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   4906篇
  免费   255篇
  国内免费   17篇
耳鼻咽喉   66篇
儿科学   253篇
妇产科学   60篇
基础医学   522篇
口腔科学   248篇
临床医学   220篇
内科学   1023篇
皮肤病学   47篇
神经病学   397篇
特种医学   135篇
外科学   669篇
综合类   127篇
一般理论   1篇
预防医学   237篇
眼科学   398篇
药学   543篇
中国医学   32篇
肿瘤学   200篇
  2023年   26篇
  2022年   107篇
  2021年   178篇
  2020年   71篇
  2019年   96篇
  2018年   165篇
  2017年   114篇
  2016年   154篇
  2015年   142篇
  2014年   195篇
  2013年   225篇
  2012年   369篇
  2011年   280篇
  2010年   215篇
  2009年   163篇
  2008年   261篇
  2007年   241篇
  2006年   246篇
  2005年   192篇
  2004年   157篇
  2003年   153篇
  2002年   142篇
  2001年   57篇
  2000年   72篇
  1999年   83篇
  1998年   42篇
  1997年   29篇
  1996年   31篇
  1995年   19篇
  1993年   25篇
  1992年   63篇
  1991年   86篇
  1990年   45篇
  1989年   73篇
  1988年   61篇
  1987年   65篇
  1986年   62篇
  1985年   37篇
  1984年   29篇
  1983年   20篇
  1982年   18篇
  1979年   33篇
  1978年   19篇
  1977年   28篇
  1975年   19篇
  1974年   39篇
  1973年   35篇
  1972年   27篇
  1971年   22篇
  1966年   20篇
排序方式: 共有5178条查询结果,搜索用时 15 毫秒
1.
We report on a child with several café au lait spots in association with a lumbar lipomeningomyelocele as an apparently new association. Cutaneous markers, the identification of which plays a crucial role in the early diagnosis and management of spinal malformations, can accompany occult spinal dysraphism. Herein we report a case of lumbar lipomeningomyelocele associated with an overlying café au lait spot that served as a marker of occult spinal dysraphism. The patient also had segmental café au lait spots on the face, making the association unique.  相似文献   
2.
3.
4.
5.
6.

Background  

Traumatic perforation of the distal oesophagus due to blunt trauma is a very rare condition and is still associated with a significant morbidity and mortality. This is further exacerbated by delayed diagnosis and management as symptoms and signs are often masked by or ascribed to more common blunt thoracic injuries.  相似文献   
7.
The aqueous extract of the fruits of Terminalia chebula Retz. has been evaluated for its antidiabetic activity in streptozotocin (STZ) induced mild diabetic rats and compared with a known drug, tolbutamide. The oral effective dose (ED) of the extract was observed to be 200 mg/kg body weight, which produced a fall of 55.6% (p<0.01) in the oral glucose tolerance test. Oral administration of ED of aqueous extract of T.chebula (AETC) daily once for two months reduced the elevated blood glucose by 43.2% (p<0.01) and significantly reduced the increase in glycosylated hemoglobin (HbA1c) (p<0.01). The same dose also showed a marked improvement in controlling the elevated blood lipids as well as decreased serum insulin levels in contrast to the untreated diabetic animals. Hepatic and skeletal muscle glycogen content decreased by 75% and 62.9% respectively in diabetic controls, these alterations were partly prevented (34.9% and 21.17%) in AETC treated group when compared to the healthy controls. The in vitro studies with pancreatic islets showed that the insulin release was nearly two times more than that in untreated diabetic animals. The treatment did not have any unfavorable effect on other blood parameters of liver and kidney function tests. LD 50 was found to be above 3 g/kg bw i.e. 15 times of ED, because there were no deaths of animals even at this dose indicating high margin of safety. These findings suggest further investigations for the possible use of the aqueous extract of fruits of T.chebula for the treatment of diabetes.  相似文献   
8.
Previous pharmacological studies with the pituitary gland have suggested that acetylcholine (ACh) might be involved in the regulation of intermediate lobe (IL) function. Whether ACh is endogenous to the IL cells or provided from an extrinsic source is unclear. The present experiments tested the possibility that the endocrine cells of the IL may be a source of ACh by measuring certain cholinergic markers in a primary culture of dissociated porcine cells. The endogenous ACh content was readily measurable in both the freshly dissociated IL cells and in 2- or 4-day primary cultures. Choline acetyltransferase activity was also measurable in the freshly dissociated and cultured IL cells and was reduced by 53% in the presence of a specific inhibitor, napthylvinylpyridine (50 μM). IL cells incubated in the presence of [14C]choline (1 μM) were able to synthesize [14C]ACh and the accumulation of the new ACh was inhibited by hemicholinium-3 (30 μM), a competitive inhibitor of high affinity choline uptake at cholinergic nerve terminals. In conclusion, these results demonstrate that the endocrine cells of the IL are capable of synthesizing and storing ACh.  相似文献   
9.
Background: Ingestion of coins is a common clinical problem in children. Many of the coins are ferromagnetic and can be retrieved with the help of a magnet. We describe the use of a novel endoscopic accessory for removing ferromagnetic coins. Material and methods: Two magnet discs of 1.5 cm diameter were joined to a 200 cm steel wire of 0.75 mm thickness with a terminal 5 cm spring. A Teflon tube (160 cm, 7 F) was used along with this instrument as a sleeve. The use of this accessory was analyzed prospectively in subjects presenting with a history of coin ingestion. The time taken for removal of coins, complications during the procedure and failure rate was noted. Effect of the magnet on cardiac rhythm was also noted during the procedure. Results: A total of 55 children (mean age 5.1 ± 2.3 years) with coin ingestion presented over a period of 1 year. Forty‐four coins were ferromagnetic. All ferromagnetic coins were removed successfully. Mean time for removal was 68 ± 22 s. No complications were encountered. Conclusion: The novel magnetic instrument is precise, safe and quick for the removal of ferromagnetic coins under direct vision.  相似文献   
10.
Supragaleal placement of tissue expander for management of alopecia of scalp excludes tough galeal layer so that easier and faster expansion of scalp may be achieved.  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