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   4692篇
  免费   381篇
  国内免费   12篇
耳鼻咽喉   18篇
儿科学   141篇
妇产科学   152篇
基础医学   619篇
口腔科学   53篇
临床医学   603篇
内科学   848篇
皮肤病学   74篇
神经病学   455篇
特种医学   111篇
外科学   479篇
综合类   59篇
一般理论   4篇
预防医学   642篇
眼科学   166篇
药学   296篇
中国医学   6篇
肿瘤学   359篇
  2023年   61篇
  2022年   92篇
  2021年   166篇
  2020年   103篇
  2019年   183篇
  2018年   170篇
  2017年   112篇
  2016年   124篇
  2015年   139篇
  2014年   169篇
  2013年   235篇
  2012年   365篇
  2011年   337篇
  2010年   191篇
  2009年   184篇
  2008年   248篇
  2007年   259篇
  2006年   263篇
  2005年   256篇
  2004年   260篇
  2003年   241篇
  2002年   231篇
  2001年   43篇
  2000年   41篇
  1999年   43篇
  1998年   44篇
  1997年   40篇
  1996年   36篇
  1995年   31篇
  1994年   29篇
  1993年   26篇
  1992年   26篇
  1991年   24篇
  1990年   16篇
  1989年   19篇
  1988年   15篇
  1987年   15篇
  1986年   18篇
  1985年   8篇
  1984年   20篇
  1983年   19篇
  1982年   16篇
  1981年   18篇
  1980年   16篇
  1978年   15篇
  1977年   8篇
  1976年   11篇
  1972年   8篇
  1970年   9篇
  1968年   7篇
排序方式: 共有5085条查询结果,搜索用时 15 毫秒
81.
Circulating levels of catestatin (Cts; human chromogranin A352-372) decrease in the plasma of patients with essential hypertension. Genetic ablation of the chromogranin A (Chga) gene in mice increases blood pressure and pretreatment of Chga-null mice with Cts prevents blood pressure elevation, indicating a direct role of Cts in preventing hypertension. This notable vasoreactivity prompted us to test the direct cardiovascular effects and mechanisms of action of wild-type (WT) Cts and naturally occurring human variants (G364S-Cts and P370L-Cts) on myocardial and coronary functions. The direct cardiovascular actions of WT-Cts and human variants were determined using the Langendorff-perfused rat heart. WT-Cts dose-dependently increased heart rate and coronary pressure and decreased left ventricular pressure, rate pressure product and both positive and negative LVdP/dt. WT-Cts not only inhibited phospholamban phosphorylation, but also the inotropic and lusitropic effects of WT-Cts were abolished by chemical inhibition of beta2-adrenergic receptors, Gi/o protein, nitric oxide or cGMP, indicating involvement of beta2-adrenergic receptors-Gi/o protein-nitric oxide-cGMP signaling mechanisms. In contrast, G364S-Cts did not affect basal cardiac performance but abolished isoproterenol-induced positive inotropism and lusitropism. P370L-Cts decreased rate pressure product and inhibited only isoproterenol-induced positive inotropism and lusitropism by 70%. Cts also inhibited endothelin-1-induced positive inotropism and coronary constriction. Taken together, the cardioinhibitory influence exerted on basal mechanical performance and the counterregulatory action against beta-adrenergic and endothelin-1 stimulations point to Cts as a novel cardiac modulator, able to protect the heart against excessive sympathochromaffin overactivation, e.g. hypertensive cardiomyopathy.  相似文献   
82.
Improved quality of life after lung volume reduction surgery.   总被引:3,自引:0,他引:3  
Lung volume reduction surgery (LVRS) improves dyspnoea, pulmonary function, and physical performance in patients with severe pulmonary emphysema. This study investigated the impact of LVRS on health-related quality of life (HRQL) over a 2-yr period following surgery. Thirty-nine consecutive patients were prospectively assessed before LVRS, and followed over 24 months postoperatively. The assessments included pulmonary function, dyspnoea (Medical Research Council (MRC) dyspnoea score), 6-min walking distance (6MWD) and HRQL using the Short Form 36-item questionnaire (SF-36). Several domains of SF-36 improved considerably over 2 yrs after surgery: Physical Functioning: 39 +/- 4 (mean +/- SEM) versus 16 +/- 2 (p<0.01); Vitality: 51 +/- 3 versus 32 +/- 3 (p<0.01); Social Functioning: 72 +/- 4 versus 51 +/- 5 (p<0.01). Also, improvements in pulmonary function (forced expiratory volume in one second (FEV1): 27 +/- 1% predicted, residual volume (RV)/total lung capacity (TLC): 0.65 +/- 0.01), 6 MWD (274 +/- 16 m) and dyspnoea (MRC: 3.9 +/- 01) were sustained for up to 2 yrs after LVRS (FEV1 36 +/- 2% pred, RV/TLC: 0.58 +/- 0.02; 6 MWD: 342 +/- 19 m; MRC: 2.0 +/- 0.2; p<0.05). In patients with severe emphysema, lung volume reduction surgery had positive effects on health-related quality of life and pulmonary function over 2 yrs.  相似文献   
83.
84.
Part of the functional benefit provided by lung volume reduction surgery (LVRS) may be related to improvement in respiratory muscle function resulting from changes in diaphragm dimension and configuration. To study these changes, we obtained 3D reconstructions of the muscle using spiral computed tomography in 11 patients with severe emphysema before and 3 mo after surgery, and in 11 normal subjects matched for sex, age, height, and weight. Bilateral LVRS was performed by thoracoscopy in eight patients and by sternotomy in three patients. Acquisitions were made in the supine posture at relaxed FRC, midinspiratory capacity, and TLC. On average, LVRS produced a 51 +/- 11% increase in FEV(1) and a 30 +/- 4% decrease in FRC. The total surface area of the diaphragm (A(di)) and of the zone of apposition (A(ap)) at FRC increased by 17 +/- 4% and 43 +/- 8%, respectively, but the surface area of the dome did not change. Compared with the values recorded in the normal subjects, postoperative values of A(di) and A(ap) at FRC were reduced by 11% (p < 0.05) and 24% (p < 0.005), respectively. The curvature of the dome increased at TLC in the left sagittal plane, but was otherwise unaffected by the procedure. We conclude that LVRS substantially increases A(di) and A(ap), but does not significantly improve diaphragm configuration at FRC.  相似文献   
85.
86.

Objectives

Osteogenesis imperfecta (OI) is the most common genetic skeletal disorder. Extraskeletal findings are common but an association with sleep-disordered breathing (SDB) has never been described. The aim of this study was to investigate clinical features of children with OI and suspected SDB.

Methods

A retrospective study of clinical records, signs of SDB and polysomnographic recordings of children with OI was performed. We paid particular attention to symptoms that could be associated with SDB in this population – scoliosis, kyphosis, vertebral arthrodesis, chest wall deformities, basilar impression, autonomy – as well as data already known to be associated with obstructive sleep apnea such as body mass index and upper-airway impairment.

Results

We reviewed the clinical charts of 188 patients referred to our genetic skeletal disorders reference center for OI. Among the 15 patients (8%) with polysomnographic recordings, 12 (6.4%) had sleep-disordered breathing. We found a negative correlation between the Brief Assessment of Motor Function score and Apnea Hypopnea Index (r = ?0.68; p = 0.01) and Desaturation Index (r = ?0.62; p = 0.02). The Apnea Hypopnea Index was higher for non-walkers than walkers (mean [SD]: 6.5 [3.6] vs. 2.4 [1.5]; p = 0.02) and with type III versus IV OI. Two patients were started on continuous positive airway pressure ventilation, with clinical improvement.

Conclusion

For OI children, symptoms suggesting obstructive sleep disorders should be searched for systematically, especially in children with compromised autonomy, high body mass index, trunk deformations, and severe OI type.  相似文献   
87.
In Western society, policy and legislation seeks to minimize restrictive interventions, including physical restraint; yet research suggests the use of such practices continues to raise concerns. Whilst international agreement has sought to define physical restraint, diversity in the way in which countries use restraint remains disparate. Research to date has reported on statistics regarding restraint, how and why it is used, and staff and service user perspectives about its use. However, there is limited evidence directly exploring the physical and psychological harm restraint may cause to people being cared for within mental health inpatient settings. This study reports on an integrative review of the literature exploring available evidence regarding the physical and psychological impact of restraint. The review included both experimental and nonexperimental research papers, using Cooper's (1998) five‐stage approach to synthesize the findings. Eight themes emerged: Trauma/retraumatization; Distress; Fear; Feeling ignored; Control; Power; Calm; and Dehumanizing conditions. In conclusion, whilst further research is required regarding the physical and psychological implications of physical restraint in mental health settings, mental health nurses are in a prime position to use their skills and knowledge to address the issues identified to eradicate the use of restraint and better meet the needs of those experiencing mental illness.  相似文献   
88.
89.

Context

Effective pain management is a priority in the palliative care of advanced cancer patients. A body of research is emerging examining the factors that influence the management and experience of pain for such individuals. Identifying such factors should allow for the development of targeted interventions to improve pain management in the home while ultimately reducing unnecessary suffering for the patient.

Objectives

The objective of this study was to identify relevant patient- and carer-related factors which have an effect on the pain experienced by advanced cancer patients cared for at home.

Method

This is a systematic review following the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) statement guidelines. Studies were retrieved from the CINAHL, MEDLINE, and Web of Science and assessed independently by two reviewers with discrepancies assessed by a third before quality assessment and data extraction. A narrative synthesis was produced.

Results

Our search strategy produced 720 hits, of which 10 studies were retained for the final analysis. The factors identified included carer knowledge of cancer pain management, carer burden, carer and patient distress, pain rating disparity, patient well-being, patient depression, patient affective experience, patient body image, and satisfaction with palliative/medical care. All factors identified are supported by only some evidence with many having only been explored in single studies.

Conclusions

There is a lack of quantitative research in the area of factors influencing the experience of pain for advanced cancer patients cared for at home. Such findings would be useful in developing theories of change that would underpin interventions aimed at improving pain outcomes for this population.  相似文献   
90.
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