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   29685篇
  免费   2481篇
  国内免费   92篇
耳鼻咽喉   540篇
儿科学   888篇
妇产科学   682篇
基础医学   4036篇
口腔科学   644篇
临床医学   2933篇
内科学   6715篇
皮肤病学   477篇
神经病学   2658篇
特种医学   1041篇
外科学   4892篇
综合类   463篇
一般理论   24篇
预防医学   2240篇
眼科学   730篇
药学   1471篇
中国医学   38篇
肿瘤学   1786篇
  2023年   204篇
  2022年   419篇
  2021年   866篇
  2020年   469篇
  2019年   684篇
  2018年   839篇
  2017年   565篇
  2016年   573篇
  2015年   716篇
  2014年   923篇
  2013年   1257篇
  2012年   1787篇
  2011年   1822篇
  2010年   1011篇
  2009年   868篇
  2008年   1508篇
  2007年   1560篇
  2006年   1549篇
  2005年   1482篇
  2004年   1347篇
  2003年   1258篇
  2002年   1224篇
  2001年   415篇
  2000年   421篇
  1999年   418篇
  1998年   249篇
  1997年   237篇
  1996年   222篇
  1995年   204篇
  1994年   187篇
  1993年   191篇
  1992年   344篇
  1991年   341篇
  1990年   332篇
  1989年   336篇
  1988年   304篇
  1987年   324篇
  1986年   282篇
  1985年   299篇
  1984年   276篇
  1983年   219篇
  1982年   222篇
  1981年   203篇
  1980年   234篇
  1979年   219篇
  1978年   193篇
  1977年   154篇
  1976年   167篇
  1974年   167篇
  1973年   210篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.

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   
6.
7.
8.
9.
This work describes the synthesis and tumor affinity testing of 8-[123I]iodo-l-1,2,3,4-tetrahydro-7-hydroxyisoquinoline-3-carboxylic acid [ITIC(OH)], a cyclic non-naturally occurring amino acid as an imaging probe for prostate cancer. Parameters for labelling were optimized with regard to the amount of precursor, the temperature and time. Thereafter, ITIC(OH) was evaluated in terms of its uptake in primary human PC-3 and DU-145 prostate cancer cells, followed by analysis of the underlying mechanisms of the radioactivity accumulation in tumor cells. No-carrier-added ITIC(OH) was obtained in 80+/-15% radiochemical yield and >98% radiochemical purity by a one-step radioiodination, using IODO-GEN as oxidant. The total synthesis time was less than 30 min, and compatible with a clinical routine production. ITIC(OH) accumulated intensively in primary human prostate cancer cells. The radioactivity incorporation in tumor following a 10-min incubation at 37 degrees C/pH 7.4 varied from 35% to 58% of the total loaded activity per 10(6) tumor cells (355-540 cpm/1000 cells). Inhibition experiments revealed that ITIC(OH) was taken up into tumor by an active transport different from the common amino acid carrier systems, including the sodium-dependent system A and B+,0, and the sodium-independent L- and ASC-type transporter. In contrast, the cellular incorporation was dependent on the membrane potential and correlated with the activity of the mitochondria. In conclusion, the specific and high-level accumulation of ITIC(OH) in human prostate carcinoma cells, indicates that the new radiopharmaceutical is a good candidate for further in vivo investigations to ascertain its potential as an imaging probe for prostate cancer by SPET.  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