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151.
Hominins, sedges, and termites: new carbon isotope data from the Sterkfontein valley and Kruger National Park 总被引:3,自引:0,他引:3
Sponheimer M Lee-Thorp J de Ruiter D Codron D Codron J Baugh AT Thackeray F 《Journal of human evolution》2005,48(3):301-312
Stable carbon isotope analyses have shown that South African australopiths did not have exclusively frugivorous diets, but also consumed significant quantities of C4 foods such as grasses, sedges, or animals that ate these foods. Yet, these studies have had significant limitations. For example, hominin sample sizes were relatively small, leading some to question the veracity of the claim for australopith C4 consumption. In addition, it has been difficult to determine which C4 resources were actually utilized, which is at least partially due to a lack of stable isotope data on some purported australopith foods. Here we begin to address these lacunae by presenting carbon isotope data for 14 new hominin specimens, as well as for two potential C4 foods (termites and sedges). The new data confirm that non-C3 foods were heavily utilized by australopiths, making up about 40% and 35% of Australopithecus and Paranthropus diets respectively. Most termites in the savanna-woodland biome of the Kruger National Park, South Africa, have intermediate carbon isotope compositions indicating mixed C3/C4 diets. Only 28% of the sedges in Kruger were C4, and few if any had well-developed rhizomes and tubers that make some sedges attractive foods. We conclude that although termites and sedges might have contributed to the C4 signal in South African australopiths, other C4 foods were also important. Lastly, we suggest that the consumption of C4 foods is a fundamental hominin trait that, along with bipedalism, allowed australopiths to pioneer increasingly open and seasonal environments. 相似文献
152.
Loss of Smad3-mediated negative regulation of Runx2 activity leads to an alteration in cell fate determination
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Hjelmeland AB Schilling SH Guo X Quarles D Wang XF 《Molecular and cellular biology》2005,25(21):9460-9468
Runx2 is required for osteoblast differentiation but is expressed in certain nonosteoblastic cells without activating the differentiation process, suggesting that its activity is suppressed through a lineage-specific mechanism. Here we report that primary mouse dermal fibroblasts lacking Smad3 can acquire an osteoblast-like phenotype, including activation of Runx2 activity, expression of osteoblast-specific genes, and calcium deposition. We further show that negative regulation of Runx2 activity by Smad3 in dermal fibroblasts is likely mediated by controlling the expression of Msx2, an antagonist of Runx2 in this cellular context. These data support the presence of a novel mechanism for controlling cell fate determination of mesenchymal lineages by preventing differentiation toward the osteoblastic lineage via negative regulation of Runx2 activity. 相似文献
153.
The human-specific pathogens Neisseria meningitidis, N. gonorrhoea, Haemophilus influenzae and Moraxella catarrhalis share the property of targeting the carcinoembryonic antigen (CEA)-related cell adhesion molecules (CEACAMs) expressed on human epithelia. CEACAMs are signalling receptors implicated in cell adhesion and regulation of several physiological functions. Their targeting by pathogens can lead to tissue invasion. Although the CEACAM-binding ligands of the bacteria are structurally diverse, they target a common site on the receptor. We have generated a recombinant polypeptide that blocks the interactions of the mucosal pathogens with human epithelial cells and antibodies against it inhibit M. catarrhalis interactions with the receptor. As such, it is a potential antimicrobial agent to prevent infection via a strategy unlikely to promote bacterial resistance and a vaccine candidate against M. catarrhalis. In addition, it could serve more widely as a novel research tool and as a potential therapeutic agent in CEACAM-based physiological disorders. 相似文献
154.
Catherine Lane Scott Burgess Anthony Kicic Darryl Knight Stephen Stick 《Respiratory research》2005,6(1):53
Background
The use of cytology brushes for the purpose of obtaining respiratory cells from adults for clinical and research purposes is well established. However, the safety and utility of non-bronchoscopic brushings to study the paediatric airway has not been assessed. The purpose of this study was to assess the practicality of using non-bronchoscopic brushing to sample epithelial cells from children for investigation of epithelial function in health and disease using a wide range of molecular and cellular techniques.Methods
Non-bronchoscopic brushing was investigated in a non-selected cohort of healthy, and mildly asthmatic children presenting for surgery unrelated to respiratory conditions, at the major children''s hospital in Perth. Safety and side-effects of the procedure were assessed. Cell number, phenotype and viability were measured for all samples. The potential of these cells for use in long-term cell culture, immunohistochemistry, western blotting, quantitative PCR and gene arraying was examined.Results
Non-bronchoscopic brushing was well tolerated in all children. The only significant side effect following the procedure was cough: nursing staff reported cough in 20% of patients; parents reported cough in 40% of patients. Cells sampled were of sufficient quantity and quality to allow cell culture in 93% of samples. Similarly, protein and RNA extracted from the cells was suitable for investigation of both gene and protein expression using micro-array and real-time PCR.Conclusion
Non-bronchoscopic brushing in children is safe and easy to perform, and is not associated with any complications. Using this technique, adequate numbers of epithelial cells can be retrieved to allow cell culture, western blotting, real time PCR, and microarray analysis. The purpose of this study is to demonstrate the utility of non-bronchoscopic airway brushing to obtain and study epithelial cells and to encourage others so that we can accelerate our knowledge regarding the role of the epithelium in childhood respiratory disease. 相似文献155.
Palmer-Toy DE Krastins B Sarracino DA Nadol JB Merchant SN 《Journal of proteome research》2005,4(6):2404-2411
Formalin-fixed and paraffin-embedded (FFPE) tissues present a particular challenge for proteomic analysis. Yet, most of the archived tissues in hospitals and tissue banks worldwide are only available in this form. We have developed conditions for removal of the embedding medium and protein digestion, such that informative tryptic peptides are released from fixed proteins which are suitable for analysis by liquid chromatography-mass spectrometry (LC-MS). We demonstrate that the peptide identifications made by this approach compare favorably to those made from matched fresh frozen tissue. Moreover, we demonstrate that a high level of sequence coverage can be observed for proteins of interest. 相似文献
156.
Cell wall deposition during morphogenesis in fucoid algae 总被引:6,自引:0,他引:6
Cell wall deposition was investigated during morphogenesis in zygotes of Pelvetia compressa (J. Agardh) De Toni. Young zygotes are spherical and wall is deposited uniformly, but at germination (about 10 h after fertilization)
wall deposition becomes localized to the apex of the tip-growing rhizoid. Wall deposition was investigated before and after
the initiation of tip growth by disrupting cytoskeleton, secretion or cellulose deposition; effects on wall strength and structure
were examined. All three were involved in generating wall strength in both spherical and tip-growing zygotes, but their relative
importance were different at the two developmental stages. Much of the wall strength in young zygotes was dependent on F-actin,
whereas cellulose and a sulfated component, probably a fucan (F2), were most important in tip growing zygotes. Some treatments
had contrasting effects at the two developmental stages; for example, disruption of F-actin or inhibition of secretion weakened
walls in spherical zygotes but strengthened those in tip-growing zygotes. Transmission electron microscopic analysis showed
that most treatments that altered wall strength induced modifications of internal wall structure.
Received: 12 June 2000 / Accepted: 26 July 2000 相似文献
157.
Anderson NL Anderson NG Haines LR Hardie DB Olafson RW Pearson TW 《Journal of proteome research》2004,3(2):235-244
A method (denoted SISCAPA) for quantitation of peptides in complex digests is described. In the method, anti-peptide antibodies immobilized on 100 nanoliter nanoaffinity columns are used to enrich specific peptides along with spiked stable-isotope-labeled internal standards of the same sequence. Upon elution from the anti-peptide antibody supports, electrospray mass spectrometry is used to quantitate the peptides (natural and labeled). In a series of pilot experiments, tryptic test peptides were chosen for four proteins of human plasma (hemopexin, alpha1 antichymotrypsin, interleukin-6, and tumor necrosis factor-alpha) from a pool of 10,203 in silico tryptic peptide candidates representing 237 known plasma components. Rabbit polyclonal antibodies raised against the chosen peptide sequences were affinity purified and covalently immobilized on POROS supports. Binding and elution from these supports was shown to provide an average 120-fold enrichment of the antigen peptide relative to others, as measured by selected ion monitoring (SIM) or selected reaction monitoring (SRM) electrospray mass spectrometry. The columns could be recycled with little loss in binding capacity, and generated peptide ion current measurements with cycle-to-cycle coefficients of variation near 5%. Anti-peptide antibody enrichment will contribute to increased sensitivity of MS-based assays, particularly for lower abundance proteins in plasma, and may ultimately allow substitution of a rapid bind/elute process for the time-consuming reverse phase separation now used as a prelude to online MS peptide assays. The method appears suitable for rapid generation of assays for defined proteins, and should find application in the validation of diagnostic protein panels in large sample sets. 相似文献
158.
J Gustavo Zayas Darryl W O'Brien Shusheng Tai Jie Ding Leonard Lim Malcolm King 《Respiratory research》2004,5(1):1-7
Background
Previous studies showing a strong relationship between Cheyne-Stokes respiration and the severity of left ventricular systolic dysfunction have usually been done in selected patient populations with lower age and a higher proportion of males than the "typical" in-hospital patient with heart failure. The purpose of the present study was test the strength of this relationship in unselected patients admitted to hospital due to decompensated chronic heart failure.Methods
We evaluated 191 patients (32% women), mean age 73 years, ready for discharge from the heart failure unit in the University Hospital of Malmö, Sweden. The patients underwent echocardiography for determination of left ventricular ejection fraction and left ventricular inner diastolic diameter. A respiratory investigation during sleep was performed the last night before discharge.Results
We found that 66% of the patients had Cheyne-Stokes respiration more than 10% of the total recording time. Only 7 (3.6%) of the patients had predominantly obstructive apnoeas. There was a significant but very weak relationship between left ventricular ejection fraction and left ventricular inner diastolic diameter on one hand and Cheyne-Stokes respiration on the other. Age was a stronger determinant of Cheyne-Stokes respiration than any of the cardiac or other clinical variables.Conclusion
Although presence of Cheyne-Stokes respiration indicates left ventricular dysfunction, its severity seems only weakly related to the severity of heart failure. Age was found to be a stronger determinant, which may reflect the underlying age-dependency found also in healthy subjects. Due to age restrictions or other selection criteria, the importance of age may have been underestimated in many previous studies on factors associated with Cheyne-Stokes respiration. 相似文献159.
Histone H3 lysine 4 methylation disrupts binding of nucleosome remodeling and deacetylase (NuRD) repressor complex 总被引:11,自引:0,他引:11
Zegerman P Canas B Pappin D Kouzarides T 《The Journal of biological chemistry》2002,277(14):11621-11624
160.
Bruce L. Riser Feridoon Najmabadi Bernard Perbal Jo Ann Rambow Melisa L. Riser Ernest Sukowski Herman Yeger Sarah C. Riser Darryl R. Peterson 《Journal of cell communication and signaling》2010,4(1):39-50
Prior work in the CCN field, including our own, suggested to us that there might be co-regulatory activity and function as
part of the actions of this family of cysteine rich cytokines. CCN2 is now regarded as a major pro-fibrotic molecule acting
both down-stream and independent of TGF-β1, and appears causal in the disease afflicting multiple organs. Since diabetic renal
fibrosis is a common complication of diabetes, and a major cause of end stage renal disease (ESRD), we examined the possibility
that CCN3 (NOV), might act as an endogenous negative regulator of CCN2 with the capacity to limit the overproduction of extracellular
matrix (ECM), and thus prevent, or ameliorate fibrosis. We demonstrate, using an in vitro model of diabetic renal fibrosis,
that both exogenous treatment with CCN3 and transfection with the over-expression of the CCN3 gene in mesangial cells markedly
down-regulates CCN2 activity and blocks ECM over-accumulation stimulated by TGF-β1. Conversely, TGF-β1 treatment reduces endogenous
CCN3 expression and increases CCN2 activity and matrix accumulation, indicating an important, novel yin/yang effect. Using
the db/db mouse model of diabetic nephropathy, we confirm the expression of CCN3 in the kidney, with temporal localization
that supports these in vitro findings. In summary, the results corroborate our hypothesis that one function of CCN3 is to
regulate CCN2 activity and at the concentrations and conditions used down-regulates the effects of TGF-β1, acting to limit
ECM turnover and fibrosis in vivo. The findings suggest opportunities for novel endogenous-based therapy either by the administration,
or the upregulation of CCN3. 相似文献