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   8544篇
  免费   666篇
  国内免费   19篇
耳鼻咽喉   76篇
儿科学   263篇
妇产科学   181篇
基础医学   1134篇
口腔科学   108篇
临床医学   1560篇
内科学   1453篇
皮肤病学   88篇
神经病学   800篇
特种医学   162篇
外科学   640篇
综合类   112篇
一般理论   10篇
预防医学   1421篇
眼科学   114篇
药学   534篇
中国医学   1篇
肿瘤学   572篇
  2023年   96篇
  2022年   84篇
  2021年   157篇
  2020年   136篇
  2019年   219篇
  2018年   222篇
  2017年   201篇
  2016年   186篇
  2015年   235篇
  2014年   315篇
  2013年   436篇
  2012年   682篇
  2011年   673篇
  2010年   332篇
  2009年   303篇
  2008年   547篇
  2007年   599篇
  2006年   567篇
  2005年   593篇
  2004年   507篇
  2003年   550篇
  2002年   489篇
  2001年   61篇
  2000年   44篇
  1999年   75篇
  1998年   111篇
  1997年   74篇
  1996年   54篇
  1995年   54篇
  1994年   58篇
  1993年   65篇
  1992年   33篇
  1991年   35篇
  1990年   24篇
  1989年   27篇
  1988年   34篇
  1987年   24篇
  1986年   27篇
  1985年   29篇
  1984年   39篇
  1983年   30篇
  1982年   26篇
  1981年   31篇
  1980年   27篇
  1979年   11篇
  1978年   13篇
  1977年   10篇
  1976年   10篇
  1975年   9篇
  1973年   10篇
排序方式: 共有9229条查询结果,搜索用时 31 毫秒
991.

Background

Despite a large number of clinical trials having been conducted to assess the efficacy of adjuvant chemotherapy after surgery for various cancers, whether it is best to use this treatment remains a generally contentious issue for many common cancers. The purpose of this study was to ascertain whether any general conclusions can be drawn about the efficacy or inefficacy of this treatment within different cancer classifications.

Methods

Meta-analyses of randomized, controlled trials (RCTs) of adjuvant chemotherapy after surgery were synthesized over as many types of cancer as possible. Data sources were Medline, Embase, and the Cochrane library. Eligible meta-analyses were meta-analyses of RCTs for any type of cancer that compared surgery followed by adjuvant chemotherapy with surgery followed by no adjuvant chemotherapy.

Results

The literature search found 25 meta-analyses for 15 cancer types that satisfied the criteria necessary for detailed analysis within this study. The estimates of relative risk for all cause mortality were reported as being less than one (indicating adjuvant chemotherapy is beneficial) by all meta-analyses apart from a meta-analysis for colorectal cancer metastasized to the liver. Moreover, 15 of these meta-analyses also reported that the 95?% confidence interval for this relative risk is less than one (indicating statistical significance at the 5?% level).

Conclusions

The results for all cancer types included in this study except for cancer metastasized to the liver can be thought of as supporting each other through the idea of there being a common treatment effect or at least a common range of effect across all (or most) of these cancer types. For example, with regard to cancer types where the evidence in favor of adjuvant chemotherapy after surgery is only moderately strong, the results of this study may encourage more clinicians to regard the use of this treatment as standard practice.  相似文献   
992.

Background/objective

Examine associations of type and quantity of physical therapy (PT) interventions delivered during inpatient spinal cord injury (SCI) rehabilitation and patient characteristics with outcomes at the time of discharge and at 1 year post-injury.

Methods

Physical therapists delivering routine care documented details of PT interventions provided. Regression modeling was used to predict outcomes at discharge and 1 year post-injury for a 75% subset; models were validated with the remaining 25%. Injury subgroups also were examined: motor complete low tetraplegia, motor complete paraplegia, and American Spinal Injury Association (ASIA) Impairment Scale (AIS) D motor incomplete tetra-/paraplegia.

Results

PT treatment variables explain more variation in three functionally homogeneous subgroups than in the total sample. Among patients with motor complete low tetraplegia, higher scores for the transfer component of the discharge motor Functional Independence Measure () are strongly associated with more time spent working on manual wheelchair skills. Being male is the most predictive variable for the motor FIM score at discharge for patients with motor complete paraplegia. Admission ASIA lower extremity motor score (LEMS) and change in LEMS were the factors most predictive for having the primary locomotion mode of “walk” or “both (walk and wheelchair)” on the discharge motor FIM for patients with AIS D injuries.

Conclusion

Injury classification influences type and quantity of PT interventions during inpatient SCI rehabilitation and is a strong predictor of outcomes at discharge and 1 year post-injury. The impact of PT treatment increases when patient groupings become more homogeneous and outcomes become specific to the groupings.

Note

This is the second of nine articles in the SCIRehab series.  相似文献   
993.
We present a case of malignant pleural mesothelioma with focal relapse in the Azygos arch region after radical pleurectomy/decortication and adjuvant chemotherapy. Tumour recurrence was successfully treated by Cyberknife radiosurgery (70 Gy in five fractions). Patient remains disease-free at 40 months without any other treatment.  相似文献   
994.
Study Type – Therapy (cohort) Level of Evidence 4 What's known on the subject? and What does the study add? Accumulating evidence suggests that inflammation may contribute to the development of BPH and LUTS. Therefore, it is plausible that anti‐inflammatory agents, such as aspirin and other NSAIDs, may reduce the risk of BPH/LUTS, as was observed in a recent analysis of daily aspirin use and BPH/LUTS risk in the Olmsted County Study of Urinary Symptoms and Health Status in Men. The present study, conducted in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial, found no association for recent aspirin or ibuprofen use with the risk of BPH/LUTS.

OBJECTIVE

  • ? To investigate the relationship between non‐steroidal anti‐inflammatory drug (NSAID) use and the incidence of benign prostatic hyperplasia (BPH)‐related outcomes and nocturia, a lower urinary tract symptom (LUTS) of BPH, in light of accumulating evidence suggesting a role for inflammation in BPH/LUTS development.

PATIENTS AND METHODS

  • ? At baseline, participants in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial completed questions on recent, regular aspirin and ibuprofen use, BPH surgery, diagnosis of an enlarged prostate/BPH, and nocturia. Participants in the intervention arm also underwent a digital rectal examination (DRE), from which prostate dimensions were estimated, as well as a prostate‐specific antigen (PSA) test. Only participants in the intervention arm without BPH/LUTS at baseline were included in the analysis (n= 4771).
  • ? During follow‐up, participants underwent annual DREs and PSA tests, provided annual information on finasteride use, and completed a supplemental questionnaire in 2006–2008 that included additional questions on diagnosis of an enlarged prostate/BPH and nocturia.
  • ? Information collected was used to investigate regular aspirin or ibuprofen use in relation to the incidence of six BPH/LUTS definitions: diagnosis of an enlarged prostate/BPH, nocturia (waking two or more times per night to urinate), finasteride use, any self‐reported BPH/LUTS, prostate enlargement (estimated prostate volume ≥30 mL on any follow‐up DRE) and elevation in PSA level (>1.4 ng/mL on any follow‐up PSA test).

RESULTS

  • ? Generally, null results were observed for any recent, regular aspirin or ibuprofen use (risk ratio = 0.92–1.21, P= 0.043–0.91) and frequency of use (risk ratios for one category increase in NSAID use = 0.98–1.11, P‐trends = 0.10–0.99) with incident BPH/LUTS.

CONCLUSION

  • ? The findings obtained in the present study do not support a protective role for recent NSAID use in BPH/LUTS development.
  相似文献   
995.
996.
Bilateral anterior temporomandibular joint dislocation is very rare, with only 2 reported cases published. In the present report, we describe a healthy 25-year-old man from Haida Gwaii, in British Columbia, Canada, who was transferred to our tertiary trauma center with life-threatening complications of a bilateral anterior temporomandibular joint dislocation with locked mandibular impaction.  相似文献   
997.
998.

Objective

To determine the effect of 6 years of routine management on body composition, physical functioning, and quality of life, and their interrelationships, in men with idiopathic vertebral fracture.

Methods

Twenty men with idiopathic vertebral fracture (patients: mean ± SD age 58 ± 6 years) were age and height matched to 28 healthy controls with no known disease. The primary outcome was skeletal muscle mass (appendicular lean mass by dual x‐ray absorptiometry) assessed at 2 visits (0 and 6 years). Physical functioning and quality of life domains were assessed by the Senior Fitness Test and Short Form 36 (SF‐36) questionnaire at visit 2 only. Data were analyzed by repeated‐measures analysis of variance, independent t‐tests, and correlation.

Results

At visit 1, appendicular lean mass was 9% lower in patients than controls. Although patients better maintained appendicular lean mass between visits (interaction P = 0.016), at visit 2 appendicular lean mass remained 5% lower in patients than controls. Furthermore, patients' appendicular lean mass change was correlated with femoral neck bone density change (r = 0.507, P = 0.023). Physical function tests were 13–27% lower in patients compared with controls (P = 0.056 to 0.003), as were SF‐36 quality of life physical domains (13–26% lower; P = 0.028 to <0.001).

Conclusion

Despite an association between changes in muscle mass and bone density, routine management of men with idiopathic vertebral fracture does not address muscle loss. Combined with the observation of reduced physical functioning and quality of life, this study identifies novel targets for intervention in men with idiopathic vertebral fracture.  相似文献   
999.
Introduction: GSK233705 is a recently developed inhaled anticholinergic being investigated for the potential treatment of chronic obstructive pulmonary disease (COPD). Objectives: This dose‐ranging, parallel‐group, double‐blind study compared the bronchodilator efficacy, safety and pharmacokinetics of GSK233705 with placebo in patients with moderate‐to‐severe COPD. Methods: Patients were randomised to receive 12.5 µg, 25 µg, 50 µg, 100 µg or 200 µg of GSK233705 or placebo once daily for 28 days. The primary endpoint was change from baseline in trough forced expiratory volume in 1 s (FEV1) on day 29. Results: The intent‐to‐treat population consisted of 576 patients (mean predicted FEV1 51%; mean age 62 years). Treatment with GSK233705 produced statistically significant improvements in pulmonary function compared with placebo. Only the 200 µg dose exceeded the predefined target threshold of 130‐mL difference compared with placebo for the primary endpoint of change from baseline in trough FEV1 on day 29. No clear pattern of dose response was observed for the other doses. Serial FEV1 (0–24 h) showed a peak effect around 2 h postdose and tended to decline to clinically insignificant levels compared with placebo at 23 and 24 h. Each dose of GSK233705 was well tolerated. The incidence of adverse events was low and similar across all treatment groups. There were no clinically significant effects on laboratory parameters, vital signs or electrocardiograms. Conclusion: All doses of GSK233705 demonstrated bronchodilatory activity and were well tolerated. Although the onset of bronchodilation was rapid, it was not sustained over 24 h making it unsuitable for once‐daily dosing. Please cite this paper as: Bateman E, Feldman G, Kilbride S, Brooks J, Mehta R, Harris S, Maden C and Crater G. Efficacy and safety of the long‐acting muscarinic antagonist GSK233705 delivered once daily in patients with COPD. Clin Respir J 2012; DOI:10.1111/j.1752‐699X.2011.00278.x.  相似文献   
1000.
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