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   3614篇
  免费   339篇
  国内免费   11篇
耳鼻咽喉   14篇
儿科学   159篇
妇产科学   129篇
基础医学   465篇
口腔科学   49篇
临床医学   307篇
内科学   751篇
皮肤病学   46篇
神经病学   259篇
特种医学   297篇
外科学   459篇
综合类   123篇
一般理论   3篇
预防医学   364篇
眼科学   90篇
药学   221篇
  1篇
中国医学   5篇
肿瘤学   222篇
  2021年   38篇
  2019年   39篇
  2018年   45篇
  2017年   50篇
  2016年   44篇
  2015年   53篇
  2014年   65篇
  2013年   92篇
  2012年   147篇
  2011年   112篇
  2010年   94篇
  2009年   115篇
  2008年   137篇
  2007年   106篇
  2006年   127篇
  2005年   100篇
  2004年   97篇
  2003年   111篇
  2002年   101篇
  2001年   108篇
  2000年   84篇
  1999年   90篇
  1998年   81篇
  1997年   102篇
  1996年   78篇
  1995年   70篇
  1994年   78篇
  1993年   85篇
  1992年   94篇
  1991年   85篇
  1990年   73篇
  1989年   99篇
  1988年   108篇
  1987年   98篇
  1986年   102篇
  1985年   86篇
  1984年   52篇
  1983年   62篇
  1982年   46篇
  1981年   54篇
  1980年   39篇
  1979年   41篇
  1978年   45篇
  1977年   40篇
  1976年   29篇
  1975年   31篇
  1974年   26篇
  1973年   33篇
  1971年   24篇
  1967年   27篇
排序方式: 共有3964条查询结果,搜索用时 15 毫秒
1.
2.

Background

The Lancet Commission on Global Surgery highlighted global surgical need but offered little insight into the specific surgical challenges of children in low-resource settings. Efforts to strengthen the quality of global pediatric surgical care have resulted in a proliferation of partnerships between low-and middle-income countries (LMICs) and high-income countries (HICs). Standardized tools able to reliably measure gaps in delivery and quality of care are important aids for these partnerships. We undertook a systematic review (SR) of capacity assessment tools (CATs) focused on needs assessment in pediatric surgery.

Methods

A comprehensive search strategy of multiple electronic databases was conducted per PRISMA guidelines without linguistic or temporal restrictions. CATs were selected according to pre-defined inclusion criteria. Articles were assessed by two independent reviewers. Methodological quality of studies was appraised using the COSMIN checklist with 4-point scale.

Results

The search strategy generated 16,641 original publications, of which three CATs were deemed eligible. Eligible tools were either excessively detailed or oversimplified. None used weighted scores to identify finer granularity between institutions. No CATs comprehensively included measures of resources, outcomes, accessibility/impact and training.

Discussion

The results of this study identify the need for a CAT capable of objectively measuring key aspects of surgical capacity and performance in a weighted tool designed for pediatric surgical centers in LMICs.

Type of Study

Systematic Review.

Level of Evidence

II.  相似文献   
3.
BACKGROUND: Posterior spinal procedures through tubular exposures have been described. However, tubes restrain visibility and require co-axial instrument manipulation, increasing difficulty and potentially compromising surgical results. An independent-blade retractor system overcomes the obstacles of working through a tube and has been used to perform minimally-disruptive decompression and instrumented tranforaminal lumbar interbody fusion (TLIF). PURPOSE: To evaluate the advantages to patient recovery and surgical efficacy of this technique. METHODS/RESULTS: Retrospective review of technique employing a minimally-disruptive approach to decompression and transforaminal lumber interbody fusion (TLIF). CONCLUSIONS: Minimally-disruptive decompression and instrumented TLIF can be performed in a safe and effective manner using an independent-blade retractor system. Relative to traditional-open techniques, surgical goals can be accomplished, but with the benefits of minimally-disruptive surgery.  相似文献   
4.
5.
We describe a myelolipoma of the thoracic spine in a patient with gradual and progressive myelopathy. MR imaging showed this predominately fatty lesion to be extradural in location.  相似文献   
6.
Conventional risk factors have very low predictive power in identifying haemodialysis patients at high risk of vascular accidents. A role for apolipoprotein E isotypes was looked for in a small, but rigorously defined, cohort of longterm haemodialysis patients. In individuals with high vascular risk, as identified by higher common carotid intima/media thickness, we found an excess of apolipoprotein E4 alleles. This preliminary result requires confirmation in large patient cohorts.   相似文献   
7.
Previous studies from this Laboratory have revealed few significant age-related changes in either hepatic microsomal cytochrome P450 content or NADPH-cytochrome P450 reductase activity, prompting the suggestion that the nearly ubiquitous age-associated decline in the hepatic metabolism of xenobiotics by the mixed-function oxidases is a result of alterations in the lipid matrix in which the macromolecular components are organized. In order to examine this postulate, the membrane microenvironment surrounding hepatic microsomal cytochrome P450 was enzymatically digested with snake venom phospholipase A2, and the kinetics of conversion of cytochrome P450 to cytochrome P420 determined for preparations obtained from rats of varying age. There were no significant differences in the kinetics of conversion of cytochrome P450 to cytochrome P420, suggesting that there are no significant age-related changes in the lipid microenvironment immediately adjacent to cytochrome P450. However, there was a slight difference, independent of age, in the rate of conversion of cytochrome P450 to cytochrome P420 between smooth and rough microsomes. The results are discussed in terms of general experimental approaches toward understanding drug metabolism in senescent organisms.  相似文献   
8.
As part of a detailed study of limb defects and associated patterns of congenital malformations, cases with lower limb deficiencies were analysed separately. We identified a total of 130 cases with deficiencies of the lower limbs without defects of the upper limbs. This gives an incidence of 1.07/10,000 livebirths, or 1/9,337 for this group of limb defects. Most common were femur deficiencies and deficiencies of the foot. A preponderance of males was found in the group of transverse defects of the leg (fibula/tibia deficiencies) and central axis deficiencies, while females had significantly more often longitudinal tibia defects and preaxial ray defects. © 1993 Wiley-Liss, Inc.  相似文献   
9.
The morphologic subgroups of intraductal carcinoma in situ (DCIS) of the breast may be biologically different. Thirty-eight patients with comedo-type DCIS treated with local resection with or without radiotherapy are presented. Thirteen of 35 patients had a family history of breast cancer, with 11 patients having an affected first-degree relative. This is significantly increased over other series of breast cancer patients. Recurrence was ipsilateral in all patients and occurred at the site of the original disease. Recurrence occurred in 4 of 30 patients treated with local resection only and 2 of 8 treated with local resection plus radiotherapy. The length of mean follow-up was 39 months. Because of the paucity of studies, these results cannot be compared with others, but there does appear to be a significant incidence of local recurrence after resection for comedo-type DCIS. Immunohistochemical and oncogene studies as they relate to comedo-type DCIS are discussed.  相似文献   
10.
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