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   8299篇
  免费   826篇
  国内免费   11篇
耳鼻咽喉   55篇
儿科学   144篇
妇产科学   160篇
基础医学   1233篇
口腔科学   203篇
临床医学   945篇
内科学   1713篇
皮肤病学   71篇
神经病学   961篇
特种医学   461篇
外科学   983篇
综合类   178篇
一般理论   2篇
预防医学   829篇
眼科学   265篇
药学   513篇
中国医学   7篇
肿瘤学   413篇
  2021年   129篇
  2020年   79篇
  2019年   136篇
  2018年   131篇
  2017年   109篇
  2016年   104篇
  2015年   123篇
  2014年   182篇
  2013年   275篇
  2012年   439篇
  2011年   390篇
  2010年   234篇
  2009年   208篇
  2008年   357篇
  2007年   356篇
  2006年   367篇
  2005年   322篇
  2004年   328篇
  2003年   264篇
  2002年   314篇
  2001年   255篇
  2000年   206篇
  1999年   197篇
  1998年   110篇
  1997年   99篇
  1996年   110篇
  1995年   92篇
  1994年   86篇
  1993年   76篇
  1992年   215篇
  1991年   186篇
  1990年   181篇
  1989年   201篇
  1988年   183篇
  1987年   165篇
  1986年   155篇
  1985年   167篇
  1984年   135篇
  1983年   120篇
  1982年   79篇
  1980年   73篇
  1979年   110篇
  1978年   88篇
  1977年   87篇
  1976年   65篇
  1975年   79篇
  1974年   85篇
  1973年   78篇
  1972年   72篇
  1970年   69篇
排序方式: 共有9136条查询结果,搜索用时 0 毫秒
21.
22.
A patient with a surgically proven intracanalicular arachnoid cyst was studied using computed tomography, magnetic resonance imaging, and air CT cisternography. The lesion had a similar radiographic appearance to acoustic neuroma and therefore, although rare, must be considered in the differential diagnosis of intracanalicular mass lesions. We report a case in which examination was performed, in evaluating the lesion, utilizing high-resolution air CT cisternography and magnetic resonance imaging (MRI).  相似文献   
23.
The opioid transmitters enkephalin and dynorphin are known to regulate pallidal output and consequently cortical excitability. Indeed, abnormal basal ganglia opioid transmission has been reported in several involuntary movement disorders, including levodopa-induced dyskinesias in Parkinson's disease (PD), tardive dyskinesias/dystonia, Huntington's disease, and Tourette's syndrome. Moreover, a previous 11C-diprenorphine PET study investigating levodopa-induced dyskinesias found reduced opioid receptor availability in PD with but not without dyskinesias. We wished to investigate if a similar alteration in basal ganglia opioid binding was present in DYT1 primary torsion dystonia (PTD). Regional cerebral 11C-diprenorphine binding was investigated in 7 manifesting carriers of the DYT1 gene and 15 age-matched normal controls using a region-of-interest (ROI) approach and statistical parametric mapping (SPM). No difference in regional mean 11C-diprenorphine binding was found between DYT1-PTD and controls, and no correlation between the severity of dystonia and opioid binding was seen. We conclude that aberrant opioid transmission is unlikely to be present in DYT1-PTD and altered opioid transmission is not a common mechanism underlying all disorders of involuntary movement.  相似文献   
24.
Selachyl alcohol (SA) is a mono-oleyl glyceryl ether. It has certain biologic activities similar to those of the antihypertensive neutral renomedullary lipid (ANRL) derived from the renal papilla and its renomedullary interstitial cells (RIC). These include a vaso-depressor effect following bolus injection and a requirement for hepatic activation for the development of biological activity. In view of this similarity to ANRL, it appeared worthwhile to test the antihypertensive action of SA when given via the GI tract. Accordingly, pure SA was given either by gavage or by tube into the stomach or duodenum of one-kidney, one-clip hypertensive rats (5-10 mg per dose). The role of hepatic activation was demonstrated by comparing the BP response to bolus injection of SA and ANRL with and without the presence of an intact circulation to the liver. Administration of SA via the GI tract resulted in a significant decline in BP without tachycardia or weight loss. In the absence of a circulation to the liver, neither SA nor ANRL was active. SA appears to be an effective antihypertensive agent when given via the GI tract.  相似文献   
25.
Studies were made comparing the corneal endothelium of bisected human corneas; one half of each was mechanically agitated in McCarey-Kaufman (M-K) medium, while the other half remained static in M-K medium for an equal period of time. Scanning electron microscopic (SEM) analysis of the corneal endothelium suggested that the endothelium of the corneas undergoing agitation does not show deterioration in morphology when compared with the non-agitated group. This finding is significant as donor corneas are now being transported in greater numbers.  相似文献   
26.
A 53-year-old Caucasian male underwent laparoscopic total extraperitoneal repair of a right indirect inguinal hernia. Postoperatively, the patient developed right testicular swelling and pain that increased over the course of a week. On examination, the patient was found to have a tender, swollen, high-riding testicle, and testicular torsion was of main concern. Doppler sonography and testicular scan suggested an infarction only to the upper pole of the right testicle. Subsequent exploration of the right testicle revealed a hydrocele and focal ischemia to the upper pole of the right testicle. Intraoperative Doppler study and a urology consultation were obtained with an initial impression of possible intermittent torsion. This report describes a rare complication seen in laparoscopic inguinal hernia repairs.  相似文献   
27.
Placental p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) concentration and cord blood atopic markers were determined in 19 neonates. Increased placental p,p'-DDE was associated with a statistically significant increase in cord plasma interleukin (IL)-13. Furthermore, both cord plasma IL-4/interferon (IFN)-gamma and IL-13/IFN-gamma ratios were significantly positively associated with placental p,p'-DDE concentration.  相似文献   
28.
Historically, tracheostomy has been used for infants with airway obstruction caused by congenital or acquired subglottic stenosis. Postoperative morbidity and mortality with this provisional operation led Cotton, in 1980, to substitute anterior cricoid split as the primary definitive procedure. Within the past three years, anterior cricoid split has been performed in 4 infants, aged 3 to 9 months, with acquired (3 patients) or congenital (1 patient) subglottic stenosis requiring ventilation through an endotracheal tube. Following cricoid split, the trachea is stented for 12 to 14 days by a nasotracheal tube, with extubation and rigid bronchoscopy in the operating room with the patient under anesthesia to confirm healing and patency. During an 18- to 24-month follow-up in these 4 patients, morbidity has been minimal, patency has persisted, and stridor has not recurred. Accordingly, a conclusive operation, cricoid split, rather than a temporizing tracheostomy may be employed for certain obstructive tracheal lesions early in life.  相似文献   
29.
30.
We report a patient with alcohol-induced necrotizing pancreatitis who developed a severe ileus followed by incarceration of a portion of the transverse colon within a ventral hernia. Laparotomy 9 days after the onset of symptoms revealed infarction of the transverse colon and infection of the pancreas. This is the first report of a case of acute pancreatitis that led to a strangulated ventral hernia of the colon. We believe that the enteric organisms that infected the pancreas originated in the incarcerated transverse colon.  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