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   370259篇
  免费   25035篇
  国内免费   10531篇
耳鼻咽喉   4537篇
儿科学   15409篇
妇产科学   7516篇
基础医学   32859篇
口腔科学   7458篇
临床医学   42574篇
内科学   64197篇
皮肤病学   5648篇
神经病学   23003篇
特种医学   16656篇
外国民族医学   25篇
外科学   47339篇
综合类   41285篇
现状与发展   46篇
预防医学   22960篇
眼科学   7618篇
药学   35370篇
  143篇
中国医学   17002篇
肿瘤学   14180篇
  2023年   4503篇
  2022年   7572篇
  2021年   15618篇
  2020年   11749篇
  2019年   16131篇
  2018年   11217篇
  2017年   10533篇
  2016年   12635篇
  2015年   15200篇
  2014年   28004篇
  2013年   26621篇
  2012年   27291篇
  2011年   25265篇
  2010年   21966篇
  2009年   21376篇
  2008年   19818篇
  2007年   19960篇
  2006年   17177篇
  2005年   12649篇
  2004年   8286篇
  2003年   7383篇
  2002年   5660篇
  2001年   4816篇
  2000年   4151篇
  1999年   3214篇
  1998年   3109篇
  1997年   2860篇
  1996年   2595篇
  1995年   2883篇
  1994年   2595篇
  1993年   2203篇
  1992年   2292篇
  1991年   1983篇
  1990年   1901篇
  1989年   1768篇
  1988年   1695篇
  1987年   1519篇
  1986年   1279篇
  1985年   2349篇
  1984年   2441篇
  1983年   1672篇
  1982年   1888篇
  1981年   1803篇
  1980年   1554篇
  1979年   1326篇
  1978年   1016篇
  1977年   971篇
  1976年   849篇
  1975年   550篇
  1974年   529篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Aortic pathology is always a challenge for the clinician, and must be diagnosed and treated by a multidisciplinary team due to the technical and technological complexity of the resources used. Ongoing efforts to implement a systematic, protocolized approach involving “Aortic teams” made up of cardiologists, cardiac surgeons, vascular surgeons, anaesthesiologists and radiologists, among others are now leading to improved outcomes. The aim of this consensus document drawn up by the Aortic working groups of the Spanish Society of Anaesthesiology, Resuscitation and Pain Therapy (SEDAR) and the Spanish Society of Thoracic and Cardiovascular Surgery (SECTCV) is to disseminate a set of working protocols. The latest consensus document of the European Association for Cardio-Thoracic Surgery (EACTS) and the European Society for Vascular Surgery (ESVS) define the concept of “AORTIC TEAM”(1). The aortic team should be closely involved from diagnosis to treatment and finally follow-up, and should be formed of cardiac and vascular surgeons working together with anaesthesiologists, cardiologists, radiologists and geneticists. Treatment of aortic pathologies should be centralised in large centres, because this is the only way to effectively understand the natural course of the disease, provide the entire range of treatment options under one umbrella and treat potential complications. A streamlined emergent care pathway (24/7 availability), adequate transportation and transfer capabilities, as well as rapid activation of the multidisciplinary team must be available. In light of the complexity and constant evolution of therapeutic options, we present this first version of the Anaesthesiology and surgical guidelines for surgery of the ascending aorta and aortic arch. Some questions will no doubt remain unanswered, and future versions will include new techniques that, though implemented in some centres, are still not widely recommended.  相似文献   
992.
BackgroundThere is evidence that continuity models of midwifery care benefit women and babies in terms of less birth interventions and higher maternal satisfaction. Studies about continuity models in a Swedish context are lacking.ObjectiveThe aim of this study was to describe how women experience continuity of midwifery care in a Swedish rural area, and thereby provide a deeper understanding of what this care entails for women.MethodsA qualitative interview study using thematic analysis was carried out. Telephone interviews were conducted with 33 women who participated in a continuity of midwifery care project in a rural area of Sweden.ResultsThe overarching theme ‘a longing for a sense of security’, pervaded the three main themes: ‘The importance of professional midwifery care’, ‘Continuity of midwifery – fulfilled expectations or full of disappointments’ and ‘New prerequisites – acceptable to some, but not a substitute for everyone’, which explains different aspects affecting the feeling of security. The endeavour to feel secure during pregnancy, birth and postpartum was a continually recurring subject that cannot be overstated.ConclusionContinuity of midwifery care strengthened women’s feelings of security during pregnancy, birth and postpartum. The deepened relationship developed over time was a central part of the positive aspects of the experience of continuity in midwifery care. Expectations and prerequisite circumstances are important to consider when developing and introducing new care models. Service providers and decision makers should pay attention to and prioritise this relational aspect when planning care for women during the childbearing period.  相似文献   
993.
BackgroundBrain iron deficiency (BID), especially for the substantia nigra (SN), without peripheral iron deficiency (ID) has been well documented as a ubiquitous finding for restless legs syndrome (RLS) patients. This close association suggests the biology of RLS BID can produce RLS symptoms. Association, however, cannot establish such a direct relationship. Instead, the BID of RLS could be experimentally produced to determine if it then produces significant RLS-like biological or behavioral features. Forward genetics approach led to identification from the BXD strains the BXD40 females (BXD40f) as a putative animal model for the RLS BID. The BXD40f on an iron-sufficient diet have a lower iron in the VMB (containing the SN) during the active but not inactive period. This was not found for the other BXD strains evaluated. The BXD40f on an ID diet uniquely have even greater reduced VMB but not peripheral iron, matching the RLS BID pathophysiology. A prior report found that the BXD40f on an iron-sufficient diet had an RLS-like behavior of increased activity occurring only in the last part of the active period that was not present in the other strains without the low VMB iron. This increased activity matches the circadian pattern of symptoms in RLS patients with increased urge or drive to move in the last part of the day. This study asks first: if you decrease the VMB iron by an iron deficient diet do the RLS-like behaviors worsen; and second will the dopaminergic treatments effective for RLS also reduce the worsened RLSlike behaviors.MethodsIn sum, 13 BXD40f mice post weaning were randomly assigned for 100 days to either a iron-sufficient diet (n = 6) or an ID diet (N = 7). They were then evaluated for 24-h activity in their home cage using implanted G2 EMitter telemetry device. At 3 h before the end of the active period IP doses were given every other day of either: saline (vehicle only), 12.5 mg levodopa, 25 mg levodopa, 0.5 mg quinpirole, or 1 0.0 mg quinpirole.ResultsThe ID compared to irons-sufficient diet produced earlier onset of the RLS-like behavior matching the earlier onset of symptoms with increasing severity of RLS. The dopaminergic treatments significantly reduced the RLS-like behavior. Added analyses of the RLS-like behaviors as decreased resting times showed similar results to activity increases.ConclusionsThese data demonstrate both that The BXD40f provide a useful animal model of RLS and also strongly support the hypothesis that the biology of RLS BID can produce RLS symptoms.  相似文献   
994.
ObjectivesTo determine the prevalence of restless legs syndrome (RLS) and RLS-mimic conditions, the risk factors for RLS, and whether RLS contributes to functional impairment in children and adolescents with attention-deficit/hyperactivity disorder (ADHD).MethodsADHD children and adolescents were prospectively studied at the outpatient psychiatric clinic. A trained registered nurse used the 2012 Revised International Restless Legs Syndrome Study Group diagnostic criteria to diagnose RLS. Sociodemographic data and medical records were reviewed. Weiss Functional Impairment Rating Scale-Parent Report (WFIRS-P) Thai version was used to identify association between RLS and 6 domains of function [family, school (learning), school (behavior), life skills, child self-concept, social activities, and risky activities].ResultsA total of 217 patients were included. Of those, 23 (11%) patients met the criteria for RLS, and 49 (23%) had RLS-mimic conditions. Those conditions included myalgia (30/49), habitual foot tapping (23/49), positional discomfort (20/49), leg ulcer/bruise (1/49), and arthralgia/arthritis (1/49). Binary logistic regression revealed first-degree relative having RLS symptom to be significantly associated with RLS in study patients (OR: 5.06, p < 0.01). Multivariate linear regression showed RLS to be independently associated with school (behavior) (Β = 1.18, p = 0.05) and life skills (Β = 2.36, p = 0.05) impairment.ConclusionsRLS was found to be common in ADHD children and adolescents. RLS-mimic conditions were found in two-thirds of patients who previously met 4 essential RLS criteria. First-degree relative with RLS symptom was associated with RLS, and RLS was associated with functional impairment in the life skills and school (behavior) domains.  相似文献   
995.
《Vaccine》2020,38(8):1989-1997
Newcastle disease (ND) is one of the most important and devastating avian diseases with considerable threat to the global poultry industry. Hepatitis-hydropericardium syndrome (HHS), caused by virulent fowl adenovirus serotype 4 (FAdV-4), is another highly infectious disease in chickens with severe economic impact. The effective way to combat ND and HHS is by vaccinating the poultry. In the present study, a recombinant NDV LaSota vaccine strain expressing full length fiber-2 gene of FAdV-4 (rLaSota-fiber2) was generated using reverse genetics. The FAdV-4 fiber-2 protein was expressed as a soluble form rather than NDV membrane-anchored form. The rLaSota-fiber2 was genetically stable, and it showed growth patterns in embryonated eggs comparable to that of parental rLaSota virus. Since our unpublished data demonstrated that delivery of live rLaSota-fiber2 in drinking water or ocular delivery of the vaccine didn’t produce protection against hypervirulent FAdV-4 challenge, even though the vaccine provide full protection against NDV challenge, the efficacy of the rLaSota-fiber2 was evaluated by delivering the vaccine intramuscularly in this study. Single-dose intramuscular vaccination of 2-week-old SPF White Leghorn chicks with the live or inactivated rLaSota-fiber2 provided complete protection against virulent NDV challenge. However, single-dose intramuscular vaccination with the live rLaSota-fiber2 vaccine provided better protection against virulent FAdV-4 challenge and significantly reduced faecal viral shedding comparing to the inactivated vaccine. These results indicate that the NDV-vectored FAdV-4 vaccine is a promising bivalent vaccine candidate to control both HHS and ND.  相似文献   
996.
997.
998.
邵昱铭 《西部医学》2016,28(12):1632-1637
目的 在建立心脏骤停后综合征(PCAS)小鼠模型的基础上,探究脑组织神经细胞凋亡与炎症介质TNFα、IL-6的关系,以及经尾静脉注射脂联素(Adiponectin,APN)后,能否减少炎症介质释放,从而减轻神经细胞凋亡损伤。方法 将60只小鼠随机分为3组:心脏骤停后综合征组(PCAS组)、脂联素干预组(APN组)及对照组(C组)。使用经食道交流电诱发室颤导致心脏骤停,再经心肺复苏恢复自主循环的方式建立PCAS小鼠模型。APN组和PCAS组在自主循环恢复(ROSC)后,通过尾静脉分别注射10μg APN溶液0.25ml和等体积无菌生理盐水,分别在ROSC后第0.5、3、6、12h采集标本,采用TUNEL染色检测脑组织神经细胞凋亡情况; 免疫组化法半定量检测脑组织中TNFα、IL-6表达情况。结果 1PCAS组小鼠的脑组织出现噬神经、神经元细胞凋亡,脑组织内TNFα、IL-6表达增加。2PCAS后神经细胞凋亡数与TNF-α、IL-6之间具有正相关性(P<0.05)。3APN减少ROSC后脑组织的细胞凋亡,减轻脑组织内TNFα、IL-6的表达。结论 PCAS后小鼠脑组织中炎症因子TNFα、IL-6的释放导致脑组织神经细胞凋亡。APN可通过降低ROSC后小鼠脑组织中TNFα及IL-6的表达而减轻神经细胞凋亡。  相似文献   
999.
INTRODUCTIONPsoriasis is a chronic inflammatory condition that affects the skin and joints, and is associated with cardiovascular risk factors, including metabolic syndrome (MetS). We aimed to assess the prevalence of MetS in patients with psoriasis and determine whether there was a correlation between psoriasis severity and MetS in a Singapore population.METHODSThis was a cross-sectional study of patients with psoriasis, aged 18–69 years, who attended a tertiary dermatology referral centre in Singapore from October 2007 to February 2009. Fasting glucose, lipids, blood pressure, Psoriasis Area and Severity Index, and body mass index were measured. MetS was diagnosed in the presence of three or more criteria of the modified National Cholesterol Education Program Adult Treatment Panel III.RESULTSAmong 338 patients with psoriasis, there were 238 (70.4%) men and 100 (29.6%) women, who were Chinese (n = 228; 67.5%), Malay (n = 52; 15.4%) and Indian (n = 58; 17.2%). The prevalence of MetS was 45.1%. MetS was 44% more prevalent in patients older than 50 years (p = 0.02). Malay patients with psoriasis were significantly more likely to have hypertriglyceridaemia, elevated fasting plasma glucose and abdominal obesity. There was no significant correlation between psoriasis severity and risk of MetS.CONCLUSIONThe prevalence of MetS in patients with psoriasis in Singapore was 45.1%, or nearly threefold higher than the Singapore general population. Patients with psoriasis should be screened yearly for MetS and any modifiable cardiovascular risk factors should be actively controlled.  相似文献   
1000.
患者男,22岁,无明显诱因咳嗽、痰中带血1周,起初干咳,后咳痰并痰中带血,偶咯出少量暗红色血液;无发热、盗汗、乏力,无胸闷、胸痛及呼吸困难,平素体健,无家族病史。查体:双肺呼吸音稍粗,右肺下叶闻及细湿啰音。胸部增强CT:右肺下叶基底段见片状磨玻璃影,内见直径约8mm粗大供血动脉自腹腔干发出;支气管树分支及肺发育正常,未见隔离肺(图1A^1C)。肺动脉CTA示右下肺基底段动脉部分缺如(图1D),考虑为右下肺异常体动脉供血并周围肺组织肺泡出血可能。  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