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   468743篇
  免费   41947篇
  国内免费   26045篇
耳鼻咽喉   4102篇
儿科学   7424篇
妇产科学   6480篇
基础医学   53110篇
口腔科学   8161篇
临床医学   62054篇
内科学   70970篇
皮肤病学   5209篇
神经病学   26559篇
特种医学   17106篇
外国民族医学   227篇
外科学   48612篇
综合类   71195篇
现状与发展   87篇
一般理论   106篇
预防医学   34572篇
眼科学   13254篇
药学   46669篇
  429篇
中国医学   24453篇
肿瘤学   35956篇
  2024年   1063篇
  2023年   5248篇
  2022年   13090篇
  2021年   19690篇
  2020年   15055篇
  2019年   13187篇
  2018年   13971篇
  2017年   12999篇
  2016年   12219篇
  2015年   18552篇
  2014年   23560篇
  2013年   23272篇
  2012年   34361篇
  2011年   38138篇
  2010年   25002篇
  2009年   20756篇
  2008年   27357篇
  2007年   27801篇
  2006年   26532篇
  2005年   25759篇
  2004年   19089篇
  2003年   18251篇
  2002年   16023篇
  2001年   9309篇
  2000年   8850篇
  1999年   9123篇
  1998年   6540篇
  1997年   6210篇
  1996年   4931篇
  1995年   4679篇
  1994年   3987篇
  1993年   2764篇
  1992年   2984篇
  1991年   2641篇
  1990年   2240篇
  1989年   2026篇
  1988年   1722篇
  1987年   1587篇
  1986年   1390篇
  1985年   1176篇
  1984年   1076篇
  1983年   1023篇
  1982年   1117篇
  1981年   1084篇
  1980年   983篇
  1979年   601篇
  1978年   606篇
  1977年   643篇
  1976年   526篇
  1975年   458篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
优选前后精子顶体酶活性与IVF受精率相关性的研究   总被引:1,自引:0,他引:1  
目的探讨优选处理前和处理后精子顶体酶活性的变化,及与体外受精(IVF)受精率的相关性。方法采用分光光度比色法,对接受IVF治疗的53例不育夫妇男方精液,分别测定优选处理前和处理后精子顶体酶活性,分析其与IVF受精率的相关性。结果优选处理后精子顶体酶活性与优选前比较有显著性差异(P<0.05);达到常规IVF标准并选择常规IVF治疗者,优选后的精子顶体酶活性与IVF受精率有相关性,精子顶体酶活性降低与IVF受精率降低有关。结论精子顶体酶活性与IVF受精率有相关性,并且通过精子顶体酶活性可以预测IVF受精率。  相似文献   
992.
Reductions in serum levels of Gc globulin, a hepatically synthesized component of the extracellular actin scavenger system responsible for complexing circulating actin and attenuating intravascular microthrombus formation, are associated with poor outcome in acute liver failure. Clinically applicable assays of the important actin-free fraction (Af-Gc) have not been available until now. We measured actin-free Gc globulin levels with a novel, rapid assay in 61 cases of acute liver failure (ALF) and in 91 patients with cirrhosis (40 of whom were clinically unstable with extrahepatic organ dysfunction), and studied associations with liver dysfunction, extrahepatic organ dysfunction, indices of disseminated coagulation, and outcome. Reductions in Af-Gc levels mirrored hepatic dysfunction and organ dysfunction in both groups, and discriminated patients with poor prognosis from those with good prognosis in the ALF cohort. Levels were lowest in patients with ALF (10% of control values), but levels were also markedly reduced in both unstable (28%) and stable (44%) patients with cirrhosis. Associations with markers of disseminated intravascular coagulation were seen in both groups, most notably in the cirrhosis cohort, supporting a pathophysiological role for reduced Af-Gc in the evolution of organ dysfunction. In acetaminophen-induced ALF, Af-Gc identified patients with poor prognosis as well as did the Acute Physiology and Chronic Health Evaluation (APACHE II) score (area under the receiver operating characteristic curve, 0.7), and in cirrhosis, Af-Gc was an independent predictor of mortality by multifactorial analysis. In conclusion, the importance of Af-Gc reductions in the development of multiple organ dysfunction in ALF and cirrhosis is highlighted, probably resulting from reduced hepatic production and peripheral exhaustion of this arm of the extracellular actin scavenger system.  相似文献   
993.
Diverticula arising from the mitral valve are very rare. They are usually detected by echocardiography as masses arising from the cardiac valves. We present a case of an incidental finding of a diverticulum arising from the mitral valve. This was initially detected by transesophageal echocardiography, and later confirmed by pathologic appearance. The case illustrates the unique findings on echocardiography that would help to differentiate diverticula from other valvular masses.  相似文献   
994.
国产奎硫平合并舒必利治疗难治性精神分裂症   总被引:1,自引:0,他引:1  
目的:了解舒必利合并国产奎硫平(启维)治疗难治性精神分裂症的疗效和安全性。方法:26例符合CCMD-Ⅲ精神分裂症诊断标准且临床判断属于难治性病人,予舒必利合并奎硫平治疗,疗程8周,分别在治疗前及治疗后进行阳性与阴性症状量表(PANSS)和不良反应状量表(TESS)评定。结果:合并治疗8周后总有效率65.3%。PANSS阳性、阴性及一般精神病理评分于治疗前后均有显著差异(P<0.01)。TESS总分治疗前后无显著差异(P>0.05)。副反应主要为肌张力增高、失眠、体重增加、静坐不能。结论:对于舒必利治疗反应不佳的难治性精神分裂症病人合并奎硫平治疗仍可取得较好的临床效果,安全性较高,耐受性及依从性好,可作为临床治疗难治性病人的方法之一。  相似文献   
995.
目的:探讨中西医结合治疗宫颈糜烂的疗效。方法:以三黄洗剂加用龙血竭胶囊外用,并配合西药消炎治疗宫颈糜烂40例。结果:治愈35例,治愈率87.5%;好转5例,好转率12.5%。结论:中西医结合治疗宫颈糜烂具有良好的疗效。  相似文献   
996.
997.
目的探讨肾盏切开联合经肾实质气压弹道碎石治疗复杂鹿角形结石的疗效。方法电刀切开积水较重的肾盏,气压弹道碎石杆对准结石碎石后分块取出。盏颈口狭窄但肾盏积水不严重者,将直径1 mm气压弹道碎石杆于肾实质处刺入结石位置,将肾盏内结石击碎后从盏颈口取出。结果19例均未阻断肾蒂,手术时间90-150 min,平均120 min。术中出血量100-250 ml,未输血。17例一次取石成功,术后无结石残余;1例术中残余泥沙状结石,术后经肾造瘘管冲洗引流排出;1例肾盏结石术中取石遗漏,术后经ESWL碎石后排净结石。15例随访10-60个月,平均18个月,结石复发2例,体外震波碎石后排净结石。结论肾盏切开联合经肾实质气压弹道碎石治疗复杂性鹿角形结石出血少,疗效可靠。  相似文献   
998.
目的 提高肾嫌色细胞癌的诊治水平。方法 回顾性分析4例肾嫌色细胞癌患者的临床资料。男3例,女1例,年龄34—76岁,平均52岁。结果 3例患者行肾癌根治术,1例行肾部分切除术。术后病理诊断为肾嫌色细胞癌,病理分期:pT1aNxMo 1例,pT1bNoMo3例。病理分级:G1 3例,G2 1例。免疫组织化学染色:CK8(低分子量细胞角蛋白)阳性,Vimentin(波型蛋白)阴性,Hale胶体铁阳性。随访4个月至8年,平均4年。4例患者均健在,无肿瘤复发或转移。结论 肾嫌色细胞癌是一种低度恶性的肾细胞癌,影像学检查对其诊断有重要帮助,确诊有赖于组织病理学检查,手术治疗后预后较好。  相似文献   
999.
Development of gene therapies for wound healing will depend on the identification of the genes involved in wound healing and tissue regeneration. Previous quantitative trait loci (QTL) studies in mice using the ear punch model have shown that major QTL exist on chromosome (Chr) 9 for soft tissue regeneration. In this study, we have developed a congenic line that contains the Chr 9 QTL chromosomal region from super healer MRL/MpJ in the genomic background of poor-healing SJL/J. The phenotypic effect of this QTL was confirmed in male mice, where the congenic line has shown significant healing improvement over SJL. Fine mapping of the Chr 9 QTL region with 23 markers at an average distance of 4.2 Mb using a total of 1,564 MRL/MpJ x SJL/J F(2) mice revealed the presence of at least three QTL peaks, implying that three separate loci may contribute to the phenotypic effect of this QTL. Based on the 2-LOD intervals, the total QTL region was confined to a combined length of no more than 28.2 Mb. Application of a Bayesian shrinkage estimation indicated that a major locus was located in a region of just 1.3 Mb.  相似文献   
1000.
OBJECTIVE: This pilot study's aim was to establish feasibility of a protocol for delayed cord clamping (DCC) versus immediate cord clamping (ICC) at preterm birth and to examine its effects on initial blood pressure and other outcomes. STUDY DESIGN: A randomized controlled trial recruited 32 infants between 24 and 32 weeks. Immediately before delivery, mothers were randomized to ICC (cord clamped at 5 to 10 seconds) or DCC (30- to 45-second delay in cord clamping) groups. RESULTS: Intention-to-treat analyses revealed that the DCC group were more likely to have higher initial mean blood pressures (adjusted OR 3.4) and less likely to be discharged on oxygen (adjusted OR 8.6). DCC group infants had higher initial glucose levels (ICC=36 mg/dl, DCC=73.1 mg/dl; p=0.02). CONCLUSION: The research design is feasible. The immediate benefit of improved blood pressure was confirmed and other findings deserve consideration for further study.  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