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   248805篇
  免费   12079篇
  国内免费   429篇
耳鼻咽喉   3317篇
儿科学   7730篇
妇产科学   5033篇
基础医学   35611篇
口腔科学   5615篇
临床医学   19882篇
内科学   54527篇
皮肤病学   6955篇
神经病学   22313篇
特种医学   7676篇
外国民族医学   103篇
外科学   31401篇
综合类   1185篇
一般理论   63篇
预防医学   22350篇
眼科学   4824篇
药学   17336篇
中国医学   722篇
肿瘤学   14670篇
  2023年   1291篇
  2022年   961篇
  2021年   3656篇
  2020年   2190篇
  2019年   4052篇
  2018年   7702篇
  2017年   5071篇
  2016年   5148篇
  2015年   5698篇
  2014年   6037篇
  2013年   9707篇
  2012年   16700篇
  2011年   16697篇
  2010年   8372篇
  2009年   6319篇
  2008年   14290篇
  2007年   15340篇
  2006年   14187篇
  2005年   14018篇
  2004年   13175篇
  2003年   12065篇
  2002年   11443篇
  2001年   6684篇
  2000年   6729篇
  1999年   6036篇
  1998年   1065篇
  1997年   871篇
  1996年   803篇
  1995年   756篇
  1992年   3440篇
  1991年   3147篇
  1990年   2967篇
  1989年   2722篇
  1988年   2561篇
  1987年   2396篇
  1986年   2287篇
  1985年   2090篇
  1984年   1531篇
  1983年   1323篇
  1979年   1338篇
  1978年   942篇
  1977年   885篇
  1975年   913篇
  1974年   1099篇
  1973年   1095篇
  1972年   1044篇
  1971年   1018篇
  1970年   937篇
  1969年   985篇
  1968年   876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