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121.
E Lewitus PR Hof CC Sherwood 《Evolution; international journal of organic evolution》2012,66(8):2551-2563
A major focus of comparative neuroanatomy has been on whether the mammalian brain evolves in a concerted or a mosaic fashion. Workers have examined variation in the volume of different brain regions across taxa to test the degree to which selection is constrained by the timing of events in neural development. Whether a conserved neurogenetic program in the mammalian brain constrains the distribution of different cell types, however, has not yet been investigated. Here we tested for evidence of evolutionary constraints on the densities of different cell types in the primary visual cortex (V1) and the hippocampus in 37 primate and 21 carnivore species. Cellular densities in V1 and the hippocampus scale isometrically with respect to one another in carnivores, as predicted by the concerted evolution hypothesis. In primates, however, cellular distributions in the hippocampus and primary visual cortex show no correlations, which supports the hypothesis of mosaic brain evolution. We therefore provide evidence for the presence of constraints controlling the adult densities of different cell types in disparate regions of the mammalian brain, but also for specializations along the primate lineage. We propose that adaptations to modularity at the cellular level may carry a deep phylogenetic signal. 相似文献
122.
Fluorescence solvent relaxation experiments are based on the characterization of time-dependent shifts in the fluorescence emission of a chromophore, yielding polarity and viscosity information about the chromophore’s immediate environment. A chromophore applied to a phospholipid bilayer at a well-defined location (with respect to the z-axis of the bilayer) allows monitoring of the hydration and mobility of the probed segment of the lipid molecules. Specifically, time-resolved fluorescence experiments, fluorescence quenching data and molecular dynamic (MD) simulations show that 6-lauroyl-2-dimethylaminonaphthalene (Laurdan) probes the hydration and mobility of the sn-1 acyl groups in a phosphatidylcholine bilayer. The time-dependent fluorescence shift (TDFS) of Laurdan provides information on headgroup compression and expansion induced by the addition of different amounts of cationic lipids to phosphatidylcholine bilayers. Those changes were predicted by previous MD simulations. Addition of truncated oxidized phospholipids leads to increased mobility and hydration at the sn-1 acyl level. This experimental finding can be explained by MD simulations, which indicate that the truncated chains of the oxidized lipid molecules are looping back into aqueous phase, hence creating voids below the glycerol level. Fluorescence solvent relaxation experiments are also useful in understanding salt effects on the structure and dynamics of lipid bilayers. For example, such experiments demonstrate that large anions increase hydration and mobility at the sn-1 acyl level of phosphatidylcholine bilayers, an observation which could not be explained by standard MD simulations. If polarizability is introduced into the applied force field, however, MD simulations show that big soft polarizable anions are able to interact with the hydrophilic/hydrophobic interface of the lipid bilayer, penetrating to the level probed by Laurdan, and that they expand and destabilize the bilayer making it more hydrated and mobile. 相似文献
123.
The effect of non-ionic detergents on baclofen (GABAB-R agonist)-stimulated G-protein activity was measured as a [35S]GTPγS binding assay in the plasma membranes (PM) isolated from the brain tissue. The effect was clearly biphasic — a decrease in the activity was followed by an activation maximum and finally, at high concentrations, drastic inhibition of the G-protein activity was noticed. Contrarily, specific radioligand binding to GABAB-receptor was inhibited in the whole range of detergent concentrations step by step, i.e. it was strictly monophasic. The magnitude of both detergent effects was decreased in the same order of potency: Brij58 > Triton X-100 > Digitonin. The identical order was found when comparing detergents ability to alter fluorescence anisotropy of the membrane probe 1,6-diphenyl-1,3,5-hexatriene (rDPH) incorporated into the hydrophobic PM interior. Decrease of rDPH, in the order of Brij58 > Triton X-100 > Digitonin, was reflected as decrease of the S-order parameter and rotation correlation time ? paralleled by an increase of diffusion wobbling constant Dw (analysis by time-resolved fluorescence according to “wobble-in-cone” model). The influence of the detergents on the membrane organization at the polar headgroup region was characterized by Laurdan generalized polarization (GP). As before, the effect of detergents on GP parameters proceeded in the order: Brij58 > Triton X-100 > Digitonin. 相似文献
124.
D. A. A. M. Schellings J. C. A. Hoorntje M. J. de Boer A. W. J. van ’t Hof H. Suryapranata 《Netherlands heart journal》2010,18(6):307-313
Background. In patients with unstable angina or non-ST-elevation acute coronary syndrome (NSTE-ACS) who are eligible for PCI, routine stenting is the recommended treatment strategy, based on the opinion of experts. Provisional stenting may provide a viable alternative by retaining the early benefits of stenting without its potential late hazards. Method. Patients with NSTE-ACS were randomised to provisional or routine stenting after coronary angiography. Patients were followed for up to ten years. The occurrence of major adverse cardiac events (MACE) was recorded. Results. 237 consecutive patients with NSTE-ACS were randomly assigned to routine stenting (n=116) or provisional stenting (n=121). No difference in the incidence of MACE at 30 days was observed. At six months, angiographic restenosis was lower in the routine stenting group (41 vs. 20%, p=0.02), paralleled by more MACE in the provisional stenting group at one year (40.5 vs. 27.6%, p=0.036). At complete follow-up the difference in MACE was not significant (61.2 vs. 50%, p=0.084) because of relatively more target lesion revascularisations in the routine stent group. There was no difference in the incidence of very late stent thrombosis (1.7 vs. 3.4%, p=0.439). The only independent predictor of MACE was β-blocker use (RR 0.62 [0.431; 0.892] p=0.010). Conclusion. In selective patients with NSTE-ACS, routine stenting was more beneficial than provisional stenting for a period of up to five years, driven by a reduction in repeat revascularisation procedures. After this period, the benefit was no longer significant. Beta-blocker use was the only independent predictor of MACE throughout the complete follow-up period. (Neth Heart J 2010;18:307-313.) 相似文献
125.
126.
We demonstrate for the first time that ellipsometry and confocal fluorescence correlation spectroscopy (FCS) are complementary methods for the characterisation of supported planar phospholipid bilayers (SPBs) formed on mica, a mineral used in atomic force microscopy investigations of SPBs. Addition of small unilamellar vesicles containing 20% dioleoyl-phosphatidylserine (DOPS) and 80% dioleoyl-phosphatidylcholine (DOPC) to an oxidised borosilicate surface, on the other hand, results in a planar lipid system characterised by lateral diffusion coefficients which are three time smaller than those obtained for SPBs. Moreover, seven labelled phospholipids were tested for their suitability in the FCS characterisation of vesicles as well as of SPBs. 相似文献
127.
128.
Helma M. Prinssen Carla F. M. Molthoff René H. M. Verheijen Tim J. Broadhead Peter Kenemans Jan C. Roos Quentin Davies Arjan C. van Hof Malcolm Frier Wim den Hollander Abraham J. Wilhelm Terry S. Baker Mark Sopwith E. Malcolm Symonds Alan C. Perkins 《Cancer immunology, immunotherapy : CII》1998,15(1):39-46
mAb hCTM01 binds a carcinoma-associated antigen, the MUC1 gene product. The antigen is also present in the circulation, and administration of 111In-labelled hCTM01 results in the formation of immune complexes with enhanced accumulation in the liver. To avoid the unwanted
effect of circulating radioactive immune complexes, a strategy to remove the circulating antigen was investigated using a
split-dosage schedule. Eleven patients suspected of having ovarian carcinoma were injected with 1 mg/kg unlabelled hCTM01,
1 h before receiving 0.1 mg/kg 111In-labelled hCTM01 (100 MBq). The amount of radioactivity was determined in resected tumour tissue, various normal tissues
and blood samples obtained at laparotomy 6 days postinjection (p.i.). In all patients, the circulating antigen decreased to
its nadir after the unlabelled antibody infusion and immune complex formation was demonstrated. Uptake in tumour deposits
6 days p.i. was 11.1 times higher than in normal tissues (P<0.0001) and 5.9 times higher than in blood (P<0.0001). 111In activity in liver tissue was comparable to 111In uptake in tumour tissue, and considerably lower than previously reported in patients not pretreated with unlabelled antibody.
The split-dosing strategy would appear to be advantageous for use of hCTM01 as a specific carrier for the delivery of cytotoxic
agents to patients with ovarian cancer.
Received: 12 February 1998 / Accepted: 30 April 1998 相似文献
129.
N-Linked glycosylation of a baculovirus-expressed recombinant glycoprotein in insect larvae and tissue culture cells 总被引:5,自引:3,他引:2
The potential of insect cell cultures and larvae infected with recombinant
baculoviruses to produce authentic recombinant glycoproteins cloned from
mammalian sources was investigated. A comparison was made of the N-linked
glycans attached to secreted alkaline phosphatase (SEAP) produced in four
species of insect larvae and their derived cell lines plus one additional
insect cell line and larvae of one additional species. These data survey
N-linked oligosaccharides produced in four families and six genera of the
order Lepidoptera. Recombinant SEAP expressed by recombinant isolates of
Autographa californica and Bombyx mori nucleopolyhedroviruses was purified
from cell culture medium, larval hemolymph or larval homogenates by
phosphate affinity chromatography. The N-linked oligosaccharides were
released with PNGase-F, labeled with 8- aminonaphthalene-1-3-6-trisulfonic
acid, fractionated by polyacrylamide gel electrophoresis, and analyzed by
fluorescence imaging. The oligosaccharide structures were confirmed with
exoglycosidase digestions. Recombinant SEAP produced in cell lines of
Lymantria dispar (IPLB-LdEIta), Heliothis virescens (IPLB-HvT1), and Bombyx
mori (BmN) and larvae of Spodoptera frugiperda, Trichoplusia ni ,
H.virescens , B.mori , and Danaus plexippus contained oligosaccharides that
were structurally identical to the 10 oligosaccharides attached to SEAP
produced in T.ni cell lines. The oligosaccharide structures were all
mannose-terminated. Structures containing two or three mannose residues,
with and without core fucosylation, constituted more than 75% of the
oligosaccharides from the cell culture and larval samples.
相似文献
130.
Wim Ament Gerard J. J. Bonga At L. Hof Gÿ sbertus J. Verkerke 《Journal of electromyography and kinesiology》1993,3(4):214-220
EMG median power frequency of the calf muscles was investigated during an exhausting treadmill exercise. This exercise was an uphill run, the average endurance time was 1.5 min. Median power frequency of the calf muscles declined by more than 10% during this exercise. In addition EMG median power frequency of isometric contractions of the same muscles was measured before and in one minute intervals for 10 min after this run. Immediately after the run isometric median power frequency had declined by less than 5% for the soleus muscle, more than 10% for the gastrocnemius medialis and gastrocnemius lateralis muscles. In the 10 min following exercise the isometric median power frequency increased to pre-execise levels. Maybe the median power frequency shift to lower frequencies during dynamic exercise can be interpreted as a sign of local muscle fatigue. 相似文献