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71.
Curcumin, which is a bright orange-yellow pigment of turmeric with antioxidant properties, has been shown to produce a potent preventative action against several types of cancers in recent studies. It has also been reported to protect the development of colon tumor in animals being fed with carcinogen. In the colon cancer cells, curcumin was illustrated to inhibit cell proliferation and induce apoptosis. As an antioxidant, it acts as an anti-inflammatory as well as an antitumor agent. Curcumin has been detected to exist in nature in the form of curcuminoids, a mixture of curcumin, the major component, with two of its related demethoxy compounds (demethoxycurcumin and bisdemethoxycurcumin). In the present study, we have investigated the antiproliferation and induced apoptosis effects of curcuminoids on colon cancer, using the primary cancer cells isolated from Taiwanese colon cancer patients as the model for colorectal cancer. Results showed that curcuminoids inhibited cell proliferation and induced apoptosis of these human primary colon cancer cells. The effects were observed in a dose-dependent manner as dose increased from 12.5 to 100 microM. With the aim of furthering the fundamental understanding of the mechanisms underlying the antiproliferation and induced apoptosis effects of curcuminoids on these human colon cancer cells, we developed a sensitive, rapid, and reproducible assay method based on high-performance liquid chromatography (HPLC). This HPLC technique developed was found to successfully determine, in a quantitative manner, the cellular uptake of curcuminoids. The uptake of these curcuminoids by the colon cancer cells was shown to increase as the dose of curcuminoids was increased. The observations of inhibited proliferation and increased apoptosis in the colon cancer cells appeared to be associated with the cellular uptake of curcuminoids. 相似文献
72.
Liao YC Chang Chien SW Wang MC Shen Y Seshaiah K 《Journal of agricultural and food chemistry》2007,55(21):8640-8649
The relationship between Pb uptake by leaf lettuce ( Lactuca sativa L.) and water-soluble low-molecular-weight organic acids (LMWOAs) in rhizosphere, as influenced by transpiration (high and low), has been studied. Studies were carried out by culturing lettuce plants grown for 2 weeks in pots filled with quartz sand mixed with anion-exchange resin and then for 30 days in a greenhouse. The potted lettuce plants were subjected to stress by the addition of Pb(NO 3) 2 solutions (100, 200, and 300 mg of Pb L (-1)) and by high and low transpiration treatments for another 10-day period. Blank experiments (without addition of Pb(NO 3) 2 solutions to the pots) were also run. There were no significant differences in the growth of the plants with the addition of Pb(NO 3) 2 solutions in either of the transpirations studies. Uptake of Pb by the shoots and roots of the plants was found to be proportional to the concentration of Pb solutions added, and more accumulation was observed in the roots than in the shoots at the end of days 3 and 10. High transpiration caused more Pb uptake than did low transpiration. One volatile acid (propionic acid) and nine nonvolatile acids (lactic, glycolic, oxalic, succinic, fumaric, oxalacetic, d-tartaric, trans-aconitic, and citric acids) in rhizosphere quartz sand or anion-exchange resin were identified and quantified by gas chromatography analysis with a flame ionization detector. The amount of LMWOAs in rhizosphere quartz sand or anion-exchange resin increased with higher amounts of Pb in quartz sand solution and also with longer duration of the study. The total quantities of the LMWOAs in the rhizosphere quartz sand or anion-exchange resin were significantly higher under high and low transpiration with a 300 mg of Pb L (-1) solution addition at the end of day 10. Compared with our previous related studies (published work), the present study shows that the presence of LMWOAs in rhizosphere does not significantly affect Pb uptake by lettuce plants under high and low transpiration. A physiological mechanism of the roots of lettuce plants governing the relationship between Pb contamination level and quantity of water-soluble LMWOAs in rhizosphere quartz sand and resin, as influenced by transpiration, was proposed. 相似文献
73.
Yeast-expressed classical swine fever virus glycoprotein E2 induces a protective immune response 总被引:4,自引:0,他引:4
Guang-Jan Lin Ting-Yu Liu Yu-Yao Tseng Zeng-Weng Chen Chia-Chin You Shih-Ling Hsuan Maw-Sheng Chien Chienjin Huang 《Veterinary microbiology》2009,139(3-4):369-374
Classical swine fever (CSF) is an economically important swine disease worldwide. The glycoprotein E2 of classical swine fever virus (CSFV) is a viral antigen that can induce a protective immune response against CSF. A recombinant E2 protein was constructed using the yeast Pichia pastoris expression system and evaluated for its vaccine efficacy. The yeast-expressed E2 (yE2) was shown to have N-linked glycosylation and to form homodimer molecules. Four 6-week-old specified-pathogen-free (SPF) piglets were intramuscularly immunized with yE2 twice at 3-week intervals. All yE2-vaccinated pigs could mount an anamnestic response after booster vaccination with neutralizing antibody titers ranging from 1:96 to 1:768. Neutralizing antibody titers at 10 weeks post booster vaccination ranged from 1:16 to 1:64. At this time, the pigs were subjected to challenge infection with a dose of 1 × 105 TCID50 (50% tissue culture infective dose) virulent CSFV strain. At 1 week post challenge infection, all of the yE2-immunized pigs were alive and without symptoms or signs of CSF. Neutralizing antibody titers at this time ranged from 1:4,800 to 1:12,800 and even to 1:51,200 one week later. In contrast, the control pigs continuously exhibited signs of CSF and had to be euthanized because of severe clinical symptoms at 6 days post challenge infection. All of the yE2-vaccinated pigs were Erns antibody negative and had seroconverted against Erns by post challenge day 11, suggesting that yE2 is a potential DIVA (differentiating infected from vaccinated animals) vaccine. The yeast-expressed E2 protein retains correct immunogenicity and is able to induce a protective immune response against CSFV infection. 相似文献
74.
Lin SY Li TY Liu Q Zhang C Li X Chen Y Zhang SM Lian G Liu Q Ruan K Wang Z Zhang CS Chien KY Wu J Li Q Han J Lin SC 《Science (New York, N.Y.)》2012,336(6080):477-481
In metazoans, cells depend on extracellular growth factors for energy homeostasis. We found that glycogen synthase kinase-3 (GSK3), when deinhibited by default in cells deprived of growth factors, activates acetyltransferase TIP60 through phosphorylating TIP60-Ser(86), which directly acetylates and stimulates the protein kinase ULK1, which is required for autophagy. Cells engineered to express TIP60(S86A) that cannot be phosphorylated by GSK3 could not undergo serum deprivation-induced autophagy. An acetylation-defective mutant of ULK1 failed to rescue autophagy in ULK1(-/-) mouse embryonic fibroblasts. Cells used signaling from GSK3 to TIP60 and ULK1 to regulate autophagy when deprived of serum but not glucose. These findings uncover an activating pathway that integrates protein phosphorylation and acetylation to connect growth factor deprivation to autophagy. 相似文献
75.
The formation of cholesterol oxidation products (COPs) during heating in the presence of stearylamine at 140 degrees C was analyzed by high-performance liquid chromatography (HPLC) and kinetically studied by use of nonlinear regression models. Results indicated that the COPs concentration increased with increasing heating time, and stearylamine was shown to reduce both oxidation and degradation rates of cholesterol. Without stearylamine, the highest rate constant (per hour) was observed for epoxidation (545.4), followed by free radical chain reaction (251.0), reduction (147.3), dehydration (95.8), triol dehydrogenation (4.7), degradation (0.34), triol formation (0.31), and dehydrogenation (0.13). With stearylamine, the epoxidation and free radical chain reaction rates could be reduced by about 800- and 3.4-fold, respectively, and triol formation during oxidation could be completely inhibited. In addition, the reactions for reduction, dehydration, degradation, and dehydrogenation could proceed slower in the presence of stearylamine. The kinetic model developed in this study can be used to predict the inhibition of COPs formation by stearylamine during heating of cholesterol. 相似文献
76.
Soil fauna has been postulated as one of the paramount determinants of decomposition in the humid tropics. However, its effect on litter decomposition has only been demonstrated in few forest sites in Central America. In addition, landslide is a common disturbance associated with heavy rainfall brought by tropical cyclones in the tropics and can potentially alter abundance and structure of soil animals and thus affect litter decomposition. In this study, we examined the effect of soil animals on litter decomposition in an Asian subtropical monsoon forest and compared the animal effects in landslide-disturbed (2 years old) and undisturbed sites. Animal exclusion by naphthalene treatment significantly reduced the density and diversity of litterbag animals and slowed down the rate of decomposition in both landslide-disturbed and undisturbed sites. However, density (per unit area) and diversity of the litter animals and litter decomposition rate did not differ between the landslide-disturbed and undisturbed sites for both control and animal-excluded treatments. Our data suggest that the abundance of soil animals is not limited by litter mass. Furthermore, soil fauna recover quickly from landslides, and fauna's facilitative effect on litter decomposition is not altered after their recovery. 相似文献
77.
Chien Yi-Chun Huang Cheng-Hua 《European journal of plant pathology / European Foundation for Plant Pathology》2022,162(1):119-130
European Journal of Plant Pathology - Bacterial spot is a destructive disease of tomato that is caused by four taxonomically distinct Xanthomonas species. This study aimed to evaluate the effects... 相似文献
78.
Shin S El-Diwany R Schaffert S Adams EJ Garcia KC Pereira P Chien YH 《Science (New York, N.Y.)》2005,308(5719):252-255
The molecular basis of gammadelta T cell receptor (TCR) recognition is poorly understood. Here, we analyze the TCR sequences of a natural gammadelta T cell population specific for the major histocompatibility complex class Ib molecule T22. We find that T22 recognition correlates strongly with a somatically recombined TCRdelta complementarity-determining region 3 (CDR3) motif derived from germ line-encoded residues. Sequence diversity around these residues modulates TCR ligand-binding affinities, whereas V gene usage correlates mainly with tissue origin. These results show how an antigen-specific gammadelta TCR repertoire can be generated at a high frequency and suggest that gammadelta T cells recognize a limited number of antigens. 相似文献
79.
Farci P Shimoda A Coiana A Diaz G Peddis G Melpolder JC Strazzera A Chien DY Munoz SJ Balestrieri A Purcell RH Alter HJ 《Science (New York, N.Y.)》2000,288(5464):339-344
The mechanisms by which hepatitis C virus (HCV) induces chronic infection in the vast majority of infected individuals are unknown. Sequences within the HCV E1 and E2 envelope genes were analyzed during the acute phase of hepatitis C in 12 patients with different clinical outcomes. Acute resolving hepatitis was associated with relative evolutionary stasis of the heterogeneous viral population (quasispecies), whereas progressing hepatitis correlated with genetic evolution of HCV. Consistent with the hypothesis of selective pressure by the host immune system, the sequence changes occurred almost exclusively within the hypervariable region 1 of the E2 gene and were temporally correlated with antibody seroconversion. These data indicate that the evolutionary dynamics of the HCV quasispecies during the acute phase of hepatitis C predict whether the infection will resolve or become chronic. 相似文献
80.
Identification of virus-encoded microRNAs 总被引:1,自引:0,他引:1
Pfeffer S Zavolan M Grässer FA Chien M Russo JJ Ju J John B Enright AJ Marks D Sander C Tuschl T 《Science (New York, N.Y.)》2004,304(5671):734-736
RNA silencing processes are guided by small RNAs that are derived from double-stranded RNA. To probe for function of RNA silencing during infection of human cells by a DNA virus, we recorded the small RNA profile of cells infected by Epstein-Barr virus (EBV). We show that EBV expresses several microRNA (miRNA) genes. Given that miRNAs function in RNA silencing pathways either by targeting messenger RNAs for degradation or by repressing translation, we identified viral regulators of host and/or viral gene expression. 相似文献