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   234798篇
  免费   11129篇
  国内免费   395篇
耳鼻咽喉   3058篇
儿科学   7310篇
妇产科学   4750篇
基础医学   33691篇
口腔科学   5316篇
临床医学   18552篇
内科学   51877篇
皮肤病学   6228篇
神经病学   20955篇
特种医学   7049篇
外国民族医学   102篇
外科学   29123篇
综合类   989篇
一般理论   62篇
预防医学   21280篇
眼科学   4557篇
药学   16637篇
中国医学   703篇
肿瘤学   14083篇
  2023年   1244篇
  2022年   918篇
  2021年   3517篇
  2020年   2081篇
  2019年   3914篇
  2018年   7431篇
  2017年   4878篇
  2016年   4868篇
  2015年   5452篇
  2014年   5762篇
  2013年   9237篇
  2012年   16036篇
  2011年   15967篇
  2010年   7992篇
  2009年   5993篇
  2008年   13757篇
  2007年   14688篇
  2006年   13536篇
  2005年   13396篇
  2004年   12568篇
  2003年   11459篇
  2002年   10846篇
  2001年   6155篇
  2000年   6252篇
  1999年   5560篇
  1998年   906篇
  1997年   744篇
  1996年   714篇
  1992年   3216篇
  1991年   2882篇
  1990年   2751篇
  1989年   2519篇
  1988年   2388篇
  1987年   2213篇
  1986年   2113篇
  1985年   1904篇
  1984年   1405篇
  1983年   1195篇
  1982年   671篇
  1979年   1208篇
  1978年   849篇
  1977年   803篇
  1975年   809篇
  1974年   999篇
  1973年   998篇
  1972年   940篇
  1971年   929篇
  1970年   869篇
  1969年   910篇
  1968年   796篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Intrastriatal transplantation of striatal neuroblasts from human fetuses is a promising approach for treatment of Huntington's disease, on the basis of many experimental animal studies and, most recently, pilot clinical trials. Technically, several issues remain to be resolved (e.g., the precise site of dissection of the fetal tissue; the number and location of the fetal striatal implants; or the use of immunosuppressive therapy), and await larger-scale trials and purposely designed protocols. Further clinical data must also be obtained, and preliminary promising results must be replicated in a patient group large enough to provide conclusive results. It is important to establish (1) the amount of clinical benefit provided to the patient by the grafted cells; (2) the anticipated duration of clinical benefits; and (3) the secondary rate of decline after the benefit of the graft has been overbalanced. Evaluation of these parameters will require very long-term follow-up of the patients involved, over several years after grafting, before the technique can eventually be proposed widely to patients.  相似文献   
22.
The degree of metabolic acidosis at birth has been calculated in cord artery and vein samples from 21 term fetuses with cord artery pH less than 7.20. The aim of the study was to compare base deficit values calculated from either Siggaard-Andersen alignment nomogram (BD blood) or the Acid-Base chart (BD extra cellular fluid, BDecf). BDblood was found to be consistently higher in the cord artery as compared with BDecf, 13.2 +/- 3.5 and 9.9 +/- 2.9 mmol/l (Mean +/- SD), respectively. A significant correlation was found between cord artery PCO2 and BDblood whereas BDecf appeared unaffected by PCO2. In cases with cord entanglement BDecf a-v differences were increased to 3.4 +/- 2.3 mmol/l as compared with the small a-v difference noted in acidotic cases without cord entanglement, 1.1 +/- 1.25 mmol/l. It is speculated that with acutely emerging, intermittent asphyxia due to cord compression, a cord artery and vein difference in metabolic acidosis may exist and where the vein captures the basal level and the artery the acute changes. It is concluded that BDecf in both cord artery and vein add valuable information on the mechanisms behind metabolic acidosis.  相似文献   
23.
24.
25.
26.
We report a prevalence study of the best visual acuity in the affected eye of 100 selected patients with herpetic keratitis seen during a two-year period. Sixty-two patients retained an acuity of 6/9 or better without requiring penetrating keratoplasty (PK). The prevalence of reduced visual acuity severe enough to warrant PK was 33%. Patients requiring PK for whom full clinical records were available suffered a mean of 6.8 episodes of keratitis. In this group of patients the vision of 18 fell from 6/6 to 6/60 over a mean period of 8.5 years. Once visual acuity was permanently reduced to 6/12, 78% of patients proceeded to lose vision to 6/60. Unilateral visual impairment occurs in at least a third of patients with severe herpetic keratitis. Once vision falls permanently to 6/12, the long-term prognosis for vision appears to be poor.  相似文献   
27.
28.
In establishing the liability of optometrists for negligence the courts have applied the same standard of care that is imposed upon other health care professionals, holding that optometrists must employ the minimum degree of skill, care and learning that is ordinarily exhibited by members of the profession who are in good standing. The leading cases establishing this standard have involved glaucoma, retinal detachment, and intraocular tumors. Optometrists have also been held liable under product liability law for injuries caused by ophthalmic lenses, which illustrates the trend toward strict liability. Other cases have involved the doctrine of informed consent.  相似文献   
29.
30.
A 28-year-old male patient diagnosed with Becker muscular dystrophy (BMD)-associated cardiomyopathy was successfully bridged to transplantation with the Cardiowest total artificial heart. Dramatic improvement of muscular functional status occurred following transplantation.  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