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901.
Pecaut MJ Haerich P Miller CN Smith AL Zendejas ED Nelson GA 《Radiation research》2004,162(2):148-156
To investigate the behavioral consequences of exposure to whole-body irradiation such as might occur for astronauts during space flight, female C57BL/6 mice were exposed to 0, 0.1, 0.5 or 2 Gy accelerated iron ions (56Fe, Z = 26, beta = 0.9, LET = 148.2 keV/microm) of 1 GeV per nucleon using the Alternating Gradient Synchrotron at the Brookhaven National Laboratory. Animal testing began 2 weeks after exposure and continued for 8 weeks. Under these conditions, there were few significant effects of radiation on open-field, rotorod or acoustic startle activities at any of the times examined. The lack of radiation effects in these behavioral models appears to offer reassurance to NASA mission designers. These results suggest that there may be negligible effects of HZE radiation on many behaviors during a 2-8-week period immediately after radiation. 相似文献
902.
903.
M protein, a classical bacterial virulence determinant, forms complexes with fibrinogen that induce vascular leakage 总被引:10,自引:0,他引:10
Herwald H Cramer H Mörgelin M Russell W Sollenberg U Norrby-Teglund A Flodgaard H Lindbom L Björck L 《Cell》2004,116(3):367-379
Increased vascular permeability is a key feature of inflammatory conditions. In severe infections, leakage of plasma from the vasculature induces a life-threatening hypotension. Streptococcus pyogenes, a major human bacterial pathogen, causes a toxic shock syndrome (STSS) characterized by excessive plasma leakage and multi-organ failure. Here we find that M protein, released from the streptococcal surface, forms complexes with fibrinogen, which by binding to beta2 integrins of neutrophils, activate these cells. As a result, neutrophils release heparin binding protein, an inflammatory mediator inducing vascular leakage. In mice, injection of M protein or subcutaneous infection with S. pyogenes causes severe pulmonary damage characterized by leakage of plasma and blood cells. These lesions were prevented by treatment with a beta2 integrin antagonist. In addition, M protein/fibrinogen complexes were identified in tissue biopsies from a patient with necrotizing fasciitis and STSS, further underlining the pathogenic significance of such complexes in severe streptococcal infections. 相似文献
904.
Faustini M Torre ML Stacchezzini S Norberti R Consiglio AL Porcelli F Conte U Munari E Russo V Vigo D 《Theriogenology》2004,61(1):173-184
The customary dilution of boar semen for subsequent artificial insemination (AI) procedures damages the cell membrane of spermatozoa, resulting in a loss of enzymes and other cytoplasmic contents and acrosomal reactions. We encapsulated non-diluted boar semen in barium alginate membranes to optimize AI procedures and to improve the functional integrity of spermatozoal membranes during storage. The percentage of non-reacted acrosomes (NRA) and measurements of enzyme leakage (cytochrome c oxidase (COX), lactate dehydrogenase (LDH), and glucose-6-phosphate dehydrogenase (G6PDH)) were used as indices of the functional status of diluted, unencapsulated and encapsulated spermatozoa, stored for 72 h at 18 degrees C. Enzymatic activity was assessed in situ by microdensitometry, and non-reacted acrosomes were microscopically determined by staining. The percentage of acrosome integrity and the intracellular enzymatic activities during storage were different for unencapsulated and encapsulated semen. Semen dilution caused a rapid decline in enzymatic activities and concomitant acrosomal reactions. Encapsulated spermatozoa had significantly higher acrosome integrity (77% versus 55%; P < 0.01 after 72 h) and an overall higher in situ enzymatic activity. For cytochrome c oxidase and lactate dehydrogenase the greatest differences between encapsulated and unencapsulated spermatozoa were present after 72 h whereas for glucose-6-phosphate dehydrogenase significant differences were found within 24h of storage. The encapsulation process maintains a better preservation environment for boar spermatozoa and could be a promising, innovative technique to improve storage of these cells. 相似文献
905.
Rapid quantitative detection of Listeria monocytogenes in meat products by real-time PCR 总被引:2,自引:0,他引:2
Rodríguez-Lázaro D Jofré A Aymerich T Hugas M Pla M 《Applied and environmental microbiology》2004,70(10):6299-6301
We describe a quick and simple method for the quantitative detection of Listeria monocytogenes in meat products. This method is based on filtration, Chelex-100-based DNA purification, and real-time PCR. It can detect as few as 100 CFU/g and quantify as few as 1,000 CFU/g, with excellent accuracy compared to that of the plate count method. Therefore, it is a promising alternative for the detection of L. monocytogenes in meat products. 相似文献
906.
Baumann CA Zeng L Donatelli RR Maroney AC 《Journal of biochemical and biophysical methods》2004,60(1):69-79
Inhibitors of receptor tyrosine kinases are implicated as therapeutic agents for the treatment of many human diseases including cancer, inflammation and diabetes. Cell-based assays to examine inhibition of receptor tyrosine kinase mediated intracellular signaling are often laborious and not amenable to high-throughput cell-based screening of compound libraries. Here we describe the development of a nonradioactive, sandwich enzyme-linked immunosorbent assay (ELISA) to quantify the activation and inhibition of ligand-induced phosphorylation of the colony-stimulating factor-1 receptor (CSF-1R) in 96-well microtiter plate format. The assay involves the capture of the Triton X-100 solubilized human CSF-1R, from HEK293E cells overexpressing histidine epitope-tagged CSF-1R (CSF-1R/HEK293E), with immobilized CSF-1R antibody and detection of phosphosphorylation of the activated receptor with a phosphotyrosine specific antibody. The assay exhibited a 5-fold increase in phosphorylated CSF-1R signal from CSF-1R/HEK293E cells treated with colony-stimulating factor (CSF-1) relative to treated vector control cells. Additionally, using a histidine epitope-specific capture antibody, this method can also be adapted to quantify the phosphorylation state of any recombinantly expressed, histidine-tagged receptor tyrosine kinase. This method is a substantial improvement in throughput and quantitation of CSF-1R phosphorylation over conventional immunoblotting techniques. 相似文献
907.
Gralak MA Bertrandt J Klos A Stryczek AB Piastowska AW Morka A Debski B 《Biological trace element research》2004,98(1):85-93
The aim of the present study was to investigate the influence of nutritional deficiency and dietary addition of vitamins (B2, B6, and folate) on hepatic concentration of zinc and copper in rats. The experiment was performed on 260 growing male Wistar
rats divided into 13 groups. Animals of 11 groups were fed isocaloric diets (14.7 MJ/kg) in which the 20% of energy was derived
from protein. Another two groups of rats were offered diets with 9% or 4.5% of energy originating from protein. Animals of
both mentioned groups and of the control group (20% of energy from protein) were offered diets ad libitum. The other 10 groups were offered 50% and 30% of the amount consumed in the control group. Eight groups, from those 10 restricted
ones, were differentiated by dietary addition of vitamins B2 and B6 and folate (300% addition). Restricted feed intake did not affect the liver zinc concentration but significantly increased
the copper concentration. The addition of vitamin B6 decreased the liver Zn concentration. The highest liver Cu concentration was noted in rats offered restricted diets to only
30% of intake in the control group and high in vitamin B2 and in rats supplemented with all of studied vitamins together. It suggests that vitamin B2 had the strongest impact on liver Cu concentration in rats fed restricted diets. 相似文献
908.
Zachara BA Koterska D Manitius J Sadowski L Dziedziczko A Salak A Wasowicz W 《Biological trace element research》2004,97(1):15-30
Patients with chronic renal failure (CRF) usually have a lower than healthy level of selenium (Se) in whole blood and plasma.
Plasma glutathione peroxidase (GSH-Px) is synthesized mostly in the kidney. In CRF patients, activity of this enzyme is significantly
reduced and its reduction increases with the progress of the disease. The aim of the study was to evaluate the effect of Se
supplementation to CRF patients at various stages of the disease on Se concentration in blood components and on plasma GSH-Px
activity.
The study group comprised 53 CRF patients at various stages of the disease supplemented with Se (200 μg/d for 3 mo as Se-enriched
yeast, containing about 70% l-selenomethionine [SeMet]). The control group consisted of 20 healthy subjects. The Se concentration in blood components was
measured spectrofluorometrically with 2,3-diaminonaphthalene as a complexing reagent. GSH-Px activity in red cell hemolysates
and plasma was assayed by the coupled method with tert-butyl hydroperoxide as a substrate.
The Se concentration in whole blood and plasma of CRF patients is significantly lower as compared with healthy subjects, but
similar at all stages of the disease. In the patients’ plasma, total protein and albumin levels are also significantly lower
than in healthy subjects. Plasma GSH-Px activity in patients is extremely low, and contrary to Se concentration, it decreases
linearly with the increasing stage of the illness. Se-supplied patients show an increased Se concentration in all blood components
and at all disease stages, whereas plasma GSH-Px activity is enhanced only at the incipient stage of the disease. Se supply
has no effect on plasma GSH-Px activity in uremic patients at the end stage of the disease. Total plasma protein and albumin
levels did not change after Se supplementation. Our data seem to show that in patients with CRF lower total protein and albumin
levels in plasma may be the chief cause of the low blood and plasma Se concentrations. GSH-Px activity decreases along with
the kidney impairment. At the end stage of the disease, Se supplementation in the form of Se-enriched yeast has no effect
on the increase in plasma GSH-Px activity. 相似文献
909.
Tóth F Horváth G Szikszay M Farkas J Tóth G Borsodi A Benyhe S 《Regulatory peptides》2004,122(2):139-146
Tyr-D-Ala-Gly-Phe-D-Nle-Arg-Phe (DADN) a synthetic analogue of the endogenous Met-enkephalin-Arg-Phe (Tyr-Gly-Gly-Phe-Met-Arg-Phe; MERF), was investigated in radioligand binding assays, [(35)S]GTPgammaS stimulation experiments as well as in in vivo algesiometric tests. Binding properties of [(3)H]DADN were measured in crude membrane fractions of rat spinal cord tissues and in homogenates of Chinese hamster ovary (CHO) cells selectively expressing delta-, kappa-or micro-opioid receptors. The highest affinity for [(3)H]DADN binding was observed in membranes from CHO cells transfected with micro-opioid receptors confirming the micro-selectivity of the peptide. Unlabeled DADN was also investigated in functional biochemical experiments by measuring opioid receptor-mediated G-protein activation in rat brain membrane fractions. The peptide stimulated the activity of the regulatory G-proteins in a concentration dependent manner, and the stimulation was efficiently inhibited in the presence of micro-receptor specific antagonist ligands further supporting the selectivity profile of DADN. Intrathecally administered DADN produced a dose-related, naloxone-reversible antinociception in rat hot water tail-flick tests. Among the selective opioid antagonists tested, the delta-selective naltrindole (NTI) and the kappa-specific norbinaltorphimine (norBNI) showed only slight blocking effects compared with naloxone. The results obtained in the in vitro agonist-stimulated [(35)S]GTPgammaS binding assays are in good agreement with the opioid agonist effect seen in the in vivo pain test. 相似文献
910.
Ahmad T Ugarph-Morawski A Li J Bileviciute-Ljungar I Finn A Ostenson CG Kreicbergs A 《Regulatory peptides》2004,119(1-2):61-67
We have previously demonstrated that Goto-Kakizaki (GK) rats with spontaneous type-2 diabetes and peripheral neuropathy exhibit regional osteopathic changes. In the present study on 18 GK rats and 21 control Wistar rats, the occurrence of the sensory neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP), and the autonomic neuropeptide Y (NPY) was analysed in bone and joints, dorsal root ganglia and lumbar spinal cord by immunohistochemistry and radioimmunoassay (RIA). Immunohistochemistry disclosed a predominance of immunoreactivities in vessel-related nerve fibers, although some were also seen in free terminals. While SP, CGRP and NPY in periosteum, cortical bone and synovium was confined to neuronal tissue, the bone marrow in addition exhibited an abundance of NPY-positive megakaryocytes. Apart from this cellular source of NPY, the observations suggest that the three neuropeptides analysed in bone and joints are of neuronal origin. Quantification by RIA showed a significant decrease of NPY in cortical bone (-36%), bone marrow (-66%) and ankle (-29%) of GK rats. CGRP was decreased in the spinal cord (-19%) and dorsal root ganglia (-26%) but was unchanged in bone and joints, as with SP. Given the suggested anabolic role of NPY and CGRP on bone, neuropeptidergic deficit in diabetes may prove to be an important factor underlying the development of regional osteopenia. 相似文献