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   31986篇
  免费   6235篇
  国内免费   235篇
耳鼻咽喉   806篇
儿科学   759篇
妇产科学   928篇
基础医学   1984篇
口腔科学   2873篇
临床医学   4993篇
内科学   6964篇
皮肤病学   1012篇
神经病学   2450篇
特种医学   1676篇
外科学   5526篇
综合类   104篇
现状与发展   12篇
一般理论   1篇
预防医学   3276篇
眼科学   502篇
药学   1106篇
中国医学   161篇
肿瘤学   3323篇
  2024年   165篇
  2023年   1144篇
  2022年   582篇
  2021年   978篇
  2020年   1384篇
  2019年   750篇
  2018年   1611篇
  2017年   1488篇
  2016年   1836篇
  2015年   2028篇
  2014年   2521篇
  2013年   3023篇
  2012年   1715篇
  2011年   1654篇
  2010年   1919篇
  2009年   2383篇
  2008年   1371篇
  2007年   1076篇
  2006年   1175篇
  2005年   992篇
  2004年   726篇
  2003年   640篇
  2002年   570篇
  2001年   589篇
  2000年   494篇
  1999年   552篇
  1998年   564篇
  1997年   525篇
  1996年   574篇
  1995年   419篇
  1994年   329篇
  1993年   285篇
  1992年   228篇
  1991年   204篇
  1990年   185篇
  1989年   177篇
  1988年   167篇
  1987年   158篇
  1986年   141篇
  1985年   137篇
  1984年   113篇
  1983年   137篇
  1982年   96篇
  1981年   83篇
  1980年   60篇
  1979年   61篇
  1978年   59篇
  1977年   64篇
  1976年   50篇
  1975年   42篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
34.
The objective of this study is to compare the effects of three different anesthetic combinations on the electroretinogram in the same animals under similar laboratory conditions. Thiopental–isoflurane (TI), medetomidine–ketamine (MK), and xylazine–ketamine (XK) were used on each of 12 healthy miniature schnauzer dogs (MS) with a period of at least 3 weeks in between subsequent anesthesia protocols, using the Dog Standard Protocol. The scotopic ERGs consisted of scotopic low stimulus strength (S) responses designated S1, S2, S3, S4, and S5, at 1, 5, 10, 15, and 20 min after dark adaptation, respectively, and scotopic standard stimulus strength (S-ST) responses. The photopic ERGs consisted of a photopic single flash (P) response and 31 Hz flicker (P-FL) responses. For S-ST (2.5 cd s/m2), the amplitude of the a-wave using TI was significantly lower than that using MK (adjusted P = 0.05) and XK (adjusted P = 0.03), and the implicit time of the a-wave was significantly shorter than that using MK (adjusted P = 0.04). For P (2.5 cd s/m2), the amplitude of the b-wave using XK was significantly higher than that using MK (adjusted P = 0.01). The implicit times of the b-wave using TI was significantly longer and shorter than that of MK for S1, S2 and P-FL and for S4 and S-ST, respectively, and than that of XK for S2 and P-FL and for S5 and S-ST, respectively. The results of the present study showed that TI affected both the amplitude and the implicit time of the a-wave for S-ST and the implicit time of the b-wave relatively more so than was the case when using XK or MK. Therefore, it appears that either XK or MK could be advantageous to use rather than TI for clinical studies.  相似文献   
35.
Chronic wounds create a formidable clinical problem resulting in considerable morbidity and healthcare expenditure. The etiology for wound healing impairment appears to be multifactorial; however, ischemia is a common factor in most types of chronic wounds. Ideal therapy for such wounds would be to correct deficiencies in growth factors and matrix components and provide cellular precursors required for timely wound closure. We hypothesized that stromal progenitor cell (SPC) therapy could correct the ischemic wound-healing defect through both direct and indirect mechanisms. To test this hypothesis, we used the ischemic rabbit ear model of chronic wound healing. We found that treatment of the wounds with SPCs was able to reverse the ischemic wound-healing impairment, with improved granulation tissue formation and reepithelialization compared with vehicle or bone marrow mononuclear cell controls. In vitro, SPCs were found to produce factors involved in angiogenesis and reepithelialization, and extracellular matrix components, providing evidence for both direct and indirect mechanisms for the observed correction of the healing impairment in these wounds. Treatment of ischemic wounds with SPCs can dramatically improve wound healing and provides a rationale for further studies focused on SPCs as a potential cellular therapy in impaired wound healing.  相似文献   
36.
37.
Many people die in emergency departments (EDs) across the United States from sudden illnesses or injuries, an exacerbation of a chronic disease, or a terminal illness. Frequently, patients and families come to the ED seeking lifesaving or life-prolonging treatment. In addition, the ED is a place of transition-patients usually are transferred to an inpatient unit, transferred to another hospital, or discharged home. Rarely are patients supposed to remain in the ED. Currently, there is an increasing amount of literature related to end-of-life care. However, these end-of-life care models are based on chronic disease trajectories and have difficulty accommodating sudden-death trajectories common in the ED. There is very little information about end-of-life care in the ED. This article explores ED culture and characteristics, and examines the applicability of current end-of-life care models.  相似文献   
38.
39.
40.
Aim: To examine the survival benefit of liver and lung resection for colorectal metastasis and the potential prognostic factors that affect patient survival. Methods: All patients who had resection of lung or liver metastasis for colorectal metastasis in Queen Elizabeth Hospital, Hong Kong from 1995 to 2004 were retrospectively reviewed. The overall and disease‐free survival was analysed, in particularly between liver and lung metastasis. All factors that may have affected the survival were entered into Cox's proportional hazards regression model to identify significant variables associated with survival. Results: At 5 years, the overall survival of patients who had resection of lung and liver metastasis was 44% and 38%, respectively; the disease‐free survival was 26% and 24%, respectively. Overall and disease‐free survival of patients with resection of lung metastasis was comparable to those with resection of liver metastasis. The differentiations of primary tumour and time to metastasis were shown to be significant prognostic factors influencing overall survival. Those patients with systemic chemotherapy after resection of colorectal metastasis demonstrated a significantly higher probability of overall survival. Conclusion: Resection of lung and liver metastases from colorectal origin was safe and both procedures improved survival. The use of chemotherapy after resection of metastasis significantly improved the overall survival.  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