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991.
Airong Li Yue Zhu Xingbing He Xingjun Tian Liang Xu Wu Ni Ping Jiang 《World journal of microbiology & biotechnology》2008,24(4):569-572
Six selected plants, belonging to 3 families from Nanjing of China, were extracted with the solvent 95% (v/v) ethanol to yield
11 extracts. The extracts were evaluated for their effects on the growth of eight clinical bacteria, two fungi and one yeast
using a modified agar diffusion method. The results showed that the majority of the extracts investigated showed greater activities
against the Gram-positive bacteria than against the Gram-negative bacteria, the fungi and the yeast. The strongest antimicrobial
activity was exhibited by the stem extracts of Mahonia fortunei against multiresistant Staphylococcus aureus strains, followed by the stem extracts of Mahonia bealei, while Bacillus thuringiensis was the most sensitive to all extracts. 相似文献
992.
Irina Vaseva Dessislava Todorova Jiří Malbeck Alena Trávníčková Ivana Macháčková 《Acta Physiologiae Plantarum》2008,30(2):151-155
Changes in cytokinin pool and cytokinin oxidase/dehydrogenase activity (CKX EC: 1.5.99.12) in response to increasing abscisic
acid (ABA) concentrations (0.5–10 μM) were assessed in the last fully expanded leaves and secondary roots of two pea (Pisum sativum) varieties with different vegetation periods. Certain organ diversity in CKX response to exogenous ABA was observed. Treatment
provoked altered cytokinin pool in the aboveground parts of both studied cultivars. Specific CKX activity was influenced significantly
basically in roots of the treated plants. Results suggest that ABA-mediated cytokinin pool changes are leaf-specific and involve
certain root signals in which CKX activity presents an important link. This enzymatic activity most probably regulates vascular
transport of active cytokinins from roots to shoots. 相似文献
993.
Woody encroachment into herbaceous ecosystems is emerging as an important ecological response to global change. A primary
concern is alterations in C and N cycling and associated variations across a variety of ecosystems. We quantified seasonal
variation in litterfall and litter N concentration in Morella cerifera shrub thickets to assess changes in litterfall and associated N input after shrub expansion on an Atlantic coast barrier
island. We also used the natural abundance of 15N to estimate the proportion of litterfall N originating from symbiotic N fixation. Litterfall for shrub thickets ranged from
8,991 ± 247 to 3,810 ± 399 kg ha−1 year−1 and generally declined with increasing thicket age. Litterfall in three of the four thickets exceeded previous estimates
of aboveground annual net primary production in adjacent grasslands by 300–400%. Leaf N concentration was also higher after
shrub expansion and, coupled with low N resorption efficiency and high litterfall, resulted in a return of as much as 169 kg N ha−1 year−1 to the soil. We estimated that ∼70% of N returned to the soil was from symbiotic N fixation resulting in an ecosystem input
of between 37 and 118 kg ha−1 year−1 of atmospheric N depending on site. Considering the extensive cover of shrub thickets on Virginia barrier islands, N fixation
by shrubs is likely the largest single source of N to the system. The shift from grassland to shrub thicket on barrier islands
results in a substantial increase in litterfall and foliar N concentration that will likely have a major impact on the size
and cycling of ecosystem C and N pools. Increasing C and N availability in these nutrient-poor soils is likely to permanently
reduce cover of native grasses and alter community structure by favoring species with greater N requirements. 相似文献
994.
Background
Expression Quantitative Trait Locus (eQTL) mapping methods have been used to identify the genetic basis of gene expression variations. To map eQTL, thousands of expression profiles are related with sequence polymorphisms across the genome through their correlated variations. These eQTL distribute in many chromosomal regions, each of which can include many genes. The large number of mapping results produced makes it difficult to consider simultaneously the relationships between multiple genomic regions and multiple expressional profiles. There is a need for informative bioinformatics tools to assist the visualization and interpretation of these mapping results. 相似文献995.
Pascal Philibert Audrey Stoessel Wei Wang Annie-Paule Sibler Nicole Bec Christian Larroque Jeffery G Saven Jérôme Courtête Etienne Weiss Pierre Martineau 《BMC biotechnology》2007,7(1):81
Background
Intrabodies are defined as antibody molecules which are ectopically expressed inside the cell. Such intrabodies can be used to visualize or inhibit the targeted antigen in living cells. However, most antibody fragments cannot be used as intrabodies because they do not fold under the reducing conditions of the cell cytosol and nucleus. 相似文献996.
Background
Little is known regarding the extent or targets of phosphorylation in mycoplasmas, yet in many other bacterial species phosphorylation is known to play an important role in signaling and regulation of cellular processes. To determine the prevalence of phosphorylation in mycoplasmas, we examined the CHAPS-soluble protein fractions of Mycoplasma genitalium and Mycoplasma pneumoniae by two-dimensional gel electrophoresis (2-DE), using a combination of Pro-Q Diamond phosphoprotein stain and 33P labeling. Protein spots that were positive for phosphorylation were identified by peptide mass fingerprinting using MALDI-TOF-TOF mass spectrometry. 相似文献997.
998.
Background
The sensory drive hypothesis predicts that divergent sensory adaptation in different habitats may lead to premating isolation upon secondary contact of populations. Speciation by sensory drive has traditionally been treated as a special case of speciation as a byproduct of adaptation to divergent environments in geographically isolated populations. However, if habitats are heterogeneous, local adaptation in the sensory systems may cause the emergence of reproductively isolated species from a single unstructured population. In polychromatic fishes, visual sensitivity might become adapted to local ambient light regimes and the sensitivity might influence female preferences for male nuptial color. In this paper, we investigate the possibility of speciation by sensory drive as a byproduct of divergent visual adaptation within a single initially unstructured population. We use models based on explicit genetic mechanisms for color vision and nuptial coloration. 相似文献999.
1000.
Elena Taycher Andreas Rolfs Yanhui Hu Dongmei Zuo Stephanie E Mohr Janice Williamson Joshua LaBaer 《BMC bioinformatics》2007,8(1):198