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   853篇
  免费   57篇
  国内免费   41篇
耳鼻咽喉   6篇
儿科学   46篇
妇产科学   2篇
基础医学   158篇
口腔科学   6篇
临床医学   86篇
内科学   134篇
皮肤病学   1篇
神经病学   113篇
特种医学   72篇
外国民族医学   3篇
外科学   132篇
综合类   32篇
预防医学   28篇
眼科学   5篇
药学   62篇
中国医学   2篇
肿瘤学   63篇
  2024年   2篇
  2023年   4篇
  2022年   9篇
  2021年   30篇
  2020年   24篇
  2019年   19篇
  2018年   27篇
  2017年   11篇
  2016年   28篇
  2015年   35篇
  2014年   42篇
  2013年   48篇
  2012年   79篇
  2011年   70篇
  2010年   45篇
  2009年   39篇
  2008年   40篇
  2007年   66篇
  2006年   38篇
  2005年   51篇
  2004年   44篇
  2003年   35篇
  2002年   30篇
  2001年   24篇
  2000年   23篇
  1999年   11篇
  1998年   10篇
  1997年   8篇
  1996年   6篇
  1995年   8篇
  1994年   3篇
  1993年   2篇
  1992年   9篇
  1991年   4篇
  1990年   1篇
  1989年   5篇
  1988年   5篇
  1987年   2篇
  1986年   4篇
  1984年   1篇
  1982年   1篇
  1980年   1篇
  1979年   2篇
  1970年   1篇
  1967年   1篇
  1961年   1篇
  1928年   1篇
  1915年   1篇
排序方式: 共有951条查询结果,搜索用时 31 毫秒
141.
The Healthy Food Environment Policy Index (Food‐EPI) aims to assess the extent of implementation of recommended food environment policies by governments compared with international best practices and prioritize actions to fill implementation gaps. The Food‐EPI was applied in 11 countries across six regions (2015‐2018). National public health nutrition panels (n = 11‐101 experts) rated the extent of implementation of 47 policy and infrastructure support good practice indicators by their government(s) against best practices, using an evidence document verified by government officials. Experts identified and prioritized actions to address implementation gaps. The proportion of indicators at “very low if any,” “low,” “medium,” and “high” implementation, overall Food‐EPI scores, and priority action areas were compared across countries. Inter‐rater reliability was good (GwetAC2 = 0.6‐0.8). Chile had the highest proportion of policies (13%) rated at “high” implementation, while Guatemala had the highest proportion of policies (83%) rated at “very low if any” implementation. The overall Food‐EPI score was “medium” for Australia, England, Chile, and Singapore, while “very low if any” for Guatemala. Policy areas most frequently prioritized included taxes on unhealthy foods, restricting unhealthy food promotion and front‐of‐pack labelling. The Food‐EPI was found to be a robust tool and process to benchmark governments' progress to create healthy food environments.  相似文献   
142.
143.
Tension pneumocephalus is a rare but treatable neurosurgical emergency. Prompt and accurate diagnosis of tension pneumocephalus requires a high index of clinical suspicion corroborated by imaging. Herein, we describe a case of extensive tension pneumocephalus in a patient who had undergone transsphenoidal surgery and repair of the sellar floor, with subsequent successful decompression. This case report discusses the pertinent imaging features of tension pneumocephalus and its management.  相似文献   
144.
145.
Purpose: The aim of this study was to investigate the driving performance of drivers with autism spectrum disorders under complex driving conditions.

Method: Seventeen drivers with autism spectrum disorders and 18 typically developed drivers participated in a driving simulator trial. Prior to the assessment, participants completed the Driving Behaviour Questionnaire and measurements of cognitive and visual-motor ability. The driving simulation involved driving in an urban area with dense traffic and unpredictable events.

Results: In comparison with the typically developed group, drivers with autism spectrum disorders reported significantly more lapses in driving, committed more mistakes on the driving simulator, and were slower to react in challenging situations, such as driving through intersections with abrupt changes in traffic lights. However, they were also less likely to tailgate other vehicles, as measured by time-to-collision between vehicles, on the driving simulator.

Conclusions: The performances of licensed drivers with autism spectrum disorders appeared to be safer in respect to car-following distance but were poorer in their response to challenging traffic situations. Driver education for individuals with autism spectrum disorders should focus on quick identification of hazards, prompt execution of responses, and effective allocation of attention to reduce lapses in driving.

  • Implications for rehabilitation
  • Drivers with autism spectrum disorders reported significantly more lapses during driving.

  • Drivers with autism spectrum disorders were observed to be poorer in traffic scenarios requiring critical response.

  • Driver education for individuals with autism spectrum disorders should focus on managing anxiety and effective attention allocation while driving.

  • Driving simulators can be used as a safe means for training critical response to challenging traffic scenarios.

  相似文献   
146.
147.

Aim

The intensity and duration of surveillance for rectal cancer after surgical resection remain contentious. We evaluated the pattern of recurrences in a rectal cancer cohort followed up beyond 10 years.

Methods

An analysis was performed on a retrospective database of 326 patients with rectal cancer who underwent curative surgical resection from 1999 to 2007. The above study duration was chosen to ensure at least 10 years of follow-up. Data on patient demographics, peri-operative details, and follow-up outcomes were extracted from the database. The pattern of recurrences and investigative modality that detected recurrences was identified. Patients were followed up until either year 2016 or the day of their demise.

Results

Two hundred seventeen patients (66.6%) were male and 109 patients (33.3%) female. Median age was 64 years old. Close to a third of the patients received adjuvant therapy (34%). Among the 326 patients studied, 29.8% of (97/326) patients developed recurrence. 7.7% (25/326) had loco-regional recurrence while 22.1% (72/326) had distant metastasis. Median time to recurrence was 16 months (4–83) and 18 months (3–81), respectively. Computed tomography scan was the best modality to detect both loco-regional and distant recurrences (48% in loco-regional and 41.7% in distant metastasis). The most common site of distant metastasis is the lung (34.7%). The salvage rate for loco-regional and distant recurrences was 52 and 12.5%, respectively.

Conclusion

The predominant pattern of recurrence in rectal cancer is distant disease. Surveillance regimes may need to be altered to increase early detection of distant metastases.
  相似文献   
148.
Platelet transfusions are indicated in a wide variety of clinical conditions especially those with thrombocytopenia. However, without proper clinical practice guidelines, inappropriate transfusions are bound to happen. To ascertain the provision of a quality and appropriate practice of platelet transfusions, an audit study was carried out over a period of one month at the Paediatric Institute, Kuala Lumpur Hospital. A prospective audit was performed during that period whilst a retrospective collection of data was carried out for the previous month for comparison. Based on a set of criteria agreed upon by the audit committee, it was found that in 18.5% (22 of 119) of the cases, the indications for platelet transfusions were inappropriate. The audit committee concluded that there is a need for a more detailed clinical practice guideline for local use to reduce or lower the incidence of inappropriate transfusions of platelets.  相似文献   
149.
CD99 is characteristically expressed in Ewing's sarcoma/primitive neuroectodermal tumor. Recently its immunoreactivity has also been reported in other tumors. However, the significance of CD99 isoforms expressed in these tumors has not been elucidated. In this study, we evaluated the expression of CD99 isoforms and its relationship with histopathologic parameters in gastric adenocarcinomas. Paraffin sections of 46 gastric adenocarcinomas were stained with an anti-CD99 monoclonal antibody, YG32. Twelve (26.1%) cases of 46 gastric adenocarcinomas showed immunoreactivity to YG32. The CD99 expression was also seen both in non-neoplastic foveolar epithelial cells and infiltrating lymphocytes. In addition, Western blot and RT-PCR analyses revealed that the type I is the predominant isoform of CD99 in non-neoplastic and neoplastic gastric tissues. The CD99 expression was usually seen in the intestinal type adenocarcinoma, while rarely in the diffuse type. The CD99 immunoreactivity decreased in MMP-2-overexpressing adenocarcinomas (p=0.028). Our results suggest that the type I is the major isoform of CD99 expressed in non-neoplastic gastric mucosa and gastric adenocarcinomas and its downregulation in gastric adenocarcinoma may be associated with cellular dedifferentiation and/or MMP-2 overexpression.  相似文献   
150.

Objectives

To investigate the effect of variant histology (VH) on survival after radical nephroureterectomy in patients with upper urinary tract urothelial carcinoma (UTUC) and the effect of adjuvant chemotherapy on the survival of patients with UTUC with VH.

Materials and methods

A total of 452 patients who underwent radical nephroureterectomy for UTUC without neoadjuvant chemotherapy in our institution between 1991 and 2012 were retrospectively analyzed. We performed a comparative analysis between pure UTUC and UTUC with VH groups. The Kaplan-Meier method was used to calculate survival estimates for cancer-specific survival (CSS) and overall survival (OS), and log-rank test was used to conduct comparisons between the groups. Univariate and multivariate Cox-proportional hazard regression analyses were performed to evaluate significant variables associated with CSS and OS.

Results

UTUC with VH was present in 41 (9.1%) patients. UTUC with VH showed aggressive clinicopathological features in comparison with pure UTUC. The Kaplan-Meier curves showed significantly decreased 5-year CSS and OS (both, P<0.001) in UTUC with VH group. Multivariate analysis revealed that VH was an independent predictor of CSS (P<0.001) and OS (P<0.002). The Kaplan-Meier curves also showed significantly decreased 5-year CSS and OS in UTUC with the VH group compared to the pure UTUC group in patients who received adjuvant chemotherapy.

Conclusions

We found that UTUC with VH harbored aggressive biologic features, and VH was an independent prognostic factor for CSS and OS on both univariate and multivariate analyses. In addition, UTUC with VH group had poorer survival outcomes than pure UTUC group in patients who received adjuvant chemotherapy. Consequently, adjuvant treatment modalities other than adjuvant chemotherapy should be considered in this group.  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