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   375986篇
  免费   24550篇
  国内免费   2715篇
耳鼻咽喉   5182篇
儿科学   8158篇
妇产科学   10073篇
基础医学   52726篇
口腔科学   11766篇
临床医学   29638篇
内科学   77659篇
皮肤病学   8537篇
神经病学   27010篇
特种医学   13872篇
外国民族医学   82篇
外科学   60367篇
综合类   9918篇
一般理论   64篇
预防医学   17148篇
眼科学   9385篇
药学   30809篇
  1篇
中国医学   2168篇
肿瘤学   28688篇
  2019年   2653篇
  2018年   4352篇
  2017年   3306篇
  2016年   3439篇
  2015年   3940篇
  2014年   5670篇
  2013年   7338篇
  2012年   9987篇
  2011年   10171篇
  2010年   6161篇
  2009年   5813篇
  2008年   9423篇
  2007年   10269篇
  2006年   10176篇
  2005年   9246篇
  2004年   8759篇
  2003年   8484篇
  2002年   8158篇
  2001年   28254篇
  2000年   28759篇
  1999年   23609篇
  1998年   5023篇
  1997年   4100篇
  1996年   3679篇
  1995年   3470篇
  1994年   3099篇
  1993年   2837篇
  1992年   16035篇
  1991年   14804篇
  1990年   14136篇
  1989年   13944篇
  1988年   12578篇
  1987年   12056篇
  1986年   11097篇
  1985年   10318篇
  1984年   6908篇
  1983年   5598篇
  1982年   2716篇
  1979年   5476篇
  1978年   3345篇
  1977年   2963篇
  1976年   2229篇
  1975年   2632篇
  1974年   3062篇
  1973年   2862篇
  1972年   2823篇
  1971年   2763篇
  1970年   2507篇
  1969年   2540篇
  1968年   2249篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Clinical Oral Investigations - To analyze differences in variation of orthodontic diagnostic measurements on lateral cephalograms reconstructed from ultra low dose-low dose (ULD-LD) cone beam...  相似文献   
2.
PurposeThis study aimed to describe the spectrum of cancers observed in Bloom Syndrome and the observed survival and age of first cancer diagnosis in Bloom syndrome as these are not well-defined.MethodsData from the Bloom Syndrome Registry (BSR) was used for this study. Cancer history, ages of first cancer diagnosis, and ages of death were compiled from the BSR and analyzed.ResultsAmong the 290 individuals in the BSR, 155 (53%) participants developed 251 malignant neoplasms; 100 (65%) were diagnosed with 1 malignancy, whereas the remaining 55 (35%) developed multiple malignancies. Of the 251 neoplasms, 83 (33%) were hematologic and 168 (67%) were solid tumors. Hematologic malignancies (leukemia and lymphoma) were more common than any of the solid tumors. The most commonly observed solid tumors were colorectal, breast, and oropharyngeal. The cumulative incidence of any malignancy by age 40 was 83%. The median survival for all participants in the BSR was 36.2 years. There were no significant differences in time to first cancer diagnosis or survival by genotype among the study participants.ConclusionWe describe the spectrum of cancers observed in Bloom syndrome and the observed survival and age of first cancer diagnosis in Bloom syndrome. We also highlight the significant differences in survival and age of diagnosis seen among different tumor types and genotypes.  相似文献   
3.
Whether the underlying mutations are homozygous, heterozygous, or co-inherited with other hemoglobinopathies, sickle cell disease is known to afflict the kidneys, leading to the clinical entity known as sickle cell nephropathy (SCN). Although common, SCN remains diagnostically elusive. Conventional studies performed in the context of renal disorders often fail to detect early stage SCN. This makes the quest for early diagnosis and treatment more challenging, and it increases the burden of chronic kidney disease-related morbidity among patients. Novel diagnostic tools have been employed to overcome this limitation. In this study, we discuss various biomarkers of SCN, including those employed in clinical practice and others recently identified in experimental settings, such as markers of vascular injury, endothelial dysfunction, tubulo-glomerular damage, and oxidative stress. These include kidney injury molecule-1, monocyte chemoattractant protein-1, N-acetyl-B-D-glucosaminidase, ceruloplasmin, orosomucoid, nephrin, and cation channels, among others. Furthermore, we explore the potential of novel biomarkers for refining diagnostic and therapeutic approaches and describe some obstacles that still need to be overcome. We highlight the importance of a collaborative approach to standardize the use of promising new biomarkers. Finally, we outline the limitations of conventional markers of renal damage as extensions of the pathogenic process occurring at the level of the organ and its functional subunits, with a discussion of the expected pattern of clinical and biochemical progression among patients with SCN.  相似文献   
4.
Bulletin of Experimental Biology and Medicine - We studied whether menthol can promote penetration of natamycin, a representative antifungal macrolide agent, through the cornea. Natamycin...  相似文献   
5.
6.
Background

Vaccination prevents severe morbidity and mortality from COVID-19 in the general population. The immunogenicity and efficacy of SARS-CoV-2 vaccines in patients with antibody deficiency is poorly understood.

Objectives

COVID-19 in patients with antibody deficiency (COV-AD) is a multi-site UK study that aims to determine the immune response to SARS-CoV-2 infection and vaccination in patients with primary or secondary antibody deficiency, a population that suffers from severe and recurrent infection and does not respond well to vaccination.

Methods

Individuals on immunoglobulin replacement therapy or with an IgG less than 4 g/L receiving antibiotic prophylaxis were recruited from April 2021. Serological and cellular responses were determined using ELISA, live-virus neutralisation and interferon gamma release assays. SARS-CoV-2 infection and clearance were determined by PCR from serial nasopharyngeal swabs.

Results

A total of 5.6% (n?=?320) of the cohort reported prior SARS-CoV-2 infection, but only 0.3% remained PCR positive on study entry. Seropositivity, following two doses of SARS-CoV-2 vaccination, was 54.8% (n?=?168) compared with 100% of healthy controls (n?=?205). The magnitude of the antibody response and its neutralising capacity were both significantly reduced compared to controls. Participants vaccinated with the Pfizer/BioNTech vaccine were more likely to be seropositive (65.7% vs. 48.0%, p?=?0.03) and have higher antibody levels compared with the AstraZeneca vaccine (IgGAM ratio 3.73 vs. 2.39, p?=?0.0003). T cell responses post vaccination was demonstrable in 46.2% of participants and were associated with better antibody responses but there was no difference between the two vaccines. Eleven vaccine-breakthrough infections have occurred to date, 10 of them in recipients of the AstraZeneca vaccine.

Conclusion

SARS-CoV-2 vaccines demonstrate reduced immunogenicity in patients with antibody deficiency with evidence of vaccine breakthrough infection.

  相似文献   
7.
8.
9.
The use of radiation for primary liver cancers has historically been limited because of the risk of radiation-induced liver disease. Treatment fields have become more conformal because of several technical advances, and this has allowed for dose escalation. Stereotactic body radiation therapy (SBRT), also known as stereotactic ablative radiotherapy, is now able to safely treat liver tumors to ablative doses while sparing functional liver parenchyma by using highly conformal therapy. Several retrospective and small prospective studies have examined the use of SBRT for liver cancers; however, there is a lack of well-powered randomized studies to definitively guide management in these settings. Recent advances in systemic therapy for primary liver cancers have improved outcomes; however, the optimal selection criteria for SBRT as a local therapy remain unclear among other liver-directed options such as radiofrequency ablation, transarterial chemoembolization, and radioembolization.  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