全文获取类型
收费全文 | 1740篇 |
免费 | 165篇 |
国内免费 | 2篇 |
专业分类
1907篇 |
出版年
2023年 | 13篇 |
2022年 | 40篇 |
2021年 | 38篇 |
2020年 | 22篇 |
2019年 | 42篇 |
2018年 | 45篇 |
2017年 | 29篇 |
2016年 | 73篇 |
2015年 | 86篇 |
2014年 | 103篇 |
2013年 | 94篇 |
2012年 | 143篇 |
2011年 | 141篇 |
2010年 | 72篇 |
2009年 | 71篇 |
2008年 | 106篇 |
2007年 | 114篇 |
2006年 | 98篇 |
2005年 | 91篇 |
2004年 | 78篇 |
2003年 | 64篇 |
2002年 | 53篇 |
2001年 | 24篇 |
2000年 | 20篇 |
1999年 | 20篇 |
1998年 | 17篇 |
1997年 | 12篇 |
1996年 | 10篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 14篇 |
1991年 | 11篇 |
1990年 | 7篇 |
1989年 | 7篇 |
1988年 | 6篇 |
1986年 | 4篇 |
1985年 | 9篇 |
1984年 | 5篇 |
1983年 | 9篇 |
1982年 | 11篇 |
1981年 | 9篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1975年 | 6篇 |
1974年 | 6篇 |
1973年 | 5篇 |
1971年 | 4篇 |
1965年 | 3篇 |
排序方式: 共有1907条查询结果,搜索用时 15 毫秒
101.
Summary A girl with partial deletion of the short arms of one chromosome 7 is described. Among many other symptoms she has craniosynostosis. Early closure of cranio-sutures has previously been described in 2 of 3 patients with partial deletion 7. Investigation of a number of genetic marker systems shows that the HL-A, MN, AcP, and GPT loci are not located in the deleted segment.
Zusammenfassung Es wird ein Mädchen mit teilweiser Deletion des kurzen Armes eines Chromosoms 7 beschrieben. Außer vielen anderen Symptomen hat sie eine Craniosynostose. Frühzeitiger Verschluß der Schädelnähte wurde auch bei 2 von 3 Patienten mit Deletion 7, die in der Literatur beschrieben sind, beobachtet. Untersuchung einer Reihe genetischer Markersysteme zeigt, daß die HL-A-, MN-, AcP- und GPT-loci nicht in dem deletierten Segment liegen.相似文献
102.
103.
104.
Objective
To summarize efficacy and safety data on a new progesterone compound which is available for subcutaneous administration as compared to vaginally administered progesterone for luteal phase support in patients undergoing IVF treatment.Design
Data from two randomized phase III trials (07EU/Prg06 and 07USA/Prg05) performed according to GCP standards with a total sample size of 1435 per-protocol patients were meta-analyzed on an individual patient data level.Setting
University affiliated reproductive medicine unit.Patients
Subcutaneous progesterone was administered to a total of 714 subjects and vaginal progesterone was administered to a total of 721 subjects who underwent fresh embryo transfer after ovarian stimulation followed by IVF or ICSI. The subjects were between 18 and 42 years old and had a BMI <30kg/m2.Interventions
Subcutaneous progesterone 25 mg daily vs. either progesterone vaginal gel 90 mg daily (07EU/Prg06) or 100 mg intravaginal twice a day (07USA/Prg05) for luteal phase support in IVF patients.Main outcome measures
Ongoing pregnancy rate beyond 10 gestational weeks, live birth rate and OHSS risk.Results
The administration of subcutaneous progesterone versus intra-vaginal progesterone had no impact on ongoing pregnancy likelihood (OR = 0.865, 95% CI 0.694 to 1.077; P = n.s.), live birth likelihood (OR = 0.889, 95% CI 0.714 to 1.106; P = n.s.) or OHSS risk (OR = 0.995, 95% CI 0.565 to 1.754; P = n.s.) in regression analyses accounting for clustering of patients within trials, while adjusting for important confounders. Only female age and number of oocytes retrieved were significant predictors of live birth likelihood and OHSS risk.Conclusion
No statistical significant or clinical significant differences exist between subcutaneous and vaginal progesterone for luteal phase support. 相似文献105.
Hennigs Jan K. Lüneburg Nicole Stage Annett Schmitz Melanie Körbelin Jakob Harbaum Lars Matuszcak Christiane Mienert Julia Bokemeyer Carsten Böger Rainer H. Kiefmann Rainer Klose Hans 《Purinergic signalling》2019,15(3):299-311
Purinergic Signalling - Dysfunction of the pulmonary endothelium is associated with most lung diseases. Extracellular nucleotides modulate a plethora of endothelial functions in the lung such as... 相似文献
106.
Michael Jakob Rupar Pawel Golusinski Wojciech Golusinski Michal M. Masternak 《Reports of Practical Oncology and Radiotherapy》2019,24(6):544-550
Human Papillomavirus (HPV) remains one of the most commonly contracted sexually transmitted diseases around the world. There are a multitude of HPV types, some of which may never present any symptoms. Others, however, are considered high-risk types, which increase the chance of the person infected to develop cancer. In recent years, the utilization of nanotechnology has allowed researchers to employ and explore the use of nanoparticles in immunotherapies.The new nanoparticle frontier has opened many doors in this area of research as a form of prevention, diagnosis, and treatment in cancers resulting from HPV. This review will provide a brief background of HPV, its relationship to head and neck cancer (HNC) and present some insight into the field of immunotherapeutic nanoparticles. 相似文献
107.
Frank Jakob Yamira Quintero Alexis Musacchio Paulina Estrada-de los Santos Lázaro Hernández Rudi F. Vogel 《Environmental microbiology》2019,21(11):4151-4165
Acetic acid bacteria (AAB) are associated with plants and insects. Determinants for the targeting and occupation of these widely different environments are unknown. However, most of these natural habitats share plant-derived sucrose, which can be metabolized by some AAB via polyfructose building levansucrases (LS) known to be involved in biofilm formation. Here, we propose two LS types (T) encoded by AAB as determinants for habitat selection, which emerged from vertical (T1) and horizontal (T2) lines of evolution and differ in their genetic organization, structural features and secretion mechanism, as well as their occurrence in proteobacteria. T1-LS are secreted by plant-pathogenic α- and γ-proteobacteria, while T2-LS genes are common in diazotrophic, plant-growth-promoting α-, β- and γ-proteobacteria. This knowledge may be exploited for a better understanding of microbial ecology, plant health and biofilm formation by sucrase-secreting proteobacteria in eukaryotic hosts. 相似文献
108.
The redox-switch domain of Hsp33 functions as dual stress sensor 总被引:1,自引:0,他引:1
Ilbert M Horst J Ahrens S Winter J Graf PC Lilie H Jakob U 《Nature structural & molecular biology》2007,14(6):556-563
The redox-regulated chaperone Hsp33 is specifically activated upon exposure of cells to peroxide stress at elevated temperatures. Here we show that Hsp33 harbors two interdependent stress-sensing regions located in the C-terminal redox-switch domain of Hsp33: a zinc center sensing peroxide stress conditions and an adjacent linker region responding to unfolding conditions. Neither of these sensors works sufficiently in the absence of the other, making the simultaneous presence of both stress conditions a necessary requirement for Hsp33's full activation. Upon activation, Hsp33's redox-switch domain adopts a natively unfolded conformation, thereby exposing hydrophobic surfaces in its N-terminal substrate-binding domain. The specific activation of Hsp33 by the oxidative unfolding of its redox-switch domain makes this chaperone optimally suited to quickly respond to oxidative stress conditions that lead to protein unfolding. 相似文献
109.
Sonia Longhi Anne Nicolas Lucia Creveld Maarten Egmond C. Theo Verrips Jakob de Vlieg Chrislaine Martinez Christian Cambillau 《Proteins》1996,26(4):442-458
In characterizing mutants and covalently inhibited complexes of Fusarium solani cutinase, which is a 197-residue lipolytic enzyme, 34 variant structures, crystallizing in 8 different crystal forms, have been determined, mostly at high resolution. Taking advantage of this considerable body of information, a structural comparative analysis was carried out to investigate the dynamics of cutinase. Surface loops were identified as the major flexible protein regions, particularly those forming the active-site groove, whereas the elements constituting the protein scaffold were found to retain the same conformation in all the cutinase variants studied. Flexibility turned out to be correlated with thermal motion. With a given crystal packing environment, a high flexibility turned out to be correlated with a low involvement in crystal packing contacts. The high degree of crystal polymorphism, which allowed different conformations with similar energy to be detected, made it possible to identify motions which would have remained unidentified if only a single crystal form had been available. Fairly good agreement was found to exist between the data obtained from the structural comparison and those from a molecular dynamics (MD) simulation carried out on the native enzyme. The crystallographic approach used in this study turned out to be a suitable tool for investigating cutinase dynamics. Because of the availability of a set of closely related proteins in different crystal environments, the intrinsic drawback of a crystallographic approach was bypassed. By combining several static pictures, the dynamics of the protein could be monitored much more realistically than what can be achieved on the basis of static pictures alone. Proteins 26:442–458 © 1996 Wiley-Liss, Inc. 相似文献
110.
Jamin B. Hein Dimitriya H. Garvanska Isha Nasa Arminja N. Kettenbach Jakob Nilsson 《The Journal of cell biology》2021,220(5)
Tight regulation of the APC/C-Cdc20 ubiquitin ligase that targets cyclin B1 for degradation is important for mitotic fidelity. The spindle assembly checkpoint (SAC) inhibits Cdc20 through the mitotic checkpoint complex (MCC). In addition, phosphorylation of Cdc20 by cyclin B1–Cdk1 independently inhibits APC/C–Cdc20 activation. This creates a conundrum for how Cdc20 is activated before cyclin B1 degradation. Here, we show that the MCC component BubR1 harbors both Cdc20 inhibition and activation activities, allowing for cross-talk between the two Cdc20 inhibition pathways. Specifically, BubR1 acts as a substrate specifier for PP2A-B56 to enable efficient Cdc20 dephosphorylation in the MCC. A mutant Cdc20 mimicking the dephosphorylated state escapes a mitotic checkpoint arrest, arguing that restricting Cdc20 dephosphorylation to the MCC is important. Collectively, our work reveals how Cdc20 can be dephosphorylated in the presence of cyclin B1-Cdk1 activity without causing premature anaphase onset. 相似文献