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   10534篇
  免费   962篇
  国内免费   8篇
耳鼻咽喉   80篇
儿科学   244篇
妇产科学   282篇
基础医学   1537篇
口腔科学   262篇
临床医学   1207篇
内科学   2421篇
皮肤病学   83篇
神经病学   813篇
特种医学   393篇
外科学   1291篇
综合类   179篇
一般理论   6篇
预防医学   1296篇
眼科学   110篇
药学   735篇
中国医学   4篇
肿瘤学   561篇
  2021年   150篇
  2020年   92篇
  2019年   145篇
  2018年   164篇
  2017年   102篇
  2016年   158篇
  2015年   146篇
  2014年   265篇
  2013年   330篇
  2012年   460篇
  2011年   533篇
  2010年   295篇
  2009年   239篇
  2008年   510篇
  2007年   462篇
  2006年   460篇
  2005年   436篇
  2004年   370篇
  2003年   353篇
  2002年   345篇
  2001年   321篇
  2000年   319篇
  1999年   293篇
  1998年   122篇
  1997年   98篇
  1996年   114篇
  1995年   91篇
  1994年   74篇
  1992年   269篇
  1991年   247篇
  1990年   242篇
  1989年   224篇
  1988年   219篇
  1987年   189篇
  1986年   219篇
  1985年   193篇
  1984年   186篇
  1983年   175篇
  1982年   119篇
  1981年   101篇
  1980年   83篇
  1979年   158篇
  1978年   119篇
  1977年   105篇
  1976年   87篇
  1975年   78篇
  1974年   110篇
  1973年   105篇
  1972年   87篇
  1968年   88篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Summary Eight patients with malignant gliomas verified on CT scan, received an intravenous injection of 50 mg of Adriamycin R, 24 hours prior to surgical removal of the tumour. Peroperatively, both tumour and surrounding tissue specimens were obtained for determination of the tissue concentrations of Adriamycin and its reduced metabolite Adriamycinol. It was found that Adriamycin could be detected in tumour tissue from all patients. The concentration varied between 0,9 and 4,6 nmol/g tissue. In contrast, Adriamycin could only be detected in surrounding brain tissue from one patient.In anin vitro study a human malignant glioma cell line (U-251 MG) was exposed to various concentrations of Adriamycin for 24 hours. It was found that an intracellular drug concentration above 30 nmol/g cells caused a concentration dependent inhibition of cell growth. Thus, it is likely that the poor effect of Adriamycin on patients with malignant gliomas is due to an ineffective drug accumulation in the tumour tissue.  相似文献   
3.
4.
OBJECTIVE: To determine whether the use of dimenhydrinate was associated with delay in the diagnosis and management of treatable illnesses or with direct adverse effects in children with vomiting presenting to an emergency department. DESIGN: Questionnaire survey and review of drug reaction and telephone inquiry records. SETTING: The emergency department of a tertiary care children's hospital and a provincial poison information centre. PATIENTS: The parents of 148 children who presented with vomiting completed the questionnaire. The database at the poison information centre included 474 reports of adverse drug reactions over an 8-year period and 105 reports of telephone inquiries over a 4-year period. MAIN RESULTS: Twenty-one (14%) of 148 children had received dimenhydrinate before arrival at the emergency department. The patients who had received dimenhydrinate were more likely than the others to present more than 12 hours after the onset of vomiting (14 [67%] of 21 v. 43 [34%] of 127, p less than 0.01). The discharge diagnoses for those who had received dimenhydrinate included asthma, pelvic inflammatory disease and urinary tract infection. No clinically important direct adverse reactions to dimenhydrinate were documented. CONCLUSIONS: The use of dimenhydrinate in children with vomiting is associated with a risk of delay in the diagnosis of treatable medical conditions.  相似文献   
5.
6.
The thesis of this article is that deficits in language and communication contribute to behavior problems in childhood. Mentally retarded children show a range of deficits in language and communication compared with normals; they are also at increased risk for behavior problems. The evidence suggests that these deficits are quantitative rather than qualitative. In addition, these linguistic deficits may contribute independently to the development of behavior disorders insofar as the linguistic deficit interferes with the child's ability to make himself understood or to understand others.  相似文献   
7.
This study evaluates the glycine potentiation of anticonvulsant drugs in subcutaneous pentylenetetrazol seizures in rats. Administered alone, glycine (30 or 40 mM/kg, PO) induced no anticonvulsant effect or neurological deficit. Coadministered with anticonvulsants, glycine significantly enhanced the anticonvulsant potency of diazepam and sodium valproate without affecting the neurological deficit induced by the anticonvulsants. Glycine did not significantly alter the anticonvulsant activity of ethosuximide or phenobarbital. These findings indicate a possible glycine-sensitive component in the mechanism of action of diazepam and sodium divalproate in subcutaneous pentylenetetrazol seizures. With the possible exception of sodium valproate, the present study provides little support for a glycine and gamma-aminobutyric acid (GABA) interaction as a mechanism of anticonvulsant activity in SC PTZ seizures. Further studies are required to determine the role of strychnine-sensitive and strychnine-insensitive glycine receptors in this experimental model of absence epilepsy.  相似文献   
8.
Islet transplants for large numbers of patients with diabetes will require xenografts. Microencapsulation is an appealing method for islet xenografting. However, graft function has been limited by a cellular reaction, particularly intense in spontaneously diabetic, NOD mice. The purpose of this study was to elucidate the mechanism of this reaction. Poly-1-lysine-alginate microcapsules containing 4000-12,000 dog or 1800-2000 rat islets were xenografted intraperitoneally into streptozotocin (SZN)-diabetic C57BL/6J and NOD mice, with or without recipient treatment with GK 1.5 (anti-CD4 monoclonal antibody) (20-30 microliters i.p. every 5 days, begun on day -7. Grafts were considered technically successful if random blood glucose (BG) was normalized (less than 150 mg/dl) within 36 hr. Graft failure was defined as BG greater than 250 mg/dl. Dog and rat islets in microcapsules normalized BG in both SZN and NOD mice within 24 hr routinely. Empty microcapsules and GK 1.5 treatments alone did not affect BG. NODs destroyed both microencapsulated dog and rat islets more rapidly than did SZN-diabetic mice (P less than .01). Graft biopsies showed an intense cellular reaction, composed of lymphocytes, macrophages and giant cells, and no viable islets. GK 1.5 treatment significantly prolonged both dog-to-NOD and rat-to-NOD grafts (P less than 0.01). Biopsies of long-term functioning grafts (on days 65-85) demonstrated viable islets and no cellular reaction around microcapsules; 1/4 rat and 1/8 dog islet xenografts continued to function indefinitely in NOD recipients, even after cessation of GK 1.5 therapy. Prediabetic NODs receiving encapsulated dog or rat islets mounted a moderate cellular reaction to grafts. Empty microcapsules excited no cellular reaction in diabetic or prediabetic NODs. We conclude that the NOD reaction to microencapsulated xenogeneic islets is helper T cell-dependent, and that the target of this reaction is not the microcapsule itself, but the donor cells within.  相似文献   
9.
H A Peterson 《Orthopedics》1992,15(7):799-808
Physeal injuries of the distal humerus comprise approximately 10% of all physeal injuries. Diagnosis of these injuries at a young age before the ossification centers have ossified and become visible radiographically is difficult. Poor outcome of distal humeral physeal injuries is not uncommon and can be best prevented by knowledge of anatomy and the use of all appropriate imaging techniques. The focus of this article is to correlate anatomy at different ages with the occurrence of specific injuries.  相似文献   
10.
Nonvoluntary sexual activity among adolescents   总被引:3,自引:0,他引:3  
Data from the 1987 round of the National Survey of Children indicate that seven percent of Americans aged 18-22 have experienced at least one episode of nonvoluntary sexual intercourse. Women were more likely than men to report having had such an experience, with just under half of all nonvoluntary experiences among women occurring before the age of 14. Multiple classification analysis reveals that white women who had lived apart from their parents before age 16, those who had been brought up in poverty, those who had had a physical, emotional or mental limitation when they were young, those whose parents had been heavy drinkers, those whose parents had used illegal drugs and those whose parents had smoked cigarettes when they themselves were teenagers were at significantly greater risk for experiencing sexual abuse. Six percent of young white women with no risk factors, nine percent of those with one, 26 percent of those with two, and 68 percent of those with three or more had been sexually abused before or during adolescence.  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