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   24108篇
  免费   1807篇
  国内免费   98篇
耳鼻咽喉   395篇
儿科学   837篇
妇产科学   379篇
基础医学   2467篇
口腔科学   554篇
临床医学   2179篇
内科学   5291篇
皮肤病学   560篇
神经病学   1283篇
特种医学   1196篇
外国民族医学   1篇
外科学   4596篇
综合类   374篇
一般理论   15篇
预防医学   1172篇
眼科学   826篇
药学   2074篇
中国医学   38篇
肿瘤学   1776篇
  2023年   223篇
  2022年   404篇
  2021年   987篇
  2020年   475篇
  2019年   817篇
  2018年   950篇
  2017年   614篇
  2016年   647篇
  2015年   678篇
  2014年   1018篇
  2013年   1196篇
  2012年   1743篇
  2011年   1718篇
  2010年   888篇
  2009年   834篇
  2008年   1282篇
  2007年   1233篇
  2006年   1150篇
  2005年   985篇
  2004年   899篇
  2003年   759篇
  2002年   653篇
  2001年   594篇
  2000年   557篇
  1999年   494篇
  1998年   187篇
  1997年   166篇
  1996年   176篇
  1995年   163篇
  1994年   124篇
  1993年   117篇
  1992年   273篇
  1991年   288篇
  1990年   250篇
  1989年   233篇
  1988年   218篇
  1987年   232篇
  1986年   202篇
  1985年   187篇
  1984年   120篇
  1983年   131篇
  1982年   90篇
  1981年   75篇
  1980年   68篇
  1979年   132篇
  1978年   80篇
  1977年   74篇
  1975年   63篇
  1974年   65篇
  1973年   88篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
The combination of kidney paired donation (KPD) with desensitization represents a promising method of increasing the rate of living donor kidney transplantation (LDKT) in immunologically challenging patients. Patients who are difficult to match and desensitize due to strong donor specific antibody are may be transplanted by a combination of desensitization and KPD protocol with more immunologically favorable donor. We present our experience of combination of desensitization protocol with three-way KPD which contributed to successful LDKT in highly sensitized end stage renal disease patient. All recipients were discharged with normal and stable allograft function at 24 mo follow up. We believe that this is first report from India where three-way KPD exchange was performed with the combination of KPD and desensitization. The combination of desensitization protocol with KPD improves access and outcomes of LDKT.  相似文献   
994.
Chronic obstructive pulmonary disease (COPD) is common and has significant morbidity and mortality as the fourth leading cause of death in the United States. In many patients, particularly those with emphysema, COPD is characterized by markedly increased residual volume contributing to exertional dyspnea. Current therapies have limited efficacy. Surgical resection of diseased areas of the lung to reduce residual volume was effective in identified subgroups but also had significant mortality in and suboptimal cost effectiveness. Lung-volume reduction, using bronchoscopic techniques, has shown substantial benefits in a broader patient population with less morbidity and mortality. This review is meant to spread the awareness about bronchoscopic lung-volume reduction and to promote its consideration and early referral for patients with advanced COPD and emphysema frequently encountered by both primary care physicians and specialists. A search was conducted on PubMed (MEDLINE), EMbase, and Cochrane library for original studies, using the following keywords: “lung-volume reduction.” “endobronchial valves,” “intrabronchial valves,” “bronchoscopic lung-volume reduction,” and “endoscopic lung-volume reduction.” We included reports from systematic reviews, narrative reviews, clinical trials, and observational studies. Two reviewers evaluated potential references. A total of 27 references were included in our review. Included studies report experience in the diagnosis and bronchoscopic treatment for emphysema; case reports and non-English or non-Spanish studies were excluded.  相似文献   
995.
BACKGROUND: Because transforming growth factor beta (TGF-beta) has been shown to have a bimodal effect on mesangial cell (MC) proliferation, we studied its effect on MC apoptosis. METHODS: Cultured mouse MCs were used to evaluate the effect of TGF-beta. Morphologic evaluation of MC apoptosis was performed by staining cells with H-33342 and propidium iodide. To confirm the effect of TGF-beta on MC apoptosis, DNA was extracted from control and TGF-beta-treated MCs and run on gel electrophoresis. We evaluated the effect of NG-nitro-L-arginine methyl ester (L-NAME), a nitric oxide (NO) synthase inhibitor, on TGF-beta-induced MC apoptosis to determine the role of NO and studied the effect of sodium nitroprusside (SNP) and SNAP (S-nitroso-N-acetyl-penicillamine) on MC apoptosis to confirm the effect of NO. We examined the role of p53 by studying the effect of TGF-beta on MCs derived from p53 knockout mice (p53KO-MC) as well as a normogenic strain (N-MC). We also examined the effect of TGF-beta, SNP, and SNAP on apoptosis of p53 mutant (MDAMB-231) and wild-type p53 (MCF-7) breast cancer cell lines. In addition, Western blots were generated from control, TGF-beta-treated, and SNAP-treated MCs and probed for the expression of p53. RESULTS: TGF-beta promoted MC apoptosis. Moreover, TGF-beta-treated MCs displayed integer multiples of 180 base pairs (ladder pattern). L-NAME inhibited TGF-beta-induced MC apoptosis. Furthermore, SNP and SNAP, NO donors, promoted MC apoptosis. TGF-beta also enhanced the MC expression of p53. TGF-beta induced only a moderate degree of apoptosis in MCs derived from p53KO-MC when compared with N-MCs. Similarly, the TGF-beta-induced apoptosis of MDAMB-231 was of a moderate degree when compared with MCF-7 cells. CONCLUSIONS: We hypothesize that TGF-beta promotes MC apoptosis through NO generation and p53-dependent and -independent pathways.  相似文献   
996.
997.
998.
999.
Development of noninvasive methods for the diagnosis of transitional cell carcinoma (TCC) of the bladder remains a challenge. A ProteinChip technology (surface enhanced laser desorption/ionization time of flight mass spectrometry) has recently been developed to facilitate protein profiling of biological mixtures. This report describes an exploratory study of this technology as a TCC diagnostic tool. Ninety-four urine samples from patients with TCC, patients with other urogenital diseases, and healthy donors were analyzed. Multiple protein changes were reproducibly detected in the TCC group, including five potential novel TCC biomarkers and seven protein clusters (mass range, 3.3 to 133 kd). One of the TCC biomarkers (3.4 kd) was also detected in bladder cancer cells procured from bladder barbotage and was identified as defensin. The TCC detection rates provided by the individual markers ranged from 43 to 70% and specificities from 70 to 86%. Combination of the protein biomarkers and clusters, increased significantly the sensitivity for detecting TCC to 87% with a specificity of 66%. Interestingly, this combinatorial approach provided sensitivity of 78% for detecting low-grade TCC compared to only 33% of voided urine or bladder-washing cytology. Collectively these results support the potential of this proteomic approach for the development of a highly sensitive urinary TCC diagnostic test.  相似文献   
1000.
In the presence of infection, neutropenia is considered to be a marker of poor prognosis; conversely, neutrophilia may not be a determinant of a better prognosis. Since apoptotic neutrophils are compromised functionally, we evaluated the effect of infection on neutrophil apoptosis. The rate of apoptosis was greater for neutrophils isolated from patients with infection than for healthy controls. Escherichia coli did not directly modulate the rate of neutrophil apoptosis. However, sera from infected patients promoted (P < 0.001) neutrophil apoptosis. Interestingly, the sera of patients with different types of infection (gram negative, gram positive, or culture negative) exerted a more or less identical response on neutrophil apoptosis. Sera of infected patients showed a fivefold greater content of FasL compared to controls. Moreover, anti-FasL antibody partly attenuated the infected-serum-induced neutrophil apoptosis. In in vitro studies, E. coli enhanced monocyte FasL expression. Moreover, conditioned media prepared from activated macrophages from control mice showed enhanced apoptosis of human as well as mouse neutrophils. On the contrary, conditioned media prepared from activated macrophages isolated from FasL-deficient mice induced only a mild degree of neutrophil apoptosis. These results suggest that neutrophils in patients with infection undergo apoptosis at an accelerated rate. Infection not only promoted monocyte expression of FasL but also increased FasL content of the serum. Because the functional status of apoptotic cells is compromised, a significant number of neutrophils may not be participating in the body's defense. Since neutrophils play the most important role in innate immunity, their compromised status in the presence of infection may transfer the host defense burden from an innate response to acquired immunity. The present study provides some insight into the lack of correlation between neutrophilia and the outcome of infection.  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