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91.
Thomas Kitzberger Ezequiel Aráoz Juan H. Gowda Mónica Mermoz Juan M. Morales 《Ecosystems》2012,15(1):97-112
The generalization that plant communities increase in flammability as they age and invariably lead to resilient self-organized
landscape mosaics is being increasingly challenged. Plant communities often exhibit rapidly saturating or even hump-shaped
age-flammability trajectories and landscapes often display strong non-linear behaviors, abrupt shifts, and self-reinforcing
alternative community states. This plethora of fire-landscape interactions calls for a more general model that considers alternative
age-flammability rules. We simulated landscape dynamics assuming communities that (1) increase in flammability with age and
(2) gain flammability up to a certain age followed by a slight and moderate loss to a constant value. Simulations were run
under combinations of ignition frequency and interannual climatic variability. Age-increasing fire probability promoted high
resilience to changes in ignition frequency and climatic variability whereas humpbacked-shaped age-flammability led to strong
non-linear behaviors. Moderate (20%) reductions in mature compared to peak flammability produced the least resilient behaviors.
The relatively non-flammable mature forest matrix intersected by young flammable patches is prone to break up and disintegrate
with slight increases in ignition/climate variability causing large-scale shifts in the fire regime because large fires were
able to sweep through the more continuous young/flammable landscape. Contrary to the dominant perception, fire suppression
in landscapes with positive feedbacks may effectively reduce fire occurrence by allowing less flammable later stage communities
composed of longer lived, obligate seeders to replace earlier stages of light demanding, often more flammable resprouters.
Conversely, increases in anthropogenic ignitions, a common global trend of many forested regions may, in synergism with increased
climate variability, induce abrupt shifts, and large-scale forest degradation. 相似文献
92.
Variation in the incidence of H2-oxidizing chemolithotrophic bacteria in rice grown under different cultivation conditions 总被引:1,自引:0,他引:1
Summary The incidence of H2-oxidizing chemolithotrophic bacteria associated with rice grown under continuous wetland, upland, and rainfed wetland conditions was studied by14C-autoradiographic technique in a neutral soil at IRRI (Maahas) and an acid rainfed wetland soil (Luisiana).In Maahas soil, H2-oxidizing chemolithotrophic bacteria were not detected in the endorhizosphere, rhizosphere, and nonrhizosphere soil of rice grown under dryland conditions. Under continuously flooded conditions a very large population of these bacteria were found in the endorhizosphere but not in the oxidized and reduced soil.A very low population of these bacteria were found in the endorhizosphere and basal culm of rice grown under rainfed wetland conditions at Luisiana. Bacteria isolated from Maahas wetland rice and inoculated to rice seedling planted in Luisiana soil failed to establish.Both Maahas and Luisiana soils consumed externally supplied H2 and produced H2 and CH4 almost at the same rate when they were amended with rice straw or sucrose. This paper discusses possible causes of variation in the number of these bacteria and their distribution in rice grown under different cultural and soil conditions. 相似文献
93.
O. Singh C. L. L. Gowda S. C. Sethi T. Dasgupta J. B. Smithson 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1992,83(8):956-962
Summary Twenty-eight diallel trials over 8 years and two locations were analysed to estimate genetic variances for agronomic characters of chickpea (Cicer arietinum L.). The data were analysed according to Method 4 and Model I of Griffing (1956). Days to flowering, plant height, and seed size were found to be predominantly under additive inheritance and were highly predictable. Both additive and non-additive genetic components were important for seed yield, number of branches, pods per plant, and seeds per pod. Although both general combining ability (gca) and specific combining ability (sca) varied significantly with generation, components of gca mean squares were invariably much larger than gca x generation interaction components, indicating that either the F1 or the F2 generation can be used to estimate the gca components effectively. Combined diallel analysis of F2s over locations revealed the importance of combining ability x location interactions and emphasized the need for testing over more than one location for the precise estimation of combining ability. The implications of these findings and those reported earlier in the literature on the breeding strategies/methods for the genetic improvement of agronomic characters in chickpea are discussed.ICRISAT journal article no. 1199 相似文献
94.
95.
Siddabasave Gowda B. Gowda Seigo Usuki Mostafa A. S. Hammam Yuta Murai Yasuyuki Igarashi Kenji Monde 《Journal of lipid research》2016,57(2):325-331
Sphingoid base derivatives have attracted increasing attention as promising chemotherapeutic candidates against lifestyle diseases such as diabetes and cancer. Natural sphingoid bases can be a potential resource instead of those derived by time-consuming total organic synthesis. In particular, glucosylceramides (GlcCers) in food plants are enriched sources of sphingoid bases, differing from those of animals. Several chemical methodologies to transform GlcCers to sphingoid bases have already investigated; however, these conventional methods using acid or alkaline hydrolysis are not efficient due to poor reaction yield, producing complex by-products and resulting in separation problems. In this study, an extremely efficient and practical chemoenzymatic transformation method has been developed using microwave-enhanced butanolysis of GlcCers and a large amount of readily available almond β-glucosidase for its deglycosylation reaction of lysoGlcCers. The method is superior to conventional acid/base hydrolysis methods in its rapidity and its reaction cleanness (no isomerization, no rearrangement) with excellent overall yield. 相似文献
96.
Abhishek Juluri Carmen Popescu Leon Zhou Reena N. Murthy Vanaja K. Gowda Chetan Kumar P Manjeet B. Pimparade Michael A. Repka S. Narasimha Murthy 《AAPS PharmSciTech》2016,17(1):99-105
The objective of this project was to investigate the potential of Kleptose Linecaps DE17 (KLD) in masking the unpleasant/bitter taste of therapeutic agents by hot melt extrusion (HME). Griseofulvin (GRI) and caffeine anhydrous (CA) were used as a bitter active pharmaceutical ingredient (API) model drugs. Thermogravimetric studies confirmed the stability of GRI, CA, and KLD at the employed extrusion temperatures. The differential scanning calorimetry (DSC) studies revealed a characteristic melting endotherm of GRI at 218–220°C and CA at 230–232°C in the physical mixtures as well as in all extrudates over the period of study, indicating the crystalline nature of drug. HME of KLD was achieved only in the presence of plasticizer. Among the several plasticizers investigated, xylitol showed improved processability of KLD at 15% w/w concentration. Dissolution studies of HME extrudates using simulated salivary medium exhibited ~threefold less release compared to physical mixture at the end of 5 min (the lesser drug release, better the taste masking efficiency). Furthermore, the results from the sensory evaluation of products in human panel demonstrated strong bitter taste in the case of physical mixture compared to the HME formulation, suggesting the potential of Kleptose Linecaps DE17 as taste masking polymer in melt extruded form. 相似文献
97.
Renu Verma Lavanya Balakrishnan Kusum Sharma Aafaque Ahmad Khan Jayshree Advani Harsha Gowda Srikanth Prasad Tripathy Mrutyunjay Suar Akhilesh Pandey T. S. Keshava Prasad Subramanian Shankar 《Journal of cell communication and signaling》2016,10(1):61-67
Interleukin-10 (IL-10) is an anti-inflammatory cytokine with important immunoregulatory functions. It is primarily secreted by antigen-presenting cells such as activated T-cells, monocytes, B-cells and macrophages. In biologically functional form, it exists as a homodimer that binds to tetrameric heterodimer IL-10 receptor and induces downstream signaling. IL-10 is associated with survival, proliferation and anti-apoptotic activities of various cancers such as Burkitt lymphoma, non-Hodgkins lymphoma and non-small scell lung cancer. In addition, it plays a central role in survival and persistence of intracellular pathogens such as Leishmania donovani, Mycobacterium tuberculosis and Trypanosoma cruzi inside the host. The signaling mechanisms of IL-10 cytokine are not well explored and a well annotated pathway map has been lacking. To this end, we developed a pathway resource by manually annotating the IL-10 induced signaling molecules derived from literature. The reactions were categorized under molecular associations, activation/inhibition, catalysis, transport and gene regulation. In all, 37 molecules and 76 reactions were annotated. The IL-10 signaling pathway can be freely accessed through NetPath, a resource of signal transduction pathways previously developed by our group. 相似文献
98.
Soujanya D. Yelamanchi Hitendra Singh Solanki Aneesha Radhakrishnan Lavanya Balakrishnan Jayshree Advani Remya Raja Nandini A. Sahasrabuddhe Premendu Prakash Mathur Pinaki Dutta T. S. Keshava Prasad Aditi Chatterjee Harsha Gowda Kanchan Kumar Mukherjee 《Journal of cell communication and signaling》2016,10(4):341-346
99.
Since concern has recently been expressed about the presence of genotoxic substances due to chlorination of water and wastewater, chloramine-T (CAT) is proposed as an alternative disinfectant to chlorine. The viricidal properties of chlorine and CAT were compared. Kinetics of inactivation of poliovirus type 2 by chlorine and CAT in chlorine demand-free water were investigated by using a kinetic apparatus. Inactivation of the virus by chlorine and CAT occurred in two steps. The initial linear part of the inactivation curve followed a pseudo-first-order reaction with the virus. An obvious dose-response relationship was demonstrated with CAT. The rate of inactivation of the virus by CAT was faster in acid medium than in alkaline medium. Inactivation kinetic studies were performed at different temperatures, and the kinetic, Arrhenius, and thermodynamic parameters were evaluated. The rate of inactivation of poliovirus type 2 by chlorine was faster than that by CAT under identical conditions. A mechanism for the viral inactivation in acid conditions was proposed which led to a rate equation consistent with the experimental results. The results indicate that CAT may be an effective viricide against poliovirus type 2 in an acid medium. 相似文献
100.
Balaji Prakash S. Selvaraj M. R. N. Murthy Y. N. Sreerama D. Rajagopal Rao Lalitha R. Gowda 《Journal of molecular evolution》1996,42(5):560-569
Plant seeds contain a large number of protease inhibitors of animal, fungal, and bacterial origin. One of the well-studied
families of these inhibitors is the Bowman-Birk family(BBI). The BBIs from dicotyledonous seeds are 8K, double-headed proteins.
In contrast, the 8K inhibitors from monocotyledonous seeds are single headed. Monocots also have a 16K, double-headed inhibitor.
We have determined the primary structure of a Bowman-Birk inhibitor from a dicot, horsegram, by sequential edman analysis
of the intact protein and peptides derived from enzymatic and chemical cleavage. The 76-residue-long inhibitor is very similar
to that ofMacrotyloma axillare. An analysis of this inhibitor along with 26 other Bowman-Birk inhibitor domains (MW 8K) available in the SWISSPROT databank
revealed that the proteins from monocots and dicots belong to related but distinct families. Inhibitors from monocots show
larger variation in sequence. Sequence comparison shows that a crucial disulphide which connects the amino and carboxy termini
of the active site loop is lost in monocots. The loss of a reactive site in monocots seems to be correlated to this. However,
it appears that this disulphide is not absolutely essential for retention of inhibitory function. Our analysis suggests that
gene duplication leading to a 16K inhibitor in monocots has occurred, probably after the divergence of monocots and dicots,
and also after the loss of second reactive site in monocots.
S. Selvaraj is on leave from Department of Physics, Bharathidasan University, Tiruchirapalli 620 024, Tamilnadu, India
Correspondence to: M.R.N. Murthy 相似文献