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21.
Bouchra Harraki Pascale Guiraud Marie-Hélène Rochat Henri Faure Marie-Jeanne Richard Michelle Fussellier Alain Favier 《Biometals》1994,7(3):237-243
Radioactive zinc was used to study the effect of a binary parenteral nutrient solution, composed of amino acids and glucose, on zinc uptake by fibroblasts. The influence of addition of taurine, l-glutamine and of the increase in l-histidine content of the admixture was assessed. The pure mixture was highly toxic for cells and so it was diluted 1/5 in tyrode buffer with 2% albumin. As compared with cells incubated in the buffer containing albumin, zinc absorption was significantly higher (P < 0.05) in the presence of the amino acids of the mixture. Amino acids thus increased bioavailability by displacing zinc bound to albumin. When the histidine concentration in the nutrient medium (4.2 mm) was doubled, inhibition was noted after 30 min of incubation and zinc uptake thereafter remained comparable to that in histidine-free medium. The addition of glutamine (4.2 mm), usually not present in binary mixtures, resulted in significant differences as compared with glutamine-free control medium. Taurine (0.8 mm), led to a constant increase in zinc uptake by fibroblasts as compared with that obtained with taurine-free mixture. However, ultrafiltration showed that taurine was not able to displace zinc from albumin. 相似文献
22.
几种濒危植物及其近缘类群总DNA的提取与鉴定 总被引:122,自引:0,他引:122
用低pH 介质,高盐沉淀蛋白质方法成功地从银杉(Cathaya argyrophylla Chun etKuang)、矮牡丹(Paeonia suffruticosa var. spontanea)、南川升麻(Cim icifuga nanchuanensisHsiao)、裂叶沙参(Adenophora lobophylla)的同属种泡沙参(A. potaninii)等植物中提取和部分纯化了细胞总DNA,并对其产率、质量和纯度作了鉴定。此方法的关键是用了一个低pH提取介质,它能有效防止组织破碎及沉淀大量材料时的电离化作用及酚化合物的进一步氧化。所得DNA 不需经氯化铯梯度离心或柱层析,直接可用于限制性片断长度多态性(RFLP)及随机扩增的DNA多态性(RAPD)等分子水平的遗传标记。为检测濒危植物的遗传多样性提供了一套迅速、简便和可靠的技术方案 相似文献
23.
24.
Kosteletzkya virginica (K. virginica) is used for revegetation of salt-affected coastal tidal flats and as a raw material
of biodiesel. K. virginica root tuber, a biowaste with low economic value, is rich in bioactive compounds. This
study aimed to extract and identify flavonoids from K. virginica root tubers. The optimal extraction conditions
were 1/25 (w/v) solid/liquid ratio, 40% ethanol concentration at 40°C for 60 min. Under these conditions,
65.2 ± 3.7 mg/g total flavonoid content was extracted from the roots, which were collected from salinized soil
in late autumn of the third year. Antioxidant activity was evaluated through 1,1-diphenyl-2-picrylhydrazyl,
hydroxyl radical, and superoxide anion scavenging assays. The extracted flavonoids exhibited antioxidant activity
in a dose-dependent manner. Five flavonoids, glucoliquiritin apioside, licoisoflavone B, 5-methoxy-7,8-diprenyl-
flavone, 7,2′-dihydroxy-6,8-dimethyl-4′,5′-methylenedioxyflavan, and 5,7,4′-trihydroxy-3′-methoxy-6,8-di-Cmethylflavanone, were identified by ultra-performance liquid chromatography–tandem mass spectrometry.
Our results suggest that the flavonoids of K. virginica root tubers might be potent antioxidants and can be effectively applied as an ingredient in food and natural medicine. 相似文献
25.
Marie-Dominique Rhoda-Hardy-Dessources René-Serge de Neef Guy Mérault Françoise Giraud 《生物化学与生物物理学报:疾病的分子基础》1993,1181(1):90-96
PtdIns and PtdInsP kinases from normal erythrocyte (AA) membranes and sickle cell anaemia erythrocyte (SS) membranes have been characterized. PtdIns kinase was studied in native membranes under conditions in which PtdInsP kinase and PtdInsP phosphatase do not express any activity. Kinetic analysis of the AA and SS PtdIns kinases indicate similar Km values for PtdIns and ATP but higher Vmax values for SS PtdIns kinase. PtdInsP kinase was partially purified from erythrocyte ghosts by NaCl extraction. The kinetic parameters of PtdInsP kinase determined under these conditions were similar in AA and SS NaCl extracts. These data suggest the presence of some effector of PtdIns kinase in SS cell membranes, resulting in a greater activity of the enzyme. This leads consequently, to increase the PtdInsP pool and to activate PtdInsP kinase, in agreement with our previous observations of a greater [32P]Pi incorporation in both polyphosphoinositides in SS cells relatively to AA cells. 相似文献
26.
黄芪总黄酮对DNA损伤防护作用的研究 总被引:10,自引:0,他引:10
用DNA解旋荧光检测法(FADU)研究了黄芪总黄酮(TFA)对γ射线和H2O2所致V79细胞DNA链断裂的防护作用. 结果表明TFA对这两种损伤因子所致的DNA损伤均有不同程度的防护作用, 当TFA浓度达到0.4g/L和0.6g/L时, 分别对H2O2和γ射线所致的损伤有保护作用(P<0.05), 而浓度增至0.8g/L和1.2g/L时, 分别对两种因素所致的DNA链断裂损伤有非常显著的防护效果(P<0.01), 对H2O2的防护效果优于对γ射线. 相似文献
27.
日粮水平对鲇鱼日总代谢,特殊动力作用和活动代谢的影响 总被引:4,自引:0,他引:4
在25℃不同日粮水平(饥饿─4%体重/d)条件下,采用封闭式呼吸仪测定了31尾鲇鱼(体重72.9─133.3g)的日总代谢率,然后,将鱼限制在呼吸室中的限动笼内测定了其中20尾鲇鱼的静止日总代谢率,并计算出了鲇鱼的特殊动力作用(SDA)和活动代谢率。日总代谢率和活动代谢率都随日粮水平的升高呈“V”形变化,分别在约1%和2%体重/d的日粮水平时最低,SDA的能量支出占摄入能量的22.14%。 相似文献
28.
Blackfoot disease is a peripheral vascular disease resulting in gangrene of the lower extremities. Although extensive epidemiological
study has implicated high arsenic content in artesian well water of the endemic area bears some important connection with
the disease, the etiology of the disease is still not clarified. In this study, attention is paid to chemical speciation of
arsenic in order to find out whether the concentrations of arsenic species in urine of Blackfoot disease patients are different
from those of controls. Experimental results indicate that the total arsenic, inorganic arsenic, monomethylarsonic acid, and
other forms of arsenic in the urine of patients are significantly higher than those of the contols. The possible connection
of those arsenic species with the etiology of the disease is discussed. 相似文献
29.
Nutrient uptake relationship to root characteristics of rice 总被引:1,自引:0,他引:1
Data on root parameters and distribution are important for an improved understanding of the factors influencing nutrient uptake
by a crop. Therefore, a study was conducted on a Crowley silt loam at the Rice Research and Extension Center near Stuttgart,
Arkansas to measure root growth and N, P and K uptake by three rice (Oryza sativa L.) cultivars at active tillering (36 days after emergence (DAE)), maximum tillering (41 DAE), 1.25 cm internode elongation
(55 DAE), booting (77 DAE) and heading (88 DAE). Soil-root core samples were taken to a depth of 40 cm after plant samples
were removed, sectioned into 5 cm intervals, roots were washed from soil and root lengths, dry weights and radii were measured.
Root parameters were significantly affected by the soil depth × growth stage interaction. In addition, only root radius was
affected by cultivar. At the 0- to 5-cm soil depth, root length density ranged from 38 to 93 cm cm-3 throughout the growing season and decreased with depth to about 2 cm cm-3 in the 35- to 40-cm depth increment. The increase in root length measured with each succeeding growth stage in each soil
horizon also resulted in increased root surface area, hence providing more exposed area for nutrient uptake. About 90% of
the total root length was found in the 0- to 20-cm soil depth throughout the season. Average root radius measured in the 0-
to 5-cm and 35- to 40-cm depth increments ranged from 0.012 to 0.013 cm and 0.004 to 0.005 cm, respectively throughout the
season. Total nutrient uptake by rice differed among cultivars only during vegetative growth. Differences in total nutrient
uptake among the cultivars in the field appear to be related to absorption kinetics of the cultivars measured in a growth
chamber study.
Published with permission of the Arkansas Agricultural Experiment Station. 相似文献
30.
S. M. Renaud H. C. Zhou D. L. Parry Luong-Van Thinh K. C. Woo 《Journal of applied phycology》1995,7(6):595-602
The effect of temperature from 10 °C to 35 °C on the growth, total lipid content, and fatty acid composition of three species of tropical marine microalgae, Isochrysis sp., Nitzschia closterium, N. paleacea (formerly frustulum), and the Tahitian Isochrysis sp. (T.ISO), was investigated.Cultures of N. closterium, Isochrysis sp. and T.ISO grew very slowly at 35 °C, while N. closterium did not grow at temperatures higher than 30 °C or lower than 20 °C. N. paleacea was low-temperature tolerant, with cells growing slowly at 10 °C. N. paleacea produced the highest percentage of lipids at 10 °C, while the other species produced maximum amounts of lipid at 20 °C. None of the species maintained high levels of polyunsaturated fatty acids (PUFAs) at high growth temperature and there was a significant inverse relationship between the percentage of PUFAs and temperature for N. paleacea. A curved relationship was found between temperature and percentage of PUFA for N. closterium and tropical Isochrysis sp., with the maximum production of PUFA at 25 °C and 20 °C, respectively. The two Nitzschia species produced higher levels of the essential fatty acid eicosapentaenoic acid [20:5(n-3)] at lower growth temperatures, but the two Isochrysis species had little change in percentage of 20:5(n-3) with temperature. Only T.ISO had the highest percentage of 22:6(n-3) at lowest growth temperature (11.4% total fatty acids at 10 °C).School of Mathematical and Physical SciencesAuthor for correspondence 相似文献