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   6724篇
  免费   373篇
  国内免费   32篇
耳鼻咽喉   63篇
儿科学   196篇
妇产科学   165篇
基础医学   963篇
口腔科学   66篇
临床医学   993篇
内科学   1275篇
皮肤病学   94篇
神经病学   678篇
特种医学   235篇
外科学   563篇
综合类   68篇
一般理论   7篇
预防医学   813篇
眼科学   98篇
药学   410篇
中国医学   12篇
肿瘤学   430篇
  2024年   30篇
  2023年   54篇
  2022年   92篇
  2021年   187篇
  2020年   109篇
  2019年   185篇
  2018年   191篇
  2017年   138篇
  2016年   160篇
  2015年   182篇
  2014年   220篇
  2013年   301篇
  2012年   465篇
  2011年   443篇
  2010年   252篇
  2009年   235篇
  2008年   378篇
  2007年   435篇
  2006年   337篇
  2005年   376篇
  2004年   362篇
  2003年   363篇
  2002年   312篇
  2001年   74篇
  2000年   74篇
  1999年   75篇
  1998年   69篇
  1997年   52篇
  1996年   55篇
  1995年   69篇
  1994年   32篇
  1993年   43篇
  1992年   34篇
  1991年   38篇
  1990年   45篇
  1989年   30篇
  1988年   35篇
  1987年   35篇
  1986年   37篇
  1985年   38篇
  1984年   40篇
  1983年   29篇
  1982年   32篇
  1981年   19篇
  1980年   27篇
  1978年   19篇
  1976年   22篇
  1974年   22篇
  1973年   18篇
  1971年   18篇
排序方式: 共有7129条查询结果,搜索用时 0 毫秒
11.
12.
13.
Although telephone advice nursing is the fastest-growing nursing specialty, useful information to guide managers' decisions about how best to structure and support advice services to achieve desired outcomes is unavailable. We identified issues and variables relevant to outcomes of telephone advice from the perspectives of callers, nurses, and the system. Subsequently, we derived a model for studying factors affecting nursing advice outcomes that will help managers identify modifiable factors to improve outcomes of care.  相似文献   
14.
Medical planning for Operation Iraqi Freedom included predictive models of expected number of burn casualties. In all but the best-case scenario, casualty estimates exceeded the capacity of the only Department of Defense burn center. Examination of existing federal-civilian disaster plans for military hospital augmentation revealed that bed availability data were neither timely nor accurate. Recognizing the need for accurate knowledge of burn bed availability, the Department of Defense requested assistance from the American Burn Association (ABA). Directors of burn centers in the United States were queried for interest in participation in a mass casualty plan to provide overflow burn bed capacity. A list of 70 participating burn centers was devised based upon proximity to planned military embarkation points. A computer tracking program was developed. Daily automated e-mail messages requesting bed status were sent to burn center directors at 6 am Central time with responses requested before 11 am. The collated list of national overflow burn bed capacity was e-mailed each day to the ABA Central Office and to federal and military agencies involved with burn patient triage and transportation. Once automated, this task required only 1-2 hours a day. Available burn-bed lists were generated daily between March 17 and May 2, 2003 and then every other day until May 9, 2003. A total of 2151 responses were received (mean, 43 burn centers per day). A system to track daily nationwide burn bed availability was successfully implemented. Although intended for military conflict, this system is equally applicable to civilian mass casualty situations. We advocate adoption of this or a similar bed tracking system by the ABA for use during burn mass casualty incidents.  相似文献   
15.
16.

Aims

Bacteria adherent to long-term urinary catheters (LTUC) may give misleading urine culture results. Guidelines in the USA recommend changing LTUC before urine collection to diagnose UTI and before commencing appropriate antimicrobial treatment. However, in the UK there is no such guidance. In this study, we evaluated differences in urine cultures before and after changing LTUC.

Methods

In a prospective study in a UK urology department, we made a quantitative and qualitative comparison between paired urines collected before and after catheter change in patients with LTUC. We measured culture growth on a four-point ordinal scale as nil, scanty (< 107 cfu/L), moderate (107–108 cfu/L) or heavy (> 108 cfu/L) and recorded the range of bacterial species isolated. Statistical analysis was by Wilcoxon matched-pairs test.

Results

Sixty-six patients (55 males, 11 females) took part in the study. Urines with no growth increased from 7/66 (11%) before change of catheter to 21/66(32%) after change of catheter. Cultures reported as heavy growth (> 108 cfu/L) reduced from 48/66 (73%) to 25/66 (38%) after catheter change (p < 0.001). Except for Pseudomonas spp., other organisms were isolated less frequently after catheter change. No Proteus spp. was isolated after catheter change.

Conclusions

This study confirms that failure to change long-term catheters before collecting urine for culture may give misleading results. In the interest of accurate diagnosis and antimicrobial stewardship, UK guidelines should recommend changing long-term urinary catheters before collection of urine for culture.
  相似文献   
17.
Treatment of recurrent cerebral metastases is an emerging challenge due to the high local failure rate after surgery or radiosurgery and the improved prognosis of patients with malignancies. A total of 36 patients with 37 metastases who underwent surgery for a local in-brain progression of a cerebral metastasis after previous metastasectomy were retrospectively analyzed. Degree of surgical resection on an early postoperative MRI within 72 h after surgery was correlated with the local in-brain progression rate and overall survival. Complete surgical resection of locally recurrent cerebral metastases as confirmed by early postoperative MRI could only be achieved in 37.8%. Detection of residual tumor tissue on an early MRI following recurrent metastasis surgery correlated with further local in-brain progression when defining a significance level of p?=?0.05 but not after ?idák or Bonferroni significance level correction for multiple testing: However, definite local tumor control could finally be achieved in 91.9% after adjuvant therapy. Overall survival after recurrent metastasectomy was significantly higher as predicted by diagnosis-specific graded prognostic assessment (12.9?±?2.3 vs. 8.4?±?0.7 months; p?<?0.0001). However, our series involved a limited number of heterogeneous patients. A larger, prospective, and controlled study is required. Considering the adequate local tumor control achieved in the vast majority of patients, surgery of recurrent metastases may represent one option in a multi-modal treatment approach of patients suffering from locally recurrent cerebral metastases.  相似文献   
18.
19.
Mammary epithelial cells (MEC) are exfoliated from the epithelium into milk, influencing the number of MEC present in the udder. This process is associated with epithelium integrity. The release of oxytocin (OT) induced by milking causes myoepithelial cell contraction, which, in turn, may stimulate MEC exfoliation through mechanical forces. To investigate the role of OT in MEC exfoliation, we inhibited or induced myoepithelial cell contraction by injecting the OT receptor antagonist atosiban (Ato) or a supraphysiological dose of OT, respectively. Eight cows were assigned to 2 treatments during 2 milkings according to a crossover experimental design: Control+OT (cows were first milked to collect standard milk and then received 5 IU of OT to collect residual milk through a second milking) and Ato?+?OT (cows were injected with Ato (50 μg/kg of body weight) and milked to collect cisternal milk, then received 5 IU of OT to collect alveolar milk through a second milking). Milk MEC were purified to determine their concentration and number in milk. Mammary epithelium integrity was assessed by measuring the kinetics of plasma lactose concentration. Inhibiting myoepithelial cell contraction by Ato injection decreased the number of exfoliated MEC in milk. In contrast, OT injection increased the concentration of MEC in the residual milk and the number of MEC in the alveolar milk. Ato injection reduced plasma lactose concentration, whereas, in both treatments, OT injections increased it. Our results suggested that myoepithelial cell contraction caused by OT could stimulate MEC exfoliation into milk and was associated with epithelium disruption.  相似文献   
20.
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