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991.
Dirlei D. Kieling Valria Reginatto Willibaldo Schmidell Diane Travers Rodolfo J. Menes Hugo M. Soares 《Process Biochemistry》2007,42(12):1579-1585
In this study sludge wash-out was evaluated as a strategy to start-up the Anammox process in order to establish it in a shorter period of time. Sludge from a domestic wastewater treatment plant (WTP) was used to seed two (RI and RII) anaerobic sequencing batch reactors (ASBR). During the start-up period RI was operated as a continuous stirred tank reactor (CSTR) using a dilution rate of 0.2 d−1, which promoted the sludge wash-out. After this period, the remaining sludge was retained in the reactor. The reactor RII was operated as an ASBR throughout the study period with a high cell retention. The performance of the two reactors in terms of nitrogen removal was compared over a period of 380 days. During the last RI operation phase the specific nitrogen removal rate increased exponentially, attaining values of 85 mg N/g TSS d. However, a rate of 190 mg N/g TSS d in the batch test under optimal conditions was achieved. The specific nitrogen removal rate remained almost constant for RII with a mean value of 6 mg N/g TSS d being observed during the operation period. The rate for the RII batch test was 20 mg N/g TSS d. These results confirm that the higher total suspended solids (TSS) in RII (reactor with high cell retention) was not effective in terms of N removal improvement. Anammox-like bacteria were found using fluorescence in situ hybridization (FISH) in reactor RI after 225 days and a new Anammox species was identified. 相似文献
992.
Alpi A Amrhein N Bertl A Blatt MR Blumwald E Cervone F Dainty J De Michelis MI Epstein E Galston AW Goldsmith MH Hawes C Hell R Hetherington A Hofte H Juergens G Leaver CJ Moroni A Murphy A Oparka K Perata P Quader H Rausch T Ritzenthaler C Rivetta A Robinson DG Sanders D Scheres B Schumacher K Sentenac H Slayman CL Soave C Somerville C Taiz L Thiel G Wagner R 《Trends in plant science》2007,12(4):135-136
993.
The mitochondrial energy transduction system and the aging process 总被引:13,自引:0,他引:13
Aged mammalian tissues show a decreased capacity to produce ATP by oxidative phosphorylation due to dysfunctional mitochondria. The mitochondrial content of rat brain and liver is not reduced in aging and the impairment of mitochondrial function is due to decreased rates of electron transfer by the selectively diminished activities of complexes I and IV. Inner membrane H+ impermeability and F1-ATP synthase activity are only slightly affected by aging. Dysfunctional mitochondria in aged rodents are characterized, besides decreased electron transfer and O2 uptake, by an increased content of oxidation products of phospholipids, proteins and DNA, a decreased membrane potential, and increased size and fragility. Free radical-mediated oxidations are determining factors of mitochondrial dysfunction and turnover, cell apoptosis, tissue function, and lifespan. Inner membrane enzyme activities, such as those of complexes I and IV and mitochondrial nitric oxide synthase, decrease upon aging and afford aging markers. The activities of these three enzymes in mice brain are linearly correlated with neurological performance, as determined by the tightrope and the T-maze tests. The same enzymatic activities correlated positively with mice survival and negatively with the mitochondrial content of lipid and protein oxidation products. Conditions that increase survival, as vitamin E dietary supplementation, caloric restriction, high spontaneous neurological activity, and moderate physical exercise, ameliorate mitochondrial dysfunction in aged brain and liver. The pleiotropic signaling of mitochondrial H2O2 and nitric oxide diffusion to the cytosol seems modified in aged animals and to contribute to the decreased mitochondrial biogenesis in old animals. oxidative damage; survival; complexes I and IV; nitric oxide synthase 相似文献
994.
Inhibitory and stimulatory adenosine receptors have been identified and characterized in both membranes and intact rat C6
glioma cells. In membranes, saturation experiment performed with [3H]DPCPX, selective A1R antagonist, revealed a single binding site with a K
D = 9.4 ± 1.4 nM and B
max = 62.7 ± 8.6 fmol/mg protein. Binding of [3H]DPCPX in intact cell revealed a K
D = 17.7 ± 1.3 nM and B
max = 567.1 ± 26.5 fmol/mg protein. On the other hand, [3H]ZM241385 binding experiments revealed a single binding site population of receptors with K
D = 16.5 ± 1.3 nM and B
max = 358.9 ± 52.4 fmol/mg protein in intact cells, and K
D = 4.7 ± 0.6 nM and B
max = 74.3 ± 7.9 fmol/mg protein in plasma membranes, suggesting the presence of A2A receptor in C6 cells. A1, A2A, A2B and A3 adenosine receptors were detected by Western-blotting and immunocytochemistry, and their mRNAs quantified by real time PCR
assays. Giα and Gsα proteins were also detected by Western-blotting and RT-PCR assays. Furthermore, selective A1R agonists inhibited forskolin- and GTP-stimulated adenylyl cyclase activity and CGS 21680 and NECA stimulated this enzymatic
activity in C6 cells. These results suggest that C6 glioma cells endogenously express A1 and A2 receptors functionally coupled to adenylyl cyclase inhibition and stimulation, respectively, and suggest these cells as a
model to study the role of adenosine receptors in tumoral cells. 相似文献
995.
The extracellular concentration of glutamate is highly regulated due to its excitotoxic nature. Failure of glutamate uptake
or reversed activation of its transporters contributes to neurodegeneration related to some pathological conditions. We have
compared the neurotoxicity of the substrate glutamate uptake inhibitor, l-trans-pyrrolidine-2,4-dicarboxylate (PDC), which promotes glutamate release by heteroexchange, with that of DL-threo-beta-benzyloxyaspartate
(DL-TBOA), a non-substrate inhibitor, in cerebellar granule cell cultures. PDC substantially increases the extracellular concentration
of glutamate during 30 min exposure and causes neuronal death at high concentrations, while DL-TBOA neurotoxicity is only
observed after long-term exposure (8–24 h). During mitochondrial inhibition by 3-nitropropionic acid (3-NP), PDC-induced neuronal
death is facilitated, but not that of DL-TBOA. In cultures containing a higher population of astrocytes DL-TBOA-induced increase
in glutamate levels is more pronounced, but neuronal death is only triggered in the presence of 3-NP. Results suggest that
cerebellar granule neurons are more vulnerable to acute transport-mediated glutamate release than to uptake blockade, which
correlates with the extracellular excitatory amino acids levels. 相似文献
996.
Pereira P Vinadé E Rodrigues L De David e Silva TL Ardenghi P da Silva Brum LF Gonçalves CA Izquierdo I 《Neurochemical research》2007,32(7):1150-1155
The participation of protein serine/threonine kinases in memory formation and retrieval is well established. In contrast,
relatively little is known on the role of protein tyrosine kinases (PTKs). Previous work showed that intra-hippocampal infusion
of the Src-PTK inhibitor radicicol inhibits memory acquisition, consolidation, and retrieval of one-trial step-down inhibitory avoidance
task. In this study, we investigated the possible interaction between levels of Src-PTK activity in hippocampus and memory acquisition, formation, and retrieval of this task. Radicicol (0.5 μg/ml) was infused
into the CA1 region of the hippocampus of rats trained in a one-trial step-down inhibitory avoidance task. Radicicol infused
15 min before training decreased Src-PTK activity, as measured 0, 1.5, and 24 h after training, and impaired memory acquisition of the task. When given immediately
after training, there was a decrease in Src-PTK activity 1.5 h, but not 0 or 24 h after training. This treatment depressed memory consolidation. Radicicol infused into
CA1 10 min prior to retrieval testing inhibited hippocampal Src-PTK activity, as measured immediately after the test session. The results suggest that Src-PTKs participate in memory acquisition, consolidation, and retrieval processes, but the timing of the role of the enzyme
is different in each case. 相似文献
997.
998.
Costa DL Dias-Melicio LA Acorci MJ Bordon AP Tavian EG Peraçoli MT Soares AM 《Microbiology and immunology》2007,51(1):73-80
Paracoccidioidomycosis, a deep mycosis endemic in Latin America, is a chronic granulomatous disease caused by the fungus Paracoccidioides brasiliensis. Phagocytic cells play a critical role against this fungus, and several studies have shown the effects of activator and suppressive cytokines on macrophage and monocyte functions. However, studies on polymorphonuclear neutrophils (PMNs), that are the first cells recruited to the infection sites, are scarcer. Thus, the objective of this paper was to assess whether interleukin-10 (IL-10), a potent anti-inflammatory cytokine, is able to block the activity of IFN-gamma-activated human PMNs upon P. brasiliensis intracellular killing, in vitro. The results showed that IFN-gamma-activated PMNs have an effective fungicidal activity against the fungus. This activity was associated with the release of high levels of H(2)O(2), the metabolite involved in phagocytic cells antifungal activities. However, the concomitant incubation of these cells with IFN-gamma and IL-10 significantly blocked IFN-gamma activation. As a consequence, PMNs killing activity and H(2)O(2) release were inhibited. Together, our results show the importance of PMNs exposure to activator or suppressor cytokines in the early stages of paracoccidioidomycosis infection. 相似文献
999.
Nogueira FC Gonçalves EF Jereissati ES Santos M Costa JH Oliveira-Neto OB Soares AA Domont GB Campos FA 《Plant cell reports》2007,26(8):1333-1343
Using a combination of two-dimensional gel electrophoresis protein mapping and mass spectrometry analysis, we have established
proteome reference maps of embryogenic cell suspensions of cowpea (Vigna unguiculata). The cell suspensions were generated from young primary leaves and contained basically pro-embryogenic masses, which enabled
us to dissect their proteome composition while eliminating the complexity of too many cell types. Over 550 proteins could
reproducibly be resolved over a pI range of 3–10. A total of 128 of the most abundant protein spots were excised, digested
in-gel with trypsin and analyzed by tandem mass spectrometry. This enabled the identification of 67 protein spots. Two of
the most abundant proteins were identified as a chitinase and as a ribonuclease belonging to the family of PR-4 and PR-10
proteins, respectively. The expression of the respective genes was confirmed by RT-PCR and the pattern of deposition of the
PR-10 protein in cell suspensions as well as in developing cowpea seeds, roots, shoots and flowers were determined by Western
blot experiments, using synthetic antibodies raised against a 14-amino acid synthetic peptide located close to the C-terminal
region of the PR-10 protein. 相似文献
1000.
Moreno SR Arnobio A De Carvalho JJ Nascimento L Oliveira Timoteo M Olej B Rocha EK Pereira M Bernardo-Filho M Caldas LQ 《Biological research》2007,40(2):131-135
The radiobiocomplexes labeled with technetium-99m (Tc-99m) have been widely used in nuclear medicine in single photon emission computed tomography and in basic research. The aim of this study was to assess the influence of a Nectandra membranacea extract on the bioavailability of the sodium pertechnetate (Na(99m)TcO(4)) radiobiocomplex in rat organs. The animals were treated with a N. membranacea extract (30 mg/ ml), for 6 days. Na(99m)TcO(4) was injected, the organs were isolated and weighed, and the radioactivity was determined in each organ (%ATI/organ). The %ATI/organ was divided by the mass of each organ to calculate the %ATI/g. A significant increase of the %ATI/organ of Na(99m)TcO(4) was observed in muscle and thyroid as well as in the %ATI/g in the heart, kidney and thyroid. These findings could result from the interaction between components of the plant extract and the radiobiocomplex which may influence the uptake Na(99m)TcO(4) in rat organs. Therefore, precaution is suggested in the interpretation of nuclear medicine results in patients using this herb. 相似文献