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861.
Batudioic acid, a new labdane type diterpene, was isolated from aerial parts of Baccharis tucumanensis. Its structure was determined by spectral analysis and some chemical transformations. Xan- thomicrol and scutellarein-7,4′-dimethyl ether were also isolated. 相似文献
862.
863.
SYNOPSIS. Acetate added to autotrophic Euglena cultures changed the period length of the circadian rhythm of phototaxis. Phase shifts were induced by acetate pulses. Since transition from one metabolic state to another (autotrophic/mixotrophic) caused a phase shift or a period change, such effects possibly result from switching metabolic pathways. As suggested (Brinkmann, K., 1966. Planta 70 , 344–89), differences in the temperature responses of the rhythm in mixotrophic and autotrophic cells might also be caused by participation of different metabolic pathways with different Q10 values, e.g. dark reactions vs photochemical reactions. However the Q10 of a given dark reaction, e.g. protein synthesis, can differ in the 2 states. Therefore temperature experiments alone do not suffice for deciding whether the pathways include photochemical reactions, dark reactions, or both. 相似文献
864.
Jacob T. Wittman Peter Silk Katie Parker Brian H. Aukema 《Agricultural and Forest Entomology》2021,23(4):527-535
- Adult emerald ash borers are attracted to green prism traps baited with the ash host volatile (3Z)-hexenol and the sex pheromone of emerald ash borer (3Z)-dodecen-12-olide [(3Z)-lactone]. Quantifying the heretofore unknown range of attraction of such traps would help optimize deployment strategies for early detection.
- Examining trap captures of traps deployed in pairs at variable distances offers insight into the range of attraction. Recent work has shown the range of attraction can be estimated as half the intertrap distance at which trap catch begins to decrease, which should occur when proximate traps overlap their respective attractive ranges.
- We estimated these traps' attractive range for emerald ash borer using 98 baited dark green prism traps deployed in pairs, one trap per tree, in an urban park in Saint Paul, Minnesota, USA in summer 2020.
- We estimate attractive range by fitting a logistic model to trap catch data using Bayesian inferential methods and describe advantages thereof.
- The attractive range of these baited traps was estimated to be between 16 and 73 m, with a median of 28 m. We recommend that dark green prism traps baited with these semiochemicals be placed 25–35 m apart near high-risk entry points.
865.
Miyano Yasuyuki Koyama Kunihiro Sreekumari Kurissery Yoshiro Sato Yasushi Kikuchi 《Biofouling》2013,29(7):851-858
Bacterial attachment and growth on material surfaces are considered to be the primary steps leading to the formation of biofilm. Biofilms in hospital and food processing settings can result in bacterial infection and food contamination, respectively. Prevention of bacterial attachment, therefore, is considered to be the best strategy for abating these menaces and therefore the development of antibacterial metals becomes important. In this study, nine pure metals, viz. titanium, cobalt, nickel, copper, zinc, zirconium, molybdenum, tin, and lead have been tested for their antibacterial properties against two bacterial strains, Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. This was accomplished using two assay methods, the film contact method and the shaking flask method. The results show that the antibacterial properties varied significantly with different metals and the effectiveness of metals to resist bacterial attachment varied with the bacterial strain. Among the metals tested, titanium and tin did not exhibit antibacterial properties. TEM images showed that metal accumulation resulted in the disruption of the bacterial cell wall and other cellular components. 相似文献
866.
In Tris-washed Photosystem-II particles we are able to induce an EPR signal in the dark by addition of an iridium salt (K2IrCl6). This signal is attributed to signal IIs (slow) (D+) and the redox titration gives an Em value of 760 mV for the couple . On the basis of our previous studies on the equilibrium between D+Z and DZ+ (K = 104) (Boussac, A. and Etienne, A.L. (1982) Biochem. Biophys. Res. Commun. 109, 1200–1205), we therefore attribute a value of 1 V for the Em of the couple. A second effect of K2IrCl6 is to modify the spectral characteristics of signal II. We conclude that K2IrCl6 is able to change the environment of the species from which signal IIs and signal IIf originate. 相似文献
867.
Davita Pillay Alain F.V. Boulangé Virginie Coustou Théo Baltz Theresa H.T. Coetzer 《Experimental parasitology》2013
Trypanosoma congolense is a haemoprotozoan parasite that causes African animal trypanosomosis, a wasting disease of cattle and small ruminants. Current control methods are unsatisfactory and no conventional vaccine exists due to antigenic variation. An anti-disease vaccine approach to control T. congolense has been proposed requiring the identification of parasitic factors that cause disease. Immunoprecipitation of T. congolense antigens using sera from infected trypanotolerant cattle allowed the identification of several immunogenic antigens including two M1 type aminopeptidases (APs). The two APs were cloned and expressed in Escherichia coli. As the APs were expressed as insoluble inclusion bodies it was necessary to develop a method for solubilisation and subsequent refolding to restore conformation and activity. The refolded APs both showed a distinct substrate preference for H-Ala-AMC, an optimum pH of 8.0, puromycin-sensitivity, inhibition by bestatin and amastatin, and cytoplasmic localisation. The two APs are expressed in procyclic metacyclic and bloodstream form parasites. Down-regulation of both APs by RNAi resulted in a slightly reduced growth rate in procyclic parasites in vitro. 相似文献
868.
Fangyu Zhou Andrew Kroetsch Vyncent P. Nguyen Xiao Huang Ogechi Ogoke Natesh Parashurama Sheldon Park 《Biotechnology journal》2019,14(5)
Direct chemical labeling of antibody produces molecules with poorly defined modifications. Use of a small antibody‐binding protein as an adapter can simplify antibody functionalization by forming a specific antibody‐bound complex and introducing site‐specific modifications. To stabilize a noncovalent antibody complex that may be used without chemical crosslinking, a bivalent antibody‐binding protein is engineered with an improved affinity of interaction by joining two Z domains with a conformationally flexible linker. The linker is essential for the increase in affinity because it allows simultaneous binding of both domains. The molecule is further circularized using a split intein, creating a novel adapter protein (“lasso”), which binds human immunoglobulin G1 (IgG1) with K D = 0.53 n m and a dissociation rate that is 55‐ to 84‐fold slower than Z. The lasso contains a unique cysteine for conjugation with a reporter and may be engineered to introduce other functional groups, including a biotin tag and protease recognition sequences. When used in enzyme‐linked immunosorbent assay (ELISA), the lasso generates a stronger reporter signal compared to a secondary antibody and lowers the limit of detection by 12‐fold. The small size of the lasso and a long half‐life of dissociation make the peptide a useful tool in antibody detection and immobilization. 相似文献
869.
870.
《Cell reports》2020,30(7):2106-2114.e5