全文获取类型
收费全文 | 2916篇 |
免费 | 274篇 |
出版年
2022年 | 10篇 |
2021年 | 37篇 |
2020年 | 27篇 |
2019年 | 18篇 |
2018年 | 36篇 |
2017年 | 25篇 |
2016年 | 58篇 |
2015年 | 90篇 |
2014年 | 101篇 |
2013年 | 128篇 |
2012年 | 168篇 |
2011年 | 193篇 |
2010年 | 140篇 |
2009年 | 126篇 |
2008年 | 193篇 |
2007年 | 187篇 |
2006年 | 198篇 |
2005年 | 151篇 |
2004年 | 168篇 |
2003年 | 161篇 |
2002年 | 165篇 |
2001年 | 37篇 |
2000年 | 35篇 |
1999年 | 40篇 |
1998年 | 41篇 |
1997年 | 50篇 |
1996年 | 41篇 |
1995年 | 44篇 |
1994年 | 30篇 |
1993年 | 22篇 |
1992年 | 31篇 |
1991年 | 26篇 |
1990年 | 26篇 |
1989年 | 34篇 |
1988年 | 35篇 |
1987年 | 19篇 |
1986年 | 17篇 |
1985年 | 18篇 |
1984年 | 28篇 |
1983年 | 16篇 |
1982年 | 23篇 |
1981年 | 21篇 |
1980年 | 17篇 |
1979年 | 21篇 |
1978年 | 12篇 |
1977年 | 9篇 |
1976年 | 10篇 |
1975年 | 15篇 |
1969年 | 9篇 |
1968年 | 6篇 |
排序方式: 共有3190条查询结果,搜索用时 31 毫秒
991.
Kondababu Kurakula Mariska Vos Iker Otermin Rubio Goran Marinkovi? Reinhard Buettner Lukas C. Heukamp Jan Stap Vivian de Waard Claudia M. van Tiel Carlie J.M. de Vries 《PloS one》2014,9(4)
The LIM-only protein FHL2, also known as DRAL or SLIM3, has a function in fine-tuning multiple physiological processes. FHL2 is expressed in the vessel wall in smooth muscle cells (SMCs) and endothelial cells and conflicting data have been reported on the regulatory function of FHL2 in SMC phenotype transition. At present the function of FHL2 in SMCs in vascular injury is unknown. Therefore, we studied the role of FHL2 in SMC-rich lesion formation. In response to carotid artery ligation FHL2-deficient (FHL2-KO) mice showed accelerated lesion formation with enhanced Ki67 expression compared with wild-type (WT)-mice. Consistent with these findings, cultured SMCs from FHL2-KO mice showed increased proliferation through enhanced phosphorylation of extracellular-regulated kinase-1/2 (ERK1/2) and induction of CyclinD1 expression. Overexpression of FHL2 in SMCs inhibited CyclinD1 expression and CyclinD1-knockdown blocked the enhanced proliferation of FHL2-KO SMCs. We also observed increased CyclinD1 promoter activity in FHL2-KO SMCs, which was reduced upon ERK1/2 inhibition. Furthermore, FHL2-KO SMCs showed enhanced migration compared with WT SMCs. In conclusion, FHL2 deficiency in mice results in exacerbated SMC-rich lesion formation involving increased proliferation and migration of SMCs via enhanced activation of the ERK1/2-CyclinD1 signaling pathway. 相似文献
992.
Reinhard Berndt 《Mycological Progress》2013,12(2):193-211
An annotated list of the rust fungi (Uredinales or Pucciniales) of French Guiana is presented. It enumerates 68 species of which 57 are new reports for the department and 3, Aecidium plukenetiae, Puccinia kourouensis and P. parianicola, are new to science. Dicheirinia guianensis and Hapalophragmium angylocalycis are excluded from the French Guianan mycobiota. New host plants are reported for Batistopsora crucis-filii, B. pistila, Cerotelium ficicola, C. sabiceae, Crossopsora piperis, Desmella aneimiae, Endophyllum guttatum, Kweilingia divina, Puccinia lateritia, Uredo anthurii and Uromyces anguriae. Previously undescribed characters are presented for Achrotelium lucumae, Chaconia ingae, Cerotelium sabiceae, Prospodium amapaensis, Sphenospora smilacina and Uromyces wulffiae-stenoglossae. Chaconia ingae showed haustorial complexes comprising both intracellular hyphae and D-haustoria. In Cerotelium sabiceae, the haustorial mother cells retained the nuclei while D-haustoria were enucleate. The occurrence of these haustorial types in tropical rust fungi is discussed. Internal basidium formation is described for the first time in Sphenospora: teliospores of S. smilacina produced external or internal basidia. The species richness and composition of the French Guianan rust mycobiota are discussed in a neotropical context. 相似文献
993.
Jens Thiel Fabian H?ssler Ulrich Salzer Reinhard E Voll Nils Venhoff 《Arthritis research & therapy》2013,15(5):R133
Introduction
Eosinophilic granulomatosis with polyangiitis (EGPA) is part of antineutrophil cytoplasmic antibodies (ANCAs)-associated vasculitides. In EGPA small-vessel vasculitis is associated with eosinophilia and asthma. About 40% of EGPA patients are ANCA-positive, suggesting a role for B cells in the pathogenesis of EGPA. B cell-depleting therapy with rituximab (RTX) can be effective in ANCA-positive EGPA, but very few patients have been published to date. The role of RTX in the treatment of ANCA-negative EGPA is unclear.Methods
We report a single-center cohort of patients with eosinophilic granulomatosis with polyangiitis. Of these patients, nine (six ANCA-positive, three ANCA-negative) had been treated with RTX for relapsing or refractory disease on standard immunosuppressive treatment. In a retrospective analysis, data on treatment response, frequency of relapses, adverse events, and peripheral B-cell reconstitution were evaluated. Furthermore, serum immunoglobulin concentrations, ANCA status, and peripheral B cell subpopulations were assessed after RTX treatment.Results
All patients had high disease activity before RTX treatment. At presentation 3 months after RTX therapy, all ANCA-positive and ANCA-negative patients had responded to RTX, with one patient being in complete remission, and eight patients being in partial remission. After a mean follow-up of 9 months, C-reactive protein concentrations had normalized, eosinophils had significantly decreased, and prednisone had been tapered in all patients. In all patients, RTX therapy was combined with a standard immunosuppressive therapy. Within the 9-month observation period, no relapse was recorded. Three patients were preemptively retreated with RTX, and during the median follow-up time of 3 years, no relapse occurred in these patients. During the follow-up of 13 patient-years, five minor but no major infections were recorded.Conclusions
In our analysis on nine patients with EGPA resistant to standard therapy, rituximab proved to be an efficient and safe treatment for ANCA-positive and ANCA-negative patients. Preemptive retreatment with RTX, combined with standard maintenance immunosuppressants, resulted in a sustained treatment response. Prospective, randomized trials evaluating the use of RTX in EGPA are warranted. 相似文献994.
Stefan Toegel Daniela Bieder Sabine André Friedrich Altmann Sonja M Walzer Herbert Kaltner Jochen G Hofstaetter Reinhard Windhager Hans-Joachim Gabius 《Arthritis research & therapy》2013,15(5):R147
Introduction
This study aimed to characterize the glycophenotype of osteoarthritic cartilage and human chondrocytes.Methods
Articular knee cartilage was obtained from nine osteoarthritis (OA) patients. mRNA levels for 27 glycosyltransferases were analyzed in OA chondrocytes using RT-qPCR. Additionally, N- and O-glycans were quantified using mass-spectrometry. Histologically, two cartilage areas with Mankin scores (MS) either ≤4 or ≥9 were selected from each patient representing areas of mild and severe OA, respectively. Tissue sections were stained with (1) a selected panel of plant lectins for probing into the OA glycophenotype, (2) the human lectins galectins-1 and -3, and (3) the glycoprotein asialofetuin (ASF) for visualizing β-galactoside-specific endogenous lectins.Results
We found that OA chondrocytes expressed oligomannosidic structures as well as non-, mono- and disialylated complex-type N-glycans, and core 2 O-glycans. Reflecting B4GALNT3 mRNA presence in OA chondrocytes, LacdiNAc-terminated structures were detected. Staining profiles for plant and human lectins were dependent on the grade of cartilage degeneration, and ASF-positive cells were observed in significantly higher rates in areas of severe degeneration.Conclusions
In summary, distinct aspects of the glycome in OA cartilage are altered with progressing degeneration. In particular, the alterations measured by galectin-3 and the pan-galectin sensor ASF encourage detailed studies of galectin functionality in OA. 相似文献995.
Anke Miriam Kr?hling Luis Alvarez Katharina Debowski Qui Van Monika Gunkel Stephan Irsen Ashraf Al-Amoudi Timo Strünker Elisabeth Kremmer Eberhard Krause Ingo Voigt Simone W?rtge Ari Waisman Ingo Weyand Reinhard Seifert Ulrich Benjamin Kaupp Dagmar Wachten 《PLoS genetics》2013,9(12)
The second messengers cAMP and cGMP activate their target proteins by binding to a conserved cyclic nucleotide-binding domain (CNBD). Here, we identify and characterize an entirely novel CNBD-containing protein called CRIS (cyclic nucleotide receptor involved in sperm function) that is unrelated to any of the other members of this protein family. CRIS is exclusively expressed in sperm precursor cells. Cris-deficient male mice are either infertile due to a lack of sperm resulting from spermatogenic arrest, or subfertile due to impaired sperm motility. The motility defect is caused by altered Ca2+ regulation of flagellar beat asymmetry, leading to a beating pattern that is reminiscent of sperm hyperactivation. Our results suggest that CRIS interacts during spermiogenesis with Ca2+-regulated proteins that—in mature sperm—are involved in flagellar bending. 相似文献
996.
Thomas Ohrt Peter Odenw?lder Julia Dannenberg Mira Prior Zbigniew Warkocki Jana Schmitzová Ramazan Karaduman Ingo Gregor J?rg Enderlein Patrizia Fabrizio Reinhard Lührmann 《RNA (New York, N.Y.)》2013,19(7):902-915
Step 2 catalysis of pre-mRNA splicing entails the excision of the intron and ligation of the 5′ and 3′ exons. The tasks of the splicing factors Prp16, Slu7, Prp18, and Prp22 in the formation of the step 2 active site of the spliceosome and in exon ligation, and the timing of their recruitment, remain poorly understood. Using a purified yeast in vitro splicing system, we show that only the DEAH-box ATPase Prp16 is required for formation of a functional step 2 active site and for exon ligation. Efficient docking of the 3′ splice site (3′SS) to the active site requires only Slu7/Prp18 but not Prp22. Spliceosome remodeling by Prp16 appears to be subtle as only the step 1 factor Cwc25 is dissociated prior to step 2 catalysis, with its release dependent on docking of the 3′SS to the active site and Prp16 action. We show by fluorescence cross-correlation spectroscopy that Slu7/Prp18 and Prp16 bind early to distinct, low-affinity binding sites on the step-1-activated B* spliceosome, which are subsequently converted into high-affinity sites. Our results shed new light on the factor requirements for step 2 catalysis and the dynamics of step 1 and 2 factors during the catalytic steps of splicing. 相似文献
997.
New organisms and biological systems designed to satisfy human needs are among the aims of synthetic genomics and synthetic biology. Synthetic biology seeks to model and construct biological components, functions and organisms that do not exist in nature or to redesign existing biological systems to perform new functions. Synthetic genomics, on the other hand, encompasses technologies for the generation of chemically-synthesized whole genomes or larger parts of genomes, allowing to simultaneously engineer a myriad of changes to the genetic material of organisms. Engineering complex functions or new organisms in synthetic biology are thus progressively becoming dependent on and converging with synthetic genomics. While applications from both areas have been predicted to offer great benefits by making possible new drugs, renewable chemicals or clean energy, they have also given rise to concerns about new safety, environmental and socio-economic risks – stirring an increasingly polarizing debate. Here we intend to provide an overview on recent progress in biomedical and biotechnological applications of synthetic genomics and synthetic biology as well as on arguments and evidence related to their possible benefits, risks and governance implications. 相似文献
998.
Serene M. L. Lee Celine Schelcher Sevdije Gashi Stefanie Schreiber Reinhard M. K. Thasler Karl-Walter Jauch Wolfgang E. Thasler 《Molecular biotechnology》2013,53(1):1-8
The accuracy of information garnered by real-time quantitative polymerase chain reaction (RT-qPCR), an important technology for elucidating molecular mechanisms of disease, is dependent on tissue quality. Thus, this study aimed to determine the effects of intra-operative manipulation, extended processing times, different temperatures or storage in RNAlater on RNA quality in liver samples for tissue banking. Liver samples, flash-frozen or in RNAlater, were collected over a time course (during surgery before blood arrest up to 1 day after surgery) with samples kept either at room temperature (RT) or on ice. This study showed that at the longest time-point at RT, the RNA quality decreased significantly by 20%. However, relative gene expressions of FOS, GUSB, MYC, HIF1?? and GFER were in general not significantly different when the time-points were compared. In conclusion, samples should be kept on ice during processing, and either RNAlater or snap-freezing should be utilised for storage. Further, intra-operative manipulation and extended postoperative processing time generally does not change relative gene expression levels for the 5 genes studied, making such sampling suitable for RT-qPCR analysis. Thus, if relative gene expression of a gene of interest is stable, these guidelines will lead to increased accrual of samples to the tissue bank. 相似文献
999.
1000.
Fabienne Wichmann Frank‐Jörg Vorhölter Lena Hersemann Franco Widmer Jochen Blom Karsten Niehaus Sonja Reinhard Constanze Conradin Roland Kölliker 《Molecular Plant Pathology》2013,14(6):576-588
Xanthomonas translucens pv. graminis (Xtg) is a gammaproteobacterium that causes bacterial wilt on a wide range of forage grasses. To gain insight into the host–pathogen interaction and to identify the virulence factors of Xtg, we compared a draft genome sequence of one isolate (Xtg29) with other Xanthomonas spp. with sequenced genomes. The type III secretion system (T3SS) encoding a protein transport system for type III effector (T3E) proteins represents one of the most important virulence factors of Xanthomonas spp. In contrast with other Xanthomonas spp. assigned to clade 1 on the basis of phylogenetic analyses, we identified an hrp (hypersensitive response and pathogenicity) gene cluster encoding T3SS components and a representative set of 35 genes encoding putative T3Es in the genome of Xtg29. The T3SS was shown to be divergent from the hrp gene clusters of other sequenced Xanthomonas spp. Xtg mutants deficient in T3SS regulating and structural genes were constructed to clarify the role of the T3SS in forage grass colonization. Italian ryegrass infection with these mutants led to significantly reduced symptoms (P < 0.05) relative to plants infected with the wild‐type strain. This showed that the T3SS is required for symptom evocation. In planta multiplication of the T3SS mutants was not impaired significantly relative to the wild‐type, indicating that the T3SS is not required for survival until 14 days post‐infection. This study represents the first major step to understanding the bacterial colonization strategies deployed by Xtg and may assist in the identification of resistance (R) genes in forage grasses. 相似文献