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   2468篇
  免费   142篇
  国内免费   17篇
耳鼻咽喉   32篇
儿科学   108篇
妇产科学   110篇
基础医学   234篇
口腔科学   90篇
临床医学   234篇
内科学   522篇
皮肤病学   60篇
神经病学   206篇
特种医学   51篇
外科学   339篇
综合类   17篇
一般理论   3篇
预防医学   301篇
眼科学   59篇
药学   138篇
中国医学   3篇
肿瘤学   120篇
  2023年   15篇
  2022年   49篇
  2021年   69篇
  2020年   39篇
  2019年   71篇
  2018年   76篇
  2017年   53篇
  2016年   74篇
  2015年   89篇
  2014年   101篇
  2013年   133篇
  2012年   185篇
  2011年   192篇
  2010年   110篇
  2009年   106篇
  2008年   179篇
  2007年   167篇
  2006年   152篇
  2005年   144篇
  2004年   153篇
  2003年   90篇
  2002年   108篇
  2001年   51篇
  2000年   38篇
  1999年   27篇
  1998年   10篇
  1997年   11篇
  1996年   5篇
  1995年   5篇
  1994年   5篇
  1993年   4篇
  1992年   9篇
  1991年   15篇
  1990年   9篇
  1989年   7篇
  1988年   6篇
  1987年   8篇
  1986年   8篇
  1985年   5篇
  1983年   7篇
  1979年   4篇
  1978年   2篇
  1977年   2篇
  1975年   4篇
  1974年   4篇
  1973年   2篇
  1972年   2篇
  1971年   11篇
  1969年   5篇
  1968年   2篇
排序方式: 共有2627条查询结果,搜索用时 218 毫秒
11.
Our aim was to study the associations between maternal vitamin C and iron intake during pregnancy and the offspring’s risk of developing islet autoimmunity and type 1 diabetes. The study was a part of the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) prospective birth cohort including children genetically at risk of type 1 diabetes born between 1997–2004. The diets of 4879 mothers in late pregnancy were assessed with a validated food frequency questionnaire. The outcomes were islet autoimmunity and type 1 diabetes. Cox proportional hazards regression analysis adjusted for energy, family history of diabetes, human leukocyte antigen (HLA) genotype and sex was used for statistical analyses. Total intake of vitamin C or iron from food and supplements was not associated with the risk of islet autoimmunity (vitamin C: HR 0.91: 95% CI (0.80, 1.03), iron: 0.98 (0.87, 1.10)) or type 1 diabetes (vitamin C: 1.01 (0.87, 1.17), iron: 0.92 (0.78, 1.08)), neither was the use of vitamin C or iron supplements associated with the outcomes. In conclusion, no association was found between maternal vitamin C or iron intake during pregnancy and the risk of islet autoimmunity or type 1 diabetes in the offspring.  相似文献   
12.
Neurosurgical Review - “Benign” metastatic leiomyomas (BML) are indolently growing metastatic tumors which mostly associate with uterine leiomyomas in women in reproductive ages. The...  相似文献   
13.
14.
Neuromagnetic responses were recorded with a 24 SQUID magnetometer in two oddball experiments to determine whether mismatch responses to changes in single stimulus features are additive. In experiment 1, the one feature deviants differed from standards in interstimulus interval (ISI) or frequency, and the two feature deviants in both ISI and frequence. In experiment 2, deviants differed in duration, frequency, or both. All deviants evoked a mismatch field (MMF) with sources close to each other in the supratemporal auditory cortex. Except for the ISI deviants, the MMF sources were about 1 cm anterior to the source of the 100ms response, N100m, to the standards. In the two experiments, MMFs obtained in response to the two feature deviants resembled closely the sum of MMFs in response to one feature deviants. The results suggest that the standards leave a multiple neuronal representation in the human auditory cortex. The particular neuronal traces of the representation react independently to changes in different features of sound stimuli.  相似文献   
15.
Serotonin transporter (5-HTT), a transmembrane protein, has been shown in adult brain to be distributed not only on synaptic terminals but to a great extent on axons as well. Here we report the ontogeny of 5-HTT and its relationship with serotonin (5-HT) neurons using established 5-HTT and 5-HT antibodies. Both 5-HTT- and 5-HT-immunostaining (-im) appear in 5-HT neurons at embryonic day 12 (E12) in rostral raphe nuclei (RRN). Soon after appearing, 5-HTT-im is highly expressed on axons, similar to adult expression. However, in contrast to adult, 5-HTT-im also outlines the soma-dendrites. Rich 5-HTT-im appears along the entire length of projecting axons, extending to the growth tip. In the next 2 days, intensive 5-HTT-im axons from RRN travel a course preferentially in the floor plate and later, the medial forebrain bundle trajectory. A group of new 5-HT-im neurons and 5-HTT-im axons appear at E13 in caudal raphe nuclei. At E16-18, taking the exact trajectory course of 5-HT axons, 5-HTT-im axons reach ganglionic eminence, olfactory bulb, and cortex and disperse into many brain regions in E18-20. No 5-HTT-im cell bodies were seen in nigral, locus ceruleus, or hypothalamus. However, the transient expression of 5-HTT on non-serotonergic system was seen in cortical and striatal neuroepithelia at E12 and sensory thalamic pathways at P0-P10. Prominent 5-HTT-im fibers in thalamocortical bundles project from sensory thalamic nuclei through reticular nucleus, internal capsule bundle and form barrels in somatosensory cortices. No 5-HTT-im was seen in glia-like cells using currently available antibody. These observations indicate that 5-HTT is: (a) associated preferentially with 5-HT neurons in brainstem, (b) temporally co-expressed with 5-HT in 5-HT neurons, (c) expressed on axons prior to synaptical sites at target neurons, which strongly indicates a volumic (extrasynaptic) transmission, (d) expressed in non-5-HT neurons within a specific window, which may affect the development of the systems "borrowing" the 5-HT. The early appearance of 5-HTT may also endow functionality as well as vulnerabilities of 5-HT, sensory thalamic, and cortical neurons to 5-HTT targeting drugs during pregnancy and after birth.  相似文献   
16.
Climate change would have a range of impacts on human health. Health impacts would be caused by the direct effect of climatic factors on human health, such as heat stress, and possible changes in the frequency and intensity of extreme weather events such as storms, floods and droughts. Impacts on health would also be mediated by the indirect effects of climate change, such as changes in availability of food and water and the distribution of vector‐borne diseases. The majority of health impacts would be adverse and would depend greatly on the vulnerability of populations.  相似文献   
17.
18.
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