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   8397篇
  免费   560篇
  国内免费   52篇
耳鼻咽喉   55篇
儿科学   261篇
妇产科学   259篇
基础医学   1267篇
口腔科学   211篇
临床医学   748篇
内科学   2065篇
皮肤病学   227篇
神经病学   987篇
特种医学   156篇
外科学   760篇
综合类   18篇
一般理论   2篇
预防医学   601篇
眼科学   98篇
药学   524篇
中国医学   18篇
肿瘤学   752篇
  2024年   4篇
  2023年   111篇
  2022年   183篇
  2021年   384篇
  2020年   258篇
  2019年   301篇
  2018年   333篇
  2017年   244篇
  2016年   289篇
  2015年   332篇
  2014年   419篇
  2013年   553篇
  2012年   804篇
  2011年   820篇
  2010年   438篇
  2009年   379篇
  2008年   569篇
  2007年   517篇
  2006年   463篇
  2005年   385篇
  2004年   333篇
  2003年   267篇
  2002年   217篇
  2001年   42篇
  2000年   29篇
  1999年   48篇
  1998年   35篇
  1997年   33篇
  1996年   26篇
  1995年   20篇
  1994年   5篇
  1993年   7篇
  1992年   20篇
  1991年   13篇
  1990年   19篇
  1989年   17篇
  1988年   14篇
  1987年   9篇
  1986年   14篇
  1985年   7篇
  1984年   6篇
  1983年   4篇
  1982年   3篇
  1981年   6篇
  1977年   4篇
  1972年   2篇
  1967年   4篇
  1966年   3篇
  1965年   3篇
  1931年   2篇
排序方式: 共有9009条查询结果,搜索用时 17 毫秒
1.
Between the 1930s and 1960s Puerto Rico was transformed from a marginal United States territory into an industrialised ‘showcase of development’. This article investigates the organisation of milk station programmes on the island during this crucial period and how these reflected the circulation of child welfare knowledge, nutrition expertise and public health practices. During the Depression, these perspectives fostered a recast of the eugenic regeneration ideologies motivating medical assessments of and sanitary interventions with Puerto Rico’s rural poor since the nineteenth century. Innovations in nutrition knowledge and an emerging rural hygiene movement highlighted the negative health effects of the island’s monocrops economy. In this context, the nourishment of children’s bodies assumed symbolic and instrumental significance for the reconfiguration of colonial and developmental models promoted by the new Popular Democratic Party (PPD). The experience of public health professionals in relief work during the 1930s contributed to the articulation of food and nutrition as key elements of this party’s populist discourse. Programmes like milk stations became part of strategies to rear and manage the labour force needed in the industrial development model promoted by the PPD. From the perspective of poor Puerto Ricans, however, they were part of the materialisation of its promise of social justice for the poorer classes.  相似文献   
2.
Purpose: To evaluate the rate and onset of intraoperative and postoperative complications post-phacoemulsification. Methods: One hundred sixty-two eyes of 145 patients with uveitis who underwent phacoemulsification between 2006 and 2009 were identified through surgical record review. Fifty-nine eyes of 46 patients met the inclusion criteria. Hazard ratio (HR) and Kaplan-Meier survival probability were calculated for each class of uveitis. Results: Macular edema (ME) resulted to be associated to chronic postoperative inflammation (r?=?0.6; p?=?0.00) and mostly related to patients who presented more than one postoperative relapse/year (r?=?0.2; p?=?0.02). Fuchs uveitis resulted to be a risk factor for posterior capsule opacification (PCO) (HR 3.36 IC95%1.0-10.5; p?=?0.03). Hypotony and elevated intraocular pressure (IOP) were detected in the anterior uveitis group (0.02 EY). Conclusion: The HR to develop ME was significantly related to chronic anterior uveitis. PCO and elevated IOP are most frequent in Fuchs uveitis. The postoperative visual acuity result was good among all the uveitis groups.  相似文献   
3.
4.
Technologies for diabetes management, such as continuous subcutaneous insulin infusion (CSII) and continuous glucose monitoring (CGM) systems, have improved remarkably over the last decades. These developments are impacting the capacity to achieve recommended hemoglobin A1c levels and assisting in preventing the development and progression of micro- and macro vascular complications. While improvements in metabolic control and decreases in risk of severe and moderate hypoglycemia have been described with use of these technologies, large epidemiological international studies show that many patients are still unable to meet their glycemic goals, even when these technologies are used. This editorial will review the impact of technology on glycemic control, hypoglycemia and quality of life in children and youth with type 1 diabetes. Technologies reviewed include CSII, CGM systems and sensor-augmented insulin pumps. In addition, the usefulness of advanced functions such as bolus profiles, bolus calculators and threshold-suspend features will be also discussed. Moreover, the current editorial will explore the challenges of using these technologies. Indeed, despite the evidence currently available of the potential benefits of using advanced technologies in diabetes management, many patients still report barriers to using them. Finally this article will highlight the importance of future studies tailored toward overcome these barriers to optimizing glycemic control and avoiding severe hypoglycemia.  相似文献   
5.
6.
Purpose

Robotic approaches have been steadily replacing laparoscopic approaches in metabolic and bariatric surgeries (MBS); however, their superiority has not been rigorously evaluated. The main goal of the study was to evaluate the 5-year utilization trends of robotic MBS and to compare to laparoscopic outcomes.

Methods

Retrospective analysis of 2015–2019 MBSAQIP data. Kruskal-Wallis test/Wilcoxon and Fisher’s exact/chi-square were used to compare continuous and categorical variables, respectively. Generalized linear models were used to compare surgery outcomes.

Results

The use of robotic MBS increased from 6.2% in 2015 to 13.5% in 2019 (N= 775,258). Robotic MBS patients had significantly higher age, BMI, and likelihood of 12 diseases compared to laparoscopic patients. After adjustment, robotic MBS patients showed higher 30-day interventions and 30-day readmissions alongside longer surgery time (26–38 min).

Conclusion

Robotic MBS shows higher intervention and readmission even after controlling for cofounding variables.

Graphical Abstract
  相似文献   
7.
Neuropsychological outcomes in children of mothers with epilepsy.   总被引:1,自引:0,他引:1  
The study investigated the nature of the effects of maternal epilepsy on cognitive performance of the offspring. One hundred fifty-four children of mothers with epilepsy aged 5 to 11 years (study group), along with 130 control children, comparable with respect to IQ, socio-economic status, age, and gender underwent a neuropsychological assessment using subtests from the NEPSY: A Developmental Neuropsychological Assessment, tapping attentional, auditory-verbal, visuomotor, fine motor, and memory abilities. The study group scored significantly lower than the controls on measures of attention, memory, and fine-motor function. Deficits were more marked in but not limited to the subset of the study group exposed to maternal medication in utero. Group differences on auditory attention were found only in younger children. Valproate-exposed children obtained lower scores on sentence repetition, as well as on the more demanding part of a test of auditory attention, than other children in the study group, suggesting weaknesses in working memory in the former subgroup. Confounding by maternal epilepsy type and polytherapy complicate interpretation of this finding. Differences between subsets of children not exposed to anti-epileptic drugs in utero and controls suggest that both drug exposure and genetic factors may contribute to cognitive deficits associated with maternal epilepsy.  相似文献   
8.
We performed the serum IgA antiendomysium antibody (EmA) assay by indirect immunofluorescence on human umbilical cord sections in 86 subjects with celiac disease, in 187 first-degree relatives of such patients, and in a control group of 68 unrelated subjects, to investigate the suitability of the method in the screening of populations at risk of gluten sensitivity. Conventional EmA assay using monkey esophagus sections was performed in parallel experiments. The results obtained showed a perfpect correlation between the two methods. All the celiac patients and none of the controls were positive for EmA. EmA positivity was also observed in 11 apparently healthy relatives: intestinal biopsy performed in five of them invariably showed villous atrophy and increase of mucosal lymphocytes. Taking into account the low cost of EmA assay on human umbilical cord, especially when compared to monkey esophagus sections, the method is probably suitable and effective in identifying latent, asymptomatic gluten sensitivity in at-risk populations.  相似文献   
9.
Four communities from Guahibo of Venezuela were analyzed for the genetic variants of nine erythrocyte enzymes and five serum proteins. Of the 14 loci determined, four were monomorphic. Significant frequency differentiation among communities, was present for ESD and TF markers. In general, Guahibo allele frequencies are in the variation ranges described for South American groups. The analysis indicates a relatively higher affinity of Guahibos with other Venezuelan groups within an irregular pattern of genetic distances that are likely related to the complex demographic history of the South American groups. Genetic diversity estimates reveal a moderate degree of genetic structure between the four Guahibo communities. This intra‐tribal variability in Guahibo appears to be lower than in Venezuelan Piaroa but higher than in other Amerindians and could be attributed to a combined effect of low population size and relative isolation of communities. At a continental level, the distribution of genetic diversity is consistent with preferential population movements along the eastern and western coastal areas. Am. J. Hum. Biol. 14:21–28, 2002. © 2002 Wiley‐Liss, Inc.  相似文献   
10.
In order to verify if H2O2 affects platelet function, platelet-rich plasma and human washed platelets were incubated with subthreshold concentrations (STC) of collagen or arachidonic acid or ADP and/or with 75-150 microM H2O2. While H2O2 alone did not affect platelet aggregation, it amplified platelet aggregation response in samples stimulated with STC of arachidonic acid and collagen but not in samples stimulated with STC of ADP. When platelets were preventively treated with aspirin, a cyclooxygenase inhibitor, the platelet activation by H2O2 was not observed. Thromboxane A2 (TxA2) was not produced by human washed platelets stimulated with STC of arachidonic acid, collagen or by H2O2 alone. On the contrary, when STC of agonists were tested on platelets supplemented with H2O2 an evident TxA2 production was seen. This effect was prevented by aspirin pretreatment or by the addition of catalase, an enzyme which destroys H2O2. This study suggests that H2O2 triggers the activation of platelets exposed to STC of collagen and arachidonic acid, via the cyclooxygenase pathway.  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