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   947篇
  免费   349篇
  国内免费   12篇
耳鼻咽喉   4篇
儿科学   44篇
妇产科学   95篇
基础医学   29篇
口腔科学   9篇
临床医学   704篇
内科学   112篇
皮肤病学   11篇
神经病学   79篇
特种医学   48篇
外科学   31篇
综合类   19篇
预防医学   74篇
眼科学   2篇
药学   16篇
中国医学   1篇
肿瘤学   30篇
  2023年   2篇
  2022年   1篇
  2021年   5篇
  2020年   5篇
  2019年   10篇
  2018年   68篇
  2017年   95篇
  2016年   112篇
  2015年   99篇
  2014年   88篇
  2013年   115篇
  2012年   45篇
  2011年   47篇
  2010年   69篇
  2009年   90篇
  2008年   61篇
  2007年   59篇
  2006年   44篇
  2005年   39篇
  2004年   45篇
  2003年   19篇
  2002年   15篇
  2001年   11篇
  2000年   11篇
  1999年   9篇
  1998年   17篇
  1997年   19篇
  1996年   18篇
  1995年   9篇
  1994年   8篇
  1993年   10篇
  1992年   3篇
  1991年   2篇
  1990年   5篇
  1989年   7篇
  1988年   8篇
  1987年   8篇
  1986年   2篇
  1985年   9篇
  1984年   4篇
  1983年   2篇
  1982年   3篇
  1981年   1篇
  1980年   2篇
  1979年   2篇
  1978年   2篇
  1977年   2篇
  1975年   1篇
排序方式: 共有1308条查询结果,搜索用时 15 毫秒
1.
2.
Bonfanti  R; Furie  BC; Furie  B; Wagner  DD 《Blood》1989,73(5):1109-1112
PADGEM protein (PADGEM), also known as GMP140, is a platelet alpha- granule membrane protein that is translocated to the external membrane after platelet activation. Although the biosynthesis of this protein was originally thought to be confined to megakaryocytes, the synthesis of PADGEM in endothelial cells was recently demonstrated (McEver et al: Blood 70:1974a, 1987). We now describe the subcellular localization of this protein in endothelial cells. Immunofluorescence staining of permeabilized human umbilical vein endothelial cells with KC4, a well characterized monoclonal antibody to PADGEM, showed positively stained elongated structures similar in distribution and shape to Weibel-Palade bodies. Their identity as Weibel-Palade bodies was confirmed by double label immunofluorescence using KC4 and a polyclonal antiserum to von Willebrand factor (vWf), a protein known to be specifically stored in these organelles. All Weibel-Palade bodies were found to contain PADGEM. In contrast to strong perinuclear staining produced with anti- vWf antibodies, no significant perinuclear staining was obtained with KC4, indicating that relatively little PADGEM is present in the endoplasmic reticulum and in the Golgi apparatus. In endothelial cells treated with secretagogues that stimulate vWf release the elongated structures positive for PADGEM disappeared, further identifying these structures as Weibel-Palade bodies. This observation extends the parallels between Weibel-Palade bodies and alpha-granules and suggests a possible functional association between vWf and PADGEM.  相似文献   
3.
This column contains the presidential address presented during the Third Annual Meeting of the American Association of Heart Failure Nurses on June 28, 2007, in San Diego, California, titled "Building the Foundation of Excellence in Heart Failure Nursing."  相似文献   
4.
The goal of Castillo-Morales’ orofacial therapy is to improve the coordination of oral motor functions in cooperation with other body systems. The processes involved in sucking, biting, chewing and swallowing are stimulated by specific techniques of sensory stimulation such as touching, stroking, stretching, exerting pressure or the vibration of mimic and tongue-bone musculature, as well as massage of the gums and palate or the application of technical apparatus. Sufficient head and posture control is fundamental and must be the first goal. Successful therapy, especially for ICP-children, has been documented in progress reports and case studies. As yet, however, there is no evidence of specific effects on eating and speech functions. Therefore, the therapy can be recommended only in order to achieve specific goals and for a limited time, being aware of the risk of overstimulation.  相似文献   
5.
Edna Cadmus PhD  RN  CNAA  BC   《Nurse Leader》2004,2(3):34-37
Did you ever think, “If we just had a little money we could…”? The current health care environment is wrought with financial stressors that can be overwhelming and take up most of our time. Such stress can limit the development of a professional practice environment if you let it. How do you not only survive but thrive in this financial climate?  相似文献   
6.
7.
8.
Dibenzo[a,l]pyrene (DB[a,l]P), an environmental polycyclic aromatic hydrocarbon, is the most potent carcinogen ever tested in mouse skin and rat mammary gland. In this study, DB[a,l]P was examined for DNA adduction, tumorigenicity, and induction of Ki-ras oncogene mutations in tumor DNA in strain A/J mouse lung. Groups of mice received a single i.p. injection of 0.3, 1.5, 3.0, or 6.0 mg/kg DB[a,l]P in tricaprylin. Following treatment, DNA adducts were measured at times between 1 and 28 days, while tumors were counted at 250 days and analyzed for the occurrence of point mutations in codons 12 and 61 of the Ki-ras oncogene. DB[a,l]P in strain A/J mouse lung induced six major and four minor DNA adducts. Maximal levels of adduction occurred between 5 and 10 days after injection followed by a gradual decrease. DB[a,l]P-DNA adducts in lung tissue were derived from both anti- and syn-11,12- dihydroxy-13,14-epoxy- 11,12,13,14-tetrahydrodibenzo[a,l]pyrene (DB[a,l]PDE) and both deoxyadenosine (dAdo) and deoxyguanosine (dGuo) residues in DNA as revealed by cochromatography. The major adduct was identified as a product of the reaction of an anti-DB[a,l]PDE with dAdo in DNA. DB[a,l]P induced significant numbers of lung adenomas in a dose- dependent manner, with the highest dose (6.0 mg/kg) yielding 16.1 adenomas/mouse. In tricaprylin-treated control animals, there were 0.67 adenomas/mouse. Based on the administered dose, DB[a,l]P was more active than other environmental carcinogens including benzo[a]pyrene. As a function of time-integrated DNA adduct levels, DB[a,l]P induced lung adenomas with about the same potency as other PAHs, suggesting that the adducts formed by DB[a,l]P are similar in carcinogenic potency to other PAHs in the strain A/J mouse lung model. Analysis of the Ki- ras mutation spectrum in DB[a,l]P-induced lung tumors revealed the predominant mutations to be G-->T transversions in the first base of codon 12, A-->G transitions in the second base of codon 12, and A-->T transversions in the second or third base of codon 61, concordant with the DNA adduct profile.   相似文献   
9.
10.
目的分析中国不同人群及不同胃部疾病病例来源的幽门螺杆菌致病相关基因cagA、iceA、vacA及HP0519的分布.方法采用特异引物聚合酶链式反应(PCR)方法分析150株幽门螺杆菌上述基因的多态性分布特点,并对其分布作初步统计分析.结果93%(139/150)中国菌株cagA基因3′端重复序列的PCR产物具有东方菌株特征.75%(113/150)菌株iceA基因为iceA1,19%(29/150)为iceA2,不同地区间iceA基因的分布差异无统计学意义.云南菌株iceA1、iceA2的分布与菌株分离个体的种族特点及临床疾病类型无显著关系.96%中国菌株(144/150)vacA基因s区的等位基因为s1;m区等位基因m2、m1b和m1b-m2的比例分别为57%(85/150)、27%(41/150)和11%(16/150),仅2株福建菌株为m1a.不同地区间vacA s1、m2、m1b分布的差异无统计学意义.云南菌株m1b-m2的分布高于福建和北京菌株.云南菌株vacA s区等位基因的多样性与分离个体的种族及临床疾病类型无显著关系.vacA m区等位基因的多样性与分离个体的临床疾病类型无显著关系,但不同民族间m2的分布有显著差异,白族人群m2的分布显著少于汉族和纳西族.93%(140/150)的中国菌株HP0519基因具有24 bp和15 bp DNA插入和缺失的多态性特点.不同地区间HP0519基因的多态性无显著不同.云南菌株HP0519的多态性与菌株分离个体的临床疾病类型无显著关系,但来源不同民族菌株的HP0519基因存在差异.结论幽门螺杆菌中国菌株cagA 3′端JF/TR特异引物的扩增结果具有东亚菌株特点.中国菌株vacA基因多为s1,其分布与菌株分离个体的临床疾病类型无关.中国菌株vacA基因m区的分布具有多样性.中国菌株HP0519基因具有24 bp和15 bp插入和缺失的多态性特点.  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