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861.
862.
One of the serious environmental problems since the 1980s has been the conflict between the high rate of deforestation and
maintenance of healthy ecosystem services and biological values in tropical forests. There is an urgent demand for setting
up an appropriate environmental assessment to keep healthy ecosystem functions and biodiversity along with sustainable forest
use based on ecology. In this study, we tried to assess logging-disturbance effects on the abundances of several flying insect
groups (higher-taxon approach) in lowland tropical rain forest (Deramakot Forest Reserve, Sabah, Malaysia), while considering
seasonal changes and vertical forest stratification. The season was the most important factor affecting the abundances of
all the insect groups. Effects of logging disturbance were prominent in the understorey but obscure in the canopy. Changes
in physical conditions caused by logging—possibly an increased evaporation due to solar radiation—may have decreased the abundance
of desiccation-sensitive insects, especially in the understorey. There are also two probable reasons for the difference between
events in the understorey and those in the canopy: (1) noise effects of various physical, environmental factors may have obscured
insect responses to logging disturbance in the canopy; (2) higher spatio-temporal variation in quality and quantity of living
food resources—such as leaves, flowers and fruits—provided in the canopy may have affected the abundance of their consumer
insects independently of logging disturbance. Thus, this study suggests that the abundance of some insect groups at higher-taxon
level, especially in the understorey, can be used as bioindicators for assessing effects of logging disturbance on the forest
ecosystem. 相似文献
863.
Hashidoko Y Kitagawa E Iwahashi H Purnomo E Hasegawa T Tahara S 《Bioscience, biotechnology, and biochemistry》2007,71(2):343-351
Throughout Central and South Kalimantan, Indonesia, strongly acidic soil (pH 2.1-3.7) is widely distributed, and the local acidic soil-tolerant plants, including local rice varieties, often possess sphingomonads in their rhizosphere and rhizoplane. To investigate the behavior of sphingomonads inhabiting the rhizosphere of such acid-tolerant plants, we designed 13 different DNA array probes (each of 72 mer) specific to a group of sphingomonads, using a hypervariable V6 region of the 16S rRNA gene. This DNA array system was used preliminarily for an analysis of microfloral dynamisms, particularly of sphingomonads, in acidic paddock ecosystems, and the results suggest that the acid-tolerant local rice shares rhizospherous sphingomonads with wild Juncus sp., a predominant weed that thrives in acidic paddocks during the off-season for rice farming. This tentative conclusion supports the bio-rationality of the traditional rice farming system with respect to functional rhizobacteria. 相似文献
864.
Uemura S Feng F Kume M Yamada K Kabayama K Nishimura S Igarashi Y Inokuchi J 《Glycobiology》2007,17(6):568-577
Ganglioside GM3, one of the sialic acid containing glycosphingolipids, is known to form clusters in lipid microdomains, which serve as platforms for effective signal transduction. In an attempt to clarify the GM3 cluster effect, we enzymatically synthesized GM3 mimetic polymer (GM3-p), with an acrylamide backbone from LacCer mimetic polymer (LacCer-p). Interestingly, GM3-p, but not LacCer-p, reversibly inhibited proliferation of NIH3T3 cells, which are normally resistant to exogenously added GM3. Moreover, we found that the introduction of carbonic acid into the acrylamide chain aided well-oriented cluster formation and enhanced the inhibitory effect of GM3-p. Since sialyllactosyl polymer and GM4 mimetic polymer, but not GM2 mimetic polymer, also inhibited cell proliferation, sialic acid-galactose units must be essential for the biological activity of GM3-p. These results suggest that the formation of sialic acid-galactose clusters is necessary for the suppressive effect of GM3-p. GM3-p treatment did not affect the serum-dependent activation of ERK1/2 or c-fos expression, but caused a reduction in the gene and/or protein expression of cyclin D1, cyclin E, cyclin-dependent kinase (cdk)4, and cdk2, which are involved in the cell cycle. Therefore, GM3-p inhibits cell proliferation by reducing cyclin D1-cdk4 and cyclin E-cdk2 complexes without affecting growth factor signaling from serum to c-fos. 相似文献
865.
Ohta H Ishizaka T Yoshinaga M Morita A Tomishima Y Toda Y Saito S 《Bioorganic & medicinal chemistry letters》2007,17(18):5133-5135
A novel series of sulfonamide derivatives 3, the CB(2) receptor agonists, was synthesized and evaluated for activity against the human CB(2) receptor. We first identified sulfonamide 3a, which was obtained by random screening of our in-house chemical library as a moderately active (CB(2) IC(50)=340nM) CB(2) receptor agonist. We then attempted to test its analogues to identify compounds with a high affinity for the CB(2) receptor. One of these, compound 3f, exhibited high affinity for the human CB(2) receptor (IC(50)=16nM) and high selectivity for CB(2) over CB(1) (CB(1) IC(50)/CB(2)IC(50)=106), and behaved as a full CB(2) receptor agonist in the [(35)S]GTPgammaS binding assay (CB(2) EC(50)=7.2nM, E(max)=100%). 相似文献
866.
Ohta H Ishizaka T Tatsuzuki M Yoshinaga M Iida I Tomishima Y Toda Y Saito S 《Bioorganic & medicinal chemistry letters》2007,17(22):6299-6304
A novel series of N-alkylidenearylcarboxamides 4, a CB(2) receptor agonist, were synthesized and evaluated for activity against the human CB(2) receptor. In a previous paper, we reported that sulfonamide derivative 1 acted as a potent CB(2) receptor agonist (IC(50)=65 nM, EC(50)=19 nM, E(max)=90%). However, compound 1 also exhibited poor metabolic stability in human liver microsomes. During the structural modification of 1, we found that a novel series of N-alkylidenearylcarboxamide, 4-1, had a moderate affinity for the CB(2) receptor (IC(50)=260 nM, EC(50)=86 nM, E(max)=100%) and good metabolic stability in human liver microsomes. We explored its analogues to discover compounds with a high affinity for the CB(2) receptor and with good oral bioavailability. Among them, compounds 4-9 and 4-27 had high affinities for the human CB(2) receptor (CB(2) IC(50)=13 nM and 1.2 nM) and a high selectivity for CB(2) (CB(1) IC(50)/CB(2) IC(50)=270 and 1600); furthermore, significant plasma levels were observed following oral administration in rats (C(max)=233 ng/mL and 148 ng/mL, respectively, after a dose of 10 mg/kg). Furthermore, compound 4-9 had good oral bioavailability (F=52%, 3mg/kg). 相似文献
867.
Kondo T Sugimoto I Nekado T Ochi K Ohtani T Tajima Y Yamamoto S Kawabata K Nakai H Toda M 《Bioorganic & medicinal chemistry》2007,15(7):2715-2735
A series of (4-substituted prolyl)prolinenitriles were synthesized and evaluated as inhibitors of dipeptidylpeptidase IV (DPP-IV). Among those tested, the 4beta-[4-(hydroxyphenyl)prolyl]prolinenitriles showed a potent inhibitory activity with a long duration of action. Metabolic formation of the corresponding phenol glucuronates was found to contribute to their long duration of action. The activity profiles of the synthesized compounds are reported and structure-activity relationships are also presented. 相似文献
868.
Mitsutake S Yokose U Kato M Matsuoka I Yoo JM Kim TJ Yoo HS Fujimoto K Ando Y Sugiura M Kohama T Igarashi Y 《Biochemical and biophysical research communications》2007,363(3):519-524
The discovery of ceramide kinase (CerK), which phosphorylates ceramide (Cer) to ceramide 1-phisphate (C1P), established a new pathway for Cer metabolism. Among mouse tissues, brain contains the highest CerK activity. In this study, we found that CerK is highly expressed in cerebellar Purkinje cells. Since Purkinje cells are important for motor-related behaviors, we generated CerK-null mice and performed behavioral analyses. The CerK-null mice were healthy, and displayed no histological abnormalities. The mice lost CerK activity completely, suggesting that CerK is the only enzyme that phosphorylate Cer. However, cellular C1P levels were not different between the CerK-null and wild-type mice, indicating the presence of other C1P-producing pathway. The general motor-coordination was not impaired in the CerK-null mice, but emotional behavior was slightly affected. Our findings suggest that CerK is not necessary for survival at an individual level, but might be involved in higher brain function related to emotion. 相似文献
869.
870.
Protective effects of carotenoids from saffron on neuronal injury in vitro and in vivo 总被引:1,自引:0,他引:1
Ochiai T Shimeno H Mishima K Iwasaki K Fujiwara M Tanaka H Shoyama Y Toda A Eyanagi R Soeda S 《Biochimica et biophysica acta》2007,1770(4):578-584
Crocus sativus L. (saffron) has been used as a spice for flavoring and coloring food preparations, and in Chinese traditional medicine as an anodyne or tranquilizer. Our previous study demonstrated that crocin, a carotenoid pigment of saffron, can suppress the serum deprivation-induced death of PC12 cells by increasing glutathione (GSH) synthesis and thus inhibiting neutral sphingomyelinase (nSMase) activity and ceramide formation. The carotenoid pigments of saffron consist of crocetin di-(beta-d-glucosyl)-ester [dicrocin], crocetin-(beta-d-gentiobiosyl)-(beta-d-glucosyl)-ester [tricrocin] and crocetin-di-(beta-d-gentiobiosyl)-ester [crocin]. Saffron also contains picrocrocin, the substance causing saffron's bitter taste. In this study, to confirm whether neuroprotective effects of saffron are caused solely by crocin, we examined the antioxidant and GSH-synthetic activities of these crocins in PC12 cells under serum-free and hypoxic conditions. Measurements of cell viability, peroxidized membrane lipids and caspase-3 activity showed that the rank order of the neuroprotective potency at a concentration of 10 muM was crocin>tricrocin>dicrocin and picrocrocin (the latter two crocins had a little or no potency). In addition, we show that among these saffron's constituents, crocin most effectively promotes mRNA expression of gamma-glutamylcysteinyl synthase (gamma-GCS), which contributes to GSH synthesis as the rate-limiting enzyme, and that the carotenoid can significantly reduce infarcted areas caused by occlusion of the middle cerebral artery (MCA) in mice. 相似文献