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   252872篇
  免费   12118篇
  国内免费   555篇
耳鼻咽喉   3270篇
儿科学   7704篇
妇产科学   5141篇
基础医学   36334篇
口腔科学   5838篇
临床医学   20098篇
内科学   56260篇
皮肤病学   6482篇
神经病学   22458篇
特种医学   7833篇
外国民族医学   108篇
外科学   32272篇
综合类   1039篇
一般理论   66篇
预防医学   22463篇
眼科学   4746篇
药学   17488篇
中国医学   742篇
肿瘤学   15203篇
  2023年   1336篇
  2022年   1051篇
  2021年   3937篇
  2020年   2352篇
  2019年   4336篇
  2018年   7931篇
  2017年   5211篇
  2016年   5284篇
  2015年   5968篇
  2014年   6427篇
  2013年   10115篇
  2012年   17336篇
  2011年   17386篇
  2010年   8826篇
  2009年   6780篇
  2008年   14994篇
  2007年   15916篇
  2006年   14750篇
  2005年   14634篇
  2004年   13695篇
  2003年   12570篇
  2002年   11863篇
  2001年   6296篇
  2000年   6350篇
  1999年   5710篇
  1998年   1141篇
  1997年   955篇
  1996年   876篇
  1995年   790篇
  1992年   3296篇
  1991年   2943篇
  1990年   2808篇
  1989年   2545篇
  1988年   2418篇
  1987年   2236篇
  1986年   2135篇
  1985年   1921篇
  1984年   1436篇
  1983年   1232篇
  1979年   1232篇
  1978年   871篇
  1977年   818篇
  1975年   827篇
  1974年   1001篇
  1973年   1008篇
  1972年   953篇
  1971年   929篇
  1970年   871篇
  1969年   920篇
  1968年   798篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
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   
73.
74.
A retrospective study of 232 bladder tumours with minimum follow-up 5 years is presented. The carcinoma was superficial in 66%, muscle-invasive in 31% and could not be staged in 3%. Primary treatment was mainly transurethral resection for superficial tumour, but was cystectomy or radiotherapy in 22 of 29 T1 G3. Of the superficial tumours, 71% recurred. Progression to higher T stage occurred in 15% of Ta and 29% of T1 tumours, and half of these patients died of bladder cancer. The corrected 5-year survival rates in grades 1, 2A, 2B and 3-4 were 96, 84, 64 and 43%, and in stages Ta, T1, T2 and T3 they were 94, 69, 40 and 31%. All patients with T4 tumour died within 4 years. Among the 45 patients with 40 Gy irradiation + cystectomy, the corrected 5-year survival rate was 83% in superficial and 64% in muscle-invasive tumours, and among the 38 with radical radiotherapy the rates in T1-3 were 46, 36 and 13%. Transurethral resection was successful in most Ta cases. Most T1 tumours were, like T2-4, of higher grade than Ta. Prognosis was worse in T1 than in Ta. After progression to muscle-invasive disease, even during close follow-up the outlook was poor, as poor as for patients with primary muscle-invasive disease.  相似文献   
75.
This study presents the result of 12–21 years' follow-up in a group of children with neonatal urinary tract infection (onset within 1 month after birth) in whom early renal growth retardation was noted without concomitant classical renal scarring. In all cases the neonatal infection was diagnosed and treated within a few days of onset and the patients were closely supervised thereafter. Renal length, parenchymal thickness and area were measured at urography. At first follow-up (22 children, mean age 4.1 years) a significant reduction of renal parenchymal thickness was noted. Long-term follow-up (18 patients, mean age 17 years) demonstrated a normalization of renal size in the entire group, although less complete in the subgroup with reflux. There were two major findings in the present study. Firstly, renal growth retardation was seen after neonatal infection, both with and without reflux. Secondly, normalization of renal size in previously small kidneys was demonstrated, suggesting that growth retardation can be a reversible phenomenon. The tendency for such normalization was slightly more marked in children without reflux. Reduction of parenchymal thickness without calyceal deformity, therefore, does not necessarily mean irreversible damage, and differentiation between permanent scarring and temporary growth retardation can thus only be made at later follow-up, possibly not until after puberty. The demonstration of renal growth retardation in spite of early diagnosis and treatment emphasizes the great vulnerability of the kidney in the newborn.  相似文献   
76.
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   
77.
In open chest dogs myocardial ischemia was induced by formation of an occlusive thrombus in the left anterior circumflex artery (LCX). Reperfusion of the LCX was achieved by infusion of the fibrin specific recombinant single-chain urokinase-type plasminogen activator (r-scu-PA). The myocardial salvage by r-scu-PA alone and in combination with the epoprostenol (prostacyclin) analog taprostene (CG 4203) was compared. There were four experimental groups: group 1 (n = 4) did not receive any treatment after LCX thrombosis; in group 2 (n = 9) at 100 min after LCX thrombosis r-scu-PA (20 micrograms.kg-1.min-1 i.v. for 30 min) was infused; in groups 3 and 4 treatment with taprostene started concomitantly with r-scu-PA infusion. The taprostene infusions lasted for 120 min and the doses were 0.1 microgram.kg-1.min-1 in group 3 (n = 6) and 0.215 microgram.kg-1.min-1 in group 4 (n = 6). Time to r-scu-PA-induced recanalisation ranged from 18-22 min with no significant difference between groups 2-4. Percent of left ventricle at risk did not differ between the groups. Infarct size as percent of the risk zone was 48.3 +/- 7.7 in group 1, 25.3 +/- 3.7 in group 2, 21.3 +/- 6.5 in group 3 and 17.1 +/- 3.5 in group 4 (p less than 0.05 groups 2-4 vs group 1). Incidence of ectopic beats increased after r-scu-PA-induced reperfusion in groups 2-4, but was significantly reduced by taprostene.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
78.
79.
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   
80.
Compromise of immune function in obstructive jaundice.   总被引:5,自引:0,他引:5  
  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