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   50097篇
  免费   3726篇
  国内免费   121篇
耳鼻咽喉   405篇
儿科学   2127篇
妇产科学   1477篇
基础医学   6576篇
口腔科学   553篇
临床医学   6721篇
内科学   9378篇
皮肤病学   783篇
神经病学   4915篇
特种医学   1089篇
外国民族医学   38篇
外科学   4785篇
综合类   517篇
一般理论   99篇
预防医学   7263篇
眼科学   688篇
药学   2677篇
中国医学   108篇
肿瘤学   3745篇
  2024年   77篇
  2023年   503篇
  2022年   740篇
  2021年   1562篇
  2020年   934篇
  2019年   1486篇
  2018年   1720篇
  2017年   1251篇
  2016年   1326篇
  2015年   1408篇
  2014年   1945篇
  2013年   2843篇
  2012年   4024篇
  2011年   4160篇
  2010年   2212篇
  2009年   1909篇
  2008年   3440篇
  2007年   3400篇
  2006年   3133篇
  2005年   3064篇
  2004年   2768篇
  2003年   2466篇
  2002年   2318篇
  2001年   334篇
  2000年   215篇
  1999年   328篇
  1998年   459篇
  1997年   347篇
  1996年   294篇
  1995年   304篇
  1994年   260篇
  1993年   231篇
  1992年   139篇
  1991年   145篇
  1990年   125篇
  1989年   112篇
  1988年   121篇
  1987年   79篇
  1986年   103篇
  1985年   111篇
  1984年   119篇
  1983年   105篇
  1982年   123篇
  1981年   158篇
  1980年   106篇
  1979年   65篇
  1978年   59篇
  1977年   60篇
  1976年   59篇
  1974年   56篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
It is well established that the circadian clock of the suprachiasmatic nuclei (SCN) is entrained by light. More recently, the potent effects of arousing, non-photic cues on the clock have been recognized. The neural mediators of non-photic entrainment are yet to be identified. To examine the contribution of the thalamic intergeniculate leaflet (IGL) and its NPY-immunopositive projection, the geniculo-hypothalamic tract to non-photic entrainment by arousal, male Syrian hamsters received lesions of the IGL (IGLX) which ablated NPY-immunoreactivity in the SCN. Their circadian responses to both photic and non-photic cues were then tested. Lesions resulted in a delay in the timing of activity onset following lights out, but had no effect on the behavioural or cellular circadian responses to phase-advancing light pulses presented at circadian time (CT) CT19 (where CT12 represents the time of activity onset). Injection with a benzodiazepine (chlordiazepoxide, 100 mg/kg) at CT6 suppressed wheel-running, increased general locomotion of intact controls and induced large phase advances of the circadian rhythm of wheel-running. Chlordiazepoxide also inhibited wheel-running in lesioned animals, but there was no significant increase in general locomotion and the lesioned animals did not phase advance. Serial arousal by injection of saline at intervals of 23.5 h for 6 days entrained the circadian rhythm of wheel-running of intact hamsters and was associated with an increase in general locomotor activity. Entrainment by serial arousal was abolished by IGLX. However, the lesioned animals did show a clear behavioural response to every presentation of the non-photic cue. These results show that the IGL is a necessary component of the neural pathways mediating both arousal- and benzodiazepine-induced non-photic entrainment.  相似文献   
15.
16.
17.
Sera from 43 leprosy patients were tested for antibodies that bound to normal human nerve. Thirty-eight percent showed positive staining as demonstrated by indirect immunofluorescence. Only 1 out of 30 control sera tested displayed similar staining. Western blots of myelin and neural intermediate filament (IF) proteins were tested with patient sera. Two of the anti-neural antibody (ANeAb)-positive leprosy sera bound to the P0 protein of PNS myelin. All 17 ANeAb-positive leprosy sera displayed 2 or more bands in the molecular weight range of Mr 45 000-55 000, when tested against IF proteins. One explanation for these findings is that leprosy patients produce antibodies to intermediate filament (IF) proteins released subsequent to the bacterial invasion of the peripheral nerves. The importance of these autoantibodies in the pathogenesis of leprosy is discussed.  相似文献   
18.
19.
Over 3 years, 972 families participated in an after-school asthma program at their child's school. Parents and children attended concurrent 21/2 -hour workshops. Parents were 74% Latino; 45% non-English speaking, with 77% of children on Medicaid. Asthma symptoms were significantly reduced, from multiple times per week to less than once per week on average. Oral steroid use decreased to one third of baseline use. Hospital days decreased from 11% to 2%; emergency visits decreased 35% to 4%; and school days missed decreased 48% to 20%. This program has now become sustainable with both private and Medicaid insurance coverage.  相似文献   
20.
To estimate the evolution of amyloid in tissue, we studied abdominal fat aspirates of cases with familial amyloidotic polyneuropathy (FAP) longitudinally at regular intervals between 1994 and 2006. In 22 cases (13 carriers and nine patients) not yet transplanted median follow-up was 3.3 years (range 0.4-11.3). We found a significant increase in the amyloid grade of fat tissue from 2+ to 4+ and from 0 to 4+ in two of three subjects with follow-ups of >7 years, after 7 and 11 years, respectively. All other subjects remained negative or did not show a significant change. In 11 liver transplant patients, follow-up with fat aspirate was available with a median duration of 3.1 years (range 1.0-10.1). A comparison was made with cardiac amyloid as judged by the cardiac septum diameter and the serum NT-ProBNP (N-terminal pro-B-type natriuretic peptide) level. No stable increase of amyloid in fat was seen in any patient. A stable decrease of amyloid grade was seen in one patient 5 years after transplantation. In contrast, the cardiac septum diameter increased >or=4 mm in six of the 11 transplant patients. Our study shows the diagnostic utility of a regularly repeated fat aspirate in carriers at risk for the development of ATTR amyloidosis. Evolution of amyloid deposition in fat tissue is very gradual. After liver transplantation, amyloid deposition in fat tissue seems to stabilize and may even decrease in the long term, whereas amyloid deposition in cardiac tissue appears to be progressive.  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