全文获取类型
收费全文 | 8978篇 |
免费 | 629篇 |
国内免费 | 36篇 |
学科分类
医药卫生 | 9643篇 |
出版年
2023年 | 90篇 |
2022年 | 50篇 |
2021年 | 273篇 |
2020年 | 161篇 |
2019年 | 251篇 |
2018年 | 253篇 |
2017年 | 195篇 |
2016年 | 213篇 |
2015年 | 203篇 |
2014年 | 313篇 |
2013年 | 393篇 |
2012年 | 537篇 |
2011年 | 488篇 |
2010年 | 305篇 |
2009年 | 274篇 |
2008年 | 454篇 |
2007年 | 468篇 |
2006年 | 415篇 |
2005年 | 416篇 |
2004年 | 387篇 |
2003年 | 361篇 |
2002年 | 377篇 |
2001年 | 224篇 |
2000年 | 206篇 |
1999年 | 190篇 |
1998年 | 96篇 |
1997年 | 69篇 |
1996年 | 82篇 |
1995年 | 71篇 |
1994年 | 63篇 |
1993年 | 45篇 |
1992年 | 109篇 |
1991年 | 106篇 |
1990年 | 98篇 |
1989年 | 101篇 |
1988年 | 95篇 |
1987年 | 76篇 |
1986年 | 91篇 |
1985年 | 74篇 |
1984年 | 51篇 |
1983年 | 49篇 |
1979年 | 60篇 |
1978年 | 34篇 |
1977年 | 32篇 |
1930年 | 34篇 |
1928年 | 33篇 |
1927年 | 33篇 |
1926年 | 34篇 |
1925年 | 41篇 |
1924年 | 37篇 |
排序方式: 共有9643条查询结果,搜索用时 347 毫秒
1.
2.
3.
4.
Ronny Redlich Ilona Schneider Nicole Kerkenberg Nils Opel Jonas Bauhaus Verena Enneking Jonathan Repple Elisabeth J. Leehr Dominik Grotegerd Claas Khler Katharina Frster Katharina Dohm Susanne Meinert Tim Hahn Harald Kugel Kathrin Schwarte Christiane Schettler Katharina Domschke Volker Arolt Walter Heindel Bernhard T. Baune Weiqi Zhang Christa Hohoff Udo Dannlowski 《Human brain mapping》2020,41(3):594-604
Epigenetic alterations of the brain‐derived neurotrophic factor (BDNF) gene have been associated with psychiatric disorders in humans and with differences in amygdala BDNF mRNA levels in rodents. This human study aimed to investigate the relationship between the functional BDNF‐Val66Met polymorphism, its surrounding DNA methylation in BDNF exon IX, amygdala reactivity to emotional faces, and personality traits. Healthy controls (HC, n = 189) underwent functional MRI during an emotional face‐matching task. Harm avoidance, novelty seeking and reward dependence were measured using the Tridimensional Personality Questionnaire (TPQ). Individual BDNF methylation profiles were ascertained and associated with several BDNF single nucleotide polymorphisms surrounding the BDNF‐Val66Met, amygdala reactivity, novelty seeking and harm avoidance. Higher BDNF methylation was associated with higher amygdala reactivity (x = 34, y = 0, z = ?26, t(166) = 3.00, TFCE = 42.39, p(FWE) = .045), whereby the BDNF‐Val66Met genotype per se did not show any significant association with brain function. Furthermore, novelty seeking was negatively associated with BDNF methylation (r = ?.19, p = .015) and amygdala reactivity (r = ?.17, p = .028), while harm avoidance showed a trend for a positive association with BDNF methylation (r = .14, p = .066). The study provides first insights into the relationship among BDNF methylation, BDNF genotype, amygdala reactivity and personality traits in humans, highlighting the multidimensional relations among genetics, epigenetics, and neuronal functions. The present study suggests a possible involvement of epigenetic BDNF modifications in psychiatric disorders and related brain functions, whereby high BDNF methylation might reduce BDNF mRNA expression and upregulate amygdala reactivity. 相似文献
5.
6.
Nicole L. Stout DPT Justin C. Brown PhD Anna L. Schwartz PhD FNP Timothy F. Marshall PhD Anna M. Campbell PhD MBE Larissa Nekhlyudov MD MPH David S. Zucker MD PhD Karen M. Basen-Engquist PhD MPH Grace Campbell PhD MSW RN Jeffrey Meyerhardt MD MPH Andrea L. Cheville MD MSSE Kelley R. Covington MS Jennifer A. Ligibel MD Jonas M. Sokolof DO Kathryn H. Schmitz PhD MPH Catherine M. Alfano PhD 《Cancer》2020,126(12):2750-2758
7.
The composition of the clientele from an ophthalmological practitioner's office is described with special reference to the occurrence of glaucoma and disc haemorrhages (h in singular; hh in plural). This study could not be planned as an epidemiological survey and gives no clue to sensitivity or specificity of hh in glaucoma. During a period of about 10 years ending with 1986 there were 731 patients with h and/or glaucoma. When detected, 185 patients had h but no glaucoma, 33 had both h and glaucoma and 513 had glaucoma but no h. During the follow-up period hh were detected in 83 cases of glaucoma, and glaucoma developed in 27 cases with hh. The detection rate of hh among glaucoma was low but steady, indicating that hh may occur at any stage of the glaucoma process. This study shows no predilection for hh in cases with general hypertension or diabetes, nor is the frequency of hh among pseudoexfoliation cases significantly lower than among cases without this stigma. 相似文献
8.
9.
10.
Heung Bae Kim James J Pomposelli Craig W Lillehei Roger L Jenkins Maureen M Jonas Laura E Krawczuk Steven J Fishman 《Liver transplantation》2005,11(11):1389-1394
Extrahepatic portal vein thrombosis (EHPVT) may occur in children or adults and usually comes to clinical attention due to complications of portal hypertension such as variceal hemorrhage. A variety of standard surgical techniques exist to manage these patients, but when these fail surgical options are limited. We describe two novel portosystemic shunts that utilize the gonadal vein as an autologous conduit. Four patients were evaluated for EHPVT with variceal bleeding. None of the patients were candidates for a standard splenorenal shunt due to prior surgical procedures. The first patient underwent a left mesogonadal shunt and the remaining 3 patients underwent a right mesogonadal shunt. Postoperative ultrasound or computed tomography (CT) scan confirmed early patency of the shunt in each patient. There have been no further episodes of variceal hemorrhage with follow-up of 3.5 years in the child who underwent the left mesogonadal shunt, and 17, 19, and 20 months in the patients who underwent the right mesogonadal shunt. Three of the 4 shunts remain patent. One shunt thrombosis occurred in a patient homozygous for the Factor V Leiden mutation despite anticoagulation with coumadin. This is the first report of the successful use of the gonadal vein as an in situ conduit for constructing a portosystemic shunt. In conclusion, the right and left mesogonadal shunts may be useful as salvage operations for patients with EHPVT who have failed standard surgical shunt procedures. 相似文献