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   249882篇
  免费   19870篇
  国内免费   13528篇
耳鼻咽喉   2253篇
儿科学   3055篇
妇产科学   4903篇
基础医学   28863篇
口腔科学   4290篇
临床医学   31678篇
内科学   40636篇
皮肤病学   2869篇
神经病学   13949篇
特种医学   8633篇
外国民族医学   96篇
外科学   27307篇
综合类   34588篇
现状与发展   48篇
一般理论   45篇
预防医学   15298篇
眼科学   6803篇
药学   24554篇
  245篇
中国医学   11292篇
肿瘤学   21875篇
  2024年   3027篇
  2023年   4658篇
  2022年   9012篇
  2021年   11710篇
  2020年   9092篇
  2019年   8172篇
  2018年   8075篇
  2017年   7084篇
  2016年   6802篇
  2015年   10155篇
  2014年   12781篇
  2013年   11930篇
  2012年   17608篇
  2011年   19249篇
  2010年   11753篇
  2009年   9403篇
  2008年   12780篇
  2007年   12837篇
  2006年   12389篇
  2005年   12461篇
  2004年   8619篇
  2003年   7651篇
  2002年   6624篇
  2001年   5999篇
  2000年   6121篇
  1999年   6413篇
  1998年   3656篇
  1997年   3679篇
  1996年   2798篇
  1995年   2589篇
  1994年   2234篇
  1993年   1501篇
  1992年   2291篇
  1991年   1996篇
  1990年   1665篇
  1989年   1456篇
  1988年   1267篇
  1987年   1176篇
  1986年   941篇
  1985年   748篇
  1984年   491篇
  1983年   382篇
  1982年   225篇
  1981年   201篇
  1980年   191篇
  1979年   244篇
  1978年   141篇
  1977年   112篇
  1976年   97篇
  1974年   116篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Timely detection is crucial for successful treatment of cancer. The current study describes a new approach that involves utilization of the tumor cell environment for bioimaging with in-situ biosynthesized nanoscale gold and iron probes and subsequent dissemination of Au-Fe nanoclusters from cargo exosomes within the circulatory system. We have isolated the Au-Fe cargo exosomes from the blood of the treated murine models after in situ biosyntheses from their respective pre-ionic solutions (HAuCl4, FeCl2), whereas Na2SeO3 supplementation added into Au lethal effect. The microarray data of various differentially expressed genes revealed the up-regulated tumor ablation and metal binding genes in SGC-7901 cell lines after treatment with Au-Fe-Se triplet ionic solution. The isolation of Au-Fe nanoclusters cargo exosomes (nano in nano) after secretion from deeply seated tumors may help in early diagnosis and reveal the tumor ablation status during and after the relevant treatment like radio-chemo therapies et al.  相似文献   
42.
Peripheral Arterial Occlusive Disease (PAOD) is an aging disease that affects the quality of life of many people by its intermittent claudication and critical limb ischemia presentations. Traditional treatment and management of PAOD are asking patients to make a life change and medication with antiplatelet, statins and cilostazol, which decrease the possibility of clot formation. Our strategy has employed a magnetic Fe3O4-PLGA polymersome to carry the cilostazol into the ischemic area by magnetic attraction following remote-control drug release through low-energy ultrasound exposure. In the animal studies, the cilostazol-loaded Fe3O4-PLGA polymersomes were injected and accumulated at ischemic leg through magnetic attraction. Then, using a clinical-use ultrasound machine the leg was irradiated to forward cilostazol release from the accumulated polymersomes. Dramatically, we found an observable result of bloody flux recovery in the leg after 7?days compared to the non-treated leg that showed no evidence of the blood recovery.  相似文献   
43.
44.
Purpose: To perform preclinical studies to determine the efficacy and safety of anthocyanins as stains for the internal limiting membrane (ILM) of the eye.

Materials and methods: Cyanidin (Cya), delphinidin (Del), luteolinidin (Lut), peonidin (Peo) and pelargonidin (Pel) were evaluated. These natural dyes were used to stain the lens capsule and ILM of pig eyes. The effects of these dyes on retinal cell viability was determined using a water-soluble tetrazolium salt assay, and oxidative stress was measured in vitro. Histopathology, in situ TUNEL labelling, transmission electronic microscopy (TEM), and electroretinography (ERG) were performed on rats following the intravitreal and subretinal injection of the neuroprotective dyes.

Results: All anthocyanins stained the lens capsule and ILM of the pigs at a concentration of 1?mg/ml. Del, Lut and Peo were non-toxic and produced survival rates in the ARPE19 and RGC5 cells that were similar to those in control cells. We treated eyes with H2O2 and three dyes (Del, Lut, and Peo) to explore the possible neuroprotective effects and observed significantly higher survival rates in the ARPE19 cells treated with Del, Lut or Peo and the RGC5 cells treated with Lut or Peo than those in the control cells. Three dyes were intravitreally and subretinally injected into rats in vivo, and the histology showed mildly disorganized retinal cell layers. TUNEL staining and TEM examinations did not reveal additional toxic effects. Rat ERGs were not altered after intravitreal injections.

Conclusions: This preclinical study, Del, Lut, and Peo show potential as staining agents and warrant further investigation as vital dyes.  相似文献   
45.
The consequences of once-weekly rifapentine plus isoniazid for 3 months (3HP) against latent tuberculosis infections in hemodialysis patients have not been studied before. This is the first study to evaluate the safety and tolerability of 3HP in this population and revealed a completion rate of 65.4%. The therapy was not associated with hepatotoxicity, but with high rates of adverse events (69.2%).  相似文献   
46.
Background/purposeMethicillin-resistant Staphylococcus aureus (MRSA) can encode proteins which directly bind bacteria to many tissues and medical devices or catheters to trigger pathogenesis. However, the relationship between genetic backgrounds and virulent factors in MRSA isolates remained incompletely understood yet.MethodsMRSA isolates were collected from blood cultures of patients with infective endocarditis, bone/joint infection, skin/soft tissue infection, or catheter-related bacteremia in hemodialysis at a tertiary medical center between 2005 and 2011. MRSA isolates were characterized by the methods of spa, multilocus sequence, and staphylococcal cassette chromosome mec (SCCmec) typing. Identification of virulence gene expression was measured by Power SYBR Green PCR Master Mix.ResultsOverall collected were 136 MRSA bacteremic isolates, including those from the cases of infective endocarditis (n = 23), bone/joint infection (n = 49), skin/soft tissue infection (n = 20), or catheter-related bacteremia in patients with acute kidney injury or end-stage renal stage receiving hemodialysis (n = 54). CC8-ST239-MRSA-SCCmec type III-spa type t037 was the most prevalent type observed in all of 136 MRSA bacteremic isolates. The prevalent genes in the group of infective endocarditis were clfA, clfB, fnbA, ebpS, eap, emp, sae, and eno; bone/joint infections clfA, emp, sae, and eno; skin/soft tissue infection eno; hemodialysis catheter-related bacteremia clfA and sae. The distribution of each gene was not statically different among four groups.ConclusionsA major MRSA lineage, CC8-ST239-MRSA-SCCmec type III-spa type t037, is noted among bacteremic MRSA isolates. No disease-specific virulent genes can be identified.  相似文献   
47.
48.
49.
50.
我们通过研究钾通道、碱性成纤维细胞生长因子(bFGF)和血管内皮细胞生长因子(VEGF)在低氧性肺动脉高压(HPH)发病过程中的变化,以及钾通道开放剂克罗卡啉(cromakalim)和左旋克罗卡啉(levocromakalim)、VEGF抑制剂干扰素诱导蛋白-10(IP-10)、bFGF抑制剂苏拉明以及汉防己甲素肺靶向微球对HPH的防治作用,探讨钾通道和细胞生长因子在HPH发病中的作用以及防治措施。  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