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51.
H R Chaudhry B Bukiet M Siegel T Findley A B Ritter N Guzelsu 《Journal of theoretical biology》1999,201(1):37-46
This article deals with providing a theoretical explanation for quantitative changes in the geometry, the opening angle and the deformation parameters of the rat ventricular wall during adaptation of the passive left ventricle in diastolic dysfunction. A large deformation theory is applied to analyse transmural stress and strain distribution in the left ventricular wall considering it to be made of homogeneous, incompressible, transversely isotropic, non-linear elastic material. The basic assumptions made for computing stress distributions are that the average circumferential stress and strain for the adaptive ventricle is equal to the average circumferential stress and strain in the normotensive ventricle, respectively.All the relevant parameters, such as opening angle, twist per unit length, axial extension, internal and external radii and others, in the stress-free, unloaded and loaded states of normotensive, hypertensive and adaptive left ventricle are determined. The circumferential stress and strain distribution through the ventricular wall are also computed. Our analysis predicts that during adaptation, wall thickness and wall mass of the ventricle increase. These results are consistent with experimental findings and are the indications of initiation of congestive heart failure. 相似文献
52.
Patel SD Habeski WM Min H Zhang J Roof R Snyder B Bora G Campbell B Li C Hidayetoglu D Johnson DS Chaudhry A Charlton ME Kablaoui NM 《Bioorganic & medicinal chemistry letters》2008,18(20):5689-5693
The discovery of the CNS-penetrant and selective alpha(2C) adrenergic receptor antagonist N-{2-[4-(2,3-dihydro-benzo[1,4]dioxin-2-ylmethyl)-[1,4]diazepan-1-yl]-ethyl}-2-phenoxy-nicotinamide, 13 is described. Structure-activity studies demonstrate the structural requirements for binding affinity, functional activity, and selectivity over other alpha(2)-AR subtypes. 相似文献
53.
Muhammad S. Chaudhry Syed U. Rahman Muhammad S. Ismaiel Ghulam Sarwar Bushra Saeed Faiz-ul-Hassan Nasim 《Symbiosis (Philadelphia, Pa.)》2009,49(1):19-28
Effect of disturbance on root colonization and vertical distribution of arbuscular mycorrhizal fungi (AMF) and dark septate
endophytes (DSE) was investigated at two adjacent sites of Lal Suhanra Biosphere Reserve, Pakistan. Disturbance clearly affected
AMF and DSE colonization, vertical distribution of AMF and plant community structure. Mean colonization of AMF and DSE was
slightly less at the disturbed site. Average spore densities, diversity and richness of AMF and DSE were higher at the undisturbed
site. A study of the vertical distribution of AMF associated with the five plant species most common to each study site indicated
that beside AMF and DSE colonization disturbance may affect AMF species composition. Correlation of AMF with DSE is also discussed. 相似文献
54.
Christian Beyer Georg Schett Steffen Gay Oliver Distler Jörg HW Distler 《Arthritis research & therapy》2009,11(2):220-9
Autoimmunity, microangiopathy and tissue fibrosis are hallmarks of systemic sclerosis (SSc). Vascular alterations and reduced
capillary density decrease blood flow and impair tissue oxygenation in SSc. Oxygen supply is further reduced by accumulation
of extracellular matrix (ECM), which increases diffusion distances from blood vessels to cells. Therefore, severe hypoxia
is a characteristic feature of SSc and might contribute directly to the progression of the disease. Hypoxia stimulates the
production of ECM proteins by SSc fibroblasts in a transforming growth factor-β-dependent manner. The induction of ECM proteins
by hypoxia is mediated via hypoxia-inducible factor-1α-dependent and -independent pathways. Hypoxia may also aggravate vascular
disease in SSc by perturbing vascular endothelial growth factor (VEGF) receptor signalling. Hypoxia is a potent inducer of
VEGF and may cause chronic VEGF over-expression in SSc. Uncontrolled over-expression of VEGF has been shown to have deleterious
effects on angiogenesis because it leads to the formation of chaotic vessels with decreased blood flow. Altogether, hypoxia
might play a central role in pathogenesis of SSc by augmenting vascular disease and tissue fibrosis. 相似文献
55.
Christina McKee Mick Perez-Cruet Ferman Chavez G Rasul Chaudhry 《World journal of stem cells》2015,7(7):1064-1077
AIM: To devise a simplified and efficient method for long-term culture and maintenance of embryonic stem cells requiring less frequent passaging.METHODS: Mouse embryonic stem cells (ESCs) labeled with enhanced yellow fluorescent protein were cultured in three-dimensional (3-D) self-assembling scaffolds and compared with traditional two-dimentional (2-D) culture techniques requiring mouse embryonic fibroblast feeder layers or leukemia inhibitory factor. 3-D scaffolds encapsulating ESCs were prepared by mixing ESCs with polyethylene glycol tetra-acrylate (PEG-4-Acr) and thiol-functionalized dextran (Dex-SH). Distribution of ESCs in 3-D was monitored by confocal microscopy. Viability and proliferation of encapsulated cells during long-term culture were determined by propidium iodide as well as direct cell counts and PrestoBlue (PB) assays. Genetic expression of pluripotency markers (Oct4, Nanog, Klf4, and Sox2) in ESCs grown under 2-D and 3-D culture conditions was examined by quantitative real-time polymerase chain reaction. Protein expression of selected stemness markers was determined by two different methods, immunofluorescence staining (Oct4 and Nanog) and western blot analysis (Oct4, Nanog, and Klf4). Pluripotency of 3-D scaffold grown ESCs was analyzed by in vivo teratoma assay and in vitro differentiation via embryoid bodies into cells of all three germ layers.RESULTS: Self-assembling scaffolds encapsulating ESCs for 3-D culture without the loss of cell viability were prepared by mixing PEG-4-Acr and Dex-SH (1:1 v/v) to a final concentration of 5% (w/v). Scaffold integrity was dependent on the degree of thiol substitution of Dex-SH and cell concentration. Scaffolds prepared using Dex-SH with 7.5% and 33% thiol substitution and incubated in culture medium maintained their integrity for 11 and 13 d without cells and 22 ± 5 d and 37 ± 5 d with cells, respectively. ESCs formed compact colonies, which progressively increased in size over time due to cell proliferation as determined by confocal microscopy and PB staining. 3-D scaffold cultured ESCs expressed significantly higher levels (P < 0.01) of Oct4, Nanog, and Kl4, showing a 2.8, 3.0 and 1.8 fold increase, respectively, in comparison to 2-D grown cells. A similar increase in the protein expression levels of Oct4, Nanog, and Klf4 was observed in 3-D grown ESCs. However, when 3-D cultured ESCs were subsequently passaged in 2-D culture conditions, the level of these pluripotent markers was reduced to normal levels. 3-D grown ESCs produced teratomas and yielded cells of all three germ layers, expressing brachyury (mesoderm), NCAM (ectoderm), and GATA4 (endoderm) markers. Furthermore, these cells differentiated into osteogenic, chondrogenic, myogenic, and neural lineages expressing Col1, Col2, Myog, and Nestin, respectively.CONCLUSION: This novel 3-D culture system demonstrated long-term maintenance of mouse ESCs without the routine passaging and manipulation necessary for traditional 2-D cell propagation. 相似文献
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58.
Plant growth promoting Pantoea agglomerans NBRISRM (NBRISRM) was able to produce 60.4 μg/ml indole acetic acid and solubilize 77.5 μg/ml tri-calcium phosphate under
in vitro conditions. Addition of 2% NaCl (w/v) in the media induced the IAA production and phosphate solubilization by 11%
and 7%, respectively. For evaluating the plant growth promotory effect of NBRISRM inoculation a micro plot trial was conducted
using maize and chickpea as host plants. The results revealed significant increase in all growth parameters tested in NBRISRM
inoculated maize and chickpea plants, which were further confirmed by higher macronutrients (N, P and K) accumulation as compared
to un-inoculated controls. Throughout the growing season of maize and chickpea, rhizosphere population of NBRISRM were in
the range 107–108 CFU/g soil and competing with 107–109 CFU/g soil with heterogeneous bacterial population. Functional richness, diversity, and evenness were found significantly
higher in maize rhizosphere as compared to chickpea, whereas NBRISRM inoculation were not able to change it, in both crops
as compared to their un-inoculated control. To the best of our knowledge this is first report where we demonstrated the effect
of P. agglomerans strain for improving maize and chickpea growth without altering the functional diversity. 相似文献
59.
Saima Chaudhry Muhammad Idrees Mateen Izhar Arshad Kamal Butt Ayyaz Ali Khan 《Current microbiology》2011,62(1):78-83
Polymerase Chain reaction (PCR) assay is considered superior to other methods for detection of Helicobacter pylori (H. pylori) in oral cavity; however, it also has limitations when sample under study is microbial rich dental plaque. The type of gene
targeted and number of primers used for bacterial detection in dental plaque samples can have a significant effect on the
results obtained as there are a number of closely related bacterial species residing in plaque biofilm. Also due to high recombination
rate of H. pylori some of the genes might be down regulated or absent. The present study was conducted to determine the frequency of H. pylori colonization of dental plaque by simultaneously amplifying two genes of the bacterium. One hundred dental plaque specimens
were collected from dyspeptic patients before their upper gastrointestinal endoscopy and presence of H. pylori was determined through PCR assay using primers targeting two different genes of the bacterium. Eighty-nine of the 100 samples
were included in final analysis. With simultaneous amplification of two bacterial genes 51.6% of the dental plaque samples
were positive for H. pylori while this prevalence increased to 73% when only one gene amplification was used for bacterial identification. Detection
of H. pylori in dental plaque samples is more reliable when two genes of the bacterium are simultaneously amplified as compared to one
gene amplification only. 相似文献
60.
Amber Afroz Zubeda Chaudhry Umer Rashid Ghulam Muhammad Ali Farhat Nazir Javaid Iqbal Muhammad Rashid Khan 《Plant Cell, Tissue and Organ Culture》2011,104(2):227-237
To enhance bacterial wilt resistance in tomato plants and simplify the protocol of Agrobacterium tumefaciens mediated gene transfer, parameters affecting transformation efficiency in tomato have been optimized. A. tumefaciens strain EHA101, harboring a recombinant binary expression vector pTCL5 containing the Xa21 gene under the control of the CaMV 35S promoter was used for transformation. Five cultivars of tomato (Rio Grande, Roma,
Pusa Ruby Pant Bahr and Avinash) were tested for transformation. Transformation efficiency was highly dependent on preculture
of the explants with acetosyringone, acetosyringone in co-cultivation media, shoot regeneration medium and pre-selection after
co-cultivation without selective agent. One week of pre-selection following selection along with 400 μM acetosyringone resulted
in 92.3% transient GUS expression efficiency in Rio Grande followed by 90.3% in Avinash. The presence and integration of the
Xa21 gene in putative transgenic plants was confirmed by polymerase chain reaction (PCR) and Southern blot analyses with 4.5–42.12%
PCR-positive shoots were obtained for Xa21 and hygromycin genes, respectively. Transgenic plants of the all lines showed resistance to bacterial wilt. T1 plants (resulting from self-pollination of transgenic plants) tested against Pseudomonas solanacearum inoculation in glasshouse, showed Mendelian segregation. 相似文献