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   22905篇
  免费   1210篇
  国内免费   79篇
耳鼻咽喉   139篇
儿科学   350篇
妇产科学   374篇
基础医学   2933篇
口腔科学   753篇
临床医学   1651篇
内科学   5481篇
皮肤病学   412篇
神经病学   2097篇
特种医学   1024篇
外科学   3503篇
综合类   87篇
预防医学   662篇
眼科学   405篇
药学   1828篇
中国医学   56篇
肿瘤学   2439篇
  2023年   100篇
  2022年   151篇
  2021年   405篇
  2020年   231篇
  2019年   326篇
  2018年   377篇
  2017年   298篇
  2016年   370篇
  2015年   390篇
  2014年   551篇
  2013年   621篇
  2012年   986篇
  2011年   1131篇
  2010年   566篇
  2009年   534篇
  2008年   970篇
  2007年   973篇
  2006年   948篇
  2005年   952篇
  2004年   915篇
  2003年   902篇
  2002年   941篇
  2001年   913篇
  2000年   936篇
  1999年   915篇
  1998年   290篇
  1997年   233篇
  1996年   219篇
  1995年   181篇
  1994年   162篇
  1993年   150篇
  1992年   653篇
  1991年   565篇
  1990年   597篇
  1989年   578篇
  1988年   493篇
  1987年   456篇
  1986年   451篇
  1985年   403篇
  1984年   278篇
  1983年   235篇
  1980年   91篇
  1979年   240篇
  1978年   142篇
  1977年   128篇
  1975年   100篇
  1974年   95篇
  1972年   105篇
  1971年   103篇
  1969年   101篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) is a rare and poorly understood ischemic colitis that occurs in the rectosigmoid colon of predominantly young, previously healthy, male patients. A 76‐year‐old Japanese man presented to our hospital with a 1‐year history of worsening diarrhea, lower abdominal pain, and weight loss (−6 kg). Laboratory evaluation revealed white blood cell count of 13 200/μL, C‐reactive protein level of 2.0 mg/dL (normal range, 0.0–0.3), and negative results for stool culture (including Clostridium difficile). Colonoscopy showed circumferential and edematous narrowing of the sigmoid colon with deep longitude ulceration. Biopsy was done and examination of the specimen demonstrated no specific ischemia. The patient was treated with bowel rest, antibiotics, and i.v. fluids; however, his symptoms worsened. Finally, sigmoidectomy was carried out. Histological examination demonstrated significant myointimal hyperplasia of mesenteric veins leading to thickening and stenosis of the venous lumen. Therefore, the final diagnosis was IMHMV. Three months following sigmoidectomy, he was asymptomatic.  相似文献   
2.
3.
4.
5.
6.
7.
Experiments were performed on spinalized rats, transected at the Cl level. The intravenous administration of TRH and its analog YM-14673 (N alpha-[(S)-4-oxo-2-azetidinyl) carbonyl]-L-histidyl-L-prolinamide dehydrate) produced marked increases in the amplitude of mono- and polysynaptic reflex potentials and those of the withdrawal flexor reflexes. The effects of YM-14673 were stronger and longer-lasting than those of TRH. The stimulant action of TRH and YM-14673 on the flexor reflexes was not antagonized by prazosin, chlorpromazine, haloperidol or cyproheptadine, suggesting no involvement of the release of catecholamines or serotonin in the stimulant effects of TRH and its analog. Therefore, YM-14673 may be beneficial for the treatment of several spinal motor neuron diseases.  相似文献   
8.
S Yamada 《Journal of UOEH》1988,10(2):211-218
Physical activity and nutrition are the most important factors in preserving and/or improving health conditions. The relationship between exercise and nutrition is focused on two different directions: one is the direction toward health promoting, the other is for performance of a long heavy muscular work. For preserving and/or promoting health conditions, energy balance between intake and expenditure must be taken into account. The amount of glycogen stored in muscles is the essential factor to promote a long distance performance of working muscles. Topics that influence the energy balance and glycogen loading used by endurance athletes to improve performance are reviewed.  相似文献   
9.
In the focal infarction model of the rat middle cerebral artery (MCA), the thalamus of the occluded side becomes gradually atrophic, mainly because of retrograde degeneration. We determined whether basic fibroblast growth factor (bFGF) administered intracisternally could prevent this thalamic atrophy. We occluded the left MCA through a small cranial opening, and animals were then divided into two groups. One group received intracisternal injections of recombinant bFGF (1 microgram dissolved in 0.1 ml of saline with 2% rat serum) starting 1 day after occlusion and repeated once a week to a total dose of 4 micrograms by four injections. The other group received vehicle solution by the same schedule. The animals were perfused and fixed at 28 days after occlusion, and histological examination was made at the level of the caudoputamen and thalamus. In the bFGF-treated rats, the area of the posterior ventral thalamus of the occluded side was 93% of that of the contralateral side, i.e., significantly larger than in the normal saline-treated rats (75%, p less than 0.01). The infarction size was not statistically different in the two groups. Microscopic observation indicated that normal-saline-treated animals showed shrinkage and disappearance of thalamic neurons, whereas bFGF-treated groups showed preservation of thalamic neurons. Computerized analysis of the cell size substantiated this observation. To assess the effect of bFGF on astrocytes, bFGF or vehicle solution was injected into normal rats, and their histology was evaluated at 1, 2, and 4 weeks after injection. The bFGF-injected group showed a significant increase in glial fibrillary acidic protein-positive astrocytes in the brain tissue facing the ventriculocisternal system.(ABSTRACT TRUNCATED AT 250 WORDS)  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