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881.
Thermotolerance in cultures of Chlorella zofingiensis was induced by heat shock treatment at supraoptimal temperatures (40and
45 °C for 30 min). Thermotolerance was assayed by two methods: the survival of the cells at 70 °C and the growth of diluted
cultures at 35 and 45 °C. A culture without heat shock treatment was unable to grow at 45 °C. According to eletrophoretic
analyses, the synthesis of proteins of 95, 73, 60, 43 and 27 kDa was induced by heat shock treatment. The large molecular
weight proteins (95, 73, 60 and43 kDa) were present in non-heat treated cells, but the heat shock treatment increased their
quantity in cells. The synthesis of a low molecular weight protein (27 kDa) was induced by heat shock treatment. The induced
thermotolerance could be inhibited by the presence of an 80S ribosomal translation inhibitor, cycloheximide(CHI). The first
12 amino acid residues from the N-terminus of the27 kDa heat shock induced protein are Val-Glu-Trp-Try-Gly-Pro-Asn-Arg-Ala-Lys-Phe-Leu.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
882.
Genetic and cytological studies were conducted with a new male-sterile, female-fertile soybean [Glycine max (L.) Merr.] mutant. This mutant was completely male sterile and was inherited as a single-recessive gene. No differences in
female or male gamete transmission of the recessive allele were observed between reciprocal cross-pollinations in the F1 or F2 generations. This mutant was not allelic to any previously identified soybean genic male-sterile mutants: ms1, ms2, ms3, ms4, ms5, or ms6. No linkage was detected between sterility and flower color (W1 locus), or between sterility and pubescence color (T1 locus). Light microscopic and cytological observations of microsporogenesis in fertile and sterile anthers were conducted.
The structure of microspore mother cells (MMC) in male-sterile plants was identical to the MMCs in male-fertile plants. Enzyme
extraction analyses showed that there was no callase activity in male-sterile anthers, and this suggests that sterility was
caused by retention of the callose walls, which normally are degraded around tetrads at the late tetrad stage. The tapetum
from male-sterile anthers also showed abnormalities at the tetrad stage and later stages, which were expressed by an unusual
formation of vacuoles, and by accumulation of densely staining material. At maturity, anthers from sterile plants were devoid
of pollen grains.
Received: 13 May 1996 / Revision accepted: 19 August 1996 相似文献
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Seungdo Kim Taeyoun Hwang Kun M. Lee 《The International Journal of Life Cycle Assessment》1997,2(4):217-222
Allocation in LCA is defined as partitioning the responsibility for environmental burdens from the economic activities to a reference flow or a reference life cycle system in some proper shares. The result of LCA study involving a multi-input/output system or an open loop recycling system is affected significantly by the choice of the allocation method. For the case of allocation in a cascade recycling system, the quality of material as well as the material flow should be considered. Therefore, environmental burdens from the primary material production, the recycling process and the waste management process have to be allocated in proportion to the quality degradation of a material and to the quantity of a material used in each life cycle system. This paper proposes an allocation method for the cascade recycling system that considers both quality and quantity of a material used. 相似文献
886.
We define the species boundaries of white-toothed shrews (genus Crocidura ) in Taiwan using karyological and morphological characteristics. Ninety-nine animals were obtained from all over Taiwan at capture rates usually less than 10%. Three species are recognized by distinct cytotypes: Crocidura attenuata tanakae 2n = 40, FN = 56; Crocidura suaveolens hosletti 2n = 40, FN = 50; Crocidura kurodai 2n = 40, FN = 54. A suite of six morphological characters diagnose the three species: shape of skull, position of incisive foramina, shape of fourth upper premolar, shape of pinna, tail vibrissae, and foot pads. A species key and notes on the life history of each species are provided. Finally, we discuss chromosomal evolution and biolgeography of Crocidura in East and South East Asia. 相似文献
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Identification of three genetic loci controlling leaf senescence in Arabidopsis thaliana 总被引:23,自引:3,他引:20
Sung Aeong Oh Joon-Hyun Park Gyu In Lee Kyung Hee Paek Soon Ki Park Hong Gil Nam 《The Plant journal : for cell and molecular biology》1997,12(3):527-535
Four mutants that show the delayed leaf senescence phenotype were isolated from Arabidopsis thaliana . Genetic analyses revealed that they are all monogenic recessive mutations and fall into three complementation groups, identifying three genetic loci controlling leaf senescence in Arabidopsis . Mutations in these loci cause delay in all senescence parameters examined, including chlorophyll content, photochemical efficiency of photosystem II, relative amount of the large subunit of Rubisco, and RNase and peroxidase activity. Delay of the senescence symptoms was observed during both age-dependent in planta senescence and dark-induced artificial senescence in all of the mutant plants. The results indicate that the three genes defined by the mutations are key genetic elements controlling functional leaf senescence and provide decisive genetic evidence that leaf senescence is a genetically programmed phenomenon controlled by several monogenic loci in Arabidopsis . The results further suggest that the three genes function at a common step of age-dependent and dark-induced senescence processes. It is further shown that one of the mutations is allelic to ein2-1 , an ethylene-insensitive mutation, confirming the role of ethylene signal transduction pathway in leaf senescence of Arabidopsis . 相似文献
890.