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   1489835篇
  免费   112401篇
  国内免费   17306篇
耳鼻咽喉   20037篇
儿科学   44382篇
妇产科学   40699篇
基础医学   212539篇
口腔科学   38941篇
临床医学   138332篇
内科学   282916篇
皮肤病学   28618篇
神经病学   111072篇
特种医学   57995篇
外国民族医学   504篇
外科学   218510篇
综合类   61516篇
现状与发展   56篇
一般理论   319篇
预防医学   105420篇
眼科学   35570篇
药学   119873篇
  195篇
中国医学   14812篇
肿瘤学   87236篇
  2021年   18839篇
  2020年   13300篇
  2019年   15511篇
  2018年   19696篇
  2017年   15869篇
  2016年   16565篇
  2015年   21680篇
  2014年   28309篇
  2013年   34777篇
  2012年   49150篇
  2011年   53478篇
  2010年   31532篇
  2009年   28017篇
  2008年   45776篇
  2007年   48699篇
  2006年   49409篇
  2005年   48866篇
  2004年   43157篇
  2003年   41804篇
  2002年   40258篇
  2001年   62572篇
  2000年   64476篇
  1999年   56006篇
  1998年   17637篇
  1997年   16208篇
  1996年   15832篇
  1995年   14897篇
  1994年   13846篇
  1992年   42688篇
  1991年   41814篇
  1990年   41036篇
  1989年   39670篇
  1988年   37019篇
  1987年   36129篇
  1986年   34357篇
  1985年   32586篇
  1984年   24196篇
  1983年   21017篇
  1982年   12498篇
  1979年   22760篇
  1978年   15921篇
  1977年   13773篇
  1976年   12997篇
  1975年   14248篇
  1974年   16730篇
  1973年   16113篇
  1972年   15361篇
  1971年   14255篇
  1970年   13230篇
  1969年   12753篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
M A Levison  D D Thomas  R G Wiencek  R F Wilson 《The Journal of trauma》1990,30(3):247-51; discussion 251-3
The records of 239 patients surviving more than 24 hours with full-thickness intraperitoneal colonic injuries over a 7-year period were reviewed. During the first 3 years, 29% (31/106) of the patients were managed by primary repair without colostomy. In the next 4 years, almost twice as many patients, 56% (75/133), with similar colonic trauma were treated without fecal diversion (p less than 0.05). Although there was no difference in the mean Trauma Score in the patients with primary repair in the two time periods, the Injury Severity Score (mean +/- sd) in the patients without colostomy in the later periods was significantly higher (17.8 +/- 2.1 vs. 20.2 +/- 5.1) (p less than 0.001). No patient suffered because of the increased incidence of primary repairs. These patients had five abdominal abscesses and only one leak, whereas the patients with colostomy had 15 intraperitoneal abscesses. Because of the safety when primary repair is performed, more liberal use of primary colonic repair following penetrating trauma is warranted.  相似文献   
992.
993.
Total parenteral nutrition is now a broadly used method whose efficacy is confirmed, even if it is still not free from risk of complications. The Authors report their own clinical experience on 130 cases in the period 1981-1988. Complications were registered in 4.6% of the observed cases. They underline the problems relating to this subject.  相似文献   
994.
Arthroscopy     
I G Stother 《Injury》1990,21(5):283-286
  相似文献   
995.
In order to clarify the physiological role in vivo of H2O2-detoxifying enzymes at low and high levels of O2 tension we studied catalase (CAT), glutathione peroxidases (GP), and in vivo peroxidation (TBA-RS) in the lung and heart of Rana perezi frogs chronically treated with hyperoxia, aminotriazole (AT) -a CAT inhibitor-, or both. Hyperoxia did not change CAT, GP or TBA-RS. Aminotriazole caused an almost complete depletion of CAT, a 30% decrease of GP and a 132% (lung) to 200% (heart) increase of TBA-RS. Changes similar to these were found in the group treated with AT in hyperoxia. No mortality or changes in total or organ weight occurred in the experimental groups. Main conclusions are: (1) The maximal hyperoxia tolerance showed by frogs among vertebrates does not need antioxidant enzyme induction from lung or heart and is probably related to the presence of high constitutive levels of GP in relation to metabolic rate. (2) Even in normoxia the tissues present significant amounts of H2O2, and CAT is needed to avoid oxidative damage. GP does not compensate its absence. The implications of these results in relation to oxygen toxicity in man is discussed.  相似文献   
996.
Cloacal exstrophy, centered on the maldevelopment of the primitive streak mesoderm and cloacal membrane, results in bladder and intestinal exstrophy, omphalocele, gender confusion, and hindgut deformity. The surgical management and outcome of 10 of 14 survivors (1965 to 1988) are described. Genotypic males (6) were assigned male (2) or female (4) phenotype. Genotypic females (4) were unchanged. All had omphalocele closure in the newborn period. Two had loop stomas. Eight had end stomas (ileostomy [6], ileocolostomy [2]). Toddler and adolescent reconstruction differed in each. Early in the study, abdominoperineal pull-through failed in four patients, necessitating permanent stoma. Four patients had a stoma from the outset. Augmentation using colon remnant improved water loss and nutrition in two infants. Exstrophy turn-in for urinary reservoir was considered in all, but was impossible in three who required urinary diversion. Six patients had exstrophy turn-in and now void by clean intermittent catheterization (4), continent vesicostomy (1), and incontinent (1). Hindgut augmentation improved urinary capacity in two. Two genotypic-phenotypic males had penile lengthening. Four genotypic male-phenotypic females had early orchiectomy with subsequent clitoroplasty or vaginoplasty. Four genotypic-phenotypic females had clitoroplasty or vaginoplasty. Cloacal exstrophy is compatible with a useful life and sound psychologic development, but requires staged reconstruction with long-term support and follow-up.  相似文献   
997.
998.
999.
There are conflicting reports on the relationship between cerebellar vermal lobule hypoplasia and autism. Using quantitative magnetic resonance image analysis, we measured the cerebellar vermis in 125 normal individuals with a broad age range and 102 patients with a variety of neurogenetic abnormalities. We conclude that hypoplasia of cerebellar vermal lobules VI and VII is a nonspecific finding that even occurs in several conditions without autistic behavior. This suggests that it is not a specific neuroanatomical marker for autism, nor is cerebellar dys- genesis likely to be solely responsible for clinical autistic behaviors.  相似文献   
1000.
The synthesis of nerve growth factor (NGF) by the hippocampus raises the possibility that NGF may play a role in the regulation of the hypothalamic-pituitary-adrenal axis (HPAA). Subchronic cold stress has been shown to activate the HPAA in a mild noninvasive manner, to stimulate serum glucocorticoid levels, and to perturb NGF binding in hippocampus and basal forebrain. One or repeated episodes of cold stress increased NGF mRNA levels in the hippocampus and p75NGFR mRNA levels in the basal forebrain. These changes were not due to elevated serum glucocorticoid levels since treatment with exogenous corticosterone had no effect on NGF and p75NGFR mRNA levels. Adrenalectomy did not prevent the stress induced increases in NGF and p75NGFR mRNA. © 1993 Wiley-Liss, Inc.  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