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   3990篇
  免费   241篇
  国内免费   6篇
耳鼻咽喉   9篇
儿科学   153篇
妇产科学   189篇
基础医学   462篇
口腔科学   52篇
临床医学   318篇
内科学   933篇
皮肤病学   20篇
神经病学   618篇
特种医学   207篇
外科学   311篇
综合类   17篇
一般理论   4篇
预防医学   441篇
眼科学   33篇
药学   238篇
肿瘤学   232篇
  2022年   22篇
  2021年   42篇
  2020年   27篇
  2019年   56篇
  2018年   89篇
  2017年   79篇
  2016年   79篇
  2015年   84篇
  2014年   93篇
  2013年   173篇
  2012年   224篇
  2011年   226篇
  2010年   109篇
  2009年   118篇
  2008年   208篇
  2007年   192篇
  2006年   197篇
  2005年   210篇
  2004年   189篇
  2003年   193篇
  2002年   139篇
  2001年   144篇
  2000年   140篇
  1999年   103篇
  1998年   43篇
  1997年   38篇
  1996年   41篇
  1995年   38篇
  1994年   28篇
  1993年   41篇
  1992年   87篇
  1991年   75篇
  1990年   75篇
  1989年   78篇
  1988年   76篇
  1987年   60篇
  1986年   53篇
  1985年   60篇
  1984年   45篇
  1983年   27篇
  1982年   20篇
  1981年   18篇
  1980年   14篇
  1979年   26篇
  1978年   12篇
  1977年   11篇
  1976年   12篇
  1975年   25篇
  1974年   15篇
  1970年   9篇
排序方式: 共有4237条查询结果,搜索用时 0 毫秒
101.
102.
103.
In 1977 Wijngaarden et al. reported a Dutch family with a congenital myopathy characterized by external ophthalmoplegia and a remarkable histological feature, focal loss of cross-striations. A small number of other families with similar clinical and pathological features led to the consideration of this congenital myopathy as a distinct entity. Here we present more than 30 years of follow-up from the Dutch family and report recently identified compound heterozygous mutations in the skeletal muscle ryanodine receptor (RYR1) gene, c.10627-2A>G and p.Arg3539His (c.10616G>A). Focal loss of cross-striations on muscle biopsy is another histopathological feature that should raise the possibility of RYR1 involvement.  相似文献   
104.
Spinal muscular atrophy with respiratory distress type 1 is an autosomal recessive disorder with early respiratory difficulties, distal muscle weakness, and contractures leading to foot deformities as the most striking clinical symptoms. Mutations of the gene encoding the immunoglobulin heavy chain μ-binding protein 2, mapped on chromosome 11q13, are the cause of the disease. We present the clinical and mutational characteristics of ten patients in the Netherlands who showed considerable clinical variability; they carried six novel mutations, including a deletion of exon 2. However, there were no clear phenotype–genotype correlations.  相似文献   
105.
The aim of the present study was to examine the validity of the Bayley-III Low Motor/Vision version, and its suitability for children with motor and/or visual impairment(s). This version contains accommodated items, that is, adaptations to minimize impairment bias, without altering what the test measures. We hypothesized that the accommodations would not affect the item scores of children without impairment, and that children with impairment(s) would benefit from the accommodations. We tested 41 children without impairment and 63 children with impairment with both the standard Bayley-III and the Low Motor/Vision versions, in randomly counterbalanced order. The test administrators filled in an evaluation form. Results showed that the accommodations did not affect the test scores of children without impairment and did improve the test scores of children with impairment on the Cognition scale, while no improvement was found for the other scales. The test administrators indicated that the vast majority of the children with impairment had been able to show their abilities on the test and that the accommodations were beneficial in 29 out of these 52 cases. For some children, the accommodated instrument appeared to be unsuitable because the impairment was too severe. The conclusion is that the accommodations improve the validity of the Bayley-III when used with children with mild to moderate motor and/or visual impairment, especially with regard to the Cognition scale.  相似文献   
106.
Background: Fetal growth restriction (intra-uterine growth restriction [IUGR]) has a considerable impact on perinatal morbidity. Preterm IUGR infants are prone to impaired intestine function. Near-infrared spectroscopy (NIRS) has been used to monitor oxygenation status of the brain and of the intestine.

Patients and methods: We conducted a prospective case–control study at our NICU in 20 preterm infants of whom 10 infants complicated by compared with 10 non-IUGR preterm infants. Splanchnic and cerebral regional oximetry values were measured with NIRS. Three hours of consecutive recordings were performed in the first 24?h of life, T0, and during the transitional period, T1. The cerebral/splanchnic oxygenation ratio, CSOR, (cerebral regional saturations [rScO2]/splanchnic regional saturations [rSsO2]) was also calculated.

Results: Both in the IUGR and the non-IUGR infants, at T0 and T1 monitoring time-points, the rSO2 values were higher in the cerebral district when compared to those of the splanchnic area. Comparison of the NIRS parameters between the IUGR and non-IUGR infants at T0 showed no difference in rScO2, while rSsO2 was significantly lower in the IUGR group. At T1, rScO2 was significantly lower and rSsO2 higher in the IUGR group.

Conclusions: Cerebral/splanchnic vascular adaptation of IUGR infants to the extra-uterine environment is characterized by a postnatal persistence of the brain sparing effect with reperfusion in the transitional period.  相似文献   
107.
BACKGROUND: Anti-Müllerian hormone (AMH) inhibits primordial follicle recruitment in the mouse ovary. We hypothesize that in women AMH signaling also regulates the usage of the primordial follicle pool and hence influences the onset of menopause. Since age at menopause has a strong genetic component, we investigated the role of AMH signaling using a candidate gene approach. METHODS: In two large population-based cohorts of Dutch post-menopausal women (n = 2381 and n = 248), we examined the association between two polymorphisms, one in the AMH gene and one in the AMH type II receptor (AMHR2) gene, and natural age at menopause. RESULTS: The AMH Ile(49)Ser polymorphism (rs10407022) was not associated with age at menopause in either cohort. In the Rotterdam cohort, the AMHR2 -482 A > G polymorphism (rs2002555) was associated with age at menopause in interaction with the number of offspring (P = 0.001). Nulliparous women homozygous for the G-allele entered menopause 2.6 years earlier compared with nulliparous women homozygous for the A-allele (P = 0.005). In the LASA cohort, women with the G/G genotype tended to enter menopause 2.8 years earlier compared with the A/A genotype (P = 0.063). CONCLUSIONS: The observed association of the AMHR2 -482 A > G polymorphism with natural age at menopause suggests a role for AMH signaling in the usage of the primordial follicle pool in women.  相似文献   
108.
109.
110.
Major hallmarks of osteoarthritis (OA) are cartilage degeneration, inflammation and osteophyte formation. COX-2 inhibitors counteract inflammation-related pain, but their prolonged oral use entails the risk for side effects. Local and prolonged administration in biocompatible and degradable drug delivery biomaterials could offer an efficient and safe treatment for the long-term management of OA symptoms. Therefore, we evaluated the disease-modifying effects and the optimal dose of polyesteramide microspheres delivering the COX-2 inhibitor celecoxib in a rat OA model. Four weeks after OA induction by anterior cruciate ligament transection and partial medial meniscectomy, 8-week-old female rats (n?=?6/group) were injected intra-articular with celecoxib-loaded microspheres at three dosages (0.03, 0.23 or 0.39?mg). Unloaded microspheres served as control. During the 16-week follow-up, static weight bearing and plasma celecoxib concentrations were monitored. Post-mortem, micro-computed tomography and knee joint histology determined progression of synovitis, osteophyte formation, subchondral bone changes, and cartilage integrity. Systemic celecoxib levels were below the detection limit 6?days upon delivery. Systemic and local adverse effects were absent. Local delivery of celecoxib reduced the formation of osteophytes, subchondral sclerosis, bone cysts and calcified loose bodies, and reduced synovial inflammation, while cartilage histology was unaffected. Even though the effects on pain could not be evualated directly in the current model, our results suggest the application of celecoxib-loaded microspheres holds promise as novel, safe and effective treatment for inflammation and pain in OA.  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