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   4955篇
  免费   204篇
  国内免费   18篇
耳鼻咽喉   24篇
儿科学   143篇
妇产科学   113篇
基础医学   750篇
口腔科学   71篇
临床医学   489篇
内科学   944篇
皮肤病学   226篇
神经病学   581篇
特种医学   163篇
外国民族医学   1篇
外科学   378篇
综合类   20篇
现状与发展   1篇
一般理论   1篇
预防医学   520篇
眼科学   77篇
药学   264篇
中国医学   18篇
肿瘤学   393篇
  2024年   39篇
  2023年   45篇
  2022年   91篇
  2021年   162篇
  2020年   108篇
  2019年   149篇
  2018年   156篇
  2017年   106篇
  2016年   145篇
  2015年   140篇
  2014年   219篇
  2013年   266篇
  2012年   387篇
  2011年   391篇
  2010年   231篇
  2009年   205篇
  2008年   293篇
  2007年   291篇
  2006年   315篇
  2005年   299篇
  2004年   262篇
  2003年   226篇
  2002年   184篇
  2001年   36篇
  2000年   34篇
  1999年   31篇
  1998年   37篇
  1997年   27篇
  1996年   30篇
  1995年   24篇
  1994年   17篇
  1993年   12篇
  1992年   13篇
  1991年   10篇
  1990年   17篇
  1989年   16篇
  1988年   15篇
  1987年   18篇
  1986年   9篇
  1985年   16篇
  1984年   11篇
  1983年   7篇
  1981年   8篇
  1975年   7篇
  1974年   5篇
  1973年   6篇
  1972年   4篇
  1971年   5篇
  1968年   4篇
  1963年   5篇
排序方式: 共有5177条查询结果,搜索用时 62 毫秒
11.
2,5-Bis(hydroxymethyl)furan monoacetate (3) and 2,5-bis(hydroxymethyl)furan diacetate (4) were obtained as new natural products from an ethyl acetate extract of the terrestrial Streptomyces sp. isolate GW11/1695. Another Streptomyces isolate, GW21/1313, delivered a dimer (6) and a trimer (7) of (hydroxymethyl)furfural. The latter strain also produced 4-hydroxy-2-(5-(hydroxymethyl)furan-2-ylmethylene)-5-methylfuran-3-one (5), perlolyrin (8), and two new beta-carboline derivatives, 9 and 10. 2,5-Bis(hydroxymethyl)furan diacetate (4) exhibited weak cytotoxic activity against brine shrimp larvae.  相似文献   
12.
13.
Endometriosis is a relatively common condition characterized by implantation and proliferation of endometrial glands outside the uterus affecting 8% to 15% of women. Intestinal involvement is common, reported in 12% to 37% of individuals with the disease. The sites most often affected are the sigmoid colon and rectum (85%), while small bowel involvement is seen less frequently (7%) and usually confined to the distal ileum. The cecum (3.6%) and appendix (3%) are the sites least affected.  相似文献   
14.
15.
A woman who was 41 y of age developed pulmonary edema after massive fungal inhalation at an orange storehouse. A provocation test by exposure in the workplace was positive. Neither immunological studies with fungi isolated nor other clinical and histological examinations showed any evidence of hypersensitivity pneumonitis. This is the first report of a subject with organic dust toxic syndrome who developed pulmonary edema associated with the handling of moldy oranges.  相似文献   
16.
Clinical and animal studies have shown a higher risk of an aggravated course of renal disease in childhood after birth for babies small for gestational age (SGA). In addition relative “supernutrition” and fast weight gain in early infancy seem to support the development of later disease. In a retrospective analysis of 62 cases of idiopathic nephrotic syndrome treated between 1994 and 2004 at a university centre for paediatric nephrology, we related the course of disease to birth weight and to the weight gain in the first 2 years of life. Six children were born SGA (birth weight <−1.5 standard deviation score), and 56 were born as appropriate for gestational age (AGA). In all SGA children renal biopsy was performed, while only 55% of the AGA children underwent renal biopsy (P = 0.07), showing no difference in renal histology. In the SGA group, four of six patients developed steroid resistance (vs 12/56 AGA, P < 0.05). Of the SGA children, 83% needed antihypertensive treatment in the course of the disease compared to 39% of the AGA children (P = 0.07). The extent of weight gain between birth and 24 months of age did not influence the course of disease. In conclusion, we were able to find evidence for an aggravated course of idiopathic nephrotic syndrome in former SGA children. Independently of birth weight, weight gain in the first 2 years of life did not influence the course of disease.  相似文献   
17.

Background  

Selective amygdalohippocampectomy (SAHE) yields 60–80% of patients with medically refractory mesial temporal lobe epilepsy seizure-free and seems to be equally effective compared to the more extended temporal lobe resections. The resection of the entire entorhinal cortex (EC) is of crucial importance to warrant complete seizure control for those patients. Thus, evidence of residual EC could be a predictor of a potentially successful reoperation in patients with recurrent seizures after SAHE. We performed an analysis of preoperative and postoperative magnetic resonance imaging (MRI) in patients who underwent a reoperation after an unsuccessful transsylvian SAHE to assess the presence of residual EC before reoperation and to determine whether certain anatomical variants may dispose patients to incomplete resection of EC.  相似文献   
18.
Chronic wounds are characterized by failure in wound-healing response and a delay in healing or nonclosure of the wounds. This results in a high effort in clinical treatment and/or home care. A major difference between acute wounds and chronic wounds is the imbalance of proteinase inhibitors and proteinase activity that regulates the degradation and regeneration of the extracellular matrix proteins. Collagen and collagen/oxidized regenerated cellulose dressings act as a competitive substrate for matrix metalloproteinase-2, matrix metalloproteinase-9, and bacterial collagenase and influence this imbalance positively. Both wound dressings, approved for chronic wound treatment, the bovine collagen type I sponge and the oxidized regenerated cellulose collagen sponge, did not differ significantly in their sorption profiles for all enzymes. In general, binding was enhanced with a longer incubation time. The density of the device and the accessible surface, which can be controlled by the manufacturing process, are the crucial factors for the efficiency of the wound dressing.  相似文献   
19.
20.
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