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111.
Seed dispersal, habitat suitability and the distribution of halophytes across a salt marsh tidal gradient 总被引:15,自引:4,他引:11
Tatyana A. Rand 《Journal of Ecology》2000,88(4):608-621
112.
Excess amino acid polymorphism in mitochondrial DNA: contrasts among genes from Drosophila, mice, and humans 总被引:10,自引:3,他引:10
Recent studies of mitochondrial DNA (mtDNA) variation in mammals and
Drosophila have shown an excess of amino acid variation within species
(replacement polymorphism) relative to the number of silent and replacement
differences fixed between species. To examine further this pattern of
nonneutral mtDNA evolution, we present sequence data for the ND3 and ND5
genes from 59 lines of Drosophila melanogaster and 29 lines of D. simulans.
Of interest are the frequency spectra of silent and replacement
polymorphisms, and potential variation among genes and taxa in the
departures from neutral expectations. The Drosophila ND3 and ND5 data show
no significant excess of replacement polymorphism using the
McDonald-Kreitman test. These data are in contrast to significant
departures from neutrality for the ND3 gene in mammals and other genes in
Drosophila mtDNA (cytochrome b and ATPase 6). Pooled across genes, however,
both Drosophila and human mtDNA show very significant excesses of amino
acid polymorphism. Silent polymorphisms at ND5 show a significantly higher
variance in frequency than replacement polymorphisms, and the latter show a
significant skew toward low frequencies (Tajima's D = -1.954). These
patterns are interpreted in light of the nearly neutral theory where mildly
deleterious amino acid haplotypes are observed as ephemeral variants within
species but do not contribute to divergence. The patterns of polymorphism
and divergence at charge-altering amino acid sites are presented for the
Drosophila ND5 gene to examine the evolution of functionally distinct
mutations. Excess charge-altering polymorphism is observed at the carboxyl
terminal and excess charge-altering divergence is detected at the amino
terminal. While the mildly deleterious model fits as a net effect in the
evolution of nonrecombining mitochondrial genomes, these data suggest that
opposing evolutionary pressures may act on different regions of
mitochondrial genes and genomes.
相似文献
113.
Osbel Almora Derya Baran Guillermo C. Bazan Carlos I. Cabrera Sule Erten-Ela Karen Forberich Fei Guo Jens Hauch Anita W. Y. Ho-Baillie T. Jesper Jacobsson Rene A. J. Janssen Thomas Kirchartz Nikos Kopidakis Maria A. Loi Richard R. Lunt Xavier Mathew Michael D. McGehee Jie Min David B. Mitzi Mohammad K. Nazeeruddin Jenny Nelson Ana F. Nogueira Ulrich W. Paetzold Barry P. Rand Uwe Rau Henry J. Snaith Eva Unger Lídice Vaillant-Roca Chenchen Yang Hin-Lap Yip Christoph J. Brabec 《Liver Transplantation》2023,13(1):2203313
Following the 2nd release of the “Emerging PV reports,” the best achievements in the performance of emerging photovoltaic devices in diverse emerging photovoltaic research subjects are summarized, as reported in peer-reviewed articles in academic journals since August 2021. Updated graphs, tables, and analyses are provided with several performance parameters, e.g., power conversion efficiency, open-circuit voltage, short-circuit current density, fill factor, light utilization efficiency, and stability test energy yield. These parameters are presented as a function of the photovoltaic bandgap energy and the average visible transmittance for each technology and application, and are put into perspective using, e.g., the detailed balance efficiency limit. The 3rd installment of the “Emerging PV reports” extends the scope toward triple junction solar cells. 相似文献
114.
In vitro immunization of human lymphocytes. I. Production of human monoclonal antibodies against bombesin and tetanus toxoid 总被引:1,自引:0,他引:1
M K Ho N Rand J Murray K Kato H Rabin 《Journal of immunology (Baltimore, Md. : 1950)》1985,135(6):3831-3838
A procedure for in vitro sensitization of human lymphocytes against bombesin conjugated to tetanus toxoid (BTT) is described. Bombesin is a tetradecapeptide associated with small cell lung carcinoma. We found that antibody responses against bombesin as well as tetanus toxoid could be generated in vitro by culturing nylon-separated human splenic lymphocytes for 6 days with lipopolysaccharide, phytohemagglutinin-activated lymphocyte supernatants, human AB serum, and bombesin conjugated to tetanus toxoid. Cells sensitized by this procedure were fused to murine myeloma cells, NS-1. The specificities of resulting hybrids were analyzed by enzyme-linked immunoassays and competitive inhibition experiments. Hybrids secreting anti-bombesin (IgM) or anti-tetanus toxoid (IgM or IgG) were obtained. The ratio of IgG to IgM antibodies against tetanus toxoid could be increased by using antigen coupled to Sepharose beads. The sensitization procedure described here offers a system for the study of antigenic stimulation of human B lymphocytes in vitro and for the production of human monoclonal antibodies with the desired specificities. 相似文献
115.
Michael A. Fusella Alyssa N. Brigeman Matthew Welborn Geoffrey E. Purdum Yixin Yan Richard D. Schaller YunHui L. Lin Yueh‐Lin Loo Troy Van Voorhis Noel C. Giebink Barry P. Rand 《Liver Transplantation》2018,8(9)
Organic photovoltaic cells possess desirable practical characteristics, such as the potential for low‐cost fabrication on flexible substrates, but they lag behind their inorganic counterparts in performance due in part to fundamental energy loss mechanisms, such as overcoming the charge transfer (CT) state binding energy when photogenerated charge is transferred across the donor/acceptor interface. However, recent work has suggested that crystalline interfaces can reduce this binding energy due to enhanced CT state delocalization. Solar cells based on rubrene and C60 are investigated as an archetypal system because it allows the degree of crystallinity to be moldulated from a highly disordered to highly ordered system. Using a postdeposition annealing method to transform as‐deposited amorphous rubrene thin films into ones that are highly crystalline, it is shown that the CT state of a highly crystalline rubrene/C60 heterojunction undergoes extreme delocalization parallel to the interface leading to a band‐like state that exhibits a linear Stark effect. This state parallels the direct charge formation of inorganic solar cells and reduces energetic losses by 220 meV compared with 12 other archetypal heterojunctions reported in the literature. 相似文献
116.
Patients who had received obesity surgery (n=144) and comparison adults (n=72) selected the most attractive male and female size and the samesex size they most wanted to look like from an array of 15 outline drawings. Subjects also reported their height, and current and desired weights (transformed into body mass index units [BMI]). There was a remarkable consensus on the sizes considered most attractive: Two male sizes were chosen by 78% of all subjects, and two female sizes by 83%. The hypothesis that adults who had obesity surgery would idealize thin sizes and, therefore, select thinner sizes and lower weights than comparison adults was not supported. Not only did patients and comparison adults selecte the same desired size, but women patients desired significantly larger BMIs than comparison women. There was a large range of desired BMIs associated with each desired size; the correlation between desired BMI and desired size was significant for women but not for men. It was speculated that subjects' desired size reflected cultural norms while subjects' desired BMI was a function of their current weight. Health professionals working in weight loss and/or physical fitness areas need to help clients understand weight-size relationships so that clients can have both realistic weight and realistic size goals. 相似文献
117.
Colleen S. W. Rand Jaquelyn L. Resnick Roberta S. Seldmant 《Obesity (Silver Spring, Md.)》1997,5(5):425-429
RAND, COLLEEN SW, JAQUELYN L RESNICK, ROBERTA S SELDMAN. Assessment of socially acceptable body sizes by university students. The objective of this study was to determine if more than one body size (the ideal) is considered socially acceptable. Two hundred undergraduates rated ideal male and female sizes, all socially acceptable male and female sizes, and their own current and desired sizes. Stimuli were arrays of nine outline drawings illustrating extremely thin to very fat male and female sizes. Most students considered three of nine sizes socially acceptable. There was high consensus on the sizes considered ideal. Although nearly three-quarters of women and half of men desired to be a different size, most considered their current size socially acceptable for other people. The results clearly demonstrate the existence of a range of socially acceptable male and female body sizes. The current size of most students was within this range. Exclusive focus on ideal body size distorts understanding of both other-size and own-size evaluations. 相似文献
118.
119.
This study examined adaptive changes of eye-hand coordination during a visuomotor rotation task under the use of terminal visual feedback. Young adults made reaching movements to targets on a digitizer while looking at targets on a monitor where the rotated feedback (a cursor) of hand movements appeared after each movement. Three rotation angles (30°, 75° and 150°) were examined in three groups in order to vary the task difficulty. The results showed that the 30° group gradually reduced direction errors of reaching with practice and adapted well to the visuomotor rotation. The 75° group made large direction errors of reaching, and the 150° group applied a 180° reversal shift from early practice. The 75°and 150° groups, however, overcompensated the respective rotations at the end of practice. Despite these group differences in adaptive changes of reaching, all groups gradually adapted gaze directions prior to reaching from the target area to the areas related to the final positions of reaching during the course of practice. The adaptive changes of both hand and eye movements in all groups mainly reflected adjustments of movement directions based on explicit knowledge of the applied rotation acquired through practice. Only the 30° group showed small implicit adaptation in both effectors. The results suggest that by adapting gaze directions from the target to the final position of reaching based on explicit knowledge of the visuomotor rotation, the oculomotor system supports the limb-motor system to make precise preplanned adjustments of reaching directions during learning of visuomotor rotation under terminal visual feedback. 相似文献
120.
Richard C. Pinnell Rand K. Almajidy Robert D. Kirch Jean C. Cassel Ulrich G. Hofmann 《PloS one》2016,11(2)
With the continued miniaturisation of portable embedded systems, wireless EEG recording techniques are becoming increasingly prevalent in animal behavioural research. However, in spite of their versatility and portability, they have seldom been used inside water-maze tasks designed for rats. As such, a novel 3D printed implant and waterproof connector is presented, which can facilitate wireless water-maze EEG recordings in freely-moving rats, using a commercial wireless recording system (W32; Multichannel Systems). As well as waterproofing the wireless system, battery, and electrode connector, the implant serves to reduce movement-related artefacts by redistributing movement-related forces away from the electrode connector. This implant/connector was able to successfully record high-quality LFP in the hippocampo-striatal brain regions of rats as they undertook a procedural-learning variant of the double-H water-maze task. Notably, there were no significant performance deficits through its use when compared with a control group across a number of metrics including number of errors and speed of task completion. Taken together, this method can expand the range of measurements that are currently possible in this diverse area of behavioural neuroscience, whilst paving the way for integration with more complex behaviours. 相似文献