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   90651篇
  免费   45597篇
  国内免费   59篇
耳鼻咽喉   1607篇
儿科学   4809篇
妇产科学   1034篇
基础医学   18155篇
口腔科学   5277篇
临床医学   14313篇
内科学   26058篇
皮肤病学   7832篇
神经病学   15211篇
特种医学   2526篇
外科学   15546篇
综合类   133篇
一般理论   44篇
预防医学   6049篇
眼科学   1719篇
药学   6582篇
中国医学   1046篇
肿瘤学   8366篇
  2024年   37篇
  2023年   245篇
  2022年   463篇
  2021年   2061篇
  2020年   5494篇
  2019年   11446篇
  2018年   10708篇
  2017年   11921篇
  2016年   12619篇
  2015年   12496篇
  2014年   12570篇
  2013年   13349篇
  2012年   5624篇
  2011年   5528篇
  2010年   9560篇
  2009年   5902篇
  2008年   3191篇
  2007年   1968篇
  2006年   1897篇
  2005年   1651篇
  2004年   1576篇
  2003年   1451篇
  2002年   1440篇
  2001年   875篇
  2000年   732篇
  1999年   343篇
  1998年   160篇
  1997年   122篇
  1996年   97篇
  1995年   76篇
  1994年   67篇
  1993年   56篇
  1992年   64篇
  1991年   53篇
  1990年   34篇
  1989年   41篇
  1988年   38篇
  1987年   44篇
  1986年   33篇
  1985年   35篇
  1984年   29篇
  1983年   26篇
  1982年   33篇
  1981年   26篇
  1980年   17篇
  1979年   13篇
  1978年   13篇
  1977年   15篇
  1973年   7篇
  1972年   11篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.
84.

Background Context

Low back pain (LBP) is a common complaint in clinical practice of multifactorial origin. Although obesity has been thought to contribute to LBP primarily by altering the distribution of mechanical loads on the spine, the additional contribution of obesity-related conditions such as diabetes mellitus (DM) to LBP has not been thoroughly examined.

Purpose

To determine if there is a relationship between DM and LBP that is independent of body mass index (BMI) in a large cohort of adult survey participants.

Study Design

Retrospective analysis of prospectively collected National Health and Nutrition Examination Survey (NHANES) data to characterize associations between LBP, DM, and BMI in adults subdivided into 6 subpopulations: normal weight (BMI 18.5–25), overweight (BMI 25–30), and obese (BMI >30) diabetics and nondiabetics. Diabetes was defined with glycohemoglobin A1c (HbA1c) 6.5%.

Patient Sample

11,756 participants from NHANES cohort.

Outcome Measures

Percentage of LBP reported.

Methods

LBP reported in the 1999-2004 miscellaneous pain NHANES questionnaire was the dependent variable examined. Covariates included HbA1c, BMI, age, and family income ratio to poverty as continuous variables as well as race, gender, and smoking as binary variables. Individuals were further subdivided by weight class and diabetes status. Regression and graphical analyses were performed on the study population as a whole and also on subpopulations.

Results

Increasing HbA1c did not increase the odds of reporting LBP in the full cohort. However, multivariate logistic regression of the 6 subpopulations revealed that the odds of LBP significantly increased with increasing HbA1c levels in normal weight diabetics. No other subpopulations reported significant relationships between LBP and HbA1c. LBP was also significantly associated with BMI for normal weight diabetics and also for obese subjects regardless of their DM status.

Conclusions

LBP is significantly related to DM status, but this relationship is complex and may interact with BMI. These results support the concept that LBP may be improved in normal weight diabetic subjects with improved glycemic control and weight loss, and that all obese LBP subjects may benefit from improved weight loss alone.  相似文献   
85.
Tuberculosis (TB) remains one of a major health problem worldwide. Tuberculosis vaccine research has made an extraordinary progress over the past few years. However, there is still no replacement for the Bacillus Calmette‐Guérin vaccine, the only TB vaccine licensed for human use. Therefore, the discovery and development of new TB vaccines remains a priority. This article discusses current strategies used to diversify TB vaccines and includes discussion of the status of efforts to improve protection against Mycobacterium tuberculosis (M tb) infection or TB disease by developing new and safe TB vaccines. This article also highlights the current research efforts in immune‐enhancing approaches to improve vaccination efficacy. The development of more effective TB vaccines might have significant impact on global TB control.  相似文献   
86.
Melatonin receptors play important roles in the regulation of circadian and seasonal rhythms, sleep, retinal functions, the immune system, depression, and type 2 diabetes development. Melatonin receptors are approved drug targets for insomnia, non‐24‐hour sleep‐wake disorders, and major depressive disorders. In mammals, two melatonin receptors (MTRs) exist, MT1 and MT2, belonging to the G protein‐coupled receptor (GPCR) superfamily. Similar to most other GPCRs, reliable antibodies recognizing melatonin receptors proved to be difficult to obtain. Here, we describe the development of the first monoclonal antibodies (mABs) for mouse MT1 and MT2. Purified antibodies were extensively characterized for specific reactivity with mouse, rat, and human MT1 and MT2 by Western blot, immunoprecipitation, immunofluorescence, and proximity ligation assay. Several mABs were specific for either mouse MT1 or MT2. None of the mABs cross‐reacted with rat MTRs, and some were able to react with human MTRs. The specificity of the selected mABs was validated by immunofluorescence microscopy in three established locations (retina, suprachiasmatic nuclei, pituitary gland) for MTR expression in mice using MTR‐KO mice as control. MT2 expression was not detected in mouse insulinoma MIN6 cells or pancreatic beta‐cells. Collectively, we report the first monoclonal antibodies recognizing recombinant and native mouse melatonin receptors that will be valuable tools for future studies.  相似文献   
87.
88.
89.
90.
Increasing evidence suggests that human epidermal melanocytes play an important role in the skin immune system; however, a role of their pigmentation in immune and inflammatory responses is poorly examined. In the study, the expression of Toll‐like receptor 4 (TLR4) and inflammatory cytokines and chemokines by cultured normal melanocytes derived from lightly and darkly pigmented skin was investigated after cell stimulation with lipopolysaccharide (LPS). The basal TLR4 mRNA level in heavily pigmented cells was higher as compared to their lightly pigmented counterparts. Melanocyte exposure to LPS upregulated the expression of TLR4 mRNA and enhanced the DNA‐binding activity of NF‐κB p50 and p65. We found substantial differences in the LPS‐stimulated expression of numerous genes encoding inflammatory cytokines and chemokines between the cells with various melanin contents. In lightly pigmented melanocytes, the most significantly upregulated genes were nicotinamide phosphoribosyltransferase (NAMPT/visfatin), the chemokines CCL2 and CCL20, and IL6, while the genes for CXCL12, IL‐16 and the chemokine receptor CCR4 were the most significantly upregulated in heavily pigmented cells. Moreover, the lightly pigmented melanocytes secreted much more NAMPT, CCL2 and IL‐6. The results of our study suggest modulatory effect of melanogenesis on the immune properties of normal epidermal melanocytes.  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