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61.
Joseph J Washington A Joseph L Koehler L Fink LM Hauer-Jensen M Kennedy RH 《American journal of physiology. Heart and circulatory physiology》2002,283(6):H2567-H2574
Hyperhomocysteinemia (Hhe), linked to cardiovascular disease by epidemiological studies, may be an important factor in adverse cardiac remodeling in hypertension. Specifically, convergence of myocardial and vascular alterations promoted by Hhe and hypertension may exacerbate cardiac remodeling and myocardial dysfunction. We studied male spontaneously hypertensive rats fed one of three diets: control, intermediate Hhe inducing, or severe Hhe inducing. After 10 wk of dietary intervention, cardiac function was assessed in vitro, and cardiac and coronary arteriolar remodeling were monitored by histomorphometric, immunohistochemical, and biochemical techniques. Results showed that Hhe induced diastolic dysfunction, as characterized by the diastolic pressure-volume curve, without significant changes in baseline systolic function. Perivascular collagen levels were increased by Hhe, and there was an increase in left ventricular hydroxyproline levels. Myocyte size was not affected. Coronary arteriolar wall thickness increased with Hhe due to smooth muscle hyperplasia. Mast cells increased in parallel with Hhe and collagen accumulation. In summary, 10 wk of Hhe caused coronary arteriolar remodeling, myocardial collagen deposition, and diastolic dysfunction in hypertensive rats. 相似文献
62.
El-hamid Ismail A Abdel Aleem AA Abdel Bary H El-Assaly S 《Nucleosides, nucleotides & nucleic acids》2002,21(6-7):469-475
2-Naphthylsulfonylhydrazine was reacted with aromatic aldehydes or aldehydo sugars to give the corresponding hydrazones which undergo Michael addition reactions with malononitrile or ethyl cyanoacetate to form pyrazole derivatives. 相似文献
63.
In this study, glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate: NADP+ oxidoreductase, EC 1.1.1.49; G6PD) was purified from parsley (Petroselinum hortense) leaves, and analysis of the kinetic behavior and some properties of the enzyme were investigated. The purification consisted of three steps: preparation of homogenate, ammonium sulfate fractionation, and DEAE-Sephadex A50 ion exchange chromatography. The enzyme was obtained with a yield of 8.79% and had a specific activity of 2.146 U (mg protein)(-1). The overall purification was about 58-fold. Temperature of +4 degrees C was maintained during the purification process. Enzyme activity was spectrophotometrically measured according to the Beutler method, at 340 nm. In order to control the purification of enzyme, SDS-polyacrylamide gel electrophoresis was carried out in 4% and 10% acrylamide for stacking and running gel, respectively. SDS-polyacrylamide gel electrophoresis showed a single band for enzyme. The molecular weight was found to be 77.6 kDa by Sephadex G-150 gel filtration chromatography. A protein band corresponding to a molecular weight of 79.3 kDa was obtained on SDS-polyacrylamide gel electrophoresis. For the enzymes, the stable pH, optimum pH, and optimum temperature were found to be 6.0, 8.0, and 60 degrees C, respectively. Moreover, KM and Vmax values for NADP+ and G6-P at optimum pH and 25 degrees C were determined by means of Lineweaver-Burk graphs. Additionally, effects of streptomycin sulfate and tetracycline antibiotics were investigated for the enzyme activity of glucose-6-phosphate dehydrogenase in vitro. 相似文献
64.
65.
Abd H Johansson T Golovliov I Sandström G Forsman M 《Applied and environmental microbiology》2003,69(1):600-606
Francisella tularensis is a highly infectious, facultative intracellular bacterium which causes epidemics of tularemia in both humans and mammals at regular intervals. The natural reservoir of the bacterium is largely unknown, although it has been speculated that protozoa may harbor it. To test this hypothesis, Acanthamoeba castellanii was cocultured with a strain of F. tularensis engineered to produce green fluorescent protein (GFP) in a nutrient-rich medium. GFP fluorescence within A. castellanii was then monitored by flow cytometry and fluorescence microscopy. In addition, extracellular bacteria were distinguished from intracellular bacteria by targeting with monoclonal antibodies. Electron microscopy was used to determine the intracellular location of F. tularensis in A. castellanii, and viable counts were obtained for both extracellular and intracellular bacteria. The results showed that many F. tularensis cells were located intracellularly in A. castellanii cells. The bacteria multiplied within intracellular vacuoles and eventually killed many of the host cells. F. tularensis was found in intact trophozoites, excreted vesicles, and cysts. Furthermore, F. tularensis grew faster in cocultures with A. castellanii than it did when grown alone in the same medium. This increase in growth was accompanied by a decrease in the number of A. castellanii cells. The interaction between F. tularensis and amoebae demonstrated in this study indicates that ubiquitous protozoa might be an important environmental reservoir for F. tularensis. 相似文献
66.
Growth of three Frankia strains associated with roots of Casuarina tree, treated with different concentrations of metal ions, was measured as total protein content. One strain was highly resistant to different aluminum ion concentrations up to 10 mmol/L. The other two strains were more sensitive to the higher aluminum concentrations (1.25-10 mmol/L). Growth inhibition by cobalt and lead concentrations varied, depending on the tested strain. Stimulation occurred only at cobalt concentrations of 0.33 and 0.65 mmol/L for one strain. 相似文献
67.
El-Bestawy E. Abou El-KHeir E. Abd El-Fatah H.I. Hassouna S.M. 《World journal of microbiology & biotechnology》1998,14(6):853-856
The objective of the present study was to obtain by mutation and selection techniques bacterial strains capable of removing heavy metals at high efficiency. Four of the bacteria most promising in metal uptake, Staphylococcus aureus, Bacillus Sphaericus, B. licheniformis and Arthrobacter sp. were selected after isolation from water heavily polluted with heavy metals. Two mutagenic agents were used: U.V. irradiation at 245nm (physical) and 1% ethidium bromide (chemical). Optimum conditions for metal removal by most of the tested bacteria were: pH 9, 50°C and 200rev/min agitation speed. Induction of mutation both physically or chemically resulted in mutants that were superior over their wild types in removing heavy metals under investigation. The highest removal efficiencies (REs) achieved were in the following order: Cd(89.9–100%); Cr(87.3–99.7%); Zn(47.7–100%); Cu(40.8–84.7%); Pb(40.2–51%); Fe(17.5–28.7%); Ni(13.8–23.9%) and finally Co(17.2–18.4%). Using mixed cultures of the wild and the selected mutants enhanced the RE(s) of some metals compared to those obtained by individual species, and the time required to achieve the highest RE was reduced. 相似文献
68.
Abd El-Aziz A. Said Adriane G. Ludwick Heshmat A. Aglan 《Bioresource technology》2009,100(7):2219-2222
Raw bagasse or sugar cane cellulosic residues were modified using acylation grafting with fatty acid. The capability of the grafted bagasse to absorb oil from aqueous solution was studied and compared with the raw bagasse. It was found that the grafted material was significantly more hydrophobic than the raw bagasse. This grafted bagasse had little affinity for water and good affinity for oil. It was also found that bleaching of raw bagasse did not enhance its oil absorptivity. The grafted raw bagasse would be most suitable for applications where oil is to be removed from an aqueous environment. For oil absorbing applications in the absence of water, the raw bagasse was an excellent material. 相似文献
69.
Muhamad Hafiz Abd Rahim Hanan Hasan Alejandro Montoya Ali Abbas 《Engineering in Life Science》2015,15(2):220-228
The use of pure substrate represents a significant proportion of the cost of manufacturing a drug such as lovastatin. This study explores the production of lovastatin and (+)‐geodin by Aspergillus terreus ATCC 20542 using biodiesel‐derived crude glycerol (CG) as a feedstock. Shake flask experiments showed reduced lovastatin production and glycerol consumption in the presence of 10–50 g/L CG with respect to pure glycerol controls. At 50 g/L, lovastatin and (+)‐geodin production was significantly reduced by 82 and 73%, respectively. The lowest lovastatin inhibition was detected in 30 g/L of CG (48%), which was accompanied by a significant rise in (+)‐geodin production (338%). Further investigation was performed on three major impurities found in CG, namely methanol (MeOH), sodium chloride (NaCl), and fatty acids (oleic acid and palmitic acid (PA), soap). None was particularly inhibitory for lovastatin, except soap and PAs, which reduced its production by more than 50% at all concentrations tested. In contrast, (+)‐geodin was inhibited in the presence of MeOH and PA by up to 46 and 91%, respectively. These observations indicate that partial purification of CG would be potentially useful in improving production of lovastatin and (+)‐geodin by A. terreus. 相似文献
70.
Mohamed Abd El Rahman Denise Haase Axel Rentzsch Julia Olchvary Hans-Joachim Sch?fers Wolfram Henn Stefan Wagenpfeil Hashim Abdul-Khaliq 《PloS one》2015,10(4)