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   8601篇
  免费   341篇
  国内免费   79篇
耳鼻咽喉   333篇
儿科学   399篇
妇产科学   377篇
基础医学   548篇
口腔科学   333篇
临床医学   621篇
内科学   1899篇
皮肤病学   162篇
神经病学   638篇
特种医学   353篇
外科学   2026篇
综合类   152篇
一般理论   1篇
预防医学   131篇
眼科学   440篇
药学   322篇
中国医学   23篇
肿瘤学   263篇
  2024年   4篇
  2023年   35篇
  2022年   113篇
  2021年   184篇
  2020年   110篇
  2019年   176篇
  2018年   212篇
  2017年   191篇
  2016年   293篇
  2015年   382篇
  2014年   432篇
  2013年   512篇
  2012年   632篇
  2011年   708篇
  2010年   428篇
  2009年   370篇
  2008年   661篇
  2007年   717篇
  2006年   669篇
  2005年   608篇
  2004年   496篇
  2003年   414篇
  2002年   319篇
  2001年   48篇
  2000年   33篇
  1999年   42篇
  1998年   30篇
  1997年   19篇
  1996年   21篇
  1995年   17篇
  1994年   16篇
  1993年   12篇
  1992年   9篇
  1991年   7篇
  1990年   11篇
  1989年   8篇
  1988年   12篇
  1987年   5篇
  1986年   6篇
  1985年   11篇
  1984年   6篇
  1983年   7篇
  1978年   2篇
  1977年   2篇
  1976年   2篇
  1975年   3篇
  1974年   4篇
  1972年   2篇
  1969年   4篇
  1967年   3篇
排序方式: 共有9021条查询结果,搜索用时 15 毫秒
141.
International Journal of Mental Health and Addiction - This study sought to develop a new scale of irrational happiness beliefs (IHB) and test its reliability and validity across two British...  相似文献   
142.
Neurological Sciences - This study aims to evaluate the differences in the sizes and configurations of various structures on brain MRIs of patients with intracranial hypotension (ICH) compared to...  相似文献   
143.
144.
Herein we report a patient who was initially thought to have renal arteriovenous fistulas 3 months after laparoscopic partial nephrectomy for a small renal mass. After timely intervention using selective renal artery embolization, computed tomography 9 months post‐surgery showed persistent renal arteriovenous fistulas and nodular lesions in the perirenal fat. The patient then underwent radical nephrectomy, and histopathological examination showed underlying recurrent clear cell renal cell carcinoma invading the intraparenchymal arteries and veins, which was simulating multiple high‐flow renal arteriovenous fistulas.  相似文献   
145.
Normothermic ex vivo lung perfusion (EVLP) has developed as a powerful technique to evaluate particularly marginal donor lungs prior to transplantation. In this study, acellular and cellular perfusate compositions were compared in an identical experimental setting as no consensus has been reached on a preferred technique yet. Porcine lungs underwent EVLP for 12 h on the basis of an acellular or a cellular perfusate composition after 24 h of cold ischaemia as defined organ stress. During perfusion, haemodynamic and respiratory parameters were monitored. After EVLP, the lung condition was assessed by light and transmission electron microscopy. Aerodynamic parameters did not show significant differences between groups and remained within the in vivo range during EVLP. Mean oxygenation indices were 491 ± 39 in the acellular group and 513 ± 53 in the cellular group. Groups only differed significantly in terms of higher pulmonary artery pressure and vascular resistance in the cellular group. Lung histology and ultrastructure were largely well preserved after prolonged EVLP and showed only minor structural alterations which were similarly present in both groups. Prolonged acellular and cellular EVLP for 12 h are both feasible with lungs prechallenged by ischaemic organ stress. Physiological and ultrastructural analysis showed no superiority of either acellular or cellular perfusate composition.  相似文献   
146.
Laser biostimulation in medicine has become widespread supporting the idea of therapeutic effects of photobiomodulation in biological tissues. The aim of this study was to investigate the biostimulation effect of laser irradiation on healing of cutaneous skin wounds, in vivo, by means of bioimpedance measurements and histological examinations. Cutaneous skin wounds on rats were subjected to 635 nm diode laser irradiations at two energy densities of 1 and 3 J/cm2 separately. Changes in the electrical properties of the wound sites were examined with multi-frequency electrical impedance measurements performed on the 3rd, 7th, 10th, and 14th days following the wounding. Tissue samples were both morphologically and histologically examined to determine the relationship between electrical properties and structure of tissues during healing. Laser irradiations of both energy densities stimulated the wound healing process. In particular, laser irradiation of lower energy density had more evidence especially for the first days of healing process. On the 7th day of healing, 3 J/cm2 laser-irradiated tissues had significantly smaller wound areas compared to non-irradiated wounds (p?<?0.05). The electrical impedance results supported the idea of laser biostimulation on healing of cutaneous skin wounds. Thus, bioimpedance measurements may be considered as a non-invasive supplementary method for following the healing process of laser-irradiated tissues.  相似文献   
147.
148.
149.
Objective: To investigate the effect of additional endometrial scratching procedure during hysteroscopy on assisted reproductive technology (ART) cycle outcomes in repeated implantation failure (RIF) patients without endometrial or uterine abnormalities on hysteroscopic evaluation.

Materials and methods: Three hundred and forty-five RIF patients who underwent ART at a university-based infertility clinic between January 2011 and June 2015 were recruited in this retrospective cohort study. Uterine cavities of all included patients were evaluated by diagnostic hysteroscopy 7–14 days prior to the subsequent ART cycle. Women without endometrial abnormalities were allocated into two groups; the scratching group was consisted of patients who underwent endometrial scratching by using monopolar electric energy with needle forceps during hysteroscopy, and the control group was consisted of patients who underwent only diagnostic hysteroscopy.

Results: The implantation rate was significantly higher in the scratching group than the control group (37.7% versus 24.5%; p?=?0.04). Clinical and ongoing pregnancy rates were also found to be significantly higher in the scratching group than the control group (37.7% versus 27.6%; p?=?0.03; and 33.3% versus 23%; p?=?0.03, respectively).

Conclusion: Endometrial scratching during diagnostic hysteroscopy seems to enhance implantation and as well pregnancy rates in comparison to diagnostic hysteroscopy alone.  相似文献   
150.
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