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   874篇
  免费   69篇
  国内免费   18篇
耳鼻咽喉   3篇
儿科学   22篇
妇产科学   19篇
基础医学   109篇
口腔科学   10篇
临床医学   104篇
内科学   284篇
皮肤病学   8篇
神经病学   28篇
特种医学   22篇
外科学   60篇
综合类   14篇
预防医学   124篇
眼科学   7篇
药学   84篇
中国医学   9篇
肿瘤学   54篇
  2024年   2篇
  2023年   13篇
  2022年   33篇
  2021年   47篇
  2020年   27篇
  2019年   37篇
  2018年   28篇
  2017年   19篇
  2016年   18篇
  2015年   24篇
  2014年   31篇
  2013年   43篇
  2012年   54篇
  2011年   53篇
  2010年   44篇
  2009年   22篇
  2008年   50篇
  2007年   44篇
  2006年   49篇
  2005年   55篇
  2004年   24篇
  2003年   19篇
  2002年   26篇
  2001年   15篇
  2000年   14篇
  1999年   13篇
  1998年   20篇
  1997年   12篇
  1996年   7篇
  1995年   9篇
  1994年   8篇
  1993年   7篇
  1992年   15篇
  1991年   10篇
  1990年   8篇
  1989年   9篇
  1988年   16篇
  1987年   6篇
  1986年   5篇
  1985年   4篇
  1984年   4篇
  1983年   2篇
  1980年   2篇
  1977年   3篇
  1974年   1篇
  1973年   1篇
  1972年   1篇
  1970年   1篇
  1968年   1篇
  1954年   1篇
排序方式: 共有961条查询结果,搜索用时 15 毫秒
41.
42.
Chondrocalcinosis, chronic pseudo-osteoarthritis arthropathy, and osteoporosis are classic osteoarticular complications of hemochromatosis (HC). Within HC, femoral head aseptic osteonecrosis (FHAO) is not notified in textbooks. We describe 3 cases of FHAO occurring in this setting in 3 patients homozygous for the C282Y mutation on HFE gene who had no other risk factors for FHAO. FHAO was diagnosed 9 years before (Case 1), concomitantly with (Case 3), or 9 years after HC (Case 2). In one case, FHAO occurred although phlebotomies were regularly carried out. There are scarce data available in the literature on HC and FHAO. Our observations suggest FHAO may be an indicator for HC, and iron balance should be determined before considering FHAO as idiopathic. Thus phlebotomy may not be protective against the occurrence of FHAO. Studies are needed to determine the prevalence of HC in consecutive patients with FHAO.  相似文献   
43.
A commercially available repetitive-sequence-based PCR (rep-PCR) DNA fingerprinting assay adapted to an automated format, the DiversiLab system, enables rapid microbial identification and strain typing. We explored the performance of the DiversiLab system as a molecular typing tool for 69 Aspergillus isolates (38 A. fumigatus, 15 A. flavus, and 16 A. terreus isolates) had been previously characterized by morphological analysis. Initially, 27 Aspergillus isolates (10 A. fumigatus, 9 A. flavus, and 8 A. terreus isolates) were used as controls to create a rep-PCR-based DNA fingerprint library with the DiversiLab software. Then, 42 blinded Aspergillus isolates were typed using the system. The rep-PCR-based profile revealed 98% concordance with morphology-based identification. rep-PCR-based DNA fingerprints were reproducible and were consistent for DNA from both hyphae and conidia. DiversiLab dendrogram reports correctly identified all A. fumigatus (n = 28), A. terreus (n = 8), and A. flavus (n = 6) isolates in the 42 blinded Aspergillus isolates. rep-PCR-based identification of all isolates was 100% in agreement with the contiguous internal transcribed spacer (ITS) region (ITS1-5.8S-ITS2) sequence-based identification of the respective isolates. Additionally, the DiversiLab system could demonstrate strain-level differentiation of A. flavus and A. terreus. Automated rep-PCR may be a time-efficient, effective, easy-to-use, novel genotyping tool for identifying and determining the strain relatedness of fungi. This system may be useful for epidemiological studies, molecular typing, and surveillance of Aspergillus species.  相似文献   
44.
45.
46.
47.
Purpose

The purpose was to determine whether Appalachian residence alone or in combination with violence was linked to poorer quality of life (QOL).

Methods

Women recently diagnosed and included in either the Kentucky or North Carolina Cancer Registries were interviewed by phone between 2009 and 2015 (n?=?3320; mean age?=?56.74). Response rates were similar by state (40.1 in Kentucky and 40.9% in North Carolina). Appalachian (N?=?990) versus non-Appalachian residents (N?=?2330) were hypothesized to have poorer QOL defined as (a) lower Functional Assessment of Cancer Therapy—General (FACT-G) scores and (b) more symptoms of depression, stress, or comorbid physical conditions. Lifetime intimate partner or sexual violence was first investigated as a moderator then mediator of regional differences. Multiple analyses of covariance (MANCOVA) models were used.

Results

Violence modified the effect of Appalachian residence on poorer QOL outcomes; FACT-G total scores (p?=?.02) were lowest for women living in Appalachia who had additionally experienced violence. Socioeconomic indicators appeared to mediate or explain differences in QOL outcomes by Appalachian residence such that when adjusting for income, education and insurance, Appalachian residence remained associated only with poorer physical QOL outcomes (p?<?.05).

Conclusions

While violence rates did not differ by residence, the combined effect of living in Appalachia and experiencing violence resulted in significantly greater impact on poorer QOL among women recently diagnosed with cancer. Clinical consideration of patients’ residence, socioeconomic status and violence experienced may help identify and mitigate the longer-term impact of these identifiable factors associated with poorer QOL.

  相似文献   
48.
Eight compounds of plant origin with potential chemopreventive properties were studied for their effects on hamster liver microsome-mediated alkoxyresorufin O-dealkylase activity. The phytochemicals investigated were (+)-catechin, chlorophyllin, crocetin, curcumin, diallyl sulphide, (-)-epigallocatechin gallate (EGCG), d-limonene and tannic acid. Each phytochemical at concentrations of 0.25 μM and 0.5 μM was incubated with 0.2 mg hamster liver microsomal protein and 0.5 μmole benzyloxyresorufin, methoxyresorufin and ethoxyresorufin. The resorufins serve as substrates for measurements of the activity of isoforms of cytochrome P450 (CYP). Benzyloxyresorufin O-dealkylase (BROD), methoxyresorufin demethylase (MROD) and ethoxyresorufin deethylase (EROD) are linked to CYP 2C11, CYP 1A2 and CYP 2C6, respectively. Chlorophyllin, curcumin, EGCG and tannic acid were all potent inhibitors of BROD, MROD and EROD activity. (+)-Catechin and diallyl sulphide inhibited BROD and EROD but not MROD activity. Crocetin and d-limonene inhibited BROD activity more than MROD and EROD. These results indicate that the enzymatic activity of cytochrome P450 isoforms 2C11, 1A2 and 2C6 can be altered by phytochemicals and that phytochemicals can affect the metabolism of substrates for these isoforms. © 1998 John Wiley & Sons, Ltd.  相似文献   
49.
50.

Background  

HIV testing for pregnant women is an important component for the success of prevention of mother-to-child transmission of HIV (PMTCT). A lack of antenatal HIV testing results in loss of benefits for HIV-infected mothers and their children. However, the provision of unnecessary repeat tests at a very late stage of pregnancy will reduce the beneficial effects of PMTCT and impose unnecessary costs for the individual woman as well as the health system. This study aims to assess the number and timing of antenatal HIV testing in a low-income setting where PMTCT programmes have been scaled up to reach first level health facilities.  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