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891.
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893.
Rebecca A. Fox Timothy C. Roth II Lara D. LaDage Vladimir V. Pravosudov 《Developmental neurobiology》2010,70(7):538-547
Brain plasticity and adult neurogenesis may play a role in many ecologically important processes including mate recognition, song learning and production, and spatial memory processing. In a number of species, both physical and social environments appear to influence attributes (e.g., volume, neuron number, and neurogenesis) of particular brain regions. The hippocampus in particular is well known to be especially sensitive to such changes. Although social grouping in many taxa includes the formation of male and female pairs, most studies of the relationship between social environment and the hippocampus have typically considered only solitary animals and those living in same‐sex groups. Thus, the aim of this study was to compare the volume of the hippocampal formation, the total number of hippocampal neurons, and the number of immature neurons in the hippocampus (as determined by doublecortin expression) in mountain chickadees (Poecile gambeli) housed in groups of males and females, male–female pairs, same sex pairs of either males or females, and as solitary individuals. The different groups were visually and physically, but not acoustically, isolated from each other. We found no significant differences between any of our groups in hippocampal volume, the total number of hippocampal neurons, or the number of immature neurons. Our results thus provided no support to the hypothesis that social group composition and/or size have an effect on hippocampal morphology and neurogenesis. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 70:538–547, 2010 相似文献
894.
Adriana Gousterova Maya Nustorova Plamen Christov Peter Nedkov Georgi Neshev Evgenia Vasileva-Tonkova 《World journal of microbiology & biotechnology》2008,24(11):2647-2652
A biotechnological procedure based on alkaline hydrolysis has been developed for effective processing of various types industrial
animal wastes to convert them into a low cost high value biodegradable end product. It was demonstrated in laboratory scale
experiments that the bioproduct obtained positively influenced microbial soil populations and ryegrass growth in both soils
used, park soil and mine spoils. As the remaining partially degraded waste residue is highly dispersed it should act as a
slow release fertilizer, thus feeding plants additionally. Therefore, the protein hydrolysate obtained is suitable for application
as a harmless and valuable biofertilizer. The proposed method for solubilization of proteinaceous wastes is simple and economically
viable making its implementation easier on an industrial scale. Therefore, the method could be of great help to the enterprises
of the meat industry, avoiding using landfills and incineration. 相似文献
895.
H. Thomas Foster II Bryan Black Marc D. Abrams 《Human ecology: an interdisciplinary journal》2004,32(1):27-47
Witness tree data from the southeastern United States (lat 33°30' N, long 86°30' W) were analyzed using catchment and distance analysis to quantify the effects of Native American settlement on the composition of forest trees. Thirty Creek Indian villages comprising 18 settlement catchments were included in the sample, which is the largest Native American–forest interaction study using witness trees to date. Lower frequencies of Pinus spp. were observed within village catchments of the Coastal Plain and Ridge and Valley. Elevated frequencies of early succession species were observed surrounding 2 km village catchments. Distance analysis at two relatively isolated towns showed that Pinus increases in frequency beyond 2000 m from villages while Carya had the opposite result. Field and fruit species were more frequent within 6000 m of villages and then dropped off in frequency. Fire-sensitive tree species appear to be in a spatially cyclical pattern. 相似文献
896.
Alvin F. Reeves II 《American journal of botany》1977,64(2):186-189
A new trichome type for the genus Lycopersicon is described in L. esculentum Mill. It is a short (0.03–0.08 mm), pendant, glandular hair with a club-shaped head consisting of 8–12 cells. Two previously described “hairless” mutations were examined microscopically. One, hl, does not affect the frequency of hairs nor the number of cells per hair, but causes abnormal enlargement of the stalk cells of all hair types, and thus produces shortened, extremely bent and twisted hairs. Observations on the time of action of this gene indicate that in trichome development two to four cell divisions occur prior to any appreciable cell enlargement. The second mutation, h, affects only the large type of trichome. This mutation effects a developmental shift from trichome to stomatal apparatus at the apex of the multicellular base normally supporting the large trichomes. 相似文献
897.
Summary Development of the plurilocular male gametangium inCutleria hancockii Dawson is fundamentally similar to that of the female gametangium. However, the sequence of mitoses is less regular and the number of divisions is more variable in the male structure. During mitosis the nucleolus disappears and the nuclear envelope breaks down into vesicles and cisternae. No well-defined chromosomal kinetochores were observed. The spindle does not persist during telophase. At least two types of vesicles, but no microtubules, are associated with cytokinesis. After cleavages are completed, each of the cells develops an eyespot and two flagella. The flagellar rootlet system consists of 4–5 bands of 5–10 microtubules radiating posteriorly from the basal bodies. Flocculent material surrounding the gamete at maturity may be involved with liberation. Prior to release, a pore is formed in each locule when the outermost layers of the surficial wall break, and the innermost layers expand out through this weakened region. The inner wall eventually bursts, releasing the gamete and flocculent material through the pore. The liberated gamete has a long, pleuronematic anterior flagellum, and a short, acronematic posterior flagellum which has a swollen base appressed to the plasmalemma. 相似文献
898.
Summary Microorganisms have evolved enzymes which catalyze a large number of reactions in the sequences to form essential cellular constituents and liberate energy and carbon for cellular processes. Regulation of the use of energy and of the monomeric cellular precursors to the synthesis of those enzymes required under changing environmental conditions depends on the one hand on the level of end products of a reaction sequence and on the other upon the presence of the first, or early members of a reaction sequence. These cases in turn represent product repression and substrate, or substrate like, induction of enzyme formation. Though the repression system has generally been considered to operate in anabolic and the induction system in catabolic processes, the experiments presented demonstrate a role for both types of control in formation of biosynthetic and peripheral pathway enzymes. The induction of biosynthetic enzymes is shown in Pseudomonas putida, and organism with three clusters of genes for the tryptophan pathway. The repression of degradative enzymes is shown in an extended pathway of peripheral oxidation of terpenoid compounds. The enzymes for steps following conversion of neutral to non-essential acidic products are repressed as well as enzymes beyond convergence with isobutyrate formation and conversion to the succinyl and propionyl intermediates.Dedicated to C. B. van Niel on the occasion of his 70th birthday. Supported in part by grant G24037 from the National Science Foundation. 相似文献
899.
M. A. Matsche K. M. Rosemary H. M. Brundage III J. C. O'Herron II 《Zeitschrift fur angewandte Ichthyologie》2013,29(1):6-14
The effects of gender, maturity, intersex condition and annual and seasonal variability were studied on hematology and plasma chemistry of wild shortnose sturgeon Acipenser brevirostrum from the Delaware River. A total of 68 fish were captured by gill net and examined in May‐June, and 61 additional fish were captured and examined in November during 2006–2011. Total leukocyte counts (WBC), leukogram, PCV and the plasmatic concentrations of 13 biochemical analytes were measured from these fish using standard clinical methods. Season and gender had no effect on hematologic indices, but PCV was inversely related to maturity of fish (robust intervals: 27–40% in immature fish, 21–36% in mature fish). Significant annual variation was detected in eosinophil (annual range in robust interval: 0–1176 lower limit, 670–7882 upper limit) and monocyte (0–210 lower limit, 560–1980 upper limit) counts (cells μl?1). The lower limit of the robust interval varied annually by as much as 6% for sodium and 12% for chloride, while the upper limit of the robust interval varied annually by as much as 8% for sodium and 15% for chloride. Seasonal differences in mean sodium and chloride (6–7% higher in autumn) and proteins (5–13% higher in autumn) may reflect environmentally induced changes in osmoregulation, while aspartate aminotransferase was 38–55% higher in the spring. In females, calcium and total protein were highest in mature fish (robust intervals: 10.5–22.1 mg dl?1 Ca2+, 4.1–6.9 g dl?1 TP) compared to immature (7.3–16.9 mg dl?1 Ca2+, 2.8–5.2 g dl?1 TP) and developing fish (7.8–18.9 mg dl?1 Ca2+, 3.2–5.6 g dl?1 TP), indicating changes associated with vitellogenesis. Glucose was significantly higher in females (robust interval: 23–167 mg dl?1) than males (35–138 mg dl?1), possibly indicating gender‐based differences in energetic requirements. Intersex condition was associated with lowered glucose, potassium and creatinine phosphokinase. Reference intervals reported here are useful for evaluating the health and physiological condition of shortnose sturgeon. 相似文献
900.
Jamon Alex Halvaksz II 《Anthropological Forum》2013,23(2):142-157
This paper considers the relationship between persons, land and food as seen in the sociality of public gatherings and gardening spaces. For Biangai speakers in the Upper Bulolo Valley of Morobe Province (Papua New Guinea), intimacies of place are often read through the work of tending to the land, the symbolic association of crops and people as well as rituals where male and female persons are made. By examining the intersection of taste and place in a public multi-language gathering, the paper offers a critical assessment of the French concept of le goût du terroir, or the taste of place, suggesting that tastes matter substantially in defining intergroup sociality. The paper reveals the significance of terroir for organising and strengthening group identity in Papua New Guinea, and its problematic extension to ideas of national foodviews. Ultimately, it is argued that such grounding informs how Biangai imagine the nation and its public places. 相似文献