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   4213篇
  免费   428篇
  国内免费   302篇
耳鼻咽喉   39篇
儿科学   39篇
妇产科学   49篇
基础医学   604篇
口腔科学   66篇
临床医学   574篇
内科学   671篇
皮肤病学   21篇
神经病学   226篇
特种医学   102篇
外国民族医学   1篇
外科学   422篇
综合类   743篇
现状与发展   1篇
预防医学   282篇
眼科学   39篇
药学   516篇
  5篇
中国医学   194篇
肿瘤学   349篇
  2024年   15篇
  2023年   56篇
  2022年   147篇
  2021年   214篇
  2020年   164篇
  2019年   142篇
  2018年   143篇
  2017年   118篇
  2016年   109篇
  2015年   191篇
  2014年   240篇
  2013年   192篇
  2012年   294篇
  2011年   365篇
  2010年   183篇
  2009年   140篇
  2008年   237篇
  2007年   234篇
  2006年   213篇
  2005年   237篇
  2004年   169篇
  2003年   111篇
  2002年   106篇
  2001年   101篇
  2000年   113篇
  1999年   132篇
  1998年   95篇
  1997年   81篇
  1996年   57篇
  1995年   39篇
  1994年   52篇
  1993年   31篇
  1992年   57篇
  1991年   39篇
  1990年   19篇
  1989年   27篇
  1988年   24篇
  1987年   15篇
  1986年   11篇
  1985年   9篇
  1984年   4篇
  1983年   4篇
  1982年   1篇
  1981年   6篇
  1980年   1篇
  1979年   3篇
  1969年   1篇
  1928年   1篇
排序方式: 共有4943条查询结果,搜索用时 31 毫秒
91.
[目的]探讨腹腔镜联合胆道镜胆总管探查切开取石术(laparoscopic common bile duct exploration,LCBDE)治疗胆石症引起的急性胆源性胰腺炎(acute biliary pancreatitis,ABP)的临床效果。[方法]选择我院行LCBDE的68例胆石症引起的ABP患者为实验组,同期行开腹胆总管切开取石T管引流术(open choledocholithotomy T-tube drainage,OCTD)的87例胆石症引起的ABP患者为对照组。比较两组手术时间、术后恢复情况、取石结果及并发症情况。[结果]实验组68例均成功完成LCBDE,无中转开腹;取净胆管内结石61例,T管拔除为术后4周;残余结石7例于术后6周经T管窦道胆道镜再次取残余结石。对照组87例行OCTD成功79例,失败8例6周后经胆道镜取尽石;OCTD术中取净结石者71例,T管拔除为术后6周,未取尽者于术后6周经T管窦道胆道镜再次取尽残余结石。两组在术后恢复、并发症发生方面,实验组优于对照组(P〈0.05,P〈0.01)。[结论]LCBDE一期治疗胆石症引起的ABP安全可行,创伤小,恢复快,疗效好。  相似文献   
92.
目的  通过建立公立医院合作决策模型,实现在任选决策单元中选择最佳合作伙伴,提升医疗资源利用效率,推动区域内医疗资源最佳配置。方法  在传统数据包络分析(data envelopment analysis,DEA)模型的基础上,构建对模糊指标和任选决策单元具有更好适用性的广义模糊DEA合作决策模型,通过输入职工总数、病床数、年门急诊量、出院人数、总收入、医院等级评价等指标信息,计算出某一区域内不同医院的合作效率区间,从而实现在任选决策单元中科学选择最佳合作伙伴。结果  以河南省某地区10所医院为例进行分析验证可知,广义模糊DEA模型对该区域内公立医院之间的合作决策具有很好的效果,可有效为区域内任一医院选择最佳合作伙伴。结论  与传统DEA方法相比,广义模糊DEA方法更具灵活性,能较好地评价复杂模型,可以对任选决策单元中的个体实现最优合作决策选择,为实现区域医疗资源优化配置提供决策支撑。  相似文献   
93.
目的通过研究经腹途径腹腔镜下右肾肾周筋膜的分层结构,为腹腔镜筋膜入路右肾切除手术的可行性及安全性提供解剖学依据。方法在国内外学者对肾周筋膜研究的基础上结合CT肾周筋膜的呈现,对经腹途径腹腔镜下肾周筋膜分层结构进行研究,并以此为基础设计好手术的筋膜入路及分离途径并应用于指导经腹腹腔镜下右肾切除术,记录2015年1月至2019年6月来自阳江市中医医院和人民医院的45例患者的术中肾周筋膜观察结果及手术时间、出血及术中术后并发症等。结果经腹途径腹腔镜下肾周间隙周围存在一个潜在连续的由疏松纤维条索填充的无血管层面,这个无血管层面存在于相邻的两层肾周筋膜之间,45例患者均按术前设计的手术路径顺利完成手术,其中42例患者可以很好或较好的保持筋膜完整性的情况下完成分离,2例脓肾患者及1例无功能肾患者由于粘连明显未能保持分离面筋膜完整性,平均手术时间73 min,平均出血50 ml,术后引流管时间2.7 d,术中无肠管及下腔静脉损伤病例,术后无肠漏及严重的继发出血病例,无围手术期死亡病例。结论肾周筋膜的分层结构及肾周间隙周围存在的连续的潜在无血管层面为经腹途径腹腔镜筋膜入路右肾切除有效的解剖依据,经腹腹腔镜下筋膜入路右肾切除是安全可行的,可以让手术更加安全及出血更少。  相似文献   
94.

Cellular arachidonic acid (AA), an unsaturated fatty acid found ubiquitously in plasma membranes, is metabolized to different prostanoids, such as prostacyclin (PGI2) and prostaglandin E2 (PGE2), by the three-step reactions coupling the upstream cyclooxygenase (COX) isoforms (COX-1 and COX-2) with the corresponding individual downstream synthases. While the vascular actions of these prostanoids are well-characterized, their specific roles in the hippocampus, a major brain area for memory, are poorly understood. The major obstacle for its understanding in the brain was to mimic the biosynthesis of each prostanoid. To solve the problem, we utilized Single-Chain Hybrid Enzyme Complexes (SCHECs), which could successfully control cellular AA metabolites to the desired PGI2 or PGE2. Our in vitro studies suggested that neurons with higher PGI2 content and lower PGE2 content exhibited survival protection and resistance to Amyloid-β-induced neurotoxicity. Further extending to an in vivo model, the hybrid of PGI2-producing transgenic mice and Alzheimer’s disease (AD) mice showed restored long-term memory. These findings suggested that the vascular prostanoids, PGI2 and PGE2, exerted significant regulatory influences on neuronal protection (by PGI2), or damage (by PGE2) in the hippocampus, and raised a concern that the wide uses of aspirin in cardiovascular diseases may exert negative impacts on neurodegenerative protection.

Our study intended to understand the crosstalk of prostanoids in the hippocampus, a major brain area impacted in AD, by using hybrid enzymes to redirect the synthesis of prostanoids to PGE2 and PGI2, respectively. Our data indicated that during inflammation, the vascular mediators, PGI2 and PGE2, exerted significant regulatory influences on neuronal protection (by PGI2), or damage (by PGE2) in the hippocampus. These findings also raised a concern that the widely uses of non-steroidal anti-inflammatory drugs in cardiovascular diseases may exert negative impacts on neurodegenerative protection.

  相似文献   
95.
There is little information in the English-language literature regarding Warthin’s tumour (WT) in the eastern-Chinese population. A large retrospective study (1084 primary tumours over a period of 18 years) was carried out to investigate the clinicopathological features (patients’ gender, age and tumour location) of these tumours in this population. A total of 994 (91.7%) patients were male and 90 (8.3%) were female, with a male/female ratio of 11:1. The mean age was 56.48 years (range 20–89 years), with a peak incidence in the fifth to seventh decade (82.1%). The favorite primary site of the tumour was the parotid gland (n = 1055), followed by intra-/peri-parotid lymph nodes (n = 13), upper neck (n = 10), submandibular gland (n = 4) and upper lip (n = 1). Multifocal WTs arose in 9.5% (103 patients) of cases whereas bilateral multifocal WTs were found in 0.65% (seven patients). In 24 (2.2%) patients, WT were found to coexist with other different types of neoplasm synchronously. The most common subtype of metaplasia was the squamous metaplasia (166/250, 66.4%). The usual treatment measure is (bilateral) superficial parotidectomy and the patients should be followed long term, in view of possible metachronous WT, even after prolonged time intervals.  相似文献   
96.
97.
Insulin-like growth factor binding protein-1 (IGFBP-1) plays an important role in the development and progression of cancer. However, the expression of IGFBP-1 remains equivocal, and little is known about its clinicopathological significance and prognostic value in hepatocellular carcinoma (HCC). In this study, we evaluated the expression of IGFBP-1 in 90 paired HCC tissues and adjacent non-cancerous liver tissues and analyzed its clinical and prognostic significance. The results showed that IGFBP-1 was detected in cytoplasm as well as cell nucleus, and down-regulated in HCC tissues compared to the adjacent non-cancerous liver tissues. The decreased expression of IGFBP-1 was correlated with tumor differentiation, liver cirrhosis, microvascular invasion or metastasis, TNM stage and poor survival. Moreover, low levels of IGFBP-1 may be an independent prognostic indicator for the survival of patients with HCC. We also evaluated its function by adding recombinant IGFBP-1 to the cultured HCC cell lines HepG2 and MHCC97-H. The result of the invasion chamber assay showed that IGFBP-1 could inhibit the invasion of HepG2 and MHCC97-H. MMP-9 secretion by these cells was significantly decreased when the cells were treated with IGFBP-1. Our results suggest that IGFBP-1 inhibits the invasion and metastasis of HCC cells and that IGFBP-1 may be useful as a valuable marker for the prognosis of patients with HCC.  相似文献   
98.
99.
介绍Teach-back的概念和在患者健康教育中实施过程、国内外应用现状、影响因素分析和应对策略,提出应用Teach-back健康教育方式能够提高患者对于医疗信息和护理技术的理解和运用,促进患者的健康结局,可为我国患者的健康教育提供指导。  相似文献   
100.
A high level of accuracy during protein synthesis is considered essential for life. Aminoacyl-tRNA synthetases (aaRSs) translate the genetic code by ensuring the correct pairing of amino acids with their cognate tRNAs. Because some aaRSs also produce misacylated aminoacyl-tRNA (aa-tRNA) in vivo, we addressed the question of protein quality within the context of missense suppression by Cys-tRNA(Pro), Ser-tRNA(Thr), Glu-tRNA(Gln), and Asp-tRNA(Asn). Suppression of an active-site missense mutation leads to a mixture of inactive mutant protein (from translation with correctly acylated aa-tRNA) and active enzyme indistinguishable from the wild-type protein (from translation with misacylated aa-tRNA). Here, we provide genetic and biochemical evidence that under selective pressure, Escherichia coli not only tolerates the presence of misacylated aa-tRNA, but can even require it for growth. Furthermore, by using mass spectrometry of a reporter protein not subject to selection, we show that E. coli can survive the ambiguous genetic code imposed by misacylated aa-tRNA tolerating up to 10% of mismade protein. The editing function of aaRSs to hydrolyze misacylated aa-tRNA is not essential for survival, and the EF-Tu barrier against misacylated aa-tRNA is not absolute. Rather, E. coli copes with mistranslation by triggering the heat shock response that stimulates nonoptimized polypeptides to achieve a native conformation or to be degraded. In this way, E. coli ensures the presence of sufficient functional protein albeit at a considerable energetic cost.  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