全文获取类型
收费全文 | 415篇 |
免费 | 19篇 |
专业分类
434篇 |
出版年
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 22篇 |
2020年 | 4篇 |
2019年 | 10篇 |
2018年 | 14篇 |
2017年 | 11篇 |
2016年 | 18篇 |
2015年 | 24篇 |
2014年 | 16篇 |
2013年 | 34篇 |
2012年 | 37篇 |
2011年 | 27篇 |
2010年 | 24篇 |
2009年 | 10篇 |
2008年 | 18篇 |
2007年 | 22篇 |
2006年 | 18篇 |
2005年 | 23篇 |
2004年 | 21篇 |
2003年 | 13篇 |
2002年 | 13篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1966年 | 2篇 |
1942年 | 1篇 |
1939年 | 2篇 |
排序方式: 共有434条查询结果,搜索用时 0 毫秒
101.
This study was done on 65 isolated pelvic bones, These cadavers belonged to adult people of mature and old age, and they had no pathological changes. These measurements were performed on osteological collection of Department of Anatomy Drago Perovi?. Many geometrical parameters of facies auricularis were measured, which we considered important for further studies, simulations of joint's action, transfer calculations of the forces from spine to hip joint. We used paper, which partially adapted to the surface of facies auricularis, so the values are closer to real ones than projection values. The results have shown that the average surface of facies auricularis is 13.46 cm(2). There was no statistical significance found between left and right cadavers. For easier orientation we divided surface of facies auricularis into two parts: vertical and horizontal. Height of the vertical part was 3.99 cm, while the width was 2.05 cm. Height of horizontal part was 2.07 cm and the width 3.62 cm. 相似文献
102.
Marinović M Cicvarić T Juretić I Grzalja N Medved I Ahel J 《Collegium antropologicum》2010,34(Z2):243-245
Because of a possible delayed wound healing, critical colonization and infection of wounds present a problem for surgeons. Colonized and infected wounds are a potential source for cross-infection. Molndal technique of wound dressing has proven to be effective in prevention of infection. Also the wound heal better and faster. In our study we wanted to describe the benefits of the Molndal technique wound dressing after laparoscopic cholecistectomy compared to traditional wound dressing technique. Molndal technique consisted of wound dressing with Aquacel Ag--Hydrofiber (ConvaTec, Dublin, Ireland). Traditional technique was performed using gauze compresses and hypoallergic adhesives. We analyzed the results of 100 patients after laparoscopic cholecystectomy. 50 patients were treated by Molndal technique and 50 patients by the traditional technique of wound dressing. In the group treated by Molndal technique only 1 (2%) patient has revealed a wound infection, proven by positive microbiological examination and suppuration, mostly in the subumbilical incision. In the traditional technique group 7 (14%) patients developed wound infection also predominantly in the subumbilical incision. The difference was statistically significant (p < 0.01). Our results are clearly showing that Molndal technique is effective in preventing the infection of subumbilical incision wound and is to by recommend for regular use at designated site after laparoscopic cholecistectomy. 相似文献
103.
104.
Tian Z Zhao R Tolić N Moore RJ Stenoien DL Robinson EW Smith RD Paša-Tolić L 《Proteomics》2010,10(20):3610-3620
An online metal-free weak cation exchange-hydrophilic interaction LC/RPLC system has been developed for sensitive, high-throughput top-down MS. Here, we report results for analyzing PTMs of core histones, with a focus on histone H4, using this system. With just ~24?μg on-column of core histones (H4, H2B, H2A, and H3) purified from human fibroblasts, 41 H4 isoforms were identified, with the type and location of PTMs unambiguously mapped for 20 of these variants. Compared to corresponding offline studies reported previously, the online weak cation exchange-hydrophilic interaction LC/RPLC platform offers significant improvement in sensitivity, with several orders of magnitude reduction in sample requirements and a reduction in the overall analysis time. To the best of our knowledge, this study represents the first online 2-D LC-MS/MS characterization of core histone mixture at the intact protein level. 相似文献
105.
Ralf Janssen Bo Joakim Eriksson Graham E. Budd Michael Akam Nikola‐Michael Prpic 《Evolution & development》2010,12(4):363-372
SUMMARY In arthropods, such as Drosophila melanogaster, the leg gap genes homothorax (hth), extradenticle (exd), dachshund (dac), and Distal‐less (Dll) regionalize the legs in order to facilitate the subsequent segmentation of the legs. We have isolated homologs of all four leg gap genes from the onychophoran Euperipatoides kanangrensis and have studied their expression. We show that leg regionalization takes place in the legs of onychophorans even though they represent simple and nonsegmented appendages. This implies that leg regionalization evolved for a different function and was only later co‐opted for a role in leg segmentation. We also show that the leg gap gene patterns in onychophorans (especially of hth and exd) are similar to the patterns in crustaceans and insects, suggesting that this is the plesiomorphic state in arthropods. The reversed hth and exd patterns in chelicerates and myriapods are therefore an apomorphy for this group, the Myriochelata, lending support to the Myriochelata and Tetraconata clades in arthropod phylogeny. 相似文献
106.
Cadherin-mediated specific cell adhesion is an important process in brain development as well as in synaptic plasticity in the adult brain. In this study the authors quantified mRNA levels of N-cadherin and cadherin-11 in different brain regions for the first time. In hippocampus N-cadherin mRNA levels were very high at embryonic stages and decreased during further development, whereas cadherin-11 mRNA levels were highest at postnatal stages. However, N-cadherin protein level was not altered during hippocampal development and cadherin-11 protein was low at embryonic but high at postnatal and adult stages. In cultured hippocampal neurons both cadherins became colocalized and recruited to synaptic sites during ongoing differentiation, with especially high accumulation of cadherin-11 at synapses. These data hint at a critical role of N-cadherin at early embryonic stages and early synaptogenesis, whereas cadherin-11 might be more important for further stabilization of synapses in the postnatal period and adulthood. 相似文献
107.
Shen Y Tolić N Liu T Zhao R Petritis BO Gritsenko MA Camp DG Moore RJ Purvine SO Esteva FJ Smith RD 《PloS one》2010,5(10):e13133
Background
Cancer invasion and metastasis are closely associated with activities within the degradome; however, little is known about whether these activities can be detected in the blood of cancer patients.Methodology and Principal Findings
The peptidome-degradome profiles of pooled blood plasma sampled from 15 breast cancer patients (BCP) and age, race, and menopausal status matched control healthy persons (HP) were globally characterized using advanced comprehensive separations combined with tandem Fourier transform mass spectrometry and new data analysis approaches that facilitated top-down peptidomic analysis. The BCP pool displayed 71 degradome protein substrates that encompassed 839 distinct peptidome peptides. In contrast, the HP 50 degradome substrates found encompassed 425 peptides. We find that the ratios of the peptidome peptide relative abundances can vary as much as >4000 fold between BCP and HP. The experimental results also show differential degradation of substrates in the BCP sample in their functional domains, including the proteolytic and inhibitory sites of the plasmin-antiplasmin and thrombin-antithrombin systems, the main chains of the extracellular matrix protection proteins, the excessive degradation of innate immune system key convertases and membrane attack complex components, as well as several other cancer suppressor proteins.Conclusions
Degradomics-peptidomics profiling of blood plasma is highly sensitive to changes not evidenced by conventional bottom-up proteomics and potentially provides unique signatures of possible diagnostic utility. 相似文献108.
Background
RNA interference (RNAi) is a process triggered by a double-stranded RNA that leads to targeted down-regulation/silencing of gene expression and can be used for functional genomics; i.e. loss-of-function studies. Here we report on the use of RNAi in the identification of a developmentally important novel Drosophila (fruit fly) gene (corresponding to a putative gene CG5652/GM06434), that we named beltless based on an embryonic loss-of-function phenotype.Results
Beltless mRNA is expressed in all developmental stages except in 0–6 h embryos. In situ RT-PCR localized beltless mRNA in the ventral cord and brain of late stage embryos and in the nervous system, ovaries, and the accessory glands of adult flies. RNAi was induced by injection of short (22 bp) beltless double-stranded RNAs into embryos or into adult flies. Embryonic RNAi altered cuticular phenotypes ranging from partially-formed to missing denticle belts (thus beltless) of the abdominal segments A2–A4. Embryonic beltless RNAi was lethal. Adult RNAi resulted in the shrinkage of the ovaries by half and reduced the number of eggs laid. We also examined Df(1)RK4 flies in which deletion removes 16 genes, including beltless. In some embryos, we observed cuticular abnormalities similar to our findings with beltless RNAi. After differentiating Df(1)RK4 embryos into those with visible denticle belts and those missing denticle belts, we assayed the presence of beltless mRNA; no beltless mRNA was detectable in embryos with missing denticle belts.Conclusions
We have identified a developmentally important novel Drosophila gene, beltless, which has been characterized in loss-of-function studies using RNA interference. The putative beltless protein shares homologies with the C. elegans nose resistant to fluoxetine (NRF) NRF-6 gene, as well as with several uncharacterized C. elegans and Drosophila melanogaster genes, some with prominent acyltransferase domains. Future studies should elucidate the role and mechanism of action of beltless during Drosophila development and in adults, including in the adult nervous system.109.
The SCF ubiquitin ligases catalyze protein ubiquitination in diverse cellular processes. SCFs bind substrates through the interchangeable F box protein subunit, with the >70 human F box proteins allowing the recognition of a wide range of substrates. The F box protein beta-TrCP1 recognizes the doubly phosphorylated DpSGphiXpS destruction motif, present in beta-catenin and IkappaB, and directs the SCF(beta-TrCP1) to ubiquitinate these proteins at specific lysines. The 3.0 A structure of a beta-TrCP1-Skp1-beta-catenin complex reveals the basis of substrate recognition by the beta-TrCP1 WD40 domain. The structure, together with the previous SCF(Skp2) structure, leads to the model of SCF catalyzing ubiquitination by increasing the effective concentration of the substrate lysine at the E2 active site. The model's prediction that the lysine-destruction motif spacing is a determinant of ubiquitination efficiency is confirmed by measuring ubiquitination rates of mutant beta-catenin peptides, solidifying the model and also providing a mechanistic basis for lysine selection. 相似文献
110.
Punda-Polic V Petrovec M Trilar T Duh D Bradaric N Klismanic Z Avsic-Zupanc T 《Experimental & applied acarology》2002,28(1-4):169-176
A total of 197 ticks belonging to four species (Haemaphysalis punctata, Hyalomma marginatum, Rhipicephalus bursa and Dermacentor marginatus) collected in October 2000 from domestic animals in southern Croatia were examined for the presence of rickettsiae by molecular
techniques. Specific sequences of the rickettsiae were detected in 25 (12.7%) of ticks tested. The prevalence of infection
in D. marginatus and H. marginatum ticks was 36.8 and 64.7%, respectively. None of the ticks belonging to the species H. punctata or Rh. bursa were infected. Sequence analysis of amplified products revealed that D. marginatus ticks are infected with Rickettsia slovaca, whereas H. marginatum are infected with R. aeschlimannii. The results of this study extend the knowledge of the geographic distribution of SFG rickettsiae and indicate that at least
two of them, with yet uncertain pathogenicity to humans, are present in ticks in southern Croatia.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献