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   30390篇
  免费   2642篇
  国内免费   2051篇
耳鼻咽喉   223篇
儿科学   407篇
妇产科学   347篇
基础医学   3442篇
口腔科学   539篇
临床医学   4032篇
内科学   4591篇
皮肤病学   267篇
神经病学   1468篇
特种医学   1277篇
外国民族医学   12篇
外科学   3429篇
综合类   4848篇
现状与发展   6篇
一般理论   3篇
预防医学   1920篇
眼科学   700篇
药学   3159篇
  37篇
中国医学   1636篇
肿瘤学   2740篇
  2024年   351篇
  2023年   588篇
  2022年   1116篇
  2021年   1405篇
  2020年   1112篇
  2019年   1017篇
  2018年   972篇
  2017年   927篇
  2016年   955篇
  2015年   1319篇
  2014年   1612篇
  2013年   1461篇
  2012年   1947篇
  2011年   2330篇
  2010年   1489篇
  2009年   1156篇
  2008年   1498篇
  2007年   1573篇
  2006年   1513篇
  2005年   1474篇
  2004年   1126篇
  2003年   1139篇
  2002年   1018篇
  2001年   863篇
  2000年   793篇
  1999年   746篇
  1998年   433篇
  1997年   501篇
  1996年   333篇
  1995年   295篇
  1994年   232篇
  1993年   189篇
  1992年   228篇
  1991年   213篇
  1990年   182篇
  1989年   164篇
  1988年   133篇
  1987年   136篇
  1986年   119篇
  1985年   76篇
  1984年   50篇
  1983年   28篇
  1982年   16篇
  1981年   17篇
  1980年   25篇
  1979年   45篇
  1978年   22篇
  1976年   12篇
  1975年   18篇
  1974年   20篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
The present study was to examine the distribution of lymphatic vessels in the penis of normal adult males, which could provide an anatomical basis for improvement of incisions in penile lengthening surgery, and may also help to prevent postoperative refractory edema. Thirteen normal adult male volunteers were recruited for this study. Contrast agent was injected subcutaneously in the foreskin of the penis, and after two minutes magnetic resonance lymphangiography (MRL) was performed. The acquired magnetic resonance images were analyzed to determine the changes in the number and diameter of lymphatic vessels in different parts of the penis. Maximum intensity projections (MIP) and materializes interactive medical image control system (MIMICS) were applied to analyze the overall distribution of lymphatic vessels in the penis. Magnetic resonance imaging (MRI) showed that the lymphatic vessels were in conspicuous contrast with surrounding tissues and could be clearly identified. Penile lymphatic vessels were clearly visible in the root of the penis. At the junction of the penis and the abdominal wall, all lymphatic vessels were found to be concentrated in the dorsal part of the penis. MIP two‐dimensional reconstruction showed that the overall distribution of relatively large lymphatic vessels in the dorsal and ventral parts of the penis could be seen clearly on bilateral 45° position, but not inside the abdominal wall because some of lymphatic vessels were overlapped by other tissues in the abdomen. MIMICS three‐dimensional reconstruction was able to reveal the overall spatial distribution of lymphatic vessels in the penis from any angle. The reconstruction results showed that there were 1–2 main lymphatic vessels on the root of dorsal penis, which coursed along the cavernous to the first physiological curvature of the penis. Lymphatic vessels merged on both sides of the ventral penis. At the root of the penis, lymphatic vessels gradually coursed to the dorsal surface of the penis and folded at the abdominal wall to the outside, and finally merged into the inguinal lymph nodes. The changes in distribution, number and diameter of the lymphatic vessels in the penis were observed by MRI. MIP and MIMICS reconstructions directly revealed the anatomical features of penile lymphatic vessels such as spatial distribution, overall alignment, and the relations to adjacent structures, drainage and reflux. The study will provide the anatomical basis for penile surgery, penile lymphatic reflux disorders caused by trauma or lymphatic vessels obstruction, and lymph node metastasis in penile cancer. Anat Rec, 298:1465–1471, 2015. © 2014 Wiley Periodicals, Inc.  相似文献   
92.
Epidemiological and histopathological studies have indicated that proliferative inflammatory atrophy (PIA) of the prostate is closely associated with the onset and development of prostate cancer (PCa). However, accurate isolation of PIA still remains a difficult matter, as well as high-quality RNA extraction from isolated PIA. These issues generated a lack of molecular evidence to support the mechanistic explanation proposed for the progression of PIA to PCa. Therefore, the isolation of PIA and the extraction of high-quality RNA from isolated PIA are of great importance to further demonstrate the correlation between PIA and the development of PCa at a molecular level. In this study, clinical samples from radical prostatectomy were stored in liquid nitrogen, PIA was identified by H&E staining of cryosections, PIA clusters were isolated by manual microdissection, total RNA was extracted from the PIA clusters by Trizol, and RNA quality was determined using the Agilent 2100 Bioanalyzer. Our results showed that PIA might be isolated by manual microdissection of cryosections stored in liquid nitrogen from clinical radical prostatectomy and used for extracting high-quality RNA (RIN > 7.5) by Trizol. Therefore, the present study established a valid method to discover molecular evidence in support of the correlation between PIA and the development of PCa.  相似文献   
93.
Renal cell carcinoma has become the most common subtype of kidney cancer, and has the highest propensity to manifest as metastatic disease. Because of lack of knowledge in events that correlated with tumor cell migration and invasion, few therapeutic options are available. Therefore, in current study, we explore the anti-tumoral effect of a potential chemopreventive natural product, quercetin, combined with anti-sense oligo gene therapy (inhibiting Snail gene). We found that either one of them had the remarkable effects in suppressing cell proliferation and migration, inducing cell cycle arrest and apoptosis in a ccRCC cell line, Caki-2 cells. The combination of both means provides even strong suppressive effects toward these ccRCC cells. Our study, for the first time, provides the possibility of using a novel treatment for renal cancer, by combining natural product and gene therapy.  相似文献   
94.
目的:总结急诊科医护人员遭受工作场所身体暴力事件后的真实体验,分析身体暴力事件对其造成的影响,以期引起相关部门的重视。方法:采用质性研究中传统的扎根理论研究方法,选择广州市3家三级甲等医院10例遭受过急诊科身体暴力事件的医护人员,进行半结构式访谈,遵循Colaizzi七步法,分析访谈内容。结果:遭受急诊科身体暴力事件的医护人员存在以委屈感、愤怒感、无助感、恐惧感、厌倦感为主的负面情绪,存在安全、心理辅导、被尊重、普及规章流程及法律知识、获得医院社会支持五个方面的需求。结论:医疗机构及社会相关部门应重视急诊科医护人员遭受身体暴力事件的情况,建立完善的遭受身体暴力事件后的支持系统,减少其负面情绪并满足其多种需求。  相似文献   
95.
96.
MicroRNAs (miRNAs) are a family of non-coding RNA that are able to adjust the expression of many proteins, including ATP-binding cassette transporter and organic cation transporter. We sought to evaluate the effect of miR-511 on the regulation of OATP1B1 expression by free fatty acids. When using free fatty acids to stimulate Chang liver cells, we found that the expression of miR-511 increased significantly while the expression of OATP1B1 decreased. We also proved that SLCO1B1 is the target gene of miR-511 with a bioinformatics analysis and using the dual luciferase reporter assay. Furthermore, the expressions of SLCO1B1 and OATP1B1 decreased if transfecting Chang liver cells with miR-511, but did not increase when transfecting the inhibitors of miR-511 into steatosis cells. Our study indicates that miR-511 may play an important role in the regulation of OATP1B1 expression by free fatty acids.  相似文献   
97.
Tong  Xianzeng  Deng  Xiaofeng  Yang  Tao  Yang  Chenlong  Wu  Liang  Wu  Jun  Yao  Yuqiang  Fu  Zhuang  Wang  Shuo  Xu  Yulun 《Journal of neuro-oncology》2015,124(3):455-463
Journal of Neuro-Oncology - Primary spinal peripheral primitive neuroectodermal tumors (pPNETs) are extremely rare entities that predominantly occur in children and young adults. Few studies have...  相似文献   
98.
OBJECTIVE: To review the clinical and endoscopic features, and outcome of ischemic colitis. METHODS: Sixty cases with the diagnosis of ischemic colitis were retrospectively analyzed. All the patients were under observation in hospital and most of them underwent colonoscopy at least twice: once for diagnosis and then follow‐up after treatment. The demographic data, presenting symptoms, endoscopic findings, laboratory tests, and treatment were reviewed. RESULTS: Fifty‐two of the 60 cases were over 50 years old (87%; mean age, 59.9 years): 40 female, 20 male (2 : 1); 76.0% of these patients had a coexistent disease such as a cardio‐cerebrovascular disorder, diabetes, hematologic diseases or a previous history of abdominal surgery. Abdominal pain (57/60, 95%), hematochezia (55/60, 91.7%), and diarrhea (26/60, 43.3%) were the main complaints. Lesions seen on colonoscopy were more commonly located in the left colon (46/60, 79.3%) and rectum (5/60, 8.6%), and were characteristically segment‐distributed, including hemorrhagic edematous mucosa, erosions, ulcerations, pseudopolyps, and stricture. Ultrasonography revealed colonic wall thickening in 13 cases (13/55, 21.7%), and small to moderate ascites was detected in 4 cases (4/55, 7.3%). In this cohort, most of the patients recovered (49/60, 81.7%) or improved (10/60, 16.7%) after conservative treatment. Only one patient who had a myocardial infarction prior to the onset of the ischemic colitis, died from peritonitis complicated with septic shock. Progress and outcome were associated with the patient's age, severity of the lesions, clinical course, underlying diseases and the complications. CONCLUSION: Colonoscopy is safe and helpful in the early diagnosis of ischemic colitis. Nongangrenous colonic ischemia usually requires only medical management and is associated with a good prognosis.  相似文献   
99.
介绍了重庆西永垃圾转运站的建筑背景、工程概况及工程总体设计方案,具体阐述了转运工艺、设备配置、车间工艺布置、除臭、渗沥液处理等设计内容,并论述了该项目特点及创新性。  相似文献   
100.
Thenatural vitreous body has a fine structure and complex functions. The imitation of the natural vitreous body by vitreous substitutes is a challenging work for both researchers and ophthalmologists. Gases, silicone oil, heavy silicone oil and hydrogels, particularly the former two vitreous substitutes are clinically widely used with certain complications. Those, however, are not real artificial vitreous due to lack of structure and function like the natural vitreous body. This article reviews the situations, challenges, and future directions in the development of vitreous substitutes, particularly the experimental and clinical use of a new artificial foldable capsular vitreous body .  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