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   4416篇
  免费   238篇
  国内免费   11篇
耳鼻咽喉   38篇
儿科学   234篇
妇产科学   65篇
基础医学   353篇
口腔科学   101篇
临床医学   285篇
内科学   884篇
皮肤病学   90篇
神经病学   272篇
特种医学   92篇
外科学   1032篇
综合类   131篇
一般理论   2篇
预防医学   160篇
眼科学   273篇
药学   286篇
中国医学   29篇
肿瘤学   338篇
  2023年   58篇
  2022年   110篇
  2021年   199篇
  2020年   103篇
  2019年   127篇
  2018年   146篇
  2017年   113篇
  2016年   145篇
  2015年   145篇
  2014年   187篇
  2013年   254篇
  2012年   379篇
  2011年   344篇
  2010年   208篇
  2009年   135篇
  2008年   237篇
  2007年   224篇
  2006年   180篇
  2005年   175篇
  2004年   182篇
  2003年   154篇
  2002年   92篇
  2001年   103篇
  2000年   80篇
  1999年   67篇
  1998年   37篇
  1997年   38篇
  1996年   25篇
  1995年   20篇
  1994年   17篇
  1993年   7篇
  1992年   33篇
  1991年   35篇
  1990年   23篇
  1989年   32篇
  1988年   28篇
  1987年   18篇
  1986年   16篇
  1985年   26篇
  1984年   19篇
  1983年   15篇
  1982年   8篇
  1981年   7篇
  1980年   13篇
  1979年   9篇
  1978年   9篇
  1976年   9篇
  1974年   15篇
  1973年   7篇
  1972年   9篇
排序方式: 共有4665条查询结果,搜索用时 12 毫秒
51.
52.
53.
54.
The different rotameric conformations of imidazo-[1,2-a]pyrazine have been synthesized and characterized by means of different experimental techniques, such as NMR, FTIR, and absorption spectroscopy and quantum chemical calculations. The different conformations were stabilized by hydrogen bonds, such as OH⋯N, ArH⋯N and ArH⋯ArH. The ground state optimizations and potential energy surface (PES) scanning profiles produced using density functional theory (DFT) show two stable rotameric forms for each molecule. The relative population of the conformations is affected by the strength of the hydrogen bonds. The calculated absorption spectra and isotopic shielding constants were acquired by time-dependent density functional theory (TD-DFT) and gauge invariant atomic orbitals (GIAO)-DFT, respectively. The strength of the hydrogen bonding interactions that resulted in the different conformations was studied by quantum theory of atoms in molecules (QTAIM).

The different rotameric conformations of imidazo-[1,2-a]pyrazine have been synthesized and characterized by means of different experimental techniques, such as NMR, FTIR, and absorption spectroscopy and quantum chemical calculations.  相似文献   
55.

Purpose of Review

This review aims to describe the nonreconstructive options for treating ulnar collateral ligament (UCL) injuries ranging from nonoperative measures, including physical therapy and biologic injections, to ligament repair with and without augmentation.

Recent Findings

Nonoperative options for UCL injuries include guided physical therapy and biologic augmentation with platelet-rich plasma (PRP). In some patients, repair of the UCL has shown promising return to sport rates by using modern suture and suture anchor techniques. Proximal avulsion injuries have shown the best results after repair. Currently, there is growing interest in augmentation of UCL repair with an internal brace.

Summary

The treatment of UCL injuries involves complex decision making. UCL reconstruction remains the gold standard for attritional injuries and complete tears, which occur commonly in professional athletes. However, nonreconstructive options have shown promising results for simple avulsion or partial thickness UCL injuries. Future research comparing reconstructive versus nonreconstructive options is necessary.
  相似文献   
56.
57.
58.
59.
Heroin use and addiction pose serious risks and side effects due to overdose. Quantification of heroin in biological samples is challenging due to rapid deacetylation of heroin to its active metabolites. In this study, we report the quantification of metabolic degradation of heroin by-products in biological urine samples. The presence of the drug was monitored after oral administration of heroin at different time intervals. Various biophysical techniques, such as high performance liquid chromatography (HPLC) and mass spectrometry (MS) were used to evaluate the presence of the drug. A competitive fluorescence based immunoassay was developed with a limit of detection (LOD) up to 0.01 ng mL−1 and the IC50 value was 0.1 ng mL−1, while the dipstick assay shows a LOD up to 5 ng mL−1. Rapid detection of narcotic drugs was carried out for biological urine samples collected at various time points. Validation of the developed dipstick was carried out for the standard as well as the spiked urine samples by fluorescence based immunoassay (FIA), using anti-morphine antibodies. A strong correlation (R = 0.94) was obtained between the developed dipstick and FIA assay for biological urine samples collected at various time points. The developed immunochromatographic dipstick is highly sensitive, field applicable and cost effective, and can serve as a first choice for the monitoring of narcotic drugs in blood, urine and saliva in drug addicts and athletes.

Pathway of heroin degradation post oral administration in mice.  相似文献   
60.
Clinical Rheumatology - Consensus on treatment of idiopathic inflammatory myositis (IIM), particularly with regard to flares and interstitial lung disease (ILD), does not exist. We studied the...  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