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   2450篇
  免费   150篇
  国内免费   7篇
耳鼻咽喉   33篇
儿科学   89篇
妇产科学   86篇
基础医学   320篇
口腔科学   49篇
临床医学   185篇
内科学   364篇
皮肤病学   34篇
神经病学   207篇
特种医学   31篇
外科学   563篇
综合类   19篇
一般理论   1篇
预防医学   172篇
眼科学   73篇
药学   172篇
中国医学   5篇
肿瘤学   204篇
  2023年   17篇
  2022年   26篇
  2021年   68篇
  2020年   39篇
  2019年   61篇
  2018年   77篇
  2017年   56篇
  2016年   61篇
  2015年   55篇
  2014年   107篇
  2013年   120篇
  2012年   219篇
  2011年   180篇
  2010年   107篇
  2009年   94篇
  2008年   172篇
  2007年   163篇
  2006年   129篇
  2005年   138篇
  2004年   88篇
  2003年   105篇
  2002年   86篇
  2001年   19篇
  2000年   21篇
  1999年   23篇
  1998年   13篇
  1997年   18篇
  1996年   10篇
  1994年   8篇
  1993年   16篇
  1992年   15篇
  1991年   14篇
  1990年   24篇
  1989年   13篇
  1988年   7篇
  1987年   14篇
  1986年   13篇
  1985年   11篇
  1984年   16篇
  1982年   18篇
  1981年   11篇
  1980年   11篇
  1979年   10篇
  1977年   7篇
  1976年   10篇
  1974年   9篇
  1973年   15篇
  1970年   6篇
  1969年   6篇
  1968年   7篇
排序方式: 共有2607条查询结果,搜索用时 46 毫秒
21.
ObjectiveTo examine characteristics that are associated with receipt of Aid and Attendance (A&A), an enhanced pension benefit for Veterans who qualify on the basis of needing daily assistance, among Veterans who receive pensions.Data sourcesSecondary data analysis of 2016‐2017 national VA administrative data linked with Medicare claims.Study designObservational study examining sociodemographic, medical, and healthcare utilization characteristics associated with receipt of A&A among Veterans receiving pension.Principal findingsIn 2017, 9.7% of Veterans with pension newly received the A&A benefit. The probability of receiving A&A among black and Hispanic pensioners was 4.6 percentage points lower than for white pensioners (95%CI = −0.051, −0.042). Married Veterans receiving pension had a 4.4‐percentage point higher probability of receiving A&A (95%CI = 0.039, 0.048). Most indicators of need for assistance (eg, home health utilization, dementia, stroke) were associated with significantly higher probabilities of receiving A&A, with notable exceptions: pensioners with a diagnosis of Post‐Traumatic Stress Disorder (marginal effect = −0.029 95%CI = −0.037, −0.021) or enrolled in Medicaid (marginal effect = −0.053, 95%CI = −0.057, −0.050) had lower probabilities of receiving A&A. Unadjusted and adjusted rates of receiving A&A among Veterans receiving pension varied by VA medical center.ConclusionsThis study identified potential inequities in receipt of the A&A enhanced pension among a sample of Veterans receiving pension. Increased Veteran outreach, provider education, and VA office coordination can potentially reduce inequities in access to this benefit.  相似文献   
22.
Implicit sequence learning describes the acquisition of serially ordered movements and sequentially structured cognitive information, that occurs without awareness. Theta, alpha and beta cortical oscillations are present during implicit motor sequence learning, but their role in this process is unclear. The current study addressed this gap in the literature. A total of 50 healthy adults aged between 19 and 37 years participated in the study. Implicit motor sequence learning was examined using the Serial Reaction Time task where participants unknowingly repeat a sequence of finger movements in response to a visual stimulus. Sequence learning was examined by comparing reaction times and oscillatory power between sequence trials and a set of control trials comprising random stimulus presentations. Electroencephalography was recorded as participants completed the task. Analyses of the behavioral data revealed participants learnt the sequence. Analyses of oscillatory activity, using permutation testing, revealed sequence learning was associated with a decrease in theta band (4–7 Hz) power recorded over frontal and central electrode sites. Sequence learning effects were not observed in the alpha (7–12 Hz) or beta bands (12–20 Hz). Even though alpha and beta power modulations have long been associated with executing a motor response, it seems theta power is a correlate of sequence learning in the manual domain. Theta power modulations on the serial reaction time task may reflect disengagement of attentional resources, either promoting or occurring as a consequence of implicit motor sequence learning  相似文献   
23.
24.
This account of the highlights of the eighth St Gallen (Switzerland) meeting in 2003 emphasizes new information that has emerged during the 2 years since the seventh meeting in 2001. This article should be read in conjunction with the report of that earlier meeting. Recommendations for patient care are so critically dependent on assessment of endocrine responsiveness that the importance of high-quality steroid hormone receptor determination and standardized quantitative reporting cannot be overemphasized. The International Consensus Panel modified the risk categories so that only endocrine receptor-absent status was sufficient to reclassify an otherwise low-risk, node-negative disease into the category of average risk. Absence of steroid hormone receptors also was recognized as indicating endocrine nonresponsiveness. Some important areas highlighted at the recent meeting include: (1) recognition of the separate nature of endocrine-nonresponsive breast cancer-both invasive cancers and ductal carcinoma-in-situ; (2) improved understanding of the mechanisms of acquired endocrine resistance, which offer exciting prospects for extending the impact of successful sequential endocrine therapies; (3) presentation of high-quality evidence indicating that chemotherapy and tamoxifen should be used sequentially rather than concurrently; (4) availability of a potential alternative to tamoxifen for treatment of postmenopausal women with endocrine-responsive disease; and (5) the promise of newly defined prognostic and predictive markers.  相似文献   
25.
26.
27.
BACKGROUND: Bilateral synchronous breast cancer is uncommon (accounting for 1.0%-2.6% of all patients with breast cancer), and most physicians do not accumulate a large personal experience of patients with this disease. We reviewed our experience with patients with bilateral synchronous breast cancer, focusing on the mode of detection and histologic features in the 2 breasts. METHODS: The charts of patients who were treated at this institution for bilateral synchronous breast cancer during the 15-year period of 1984 through 1999 were reviewed. Information regarding age, mode of detection, histopathologic features, treatment, and overall survival were analyzed. RESULTS: During the study period, 51 patients (all women) were treated at our institution for bilateral synchronous breast cancer. This comprised 2.1% of all patients (n = 2382 patients) treated for breast cancer during the same period of time. The first cancer was detected by palpation in 81% and by mammography in 14%. The corresponding figures for the contralateral cancer were 24% and 54%, respectively. The histologic type of cancer was identical in the 2 breasts in 29 patients (57%) and was different between the 2 breasts in 22 patients (43%). The overall 10-year survival rate was 63%. CONCLUSIONS: Bilateral synchronous breast cancer is often detected by mammography and is frequently of the same histologic type as the index cancer. A better awareness of the risk for this disease may help detect bilateral breast cancer earlier.  相似文献   
28.
Introduction

It has been shown previously that a history of low back pain often begins in childhood or adulthood. Indeed, the prevalence of severe back symptoms among schoolchildren is not insignificant. Possibilities for the primary prevention of intervertebral disc degeneration-related conditions are poorly reported in the literature despite the assumed socio-economical impact of the prevention of these conditions.

Methods

In this review, the authors have collated published data on the prevalence and risk factors of childhood low back pain as well as the structure and results of published primary prevention programs.

Results

The prevalence of self-reported low back pain is 7–65 % among children and it increases with age. Several lifestyle factors have been reported as significant risk factors for back pain, many of which are related to the schools. Current educational primary prevention programs in schools show no clear or long-term stable effect.

Conclusion

Considering the growing evidence about the importance of normal and bad posture, an exercise-based posture correction program is suggested as a school-based primary prevention of disc degeneration-related symptoms. Further, prospective randomized studies with more than 20 years follow-up, however, are strongly required to confirm it.

  相似文献   
29.
A 39-year-old female previously treated with shock wave lithotripsy developed extensive ureteral stricture disease. After 2 unsuccessful attempts at retrograde balloon dilatation, she was evaluated at our center for further management. Successful reconstruction was performed with laparoscopic-assisted vesicocalicostomy.  相似文献   
30.
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