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181.
Antisymmetry of the amino acid code table in terms of codon degeneracy is pointed out, and it is related to a physico-chemical problem of codon-anticodon interaction energy. A strong negative correlation between molecular weight of an amino acid and its codon degeneracy is pointed out, and its implication to the origin of the amino acid code table is discussed. Finally, an earlier form of the amino acid code table is proposed. 相似文献
182.
Kozo Hayashi Kazuo Yamada Keiji Ohe Akima Miyoshi Takashi Kawasaki 《生物化学与生物物理学报:生物膜》1980,596(3):414-419
The effect of amytal on energy metabolism and acid secretion in an isolated gastric mucosa of the guinea-pig were studied. Determination of adenine nucleotides, creatine phosphate, pyruvate and lactate in the gastric mucosa showed that amytal depressed the levels of ATP, creatine phosphate and energy charge with elevation of the AMP and pyruvate levels. This treatment inhibited concomitantly acid secretion and active chloride transport detected by short circuit current. The addition of menadione with ascorbate to the medium in the presence of amytal partially restored ATP and energy charge levels and also induced a partial recovery of acid secretion and active chloride transport. These results suggest that ATP is a direct energy donor for acid secretion in the gastric mucosa of the guinea-pig. 相似文献
183.
There are two 3-hydroxyacyl-CoA dehydrogenase (EC 1.1.1.35) in rat liver, one in mitochondria (type I enzyme), and another in peroxisomes (type II enzyme). In a series of the studies on the properties and the physiological roles of fatty acid oxidation systems in both organelles, the two enzymes were purified and compared for their properties. The final preparations obtained were judged to be homogeneous based on the results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and sedimentation velocity analysis. Type I enzyme was composed of two identical subunits of molecular weight of 32,000, whereas type II enzyme was a monomeric enzyme having a molecular weight of 70,000–77,000. These subunit structures were confirmed by the results of fluorescence studies. Both enzymes were different in amino acid compositions, especially in the contents of tryptophan and half-cystine. Antibodies against them formed single precipitin lines for the corresponding enzymes, but not for the others when subjected to an Ouchterlony double-diffusion test. The Km values of type II enzyme for various substrates were lower than those of type I enzyme except those for acetoacetyl-CoA. As for 3-hydroxyacyl-CoA substrates, both enzymes had lower Km's for longer-chain substrates. The V for the substrates of C4C10 were similar for each enzyme, though the value of type II enzyme for C10 substrate was rather lower. The results of fluorescence studies suggested that their dissociation constants for NADH were lower and those for NAD+ were higher at lower pH. Both enzymes were specific to l-form of 3-hydroxyacyl-CoA substrate. The optimal pH of the forward reaction of type I and type II enzymes was 9.6 and 9.8, and of the reverse reaction, 4.5 and 6.2, respectively. From these results they were concluded to be completely different enzymes. 相似文献
184.
Yoshio Honma Keizo Takenaga Takashi Kasukabe Motoo Hozumi 《Biochemical and biophysical research communications》1980,95(2):507-512
Human promyelocytic leukemia cells (HL-60) were induced to phagocytize, reduce NBT dye(nitroblue tetrazolium), and change into forms that were morphologically similar to mature granulocytes by retinoic acid and related retinoids, but not by the pyridyl analog of retinoic acid. Induction of differentiation could be detected after 4 days of treatment of the cells with retinoic acid at as low a dose as 4 × 10?8 M. Thus, retinoids may be used in studies on the control of cell differentiation and malignancy of human myeloid leukemia cells. 相似文献
185.
Kazuyuki Morihara Tatsushi Oka Hiroshige Tsuzuki Yoshiharu Tochino Takashi Kanaya 《Biochemical and biophysical research communications》1980,92(2):396-402
We have established a procedure for converting porcine insulin into human insulin using a serine protease from M497-1 which shows unique specificity against lysine residues on the carboxyl side of the splitting point. Desalanine-(B30)-insulin (DAI) was prepared by digestion of porcine insulin with protease. The coupling between DAI and Thr-OBut was performed by the same enzyme at pH 6.5 with a large excess of the amine component (Thr-OBut) in the presence of high concentrations of organic co-solvents. The highest yield was 85% by 20 h reaction at 37°C. The synthesized [Thr-OBut-B30]-insulin was isolated, then deprotected with trifluoroacetic acid in the presence of anisole to obtain semisynthetic human insulin. 相似文献
186.
Measurement of endogenous growth rates and the mechanical propertyof the cell wall in various regions of light-grown azuki beanepicotyls revealed diat the minimum stress-relaxation time (To)was the shortest in the upper region (030 mm below theapex) of the epicotyl, where vigorous endogenous growth tookplace, and became longer toward the basal region, which wasmature and not growing. In the upper region of the epicotyl, a lower percentage of a-celluloseand a higher percentage of pectic substances than in the lowerregion were found. The percentage of hemicellulose content wasalmost constant over the whole epicotyl. Major components ofnoncellulosic neutral sugars in the cell wall were galactoseand xylose. The percentage of the galactose content to the noncellulosicpolysaccharide was highest in the upper region and lowest inthe basal region of the epicotyl, and a clearly negative correlationbetween the galactose composition and the To value was obtained.On the contrary, the percentage of die xylose content was highestin the basal region and lowest in die upper region, and a clearlypositive correlation between die xylose composition and theTo value was obtained. During die endogenous growth of die intactepicotyl, all die neutral sugars, particularly galactose, increasedin die upper region, whereas in die middle and basal regions,only xylose increased. Similar changes in sugar compositionswere observed during IAA-induced elongation of die segment excisedfrom various regions of die epicotyl. (Received July 27, 1978; ) 相似文献
187.
Inoue Mitsugu; Maeda Eizo; Yoshida Ryuji; Oritani Takashi 《Plant & cell physiology》1979,20(5):917-924
Rice callus tissues contained at least three active cytokinincompounds: zeatin, its riboside and N6-(2-isopentenyl) adenosine.These butanol-extractable cytokinins were identified by theirchromatographic mobilities in Sephadex LH-20, paper and gaschromatography. Zeatin, the apparent major cytokinin, was presentat concentrations of 0.7 to 1.0 µg/g fresh tissue and1.3 to 1.7 µg/g fresh tissue in 107 M and 1055M 2,4-D callus, respectively. On the basis of these and earlierresults, the induction and growth of rice callus tissue is discussedin relation to the occurrence of cytokinins in the tissue. (Received December 27, 1978; ) 相似文献
188.
Changes in cell wall polysaccharides and mechanical propertiesof the cell wall were examined during IAA-induced elongationgrowth of excised azuki bean epicotyl segments under differentgrowth conditions. Sucrose promoted IAA-induced cell elongation,but had very little effect on IAA-induced cell wall loosening.In the absence of sucrose, the amount of galactose in the cellwall decreased during the incubation period. IAA enhanced thedecrease in the galactose level. In the presence of sucrose,on the other hand, IAA induced increases in the amounts of cellulose,galactose and xylose in noncellulosic polysaccharides. TheseIAA-induced increases were not observed in the presence of mannitolat concentrations higher than 0.1 M, although cell wall looseningwas induced by IAA even in the presence of 0.2 M mannitol. (Received November 21, 1978; ) 相似文献
189.
Nakajima Hiromitsu; Yokota Takao; Matsumoto Takashi; Noguchi Masao; Takahashi Nobutaka 《Plant & cell physiology》1979,20(8):1489-1499
Various autonomous cultured tobacco cells including crown gallwere examined for their contents of growth regulators by meansof Avena curvature test, cell-division induction test, and tobaccopith callus test. The crown gall cells derived from cv. Hicks produced auxin andcytokinin in the high levels of 300500 µg IAA equivalentsand 4080 µg kinetin equivalents per kg, respectively.The major auxin was identified as indole-3-acetic acid basedon mass spectrometry and gas chromatography. These cells alsoproduced methyl indole-3-acetate as a minor component. One ofthe cytokinins was identified as ribosyl-trans-zeatin by meansof both gas chromatography-mass spectrometry and high performanceliquid chromatography. Auxin and cytokinin activities were not detected in the followingthree suspension cultured tobacco cells: cells requiring neithercytokinin nor auxin derived from the callus of N. tabacum cv.Bright Yellow and cells requiring auxin but not cytokinin derivedfrom the calluses of cv. Bright Yellow and cv. Hicks. Theirauxin and cytokinin contents per kg were less than 1 µgIAA equivalent and less than 0.1 µg kinetin equivalent,respectively. The results obtained in this study indicate that enhanced hormonalcontent is not the only reason for autonomous growth. (Received August 16, 1979; ) 相似文献
190.
Growth regulators were measured in extracts from the upper and lower halves of 7-mm apical segments of horizontally oriented, red-light-irradiated and non-irradiated roots of Zea mays L. cv. Golden Cross Bantam 70 which exhibit a georesponse only after an exposure to light. Abscisic acid (ABA) was measured by gas-liquid chromatography, auxin (indole-3-acetic acid, IAA) by the Avena straight-growth assay, and an unidentified growth inhibitor by a Zea root-growth assay. The ratio of ABA in the upper and lower halves was 1.6 in the irradiated roots and 1.0 in the non-irradiated ones. The total amount of ABA after irradiation was increased by a factor of ca. 1.8. The ratio of IAA in the upper and lower halves of irradiated and non-irradiated roots was 1:3.4 and 1:2.9, respectively. The content (or activity) of an unidentified growth inhibitor was highest in the lower halves of horizontally oriented roots which had been irradiated with red light. The unidentified growth inhibitor, rather than IAA or ABA, may be the major factor in the light-induced geotropic responsiveness in Zea roots. 相似文献