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91.
Thermoanaerobacter ethanolicus gen. nov., spec. nov., a new,extreme thermophilic,anaerobic bacterium
Two strains, JW 200 and JW 201, of an extreme thermophilic, non-spore-forming anaerobic bacterium were isolated from alkaline and slightly acidic hot springs located in Yellowstone National Park. Both strains were peritrichously flagellated rods. Cell size varied from 0.5–0.8 by 4–100 m; coccoid-shaped cells of about 1 m in diameter frequently occurred. Division was often unequal. Spheroplast-like forms were visible at the late logarithmic growth phase. The Gram reaction was variable. The DNA base composition of the two strains was between 37 and 39 mol% guanine plus cytosine as determined by buoyant density measurements and approximately 32% by the thermal denaturation method. The main fermentation products from hexoses were ethanol and CO2. Growth occurred between 37 and 78°C and from pH 4.4 to 9.8. The name Thermoanaerobacter ethanolicus gen. nov., spec. nov. was proposed for the two, new isolates. Strain JW 200 was designated as the type strain.A preliminary account of this work was presented at the annual meeting of the American Society for Microbiology, Los Angeles, CA, 1979 (J. Wiegel and L. G. Ljungdahl, Abstr. Annu. Meet. Am. Soc. Microbiol., 1979, 163, p. 105) and at the 27th IUPAC Congress Helsinki, 1979 (L. G. Ljungdahl and J. Wiegel, Abstracts p. 546) 相似文献
92.
The distributions of grains and tracks per cell, as functions of the isotope content in the cell, are basic to all quantitative autoradiography. In this paper a formulation of these distributions in terms of the distribution of grains per disintegration is suggested. An empirical method for evaluating this distribution for various isotopes and various geometrical relationships between source and emulsion is described. The results are used to examine the usefulness of different techniques for double labelling autoradiography. 相似文献
93.
A simple and selective assay for monomeric and filamentous actin is presented, based on the inhibition of DNAase I by actin. In mixtures of monomeric and filamentous actin, only the monomeric form is measured as DNAase inhibitor. The total amount of actin in a sample can be determined after depolymerization of F actin with guanidine hydrochloride. The assay is rapid enough to detect changes in the polymerization state of actin in vitro over time intervals as short as 3 min. Data characterizing unpolymerized and filamentous actin pools in extracts of human platelets, lymphocytes and HeLa cells are presented. 相似文献
94.
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96.
Mass spectrometric measurements of methane and oxygen utilization by methanotrophic bacteria 总被引:3,自引:0,他引:3
Abstract A mass spectrometer with membrane inlet was used to measure methane and oxygen utilization rates at various methane concentrations in Methylosinus trichosporium and a locally isolated strain of a methane-oxidizing coccus (OU-4-1). The apparent K m for methane was found to be 2 μM for M. trichosporium and 0.8 μM for strain OU-4-1. These K m -values are 10–30 times lower than most previously reported values. The ratio of oxygen to methane utilization rates was 1.7 for M. trichosporium and 1.5 for strain OU-4-1 corresponding to a growth yield of 0.38 and 0.63 g dry weight/g methane, respectively. 相似文献
97.
Lars Siln 《Acta zoologica》1982,63(1):25-32
Two principally different wall types occur in the bryozoan colony: Exterior walls delimiting the super-individual, the colony, against its surroundings and interior walls dividing the body cavity of the colony thus defined into units which develop into sub-individuals, the zooids. In the gymnolaemate bryozoans generally, whether uniserial or multiserial, the longitudinal zooid walls are exterior, the transverse (proximal and distal) zooid walls interior ones. The radiating zooid rows grow apically to form “tubes” each surrounded by exterior walls but subdivided by interior (transverse) walls. The stenolaemate bryozoans show a contrasting mode of growth in which the colony swells in the distal direction to form one confluent cavity surrounded by an exterior wall but internally subdivided into zooids by interior walls. In the otherwise typical gymnolaemate Parasmittina trispinosa the growing edge is composed of a series of “giant buds” each surrounded by exterior walls on its lateral, frontal, basal and distal sides and forming an undifferentiated chamber usually 2–3 times as broad and 3 or more times as long as the final zooid. Its lumen is subdivided by interior walls into zooids 2–3, occasionally 4, in breadth. This type of zooid formation is therefore similar to the “common bud” or, better-named, “multizooidal budding” characteristic of the stenoleamates but has certainly evolved independently as a special modification of the usual gymnolaemate budding. 相似文献
98.
99.
Neuropeptide Y modulates the action of vasodilator agents in guinea-pig epicardial coronary arteries
S rgio Gulbenkian Lars Edvinsson Ole Saetrum Opgaard Angela Valen a John Wharton Julia M. Polak 《Regulatory peptides》1992,40(3):351-362
Recently, we have demonstrated that guinea-pig epicardial coronary arteries are supplied by numerous nerve fibres containing neuropeptide Y (NPY) immunoreactivity. However, examination of vasomotor responses revealed that NPY did not elicit a contractile response in these arteries. In contrast, acetylcholine (ACh), calcitonin gene-related peptide (CGRP), substance P and vasoactive intestinal polypeptide (VIP) all relaxed precontracted arteries. In the present study, we have used histochemical, immunohistochemical and in vitro pharmacological techniques, in order to further investigate the possible role of NPY in guinea-pig epicardial coronary arteries. A double-immunofluorescence staining technique revealed that CGRP and substance P were co-localized in nerve fibres distinct from those displaying NPY immunoreactivity. Furthermore, using a method combining immunofluorescence and histochemical techniques, we observed that putative cholinergic nerve fibres (identified by their acetylcholinesterase content) and NPY-immunoreactive nerve fibres are two different nerve populations. An in vitro pharmacological method demonstrated that NPY markedly inhibited the relaxant responses mediated by ACh, VIP, substance P and isoprenaline but had no effect on CGRP. These results suggest that NPY-containing nerves associated with guinea-pig epicardial coronary arteries may be predominantly involved in modulating the action of vasodilator agents. 相似文献
100.
Sulfide-Dependent Methane Production and Growth of a Thermophilic Methanogenic Bacterium 总被引:7,自引:5,他引:2 下载免费PDF全文
Two strains of a thermophilic methanogenic bacterium, designated MT1 a and b, were isolated from a coastal surface sediment in the northern part of the Swedish West Coast. The two strains were identical in appearance and nutritional requirements and resembled Methanobacterium thermoautotrophicum. MT1 had an extraordinary requirement for sulfide. At sulfide levels below 0.1 mM, growth was poor and the methane production rate decreased. Other sources of sulfur, such as cysteine, sulfate, or thiosulfate, could not replace sulfide. The results indicate that a fast turnover rate of reduced sulfur compounds is involved in the energy metabolism of this organism. 相似文献