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151.
Julia Marín-Navarro Maria Gloria Esquivel Joaquín Moreno 《World journal of microbiology & biotechnology》2010,26(10):1785-1793
Hydrogen production by C. reinhardtii seems a promising alternative as a source of non-polluting biofuel. Hydrogen is generated as a result of combining free protons
and electrons (supplied by ferredoxin) through the activity of an oxygen-sensitive hydrogenase. Thus, substantial hydrogen
production is only observed in the light under anaerobic conditions. These require a reduced rate of photosynthetic oxygen
evolution which is usually achieved by impairing photosystem II through sulphur starvation. Several approaches have been conducted
to enhance and extend hydrogen production by addressing problems such as the mechanism of hydrogenase inhibition by oxygen,
the stressing impact on the cells of the culture conditions, the use of starch as an alternate source of electrons under reduced
photosynthetic activity, and the need of maintaining a balance between oxygen evolution and consumption. The photosynthetic
enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) appears as suitable objective for biotechnological optimization
of hydrogen production because of its relevance controlling the hydrogenase main competitor electron sink (the Calvin-Benson
cycle), as well as starch accumulation and photorespiratory oxygen consumption. Possible strategies for increasing hydrogen
generation based on alteration of Rubisco properties and/or catabolism through site-directed mutagenesis are discussed. 相似文献
152.
153.
Contraception with lynestrenol-mestranol (Lyndiol) was studied in 332 Mexican women during a period of two and one-half years. Side effects were minimal or transient. No pregnancies occurred in those who took the medication according to instructions. The women were followed with yearly pelvic examinations and Papanicolaou smears, serial endometrial biopsies and extensive studies of blood, liver and glandular function. Complete ophthalmological studies were done on 30 patients. No clinical or laboratory evidence of harmful effects could be demonstrated. Return to ovulation (using pregnanediol excretion and endometrial biopsies as parameters) occurred in all of 22 women studied in the first three post-treatment cycles. Eight posttreatment pregnancies and the resulting offspring were normal. The first post-treatment cycle, as with other oral contraceptives, was unpredictable and tended to be prolonged. It varied in length from 22 to 60 days. 相似文献
154.
A variety of specific conditions often stimulate controversy regarding candidacy for liver transplantation. We review the published experience with liver transplantation for alcoholic liver disease, fulminant and chronic hepatitis B, and hepatocellular carcinoma and transplantation in older subjects. Liver transplantation for alcoholic liver disease and in subjects older than 60 years is becoming less controversial because recent data demonstrate that these patients have excellent survival and good quality of life after transplantation. Only 10% to 15% of persons with alcoholism return to drinking after transplantation, and most do so only transiently. Liver transplantation for patients with hepatitis B virus infection or primary liver cancer is more problematic because recurrent disease is common in both conditions. After transplantation for chronic hepatitis B, 80% to 90% of patients have reinfection of the allograft and long-term survival is 45% to 50%. Patients receiving transplants for hepatocellular carcinoma have only 20% to 30% long-term survival, but these survivors are cured of malignancy. Data are presented to support continued liver transplantation for chronic hepatitis B and hepatocellular carcinoma; however, patients must be selected based on factors that predict a favorable outcome, and experimental therapies should be employed to explore ways to improve the existing survival rates. 相似文献
155.
Dafne Moreno-Lorenzana Sócrates Avilés-Vazquez Miguel Angel Sandoval Esquivel Antonio Alvarado-Moreno Vianney Ortiz-Navarrete Héctor Torres-Martínez 《Cell cycle (Georgetown, Tex.)》2016,15(9):1276-1287
Chronic Myeloid Leukemia (CML) is sustained by a small population of cells with stem cell characteristics known as Leukemic Stem Cells that are positive to BCR-ABL fusion protein, involved with several abnormalities in cell proliferation, expansion, apoptosis and cell cycle regulation. Current treatment options for CML involve the use of Tirosine Kinase Inhibitor (Imatinib, Nilotinib and Dasatinib), that efficiently reduce proliferation proliferative cells but do not kill non proliferating CML primitive cells that remain and contributes to the persistence of the disease.In order to understand the role of Cyclin Dependent Kinase Inhibitors in CML LSC permanence after TKI treatment, in this study we analyzed cell cycle status, the levels of several CDKIs and the subcellular localization of such molecules in different CML cell lines, as well as primary CD34+CD38?lin? LSC and HSC.Our results demonstrate that cellular location of p18INK4c and p57Kip2 seems to be implicated in the antiproliferative activity of Imatinib and Dasatinib in CML cells and also suggest that the permanence of quiescent stem cells after TKI treatment could be associated with a decrease in p18INK4c and p57Kip2 nuclear location. The differences in p18INK4cand p57Kip2activities in CML and normal stem cells suggest a different cell cycle regulation and provide a platform that could be considered in the development of new therapeutic options to eliminate LSC. 相似文献