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   1479篇
  免费   125篇
  国内免费   19篇
耳鼻咽喉   8篇
儿科学   47篇
妇产科学   51篇
基础医学   136篇
口腔科学   12篇
临床医学   338篇
内科学   243篇
皮肤病学   24篇
神经病学   93篇
特种医学   115篇
外科学   143篇
综合类   27篇
一般理论   4篇
预防医学   177篇
眼科学   9篇
药学   118篇
中国医学   1篇
肿瘤学   77篇
  2022年   8篇
  2021年   14篇
  2020年   13篇
  2019年   13篇
  2018年   30篇
  2017年   15篇
  2016年   16篇
  2015年   30篇
  2014年   36篇
  2013年   43篇
  2012年   44篇
  2011年   58篇
  2010年   39篇
  2009年   31篇
  2008年   53篇
  2007年   88篇
  2006年   50篇
  2005年   54篇
  2004年   51篇
  2003年   52篇
  2002年   50篇
  2001年   60篇
  2000年   57篇
  1999年   45篇
  1998年   35篇
  1997年   35篇
  1996年   46篇
  1995年   40篇
  1994年   25篇
  1993年   19篇
  1992年   48篇
  1991年   36篇
  1990年   42篇
  1989年   48篇
  1988年   34篇
  1987年   33篇
  1986年   20篇
  1985年   23篇
  1984年   25篇
  1983年   18篇
  1982年   17篇
  1981年   10篇
  1979年   16篇
  1978年   8篇
  1977年   11篇
  1976年   12篇
  1975年   13篇
  1973年   10篇
  1972年   5篇
  1969年   6篇
排序方式: 共有1623条查询结果,搜索用时 62 毫秒
51.
52.
In the UK, an estimated 95,000 families are homeless. Nurses who work with these people need a wide range of skills and stand to benefit from a new UK-wide network that has received lottery funding.  相似文献   
53.
Long-term follow-up is initially considered appropriate for the majority of patients with primary hyperparathyroidism (PHPT) having small increases in calcium levels (< 2.8 mmol/l) and lacking the 'classical' symptoms of PHPT. The supportive reasoning is that many such patients never progress to more severe biochemical or clinical disease. There are, however, arguments in favour of early surgical treatment of such patients but adequately powered studies have not been carried out in this subgroup of patients to asses the impact of PHPT on their quality of life, cardiovascular risk and bone density. Progressive loss in bone mineral density and an increased risk of bone fracture become increasingly significant in an ageing population. Left ventricular hypertrophy, an increased risk of arrhythmia and/or myocardial infarction in addition to changes in atherogenic lipid profile and impaired glucose tolerance may translate into an increased risk of premature death in this group of patients. Changes in the quality of life identified using standardized questionnaires are sometimes recognized by patients only in retrospect (i.e. after resolution of symptoms following successful parathyroidectomy). In addition, many series fail to assess and record accurately such symptoms. Multicentre cohort studies of patients with asymptomatic PHPT randomized to immediate or delayed surgical treatment could address some of the debated issues highlighted in this review. Until such studies are set up, most surgeons would consider that parathyroid surgery should represent the first choice of treatment for all patients, but many physicians would favour a long-term follow-up. Nevertheless, the threshold for referral for surgical treatment has been lowered since the introduction of scan-directed minimally invasive parathyroidectomy, which enables the experienced parathyroid surgeon to successfully treat patients with PHPT with a minimum of complications as a day-case operation. In the context of improved surgical treatment, we need more data on the benefits or otherwise in so-called asymptomatic patients with a thorough assessment of their bone quality, cardiovascular risk and quality of life.  相似文献   
54.
Objectives. This study examined the psychometric properties of the Multidimensional Fatigue Symptom Inventory-Short Form (MFSI-SF) in a community-based sample of African-Americans.

Design. A sample of 340 African-Americans (116 men, 224 women) ranging in age from 18–81 years were recruited from the community (e.g., churches, health fairs, and beauty salons). Participants completed a brief demographic survey, the MFSI-SF and the Positive and Negative Affect Schedule.

Results. The structural validity of the MFSI-SF for a community-based sample of African-Americans was not supported. The five dimensions of fatigue (General, Emotional, Physical, Mental, Vigor) found for Whites in prior research were not found for African-Americans in this study. Instead, fatigue, while multidimensional for African-Americans, was best represented by a unique four-four profile in which general and emotional fatigue are collapsed into a single dimension and physical fatigue, mental fatigue, and vigor are relatively distinct. Hence, in the absence of modifications, the MFSI-SF cannot be considered to be structurally invariant across ethnic groups. A modified four-factor version of the MFSI-SF exhibited excellent internal consistency reliability and evidence supports its convergent validity. Using the modified four-factor version, gender, and age were not meaningfully associated with MFSI-SF scores.

Conclusion. Future research should further examine whether modifications to the MFSI-SF would, as the findings suggest, improve its validity as a measure of multidimensional fatigue in African-Americans.  相似文献   

55.
Traumatic injury is the leading cause of potentially preventable lost years of life in the Western world and exsanguination is the most potentially preventable cause of post-traumatic death. With mature trauma systems and experienced trauma centres, extra-abdominal sites, such as the pelvis, constitute the most frequent anatomic site of exsanguination. Haemorrhage control for such bleeding often requires surgical adjuncts most notably interventional radiology (IR). With the usual paradigm of surgery conducted within an operating room and IR procedures within distant angiography suites, responsible clinicians are faced with making difficult decisions regarding where to transport the most physiologically unstable patients for haemorrhage control. If such a critical patient is transported to the wrong suite, they may die unnecessarily despite having potentially salvageable injuries. Thus, it seems only logical that the resuscitative operating room of the future would have IR capabilities making it the obvious geographic destination for critically unstable patients, especially those who are exsanguinating.  相似文献   
56.
57.
58.
Primary resistance to pathogens is reliant on both basal and inducible immune defenses. To date, research has focused upon inducible innate immune responses. In contrast to resistance via cytokine induction, basal defense mechanisms are less evident. Here we showed that the antiviral protein kinase R (PKR) inhibited the key actin-modifying protein gelsolin to regulate actin dynamics and control cytoskeletal cellular functions under homeostatic conditions. Through this mechanism, PKR controlled fundamental innate immune, actin-dependent processes that included membrane ruffling and particle engulfment. Accordingly, PKR counteracted viral entry into the cell. These findings identify a layer of host resistance, showing that the regulation of actin-modifying proteins during the innate immune response bolsters first-line defense against intracellular pathogens and has a sustained effect on virus production. Moreover, these data provide proof of principle for a concept in which the cell cytoskeleton could be targeted to elicit broad antiviral protection.  相似文献   
59.
目的:通过对老年人进行血浆溶血磷脂酸和磷脂酸的筛检,从而认识血浆溶血磷脂酸和磷脂酸在血栓预防中的作用。方法:对2004-04/07期间的1657名和2005-04/07期间的1748名离休干部进行血浆溶血磷脂酸和磷脂酸含量测定,并对溶血磷脂酸>3.0μmol/L和磷脂酸>5.0μmol/L的阳性人员进行药物干预。同时,选择2004年溶血磷脂酸和/或磷脂酸阳性人员119人,随机分为两组:①干预组(n=72):男63人,女9人,平均年龄78岁。口服阿司匹林100mg/d,持续1个月。②对照组(n=47):男42人,女5人,平均年龄76岁。干预后,测定两组血浆中溶血磷脂酸和磷脂酸的含量。结果:纳入对象全部进入结果分析。2005年磷脂酸及血浆溶血磷脂酸 磷脂酸阳性率均明显低于2004年(P<0.01),尤其是磷脂酸的阳性率降低的更为明显。2005年血浆溶血磷脂酸和磷脂酸的平均值均明显低于2004年(P<0.01)。干预组干预后血浆溶血磷脂酸和磷脂酸明显低于干预前及对照组(P<0.01)。结论:①血浆溶血磷脂酸和磷脂酸的测定可作为血栓预警和了解抗血栓药物疗效的一种手段。②阿司匹林干预后,血浆溶血磷脂酸和磷脂酸的含量均降低,可作为一种降低缺血性疾病发生率的有效途径。  相似文献   
60.
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