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941.
Depth of edge influence of the agricultural-forest landscape boundary,Southwestern China 总被引:2,自引:0,他引:2
The landscape boundary is an important component of a landscape and often plays an indispensable role in regulating ecological
flows. The primary objective of this study was to estimate how far the edge effects on agricultural-forest landscape boundaries
can penetrate into the forest and agricultural field. This will serve as a basis for understanding the interaction between
forest and agricultural fields in the mountainous area of southwestern China and provide scientific basis for the practice
of the policy of “returning agricultural field to forest.” Based on field investigations, three types of boundaries with six
sampling transects were selected. We investigated the soil moisture, soil nutrients and vegetation diversity along the transect
gradient and explored the depth of edge influence (DEI) with moving split-window techniques for analyzing the data. DEI for
soil moisture changed with the seasons, ranging from 6 m in the pepper field to 2 m in the forest during the dry season, and
from 12 m in the pepper field to 2 m in the forest after heavy rain. DEI based on soil organic matter ranged from 1.5 to 10 m
in the forest field, while it was not detected based on other soil nutrient factors. DEI based on vegetation diversity varied
from 4 to 26 m and from 10 to 31 m in the forest and agricultural fields, respectively. These results provide the scientific
basis for the policy “returning agricultural field to forest”. Based on these field observations, reducing human disturbance
and revegetating with natural shrubs and meadows could be more effective for vegetation conservation in terms of soil moisture
and soil nutrient content in the arid valley of the Minjiang River. 相似文献
942.
A study was performed to validate 3 FMDV 3ABC-I-ELISA kits developed in China for the differentiation of FMDV infected and vaccinated animals. Sets of sera from naive and vaccinated cattle as well as from cattle that had been infected were tested for antibodies against nonstructural proteins (NSPs) of FMDV by commercial diagnosis kits, Ceditest® FMDV-NS (Ceditest® kit), UBI® FMDV NONSTRUCTURAL PROTEIN ELISA DIRECTION INSERT (UBI® kit) and a FMDV 3ABC-I-ELISA kit developed at the Lanzhou Veterinary Research Institute. The test parameters (sensitivity and specificity) of the three kits were determined, and the result obtained from FMD 3ABC-I-ELISA kit was compared with that obtained from two foreign kits. The results indicated that the coincidence rate between the FMDV 3ABC-I-ELISA and Ceditest® kits was 98.05%, and the coincidence rate between the FMDV 3ABC-I-ELISA and UBI® kits was 94.4%; the sensitivity of both Ceditest® and FMDV 3ABC-I-ELISA kit was 100%. However, the sensitivity of the UBI® kit was only 81.8%. With sera from naive or vaccinated non-infected animals, the specificity of all tests exceeded 90%. 相似文献
943.
Pierre-Paul Lizotte Lana E Hanford Jan J Enghild Eva Nozik-Grayck Brenda-Louise Giles Tim D Oury 《BMC developmental biology》2007,7(1):15
Background
The receptor for advanced glycation end products (mRAGE) is associated with pathology in most tissues, while its soluble form (sRAGE) acts as a decoy receptor. The adult lung is unique in that it expresses high amounts of RAGE under normal conditions while other tissues express low amounts normally and up-regulate RAGE during pathologic processes. We sought to determine the regulation of the soluble and membrane isoforms of RAGE in the developing lung, and its expression under hyperoxic conditions in the neonatal lung. 相似文献944.
Bilayer films prepared by the lamination of fish gelatin film (GF) and its corresponding emulsified film (EF) with different thickness ratios (7:3, 5:5 and 3:7) were characterized. Bilayer films had the similar tensile strength (TS) to EF (p > 0.05) but showed lower elongation at break (EAB) (p < 0.05). All bilayer films showed the lower water vapor permeability (WVP) but higher oxygen permeability (OP) than GF. Bilayer films had varying ΔE* (total color different), where the highest value was observed in that laminated with higher thickness ratio of EF (p < 0.05). Lower light transmission and higher transparency value were obtained for bilayer films, compared to GF (p < 0.05). Based on scanning electron microscopic (SEM) cross-section micrographs, all bilayer films consisted of two layers. Differential scanning calorimetric (DSC) analysis revealed that the bilayer films had the higher glass transition temperature (T g) than GF but lower than EF. All bilayer films were heat sealable, however their seal strength and seal efficiency were lower than those of GF (p < 0.05). Therefore, the thickness ratios of GF and EF had a marked effect on the mechanical and barrier properties as well as heat sealing ability of resulting bilayer films. 相似文献
945.
Yong Cheol Park Tae Hyun Kim Jun Seok Kim 《Biotechnology and Bioprocess Engineering》2017,22(4):431-439
In this study, we determined the effect of organosolv pretreatment on herbaceous biomasses corn stover and wheat straw, by using high-concentration ethanol as the solvent. A high-concentration of ethanol allows for the easy reuse and recycling of the solvent. First, we tested the effects of ethanol pretreatments at 60 and 99.5% (w/w) and found that highest solvent concentration resulted in low glucose digestibility. The maximum enzymatic glucose digestibility with 60% ethanol was 92.6% at 190°C for 120 min (using corn stover) and 86.9% at 190°C for 120 min (using wheat straw). In contrast, the digestion rates with 99.5% ethanol were 68.8 and 77.4% under the same conditions, respectively, indicating that there is a limit to the use of high-concentration ethanol as the solvent. To overcome this limitation, we applied a mechanical pretreatment step before the chemical pretreatment. Subsequently, glucose digestibility increased significantly to 93.1% with 99.5% ethanol as the solvent. Additionally the enzymatic digestibility of mechanically pretreated corn stover was higher than that of non-pretreated corn stover by about 40%. Taken together, these results confirm the efficacy of using high-concentration ethanol as a solvent for organosolv pretreatment when done in conjunction with mechanical pretreatment. 相似文献
946.
Schmidgen H 《Journal of the history of biology》2004,37(3):477-513
This paper addresses the visual culture of late-19th-century experimental physiology. Taking the case of Johann Nepomuk Czermak (1828–1873) as a key example, it argues that images played a crucial role in acquiring experimental physiological skills. Czermak, Emil Du Bois-Reymond (1818–1896) and other late-19th-century physiologists sought to present the achievements and perspective of their discipline by way of immediate visual perception (unmittelbare Anschauung). However, the images they produced and presented for this purpose were strongly mediated. By means of specifically designed instruments, such as the cardioscope, the contraction telegraph, and the frog pistol, and of specifically constructed rooms, so-called spectatoriums, physiologists trained and controlled the perception of their students before allowing them to conduct experiments on their own. Studying the material culture of physiological image production reveals that technological resources such as telegraphy, photography, and even railways contributed to making physiological facts anschaulich. At the same time, it shows that the more traditional image techniques of anatomy played an important role in physiological lecture halls, especially when it came to displaying the details of vivisection experiments to the public. Thus, the images of late 19th century physiology stood half-way between machines and organisms, between books and instruments.This paper was written in the context of ten project, The Experimentalizaiton of Life: Configurations of Life Sciences, Art, and Technology (1830–1930). The project is based at the Max Planck Institute for the History of Science (Dept. III: Hans-Jörg Rheinberger), Berlin, and receives funding from the Volkswagen Stiftung, Hannover. A first draft of this paper was presented, accompanied by Sven Dierig on the Virtual Laboratory, at the Institute of Theater Sciences, Free university Berlin, in December 2000. I would like to thank Sven Dierig and the other members of the project as well as Nick Hopwood, Skúli Sigurdsson and the anonymous referees and the editors of this journal for their helpful comments on an earlier version of this paper. Thanks also to Laurie McLaughlin and Nancy Anderson for helping me with the English version of the text. 相似文献
947.
自身多聚化的SATB1(special AT-rich sequences binding protein 1)围绕异染色质形成笼状结构分布在细胞核中,SATB1不仅结合染色质DNA的核基质结合区(matrix attachment regions,MARs),也结合核基质,能够使DNA锚定在核基质并形成袢环状结构(loop)。SATB1的磷酸化、乙酰化和小泛素化样修饰可调节其DNA结合能力和细胞核内亚结构的定位;SATB1与多种蛋白质相互作用,能够募集染色质重塑复合物和组蛋白修饰酶,实现对其靶基因表达的时空特异性调控。SATB1在调节细胞分化、细胞凋亡、肿瘤生长与转移和X染色体失活等方面起到重要作用,并有可能成为肿瘤转移的治疗靶点。 相似文献
948.
949.
We investigated clonal traits in the dioecious herb Rumex acetosella to characterize sexual dimorphism in clonal forms and to correlate below-ground clonal patterns and above-ground ramet distributions.
We recorded creeping root length, branching patterns, ramet and clump (caespitose ramets from the same position on the root)
sprouting patterns, and biomass allocations in three females and males. We also estimated the patch size of flowering ramets
within a quadrat. No sexual dimorphism was detected in the frequencies of branches and flowering ramets per root length. Male
plants allocated proportionally more biomass to below-ground organs. Total root length did not differ between the sexes. Females
sprouted more clumps with fewer flowering ramets per root length than males, which sprouted fewer clumps with more flowering
ramets, which meant that clump sprouting patterns were phalanx-like in females and guerrilla-like in males. Flowering ramets
were aggregately distributed in both females and males and patch sizes were similar between sexes, indicating that the spreader
propagations were not found in the guerrilla-like males. We assumed that sexual dimorphism occurred in response to physiological
integration for higher reproductive effort in females. 相似文献
950.
This study describes the effect of soil fauna and vegetation on the development of landscapes and how these actually control
soil formation, geomorphological development and hydrological response. The study area is located in a semi-natural deciduous
forest on marl in Luxembourg, with a strong texture contrast in the soil at 15–25 cm depth (luvic planosols).
The methodology applied is both based on hydrological and geomorphological field measurements on runoff, sediment yield, perched
water table dynamics, geomorphological survey, pedological survey and measurements related to in situ ectorganic horizon dynamics
and litter decay, soil animal activity, as well as measurements of dynamic soil properties such as soil moisture and swelling
and shrinkage.
The results show that there is a positive feedback between tree type, soil fauna activity and the development of pipes, partial
areas, soils and geomorphology. The landscape can be divided into two main types: Areas where Stellario-Carpinetum vegetation
and partial areas are common and areas with Milio-Fagetum vegetation on dry slopes, which are differentiating more and more
over time as a result of ongoing geo-ecosystem processes, and which also reflected in their sediment yield. The hydrological
response is highly different for both landscape compartments as they are dominated by matrix (Beech) and pipe flow (Hornbeam)
respectively. Soil fauna and tree type drive both soil and geomorphological evolution and they both can be considered as important
ecosystem engineers. 相似文献