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21.
Comparison of arginase activity in red blood cells of lower mammals, primates, and man: evolution to high activity in primates.
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E B Spector S C Rice R M Kern R Hendrickson S D Cederbaum 《American journal of human genetics》1985,37(6):1138-1145
Arginase activity in red blood cells (RBC) of various mammalian species including man was determined. In nonprimate species, the activity generally fell below the level of detectability of the assay: less than 1.0 mumol urea/g hemoglobin per hr. Activities in higher nonhuman primates were equal to or of the same order of magnitude as those in man (approximately 950 mumol/g hemoglobin per hr). RBC arginase deficiency with normal liver arginase activity has been shown to segregate as an autosomal codominant trait in Macaca fascicularis established and bred in captivity. This study confirms the presence of this polymorphism in wild populations trapped in several geographic areas and demonstrates the absence of immunologically cross-reactive material in the RBC of RBC arginase-deficient animals. These data when taken together suggest that the expression of arginase in RBC is the result of a regulatory alteration, has evolved under positive selective pressure, and is not an example of the vestigial persistence of an arcane function. The expression of arginase in the RBC results in a marked drop in the arginine content of these cells. 相似文献
22.
Thomas C. Noonan David F. Kern Asrar B. Malik 《Prostaglandins & other lipid mediators》1985,30(3):419-434
The pulmonary microvascular responses to leukotrienes B4, C4 and D4 (total dosage of 4 μg/kg i.v.) were examined in acutely-prepared halothane anesthetized and awake sheep prepared with lung lymp fistulas. In anesthetized as well as unanesthetized sheep, LTB4 caused a marked and transient decrease in the circulating leukocyte count. Pulmonary transvascular protein clearance (pulmonary lymph flow x lymph-to-plasma protein concentration ratio) increased transiently in awake sheep, suggesting a small increase in pulmonary vascular permeability. The mean pulmonary artery pressure (P
) also increased. In the acutely-prepared sheep, the LTB4-induced pulmonary hemodynamic and lymph flow responses were damped. Leukotriene C4 increased P
to a greater extent in awake sheep than in anesthetized sheep, but did not significantly affect the pulmonary lymph flow rate (Q̇lym) and lmph-to-plasma protein concentration (L/P) ration in either group. LTD4 increased P
and Q̇lymp in both acute and awake sheep; Q̇lym increased without a significant change in the L/P ratio. The LTD4-induced rise in P
occurred in association with an increase in plasma thromboxane B2 (Txb2) cocentration. The relativity small increase in Q̇lym with LTD4 suggests that the increase in the transvascular fluid filtration rate is the result of a rise in the pulmonary capillary hydrostatic pressure. In conclusion, LTB4 induces a marked neutropenia, pulmonary hypertension, and may transiently increase lung vascular permeability. Both LTC4 and LTD4 cause a similar degree of pulmonary hypertension in awake sheep, but had different lymph flow responses which may be due to pulmonary vasoconstriction at different sites, i.e. greather pre-capillary constriction with LTC4 because Q̇lym did not change and greater post-capillary constriction with LTD4 because Q̇ increased with the same rise in P
. 相似文献
23.
We examined the effects of decreases in perfusate concentrations of calcium and magnesium on the pulmonary vascular permeability in the isolated perfused rabbit lung. The albumin permeability-surface area product (PS) and the albumin reflection coefficient (sigma) were determined in the same lung using 125I- and 131I-labeled albumin tracers. Decreases in vascular Ca2+ and Mg2+ concentrations were induced by adding ethylenediaminetetraacetic acid (EDTA) to the perfusate. Decreases in the concentration of these cations resulted in an increase in the PS from a control value of 1.18 +/- 0.13 X 10(-3) to 7.69 +/- 0.75 X 10(-3) cm3 X min-1 X g wet lung wt-1 and a decrease in the sigma from 0.96 +/- 0.01 to 0.74 +/- 0.02. The decrease in sigma suggests an increase in the calculated equivalent pore radius from 44 to 63 A. The results indicate that Ca2+ and Mg2+ play a role in the maintenance of normal pulmonary vascular permeability to proteins. 相似文献
24.
D F Haggerty F Chiappelli R Kern S Scully M Lynch 《Biochemical and biophysical research communications》1983,115(3):965-970
Phenylalanine hydroxylase, a liver-associated enzyme, is induced markedly by glucocorticoids in two permanent rat-hepatoma cell lines. In order to gain evidence that this phenomenon also occurs in vivo, we examined the effect of adrenalectomy and/or hormone supplementation on the levels of phenylalanine hydroxylase in the livers of adult rats: glucocorticoid administration increases, and adrenal ablation reduces, the activity of the hepatic enzyme, and the diminution occurring in the latter instance is entirely prevented by concurrent hormone replacement. These results thus corroborate earlier findings from a single experiment and are consistent with the hypothesis that adrenal corticosteroid hormones participate in modulating phenylalanine-hydroxylase levels within the diploid hepatocyte. 相似文献
25.
Ineffective erythropoiesis in acute human P. falciparum malaria 总被引:5,自引:0,他引:5
An analysis of erythroblast cell kinetics utilizing quantitative 14C-autoradiography has been performed in five cases of acute Plasmodium falciparum malaria prior to and, in four patients, 3 or 6 days after the onset of antimalarial therapy. Associated with no or only moderate anemia were changes of erythroblast morphology, a considerable shift in the frequency of red and white blood cell precursors in the bone marrow, and a reduced rate of erythroblast proliferation. There was a marked loss of polychromatic erythroblasts, which was smaller but still detectable during the therapeutic phase. The results provide some quantitative data on the extent of "parenchymal damage" of bone marrow and stress the impact of ineffective erythropoiesis and reduced rate of erythropoietic proliferation on the emergence of anemia in Plasmodium falciparum malaria. 相似文献
26.
27.
28.
Serological Studies of the T and Tumor Antigens of the Oncogenic Simian Adenoviruses 总被引:1,自引:0,他引:1
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Raymond V. Gilden Jerome Kern Richard L. Heberling Robert J. Huebner 《Applied microbiology》1968,16(7):1015-1018
Tumor-specific antigens and antisera were prepared for eight of the oncogenic simian adenoviruses. Complement-fixation tests revealed three distinct serological subgroups. This grouping was maintained in studies of virus-infected cells (T antigens) although high titered preparations were obtained for only the major subgroup I. The current grouping is as follows: (I) SV1, SV11, SV25, SV33, SV34, SV38; (II) SV20, SV23; (III) SA 7. Antigens from each subgroup were rapidly inactivated at 56 C, and group II and III antigens were also markedly inactivated at 37 C. One of the tumors (SV1) also contained SV40 T antigen, suggesting origin from a simian adenovirus-SV40 "hybrid." 相似文献
29.
Atrial or ventricular myocardium from patients with surgically corrected rheumatic valvular disease was studied for rheumatic lesions in 86 cases. Histologically active Aschoff bodies were found in 20 per cent of the cases. A slight, but statistically not significant relationship was demonstrated in comparison of elevated serologic tests for rheumatic activity with the presence of Aschoff bodies. 相似文献
30.