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671.
672.
673.
Metabotropic glutamate receptors (mGluRs) are G protein-coupled receptors that are distributed throughout the brain and play
important roles in regulation of synaptic efficacy. Some studies report that mGluRs heterologously expressed in nonneuronal
cells are sensitive not only to glutamate but also to extracellular Ca2+ (Ca
o
2+
). We studied the Ca
o
2+
-sensitivity of native mGluRs in mammalian central neurons. In cerebellar Purkinje cells that naturally express type-1 mGluR
(mGluR1), physiological levels of Ca
o
2+
(around 2 mM) activate mGluR1-mediated intracellular Ca2+ mobilization. The activation of the native mGluR1 response to Ca
o
2+
appears to be slower than that to glutamate. Ca
o
2+
(2 mM) also augments glutamate analog-evoked, native mGluR1-mediated inward cation current and intracellular Ca
o
2+
mobilization. Detailed analysis of this effect suggests that Ca
o
2+
modulates the glutamate responsiveness of native and heterologously expressed mGluR1s in different manners. These findings
suggest that Ca
o
2+
may enhance the basal level and glutamate responsiveness of neuronal mGluR signaling in vivo. 相似文献
674.
Deshimaru M Yoshimi S Shioi S Terada S 《Bioscience, biotechnology, and biochemistry》2004,68(6):1279-1286
Genes for Bowman-Birk type protease inhibitors (BBIs) of wild soja (Glycine soja) and soybean (Glycine max) comprise a multigene family. The organization of the genes for wild soja BBIs (wBBIs) was elucidated by an analysis of their cDNAs and the corresponding genomic sequences, and compared with the counterparts in the soybean. The cDNAs encoding three types of wild soja BBIs (wBBI-A, -C, and -D) were cloned. Two subtypes of cDNAs for wBBI-A, designated wBBI-A1 and -A2, were further identified. Similar subtypes (sBBI-A1 and -A2) were also found in the soybean genome. cDNA sequences for wBBIs were highly homologous to those for the respective soybean homologs. Phylogenetic analysis of these cDNAs demonstrated the evolutional proximity between these two leguminae strains. 相似文献
675.
Liu H Kawabe A Matsunaga S Murakawa T Mizukami A Yanagisawa M Nagamori E Harashima S Kobayashi A Fukui K 《Journal of plant research》2004,117(2):95-99
Several methods of transformation are currently available for delivering exogenous DNA into animal and plant cells. In this study, a novel and efficient transformation system for DNA delivery/expression with a capacity to transport DNA of high molecular weight was developed. This system can overcome the shortcomings of traditional transformation methods such as Agrobacterium-mediated transformation, particle bombardment, and the electroporation method. The method developed in this study uses calcium alginate micro beads to immobilize DNA molecules in combination with polyethylene glycol treatment. In addition, it is simple and low-cost, and requires limited equipment. Using this method, we have successfully transformed tobacco plants, screening by kanamycin resistance. The transformed genes in the transformants were confirmed by PCR and Southern hybridization. 相似文献
676.
Cultured plant cells are often highly heterogeneous in terms of secondary metabolite production. We have developed a quantitative determination method that uses an image processing system to estimate such individual cell characteristics as content of the secondary metabolite, anthocyanin. In this study, strawberry cells producing anthocyanins were grown in modified Linsmaier-Skoog medium. Anthocyanin accumulation profiles of individual cells depended on medium compositions and were quantitatively determined using the new method. The modified medium supplemented with riboflavin and high sugar concentration showed a markedly higher anthocyanin accumulation profile and pigmented cell ratio than the other modified media. The maximum content was about 11mg (g-fresh cell weight)(-1), which was three times higher than that in the control medium. Moreover, the anthocyanin accumulation profiles in the individual cells cultured in all modified media could be approximated to the parts of the normal distribution curves with the constant variance. 相似文献
677.
Takashi Yamada Takaaki Mishima Makoto Sakamoto Minako Sugiyama Satoshi Matsunaga Masanobu Wada 《Journal of applied physiology》2007,102(5):1850-1855
The purpose of the present study was to test the hypothesis that administration of thyroid hormone [3,5,3'-triiodo-L-thyronine (T(3))] could result in oxidation of myofibrillar proteins and, in turn, induce alterations in respiratory muscle function. Daily injection of T(3) for 21 days depressed isometric forces of diaphragm fiber bundles across a range of stimulus frequencies (1, 10, 20, 40, 75, and 100 Hz) (P < 0.05). These reductions in force production were accompanied by a remarkable increment (104%; P < 0.05) in carbonyl groups of myofibrillar proteins. In contrast, T(3) treatment has no effects on the carbonyl content in myosin heavy chain. In additional experiments, we have also tested the efficacy of carvedilol, a nonselective beta(1)- beta(2)-blocker that possesses antioxidative properties. Treatment with carvedilol dramatically improved isometric tetanic force production at stimulus frequencies from 40 to 100 Hz (P < 0.05). Carvedilol also prevented T(3)-induced contractile protein oxidation (P < 0.05). These data suggest that the oxidative modification of myofibrillar proteins may account, at least in part, for an impairment of diaphragm in hyperthyroidism. 相似文献
678.
Masanobu Hayashi Sayaka Fuse Daiji Endoh Noboru Horiguchi Kenji Nakayama Yasuhiro Kon Toyo Okui 《Experimental Animals》2006,55(5):419-426
Copper accumulation and induction of DNA strand breaks were investigated in the brain of Long-Evans Cinnamon (LEC) rats, an animal model for human Wilson disease that is a heritable disease of copper accumulation and copper toxicity in the liver, kidney and brain. Copper contents in the brain of LEC rats increased from 20 weeks of age and were approximately 3.5 to 6 folds higher than those in the brain of WKAH rats at 24 weeks of age. Hepatic copper contents in LEC rats increased from 4 to 12 weeks of age in an age-dependent manner, and then decreased from 16 to 20 weeks of age. Thus, we consider that copper accumulated in the liver was released from severely damaged hepatocytes and deposited in the brain, although copper contents in the brain were 1/20-fold lower than those in the liver. We also evaluated the amounts of DNA single-strand breaks (SSBs) in the brain by comet analysis. The proportions of nuclei in the cerebrum and cerebellum without DNA damage decreased, and nuclei with severe DNA damage appeared in LEC rats at 24 weeks of age. The comet scores of cerebrum and cerebellum cells significantly increased in LEC rats and were significantly higher than those in WKAH rats at 24 weeks of age. The results show that SSBs in LEC rat brain cells are induced at a lower concentration of copper than are SSBs in hepatic cells. 相似文献
679.
Masatoshi Takagi Masaki Sato Jinhua Piao Satoshi Miyamoto Takeshi Isoda Masanobu Kitagawa Hiroaki Honda Shuki Mizutani 《DNA Repair》2013,12(7):500-507
Chronic myelogenous leukemia (CML) begins with an indolent chronic phase, and subsequently progresses to an accelerated or blastic phase. Although several genes are known to be involved in the progression to blastic phase, molecular mechanisms for the evolution toward blast crisis have not been fully identified. Oncogenic stimuli enforce cell proliferation, which requires DNA replication. Unscheduled DNA replication enforced by oncogenic stimuli leads to double strand breaks on DNA. We found the DNA damage-response pathway is activated in bone marrow of chronic-phase CML patients possibly due to an enforced proliferation signal by BCR-ABL expression. Since ataxia telangiectasia mutated (ATM) is a central player of the DNA damage-response pathway, we studied whether loss of this pathway accelerates blast crisis. We crossed Atm-knockout mice with BCR-ABL transgenic mice to test this hypothesis. Interestingly, the loss of one of the Atm alleles was shown to be enough for the acceleration of the blast crisis, which is supported by the finding of increased genomic instability as assayed by breakage–fusion–bridge (BFB) cycle formation. In light of these findings, the DNA damage-response pathway plays a vital role for determination of susceptibility to blast crisis in CML. 相似文献
680.
Masanobu Kawai Ryoichi Katsumata Teruyuki Tsuruta Gen Shimura Yoshito Suga Hirotoshi Samejima 《Bioscience, biotechnology, and biochemistry》2013,77(9):1855-1862
It was found that there was a fairly well correlation between the soybean disintegrating activity (SD activity) of Driselase, a cellulase preparation from Irpex lacteus, and the improvement of feed efficiency caused from its supplementation to a ration.When the seed coat of soybean was hydrolysed by Driselase, arabinose, galactose, and other aldoses were liberated; on the other hand, some ketoses such as fructose, sucrose, raffinose and such were detected as a result of the hydrolysis of the cotyledon. On the fractionation of Driselase with column chromatography, acid proteinase was appeared to be parallel, in a certain extent, with SD activity. These suggested that Driselase partially attacked the cell walls of the cotyledon and led to the leakage of intracellular substances such as ketoses and protein.Since it was revealed, however, that only a kind of pectin hydrolase was detected in the fraction with high SD activity, the maceration of soybean by a pectin hydrolase was thought to be chiefly concerned with SD activity. 相似文献