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   1445篇
  免费   170篇
  国内免费   17篇
耳鼻咽喉   12篇
儿科学   86篇
妇产科学   14篇
基础医学   164篇
口腔科学   17篇
临床医学   188篇
内科学   425篇
皮肤病学   18篇
神经病学   40篇
特种医学   123篇
外科学   148篇
综合类   124篇
一般理论   2篇
预防医学   132篇
眼科学   12篇
药学   82篇
中国医学   1篇
肿瘤学   44篇
  2021年   16篇
  2020年   7篇
  2019年   26篇
  2018年   17篇
  2017年   12篇
  2016年   21篇
  2015年   24篇
  2014年   43篇
  2013年   51篇
  2012年   57篇
  2011年   45篇
  2010年   56篇
  2009年   60篇
  2008年   75篇
  2007年   82篇
  2006年   60篇
  2005年   42篇
  2004年   38篇
  2003年   42篇
  2002年   33篇
  2001年   46篇
  2000年   40篇
  1999年   52篇
  1998年   61篇
  1997年   47篇
  1996年   49篇
  1995年   29篇
  1994年   38篇
  1993年   32篇
  1992年   31篇
  1991年   35篇
  1990年   41篇
  1989年   32篇
  1988年   32篇
  1987年   33篇
  1986年   22篇
  1985年   25篇
  1984年   26篇
  1983年   15篇
  1982年   20篇
  1981年   10篇
  1980年   8篇
  1979年   7篇
  1978年   14篇
  1977年   6篇
  1976年   11篇
  1975年   9篇
  1971年   8篇
  1969年   5篇
  1968年   8篇
排序方式: 共有1632条查询结果,搜索用时 109 毫秒
61.
62.

Background

Onchocerciasis has been implicated in the pathogenesis of epilepsy. The debate on a potential causal relationship between Onchocerca volvulus and epilepsy has taken a new direction in the light of the most recent epidemic of nodding syndrome.

Objective

To document MRI changes in people with different types of epilepsy and investigate whether there is an association with O. volvulus infection.

Methods

In a prospective study in southern Tanzania, an area endemic for O. volvulus with a high prevalence of epilepsy and nodding syndrome, we performed MRI on 32 people with epilepsy, 12 of which suffered from nodding syndrome. Polymerase chain reaction (PCR) of O. volvulus was performed in skin and CSF.

Results

The most frequent abnormalities seen on MRI was atrophy (twelve patients (37.5%)) followed by intraparenchymal pathologies such as changes in the hippocampus (nine patients (28.1%)), gliotic lesions (six patients (18.8%)) and subcortical signal abnormalities (three patients (9.4%)). There was an overall trend towards an association of intraparenchymal cerebral pathologies and infection with O. volvulus based on skin PCR (Fisher''s Exact Test p=0.067) which was most pronounced in children and adolescents with nodding syndrome compared to those with other types of epilepsy (Fisher''s Exact Test, p=0.083). Contrary to skin PCR results, PCR of CSF was negative in all patients.

Conclusion

The observed trend towards an association of intraparenchymal cerebral pathological results on MRI and a positive skin PCR for O. volvulus despite negative PCR of CSF is intriguing and deserves further attention.  相似文献   
63.
The basal forebrain (BF) strongly regulates cortical activation, sleep homeostasis, and attention. Many BF neurons involved in these processes are GABAergic, including a subpopulation of projection neurons containing the calcium‐binding protein, parvalbumin (PV). However, technical difficulties in identification have prevented a precise mapping of the distribution of GABAergic and GABA/PV+ neurons in the mouse or a determination of their intrinsic membrane properties. Here we used mice expressing fluorescent proteins in GABAergic (GAD67‐GFP knock‐in mice) or PV+ neurons (PV‐Tomato mice) to study these neurons. Immunohistochemical staining for GABA in GAD67‐GFP mice confirmed that GFP selectively labeled BF GABAergic neurons. GFP+ neurons and fibers were distributed throughout the BF, with the highest density in the magnocellular preoptic area (MCPO). Immunohistochemistry for PV indicated that the majority of PV+ neurons in the BF were large (>20 μm) or medium‐sized (15–20 μm) GFP+ neurons. Most medium and large‐sized BF GFP+ neurons, including those retrogradely labeled from the neocortex, were fast‐firing and spontaneously active in vitro. They exhibited prominent hyperpolarization‐activated inward currents and subthreshold “spikelets,” suggestive of electrical coupling. PV+ neurons recorded in PV‐Tomato mice had similar properties but had significantly narrower action potentials and a higher maximal firing frequency. Another population of smaller GFP+ neurons had properties similar to striatal projection neurons. The fast firing and electrical coupling of BF GABA/PV+ neurons, together with their projections to cortical interneurons and the thalamic reticular nucleus, suggest a strong and synchronous control of the neocortical fast rhythms typical of wakefulness and REM sleep. J. Comp. Neurol., 521:1225–1250, 2013. © 2012 Wiley Periodicals, Inc.  相似文献   
64.

Background

The Australian 2021 Royal Commission identified that the dietetic workforce needs to grow in size and capacity to support nutrition care in older adults. However, little is known about dietitians' knowledge, skills and attitudes (KSA) regarding working with older adults in residential aged care facilities (RACFs) or their homes. This review describes dietitians' KSA regarding older adults in RACFs and home care services.

Methods

A systematic literature search was conducted in August 2021 to identify studies examining any aspect of dietitians or student dietitians' KSA working in RACFs and home care services. No restrictions were applied to methodological design, language, location or publication year. Studies were assessed for quality using the Johanna Briggs Institute Quality Appraisal Tools. Study findings were analysed thematically using meta-synthesis.

Results

All 17 studies that met the inclusion criteria explored dietitians' attitudes towards their role, three studies examined perceived knowledge, although no studies objectively explored dietitians' skill levels. Five themes were developed inductively: (1) recognising their contribution as dietitians; (2) lacking clarity about the boundaries of their role; (3) all team members have a role to play in nutrition care; (4) assumptions and biases about working with older people; and (5) needing to build capacity in the workforce.

Discussion

Dietitians have mixed attitudes about working in RACFs and home care services. Future directions include evaluating dietitians' role in RACFs, reviewing education and training and practical opportunities for student dietitians, and assessing the impact of more dietitian support on an older person's dietary intake and nutrition.  相似文献   
65.
66.
Phosphodiesterase 3 inhibitors have been used successfully in pediatric patients with acute or chronic myocardial dysfunction over the last two decades. Their protracted continuous intravenous administration is associated with risk of infectious and thromboembolic complications. Weaning intravenous medication and starting oral angiotensin-converting enzyme (ACE) inhibitors and/or beta-blockers can be challenging. We reviewed retrospectively hospital records of 48 patients receiving oral enoximone treatment in a single tertiary pediatric cardiac center between November 2005 and April 2014. Failure to wean from intravenous milrinone infusion and/or intolerance of ACE inhibitors and/or beta-blockers was indications for oral enoximone treatment. Age of the patients ranged between 0.5 and 191 months (median 7.5 months) at the time of starting enoximone treatment. There were 14 patients (29 %) with left ventricular dysfunction due to myocarditis or dilated cardiomyopathy and 34 patients (71 %) with myocardial dysfunction complicating congenital heart disease. Fifteen (44 %) of these 34 patients had left ventricular dysfunction, 13 (38 %) right ventricular dysfunction, and in 6 (18 %) both ventricles were failing. Duration of oral enoximone treatment was between 3 days and 34 months (median of 2.3 months). Myocardial functional recovery allowed for weaning of enoximone treatment in 15 patients (31 %) after 6 days–15 months (median 5 months). No adverse hemodynamic effects were noted. Blood stained gastric aspirates encountered in two patients resolved with concomitant milk administration. Based on our limited experience, oral enoximone is a well-tolerated and promising alternative to intravenous medication and/or other commonly used oral medications in selected pediatric patients with chronic heart failure.  相似文献   
67.
This is the second report on the continuing efforts of LAGID to increase the recognition and registration of patients with primary immunodeficiency diseases in 12 Latin American countries: Argentina, Brazil, Chile, Colombia, Costa Rica, Honduras, Mexico, Panama, Paraguay, Peru, Uruguay, and Venezuela. This report reveals that from a total of 3321 patients registered, the most common form of primary immunodeficiency disease was predominantly antibody deficiency (53.2%) with IgA deficiency reported as the most frequent phenotype. This category was followed by 22.6% other well-defined ID syndromes, 9.5% combined T- and B-cell inmunodeficiency, 8.6% phagocytic disorders, 3.3% diseases of immune dysregulation, and 2.8% complement deficiencies. All countries that participated in the first publication in 1998 reported an increase in registered primary immunodeficiency cases, ranging between 10 and 80%. A comparison of the estimated minimal incidence of X-linked agammaglobulinemia, chronic granulomatous disease, and severe combined immunodeficiency between the first report and the present one shows an increase in the reporting of these diseases in all countries. In this report, the estimated minimal incidence of chronic granulomatous disease was between 0.72 and 1.26 cases per 100,000 births in Argentina, Chile, Costa Rica, and Uruguay and the incidence of severe combined immunodeficiency was 1.28 and 3.79 per 100,000 births in Chile and Costa Rica, respectively. However, these diseases are underreported in other participating countries. In addition to a better diagnosis of primary immunodeficiency diseases, more work on improving the registration of patients by each participating country and by countries that have not yet joined LAGID is still needed. Latin American Group for Primary Immunodeficiency Diseases  相似文献   
68.
69.
70.
Incident pain related to bone metastases is a problematic symptom to treat. The difficulty in treating this type of pain is reflected in the wide variety of treatment modalities recommended. The aims of this prospective observational study were to determine the patterns of pain severity at rest and on movement over time and which treatment modalities are employed. In addition, we were interested in ascertaining any correlations between bone pain at rest, bone pain on movement and functional ability. Thirty-two patients were followed up for a mean of 22 weeks (range: 2-52). In total, there were 704 patient follow-up weeks. Patients were followed up for one year or until death. A total of 19 different treatment modalities were employed. There were strong correlations between pain at rest and pain on movement. There were no significant correlations between functional ability and pain at rest or movement. Our study demonstrates the complex management of patients with bone pain. This is the first study that highlights the correlation between pain at rest and pain on movement in patients with bone metastases in a palliative care population. It highlights the need for intensive follow-up of these patients, as they require multiple interventions to help control their pain. These data can also be used to power further interventional studies.  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