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971.
The effects of potassium nitrate (KNO3) application on Phytophthora stem rot disease reduction of Glycine max (L.) Merr. cvs. Chusei-Hikarikuro and Sachiyutaka, and mycelium growth and zoospore release of a Phytophthora sojae isolate were investigated under laboratory conditions. The application of 4–30 m m KNO3 prior to inoculation greatly reduced incidence of disease in the two soybean cultivars. Although a concentration of 20–30 m m KNO3 led to a slight decrease in the growth rate of the PJ-H30 isolate on PDA medium, no significant relationship was observed between inhibition of the growth rate and disease reduction on application of 0.4–10 m m KNO3. Disease suppression recorded in laboratory experiments using pathogen mycelium was due to the response of plant tissues rather than a direct inhibition of pathogen hyphal growth by the application of KNO3. The extent of disease reduction was related to increased potassium concentration in plants of the two cultivars (except for some cases involving cv. Sachiyutaka), suggesting that differences existed between the two cultivars in terms of the effect of KNO3 application on disease suppression. Scanning electron microscopic observation with fresh samples indicated marked accumulation of potassium at the penetration-stopping sites of P. sojae in the cortex layer of soybean plants treated with 30 m m KNO3, compared with the non-treated control plants. The presence of 0.4–30 m m KNO3 decreased the release of zoospores. These results suggest the possibility of applying a solution containing 20–30 m m of KNO3 to decrease the incidence of disease in agricultural fields by the response of plant tissues to KNO3.  相似文献   
972.
The latex agglutination test was used to compare cryptococcal antigen titers before and after protease treatment in 19 patients with pulmonary cryptococcosis. Antigen was detected by the LA test in 13 of 33 serum samples before protease treatment, and in an additional 13 samples following treatment. Of 26 antigen-positive serum samples, 22 (84.6%) showed an increased antigen titer after protease treatment. Using the cell slide agglutination test, antibody was detected in 3 of 19 cases. In one of these 3, antigen could only be detected after protease treatment. Soluble immune complex was prepared in vitro using anti-C. neoformans rabbit antiserum and polysaccharide antigen of C. neoformans, and the effects of immune complexes on the LA test were examined. In this experimental model, soluble immune complexes seemed to be observed in antibody excess region, because the antigen titers were increased after the protease treatment. We concluded that C. neoformans capsular polysaccharide antigen and anti-C. neoformans antibody formed soluble immune complexes in patients' sera, which interfered with antigen detection by the latex agglutination test without protease treatment.  相似文献   
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Ca2+/Calmodulin-dependent protein kinase II (CaMKII) has been shown to play a major role in establishing memories through complex molecular interactions including phosphorylation of multiple synaptic targets. However, it is still controversial whether CaMKII itself serves as a molecular memory because of a lack of direct evidence. Here, we show that a single holoenzyme of CaMKII per se serves as an erasable molecular memory switch. We reconstituted Ca2+/Calmodulin-dependent CaMKII autophosphorylation in the presence of protein phosphatase 1 in vitro, and found that CaMKII phosphorylation shows a switch-like response with history dependence (hysteresis) only in the presence of an N-methyl-D-aspartate receptor-derived peptide. This hysteresis is Ca2+ and protein phosphatase 1 concentration-dependent, indicating that the CaMKII memory switch is not simply caused by an N-methyl-D-aspartate receptor-derived peptide lock of CaMKII in an active conformation. Mutation of a phosphorylation site of the peptide shifted the Ca2+ range of hysteresis. These functions may be crucial for induction and maintenance of long-term synaptic plasticity at hippocampal synapses.  相似文献   
977.
A unicellular cyanobacterium that produces a large amount of exopolysaccharide (EPS) was isolated from a rice field in Phu Tho Province, Vietnam. Morphological characteristics and phylogenetic analysis using a partial sequence of the 16S rRNA gene revealed that the isolate was closely related to the genus Cyanothece. The isolate, named Cyanothece sp. Viet Nam 01, grew at a wide range of temperatures (25–40 °C), but was not viable below 20 °C. The isolate had an ability of aerobic nitrogen fixation. The EPS was purified using NaOH extraction and ethanol precipitation, and the absolute molecular weight was estimated to be 4.5?×?104 kDa. The pattern of the Fourier transform infrared spectrum indicated that the EPS had carbonyl and sulfate groups, as well as the typical functional groups of sugars. The uronic acid and sulfur contents were 23 and 8.4 mol% per total monosaccharide, respectively. The EPS constituent monosaccharides were rhamnose, glucose, galactose, xylose, mannose, fucose, arabinose, ribose, and unknown sugar, with molar compositions of 38.6:13.8:4.8:4.8:2.4:3.5:2.0:0.6:6.5, respectively.  相似文献   
978.
The sensitivity of influenza rapid diagnostic tests (IRDTs) currently available in Japan for various influenza virus strains, including human H7N9 and H5N1 isolates, were compared and it was found that all of the IRDTs examined detected these viruses; however, their detection sensitivities differed.  相似文献   
979.
For Thermus caldophilus l-lactate dehydrogenase (TcLDH), fructose 1,6-bisphosphate (FBP) reduced the pyruvate S0.5 value 103-fold and increased the Vmax value 4-fold at 30 °C and pH 7.0, indicating that TcLDH has a much more T state-sided allosteric equilibrium than Thermus thermophilus l-lactate dehydrogenase, which has only two amino acid replacements, A154G and H179Y. The inactive (T) and active (R) state structures of TcLDH were determined at 1.8 and 2.0 Å resolution, respectively. The structures indicated that two mobile regions, MR1 (positions 172–185) and MR2 (positions 211–221), form a compact core for allosteric motion, and His179 of MR1 forms constitutive hydrogen bonds with MR2. The Q4(R) mutation, which comprises the L67E, H68D, E178K, and A235R replacements, increased Vmax 4-fold but reduced pyruvate S0.5 only 5-fold in the reaction without FBP. In contrast, the P2 mutation, comprising the R173Q and R216L replacements, did not markedly increase Vmax, but 102-reduced pyruvate S0.5, and additively increased the FBP-independent activity of the Q4(R) enzyme. The two types of mutation consistently increased the thermal stability of the enzyme. The MR1-MR2 area is a positively charged cluster, and its center approaches another positively charged cluster (N domain cluster) across the Q-axis subunit interface by 5 Å, when the enzyme undergoes the T to R transition. Structural and kinetic analyses thus revealed the simple and unique allosteric machinery of TcLDH, where the MR1-MR2 area pivotally moves during the allosteric motion and mediates the allosteric equilibrium through electrostatic repulsion within the protein molecule.  相似文献   
980.
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