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   35234篇
  免费   2062篇
  国内免费   183篇
耳鼻咽喉   421篇
儿科学   1132篇
妇产科学   996篇
基础医学   3600篇
口腔科学   1177篇
临床医学   2640篇
内科学   7445篇
皮肤病学   664篇
神经病学   2157篇
特种医学   1260篇
外国民族医学   4篇
外科学   6677篇
综合类   817篇
一般理论   27篇
预防医学   2341篇
眼科学   1320篇
药学   2770篇
  1篇
中国医学   257篇
肿瘤学   1773篇
  2023年   354篇
  2022年   300篇
  2021年   1065篇
  2020年   879篇
  2019年   1165篇
  2018年   1505篇
  2017年   1109篇
  2016年   1192篇
  2015年   1312篇
  2014年   1667篇
  2013年   2038篇
  2012年   3088篇
  2011年   2989篇
  2010年   1683篇
  2009年   1455篇
  2008年   2218篇
  2007年   2289篇
  2006年   2014篇
  2005年   1782篇
  2004年   1617篇
  2003年   1343篇
  2002年   1174篇
  2001年   359篇
  2000年   302篇
  1999年   270篇
  1998年   165篇
  1997年   121篇
  1996年   120篇
  1995年   105篇
  1994年   95篇
  1993年   75篇
  1992年   146篇
  1991年   160篇
  1990年   128篇
  1989年   123篇
  1988年   102篇
  1987年   97篇
  1986年   88篇
  1985年   116篇
  1984年   77篇
  1983年   51篇
  1982年   53篇
  1981年   54篇
  1980年   40篇
  1979年   49篇
  1978年   40篇
  1977年   34篇
  1975年   35篇
  1974年   36篇
  1973年   35篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Objective: Nucleolar organizer regions (NORs) are DNA coils that transcribe to ribosomal RNA. The NOR-associated protein, termed argyrophilic NOR (AgNOR), was visible within the nucleus by staining with silver nitrate examination via the light microscope. AgNOR counting is a proliferation marker and may help in the diagnosis and prognosis of various neoplastic lesions. Aneuploidy (abnormal DNA content) can predict the progression, survival and prognosis of the tumors. The aim of this study was to evaluate the role of AgNORs, DNA ploidy status, and total S-phase fraction (TSPF) as prognostic parameters in malignant salivary gland tumors (MSGTs). Methods: The current study is a retrospective study on a cohort of MSGTs (N=47), to assess AgNORs using Silver Nitrate stain, DNA index (DI), and TSPF using flow cytometry (FCM). Data including tumor size and site, lymphovascular invasion (LVI), lymph node metastasis (LNM) were collected. Results: The AgNORs count was statistically significant with MSGT type. DI was found to have a significant association with tumor site, tumor size and MSGT type. In addition, TSPF was found to be significantly associated with LVI. A moderate positive correlation was noted between AgNORs count and TSPF. LNM, tumor site, high AgNORs and low DI were all associated with short disease-free survival (DFS) and poor overall survival (OS). Conclusion: The present study revealed that high AgNORs count, DNA aneuploidy and TSPF had a poor influence on MSGTs prognosis.  相似文献   
2.
Management of colorectal cancer (CRC) was severely affected by the changes implemented during the pandemic, and this resulted in delayed elective presentation, increased emergency presentation, reduced screening and delayed definitive therapy. This review was conducted to analyze the impact of the coronavirus disease 2019 (COVID-19) pandemic on management of CRC and to identify the changes made in order to adapt to the pandemic. We performed a literature search in PubMed, Medline, Index Medicus, EMBASE, SCOPUS, Reference Citation Analysis (https://www.referencecitationanalysis.com/) and Google Scholar using the following keywords in various combinations: Colorectal cancer, elective surgery, emergency surgery, stage upgrading, screening, surveillance and the COVID-19 pandemic. Only studies published in English were included. To curtail the spread of COVID-19 infection, there were modifications made in the management of CRC. Screening was limited to high risk individuals, and the screening tests of choice during the pandemic were fecal occult blood test, fecal immunochemical test and stool DNA testing. The use of capsule colonoscopy and open access colonoscopy was also encouraged. Blood-based tests like serum methylated septin 9 were also encouraged for screening of CRC during the pandemic. The presentation of CRC was also affected by the pandemic with more patients presenting with emergencies like obstruction and perforation. Stage migration was also observed during the pandemic with more patients presenting with more advanced tumors. The operative therapy of CRC was altered by the pandemic as more emergencies surgeries were done, which may require exteriorization by stoma. This was to reduce the morbidity associated with anastomosis and encourage early discharge from the hospital. There was also an initial reduction in laparoscopic surgical procedures due to the fear of aerosols and COVID-19 infection. As we gradually come out of the pandemic, we should remember the lessons learned and continue to apply them even after the pandemic passes.  相似文献   
3.
Clinical Rheumatology - Nociplastic pain (NP), as a mechanistic term, denotes pain arising from altered nociception without clear evidence of tissue or somatosensory damage. Fibromyalgia (FM), a...  相似文献   
4.
5.
6.
7.
Hepatitis C virus(HCV)is a significant cause of hepatocellular carcinoma(HCC).The direct-acting antivirals marked a new era of HCV therapy and are associated with greater than 95%cure rate.Successful treatment of chronic hepatitis C greatly reduces the risk of HCC.A proportion of patients,especially those with pre-existing cirrhosis,remain at risk for HCC despite sustained virologic response(SVR).Diabetes mellitus,hepatic steatosis,alcohol consumption and lack of fibrosis regression are associated with risks of HCC after HCV cure.Noninvasive modalities such as aspartate aminotransferase to platelet ratio index and fibrosis-4 index and transient elastography have been used to monitor hepatic fibrosis.More recently,various fibrosis scores have been combined with clinical parameters and other novel biomarkers to predict risks of HCC for patients who achieved SVR.These models still need to be validated and standardized prior to applying to routine clinical care.  相似文献   
8.
International Ophthalmology - To compare the efficacy of gonioscopy-assisted transluminal trabeculotomy combined with cataract surgery (PGATT) and trabeculectomy combined with cataract surgery...  相似文献   
9.
International Ophthalmology - We describe a portable practice model for acquisition of microsurgical skills using widely available inexpensive tools and materials as a model in learning ophthalmic...  相似文献   
10.

Associations between social determinants of health (SDOH), demographic factors including preferred language, and SARS-CoV-2 detection are not clear. We conducted a retrospective cohort study among those seeking testing for SARS-CoV-2 at a multi-site, urban community health center. Logistic regression and exact matching methods were used to identify independent predictors of SARS-CoV-2 detection among demographic, SDOH, and neighborhood-level variables. Of 1,361 included individuals, SARS-CoV-2 was detected among 266 (19.5%). Logistic regression demonstrated that SARS-CoV-2 detection was less likely in White participants relative to Hispanic participants (adjusted odds ratio [aOR] 0.18, 95% confidence interval [CI] 0.05–0.46). and more likely in patients who prefer Spanish relative to those that prefer English (aOR 2.04, 95% CI 1.43–2.96). No observed SDOH predicted SARS-CoV-2 detection in adjusted models. A robustness analysis using a matched subset of the study sample produced findings similar to those in the main analysis. Preferring to receive care in Spanish is an independent predictor of SARS-CoV-2 detection in a community health center cohort.

  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