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   986篇
  免费   59篇
  国内免费   4篇
儿科学   24篇
妇产科学   12篇
基础医学   143篇
口腔科学   5篇
临床医学   88篇
内科学   200篇
皮肤病学   29篇
神经病学   64篇
特种医学   31篇
外科学   144篇
综合类   30篇
一般理论   2篇
预防医学   40篇
眼科学   31篇
药学   122篇
中国医学   6篇
肿瘤学   78篇
  2024年   1篇
  2023年   7篇
  2022年   21篇
  2021年   46篇
  2020年   28篇
  2019年   32篇
  2018年   27篇
  2017年   28篇
  2016年   49篇
  2015年   36篇
  2014年   45篇
  2013年   69篇
  2012年   88篇
  2011年   97篇
  2010年   59篇
  2009年   27篇
  2008年   72篇
  2007年   68篇
  2006年   54篇
  2005年   49篇
  2004年   48篇
  2003年   44篇
  2002年   24篇
  2001年   5篇
  2000年   1篇
  1999年   4篇
  1998年   5篇
  1997年   5篇
  1995年   3篇
  1993年   1篇
  1992年   1篇
  1991年   2篇
  1990年   1篇
  1987年   1篇
  1976年   1篇
排序方式: 共有1049条查询结果,搜索用时 15 毫秒
11.
Curcumin has been transformed to several diversely substituted bis-pyrrolizidino/thiopyrrolizidino oxindolo/acenaphthyleno curcuminoids via a sequential azomethine ylide cycloaddition reaction using isatins/acenaphthoquinone and proline/thioproline as the reagents. The products were separated via extensive chromatography and characterized by 1D/2D NMR and HRMS analysis.

Curcumin has been transformed to several diversely substituted bis-pyrrolizidino/thiopyrrolizidino oxindolo/acenaphthyleno curcuminoids via a sequential azomethine ylide cycloaddition reaction.  相似文献   
12.
13.

Purpose

Antropylorus transposition in the perineum for end-stage anal incontinence has shown to be feasible in humans. Vascular anatomy of the antro-pyloro-duodenal area is critical in preventing complications and increasing pyloric graft survival. This study was undertaken to examine the vascular anatomy of antro-pyloro-duodenal area in an attempt to safeguard the graft blood supply and improve its survival.

Methods

After obtaining preoperative CT angiography to delineate the infrapyloric artery (IP a.), bench dissection of resected pancreaticoduodenectomy specimens was performed in 12 patients. Ex vivo angiography of these specimens were also performed. Subsequent to the information obtained from these dissections, the method of antropylorus mobilization during transposition was modified in terms of the site of division of the right gastroepiploic a. (Rt GEA). Perioperative outcomes (graft related complications, fecal incontinence scores, Doppler flow studies, and manometry studies of the graft) were compared between the two groups.

Results

IP a. originated only from the Rt GEA in 8 cases (66 %) and from both the gastroduodenal a. and the Rt GEA in the rest. However, its origin solely from the gastroduodenal a. was not observed. The pyloric graft survival, pyloric valve pressures and Doppler flow velocities were significantly (p < 0.05) better when the infrapyloric a. was preserved following this refinement. However, no immediate significant difference in incontinence scores was observed.

Conclusions

Careful preservation of the pyloric valve vascularity by preserving the IP a. by dividing the Rt GEA at its origin increases vascularity, survival and contractility of the pyloric graft in perineum.  相似文献   
14.
Microcapsules are widely used by researchers in self-healing composites. In this study, multi-walled carbon nanotubes (CNT) were incorporated into the core of the microcapsules, along with the self-healing agent. Dicyclopentadiene (DCPD) and urea-formaldehyde (UF) were chosen as the core and shell materials respectively, and DCPD–CNT–UF based dual core microcapsules were synthesized. Two types of microcapsules, namely, DCPD–UF and DCPD–CNT–UF were successfully synthesized by the in situ polymerization technique. The novelty of this work is the development of dual core microcapsules with DCPD–CNT–UF combination. Surface morphology characterization and elemental analysis of the microcapsules were carried out using a scanning electron microscope (SEM-EDX). TGA and DSC analysis show that DCPD–CNT–UF microcapsules have better thermal stability than DCPD–UF microcapsules. These novel DCPD–CNT–UF microcapsules were found to be compatible with epoxy base resin for making resin castings. The presence of CNT is found to improve the mechanical, thermal and electrical properties of the resin cast specimens without compromising on self-healing efficiency.

Carbon nanotubes incorporated microcapsules based self-heating composites.  相似文献   
15.
Distal radius fractures are often treated using percutaneous Kirschner wires (K-wires). The sensory nerves in this area, extensor tendons, radial artery and cephalic vein are at risk of injury in this procedure. We undertook a cadaveric investigation to identify probability of damage to these ‘at risk’ structures by measuring their distances in relation to standard K-wire sites. Nine upper limbs from six formalin-preserved cadavers were studied. Four K-wires were placed percutaneously simulating fixation of a distal radius fracture. Careful dissection was done preserving the original position of neurovascular and tendinous structures. Distances to relevant soft-tissue structures from each K-wire were measured using an electronic digital caliper. Distance of superficial nerves from radial styloid and Lister’s tubercle was measured to determine their ‘safe distance’ from these fixed landmarks. None of the superficial nerves were injured by a K-wire. Cephalic vein had been pierced on 4 occasions (4/18) and extensor tendons on 3 occasions (3/18). Wilcoxon signed-rank test was used to compare distance of the superficial nerves from radial styloid and Lister tubercle, and the latter was found to be the safer option. This study highlights the inherent danger in percutaneous K-wire fixation of wrist fractures. Limited size of the area, where K-wires can be positioned, and anatomic variations of neurovascular structures pose obstacles in developing guidelines for reducing risk of injury. We advocate use of mini-open approach and guiding devices to avert complications of inadvertent impalement and damage to these structures.  相似文献   
16.
17.

Background

Medical errors are being detected with increasing frequency in healthcare environment, in many cases leading to patient harm. Measurement and improvement of patient safety climate has been identified as a strategic effort towards addressing this vital issue.

Method

Safety Attitude Questionnaire (SAQ), validated by previous research was administered to 300 respondents in three tertiary care hospitals of India, the respondents representing various categories of healthcare workers and variations in safety scale score was analyzed by various statistical tools.

Results

No variation was observed in the Patient Safety Index score among the study hospitals. However, significant variations were observed among different categories of healthcare workers across dimensions of Teamwork, Perception of Management and Stress Recognition. Multiple Regression models identified Teamwork and Perception of Management to have significant correlation with Patient Safety Index Score.

Conclusion

Patient Safety Climate can be effectively assessed and such assessment utilized for focused improvement efforts towards safety in healthcare organizations.  相似文献   
18.
Candida spp have often been reported in cervical cytology, other fungal organisms are very rare in modern literature. We report nine cases of conventional cervical smears showing Penicillium, Aspergillus, and Cladosporium spp in healthy imunocompetent females. Penicillium spp seen in four out of nine smears, Cladosporium spp alone in three out of nine smears, and Cladosporium spp along with Aspergillus spp in two out of nine smears. A detail of these nine cases is presented with discussion on importance of these structures when observed in conventional cervical smears. Awareness of such contaminants is important to differentiate from true infection for relevant therapeutic implications. A systematic step‐wise approach to such structures is also suggested. Diagn. Cytopathol. 2015;43:234–237. © 2014 Wiley Periodicals, Inc.  相似文献   
19.
Multinucleated giant cells of osteoclastic type are known to occur in nodal and extranodal lesions of Langerhans cell histiocytosis (LCH). These giant cells are thought to be derived from phagocytic histiocytes, which correlate with the degree of necrosis in LCH lesions. Emperipolesis commonly seen in Rosai–Dorfman disease is a distinct phenomenon characterized by intact phagocytosed cells in an intracytoplasmic vacuole protected from proteolytic digestion. We present a case of emperipolesis of inflammatory cells especially of eosinophils by multinucleated giant cells of Langhans type in a lymph node involved by LCH—a finding that has not been described previously in the literature. Diagn. Cytopathol. 2015;43:1000–1002. © 2015 Wiley Periodicals, Inc.  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