The left coronary artery was occluded in Sprague-Dawley rats for 0, 10, 20, and 30 min. 99mTc-C2A was injected intravenously at 2 h of reperfusion. Anterior planar images were acquired with one million counts on a gamma camera 3 h after injection. 99mTc-C2A uptake was calculated as the total counts in the left ventricle region minus blood pool signal. The in-vivo signal detected was correlated with wall motion score index at 1 and 3 weeks follow-ups measured by echocardiography. RESULTS: 99mTc-C2A uptake was higher with increased ischemic time (2244+/-852, 4054+/-1223, and 6178+/-1451 for 10, 20, and 30 min ischemia, analysis of variance P<0.001). A significant correlation was found between 99mTc-C2A uptake and wall motion score index at 1 week (R=0.800, P=0.0006) and 3 weeks (R=0.810, P=0.0008). CONCLUSION: In this ischemia/reperfusion model, 99mTc-C2A uptake in the acute phase was associated with functional abnormality at 1 and 3 weeks. This demonstrates the potential diagnostic and prognostic value of 99mTc-C2A as a novel imaging agent.  相似文献   
34.
切开复位内固定治疗骨盆桶柄样Tilt骨折   总被引:1,自引:1,他引:0  
目的探讨骨盆桶柄样Tilt骨折手术治疗方法。方法切开复位内固定治疗52例骨盆桶柄样Tilt骨折。前骨盆经Plan—nenstiel入路固定9例,Pfannenstiel入路结合部分髂腹般沟入路固定43例。37例行骨盆重建钢板固定,骨盆重建钢板固定结合耻骨上支髓内螺钉固定9例,6例2块骨盆重建钢板固定。后环37例经患侧髂嵴入路以骨盆重建钢板固定。8例骶骨骨折行骶髂关节螺钉固定。7例未行后骨盆固定。结果平均随访18个月。全部骨性愈合,无下肢不等长,骨盆畸形基本纠正。按Majeed疗效评定标准优良率为93.8%。结论通过前后联合入路,切开复位治疗骨盆桶柄样Tilt骨折疗效满意,并可防止远近期并发症的发生。  相似文献   
35.
36.
Degranulating mast cells are increased in the airway smooth muscle (ASM) of asthmatics, where they may influence ASM function. The aim of the present study was to determine whether histamine and tryptase modulate ASM cell granulocyte-macrophage colony-stimulating factor (GM-CSF) and RANTES (regulated on activation, normal T-cell expressed and secreted) release and also to examine which receptors are involved in this release. Confluent, quiescent ASM cells from asthmatic and nonasthmatic donors were treated with histamine (1 microM-100 microM) with and without histamine receptor antagonist pre-treatment, or the protease-activated receptor (PAR)-2 agonists tryptase (0.5-5 nM) and SLIGKV (100 and 400 microM). The cells were then stimulated with interleukin (IL)-1beta and/or tumour necrosis factor (TNF)-alpha (10 ng.mL(-1)) or left unstimulated for 24 h. Release of GM-CSF and RANTES was determined by ELISA and prostaglandin (PG)E(2) measured by enzyme immunoassay. Neither histamine nor tryptase induced ASM GM-CSF or RANTES secretion. However, histamine increased IL-1beta-induced GM-CSF release and markedly reduced TNF-alpha-induced RANTES release by both asthmatic and nonasthmatic cells to a similar extent, but did not modulate PGE(2) release. All changes involved activation of the histamine H1 receptor as they were partially or fully blocked by chlorpheniramine, but not ranitidine. Tryptase, via its proteolytic activity, also potentiated GM-CSF, but not RANTES, release from asthmatic and nonasthmatic ASM cells induced by both cytokines. PAR-2 involvement in the tryptase potentiation was unlikely because SLIGKV had no effect. In conclusion, mast cells, through histamine and tryptase, may locally modulate airway smooth muscle-induced inflammation in asthma.  相似文献   
37.
38.
39.
40.
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