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1.
Dyscalculia, dyslexia, and specific language impairment (SLI) are relatively specific developmental learning disabilities in math, reading, and oral language, respectively, that occur in the context of average intellectual capacity and adequate environmental opportunities. Past research has been dominated by studies focused on single impairments despite the widespread recognition that overlapping and comorbid deficits are common. The present study took an epidemiological approach to study the learning profiles of a large school age sample in language, reading, and math. Both general learning profiles reflecting good or poor performance across measures and specific learning profiles involving either weak language, weak reading, weak math, or weak math and reading were observed. These latter four profiles characterized 70% of children with some evidence of a learning disability. Low scores in phonological short-term memory characterized clusters with a language-based weakness whereas low or variable phonological awareness was associated with the reading (but not language-based) weaknesses. The low math only group did not show these phonological deficits. These findings may suggest different etiologies for language-based deficits in language, reading, and math, reading-related impairments in reading and math, and isolated math disabilities. 相似文献
2.
Mindaugas Tamoinas Emilija V. Plorina Marta Lange Aleksandrs Derjabo Ilona Kuzmina Dmitrijs Bizuks Janis Spigulis 《Journal of biophotonics》2020,13(3)
This clinical study is a first attempt to use autofluorescence for recurrence diagnosis of skin cancer in postoperative scars. The proposed diagnostic parameter is based on a reduction in scar autofluorescence, evaluated in the green spectral channel. The validity of the method has been tested on 110 postoperative scars from 56 patients suspected of non‐melanoma skin cancer, with eight patients (13 scars) available for the repeated examination. The recurrence diagnosis within a scar has been made after two subsequent autofluorescence check‐ups, representing the temporal difference between the scar autofluorescence amplitudes as a vector. The recognition of recurrence has been discussed to represent the significant deviations from the value of vector angle θ. This new autofluorescence‐based method can be easily integrated into the postoperative monitoring of surgical scars and can help diagnose the recurrence of skin cancer from the early stage of scar development. 相似文献
3.
BAY K 8644, a 1,4-Dihydropyridine Ca2+ Channel Activator: Dissociation of Binding and Functional Effects in Brain Synaptosomes 总被引:6,自引:0,他引:6
K+-stimulated 45Ca2+ uptake into rat brain and guinea pig cerebral cortex synaptosomes was measured at 10 s and 90 s at K+ concentrations of 5-75 mM. Net increases in 45Ca2+ uptake were observed in rat and guinea pig brain synaptosomes. 45Ca2+ uptake under resting or depolarizing conditions was not increased by the 1,4-dihydropyridine BAY K 8644, which has been shown to activate Ca2+ channels in smooth and cardiac muscle. High-affinity [3H]nitrendipine binding in guinea pig synaptosomes (KD = 1.2 X 10(-10) M, Bmax = 0.56 pmol mg-1 protein) was competitively displaced with high affinity (IC50 2.3 X 10(-9) M) by BAY K 8644. Thus high-affinity Ca2+ channel antagonist and activator binding sites exist in synaptosome preparations, but their relationship to functional Ca2+ channels is not clear. 相似文献
4.
Interference by Trypsin in the Interaction of Staphylococcal Enterotoxin B and Cell Cultures of Human Embryonic Intestine 总被引:6,自引:1,他引:5 下载免费PDF全文
The inhibitory effect of trypsin on the cytotoxicity of staphylococcal enterotoxin B acting with human embryonic intestine cell cultures was examined. Trypsin treatment of the cells rendered them resistant to enterotoxin for a period of 48 hr. The resistance increased proportionally with increased time of exposure of the cells to trypsin. Neither ethylenediaminetetraacetic acid nor scraping, which were used as alternate means of cell suspension, caused any resistance to the toxin. The effect is enzymatic and appears to be similar to the inhibitory action of trypsin and chymotrypsin on the attachment of polioviruses and coxsackieviruses to HeLa cells. 相似文献
5.
David Crews Judith M. Bergeron James J. Bull Deborah Flores Alan Tousignant James K. Skipper Thane Wibbels 《Genesis (New York, N.Y. : 2000)》1994,15(3):297-312
In many egg-laying reptiles, the incubation temperature of the egg determines the sex of the offspring, a process known as temperature-dependent sex determination (TSD). In TSD sex determination is an “all or none” process and intersexes are rarely formed. How is the external signal of temperature transduced into a genetic signal that determines gonadal sex and channels sexual development? Studies with the red-eared slider turtle have focused on the physiological, biochemical, and molecular cascades initiated by the temperature signal. Both male and female development are active processes—rather than the crganized/default system characteristic of vertebrates with genotypic sex determination—that require simultaneous activation and suppression of testis- and ovary-determining cascades for normal sex determination. It appears that temperature accomplishes this end by acting on genes encoaing for steroidogenic enzymes and steroid hormone receptors and modifying the endocrine microenvironment in the embryo. The temperature experienced in development also has long-term functional outcomes in addition to sex determination. Research with the leopard gecko indicates that incubation temperature as well as steroid hormones serve as organizers in shaping the adult phenotype, with temperature modulating sex hormone action in sexual differentiation. Finally, practical applications of this research have emerged for the conservation and restoration of endangered egg-laying reptiles as well as the embryonic development of reptiles as biomarkers to monitor the estrogenic effects of common environmental contaminants. © 1994 Wiley-Liss, Inc. 相似文献
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7.
Fitness consequences of helping behavior in the western bluebird 总被引:5,自引:4,他引:1
We examined the fitness consequences of helping behavior inthe western bluebird (Sialia mexicana) at Hastings Reservationin Carmel Valley, California, USA, and tested hypotheses forhow helpers benefit from engaging in alloparental behavior.Both juvenile and adult western bluebirds occasionally helpat the nest During a 12 year period, all adult helpers and mostjuvenile helpers were male. Helpers usually fed at nests ofboth their parents and rarely helped when only one parent waspresent. The frequency of pairs with adult helpers was only7%, but nearly one-third of adult males helped among those withboth parents on the study area. At least 28% were breeders whosenests failed. The propensity to help appears to depend uponparental survival, male philopatry, and the breeding successof potential helpers. Feeding rates were not increased at nestswith juvenile helpers, apparendy because breeding males reducedtheir feeding rates. In contrast, adult helpers increased theoverall rates of food delivery to the nest in spite of a reductionin the number of feeding trips made by both male and femaleparents. Helpers did not derive any obvious direct fitness benefitsfrom helping, but they had greater indirect fitness than nonhelpersdue to increases in nestling growth rates and fledging successat their parents' nests. Helpers fledged fewer offspring intheir first nests than did nonhelpers, suggesting that theywere birds with reduced reproductive potential. Although wehave not yet measured the effect of extrapair fertilizationson the fitness benefits of helping, we calculated the differencein fitness between helpers and nonhelpers as a function of thepotential helper's paternity when breeding independently andhis father's paternity in the nest at which he might help. Inconjunction with constraints on breeding and indirect fitnessbenefits, we predict that relatedness of males to the youngin their own as well as their parents' nests will influencehelping behavior in western bluebirds. 相似文献
8.
Specific binding of a calcium channel activator, [3H]BAY k 8644, to membranes from cardiac muscle and brain 总被引:8,自引:0,他引:8
R A Janis D Rampe J G Sarmiento D J Triggle 《Biochemical and biophysical research communications》1984,121(1):317-323
BAY k 8644 is a member of a new class of drugs that directly activates Ca2+ channels. This 1,4-dihydropyridine was found to bind to both high and low affinity sites on rabbit ventricular microsomes and guinea pig brain synaptosomes. The dissociation constant obtained from Scatchard analysis with [3H]BAY k 8644 was 2 to 3 nM for the high affinity binding site, and the estimated maximal number of binding sites was 0.8 and 0.4 pmol/mg protein for heart and brain membranes, respectively, at 15 degrees C. Competition between nitrendipine and [3H]BAY k 8644 indicated a common high affinity binding site for Ca2+ channel activators and antagonists. The results suggest that the 1,4-dihydropyridine Ca2+ channel antagonists do not act as simple channel plugs. 相似文献
9.
10.
Eighteen Adh-negative mutations were selected with 1-pentyn-3-ol after feeding of formaldehyde. Twelve of the 18 were shown by cytological and genetic analysis to be deletions. Cytological examination of the deletions allowed us to localize the Adh gene to a region including bands 35B3-5 on the left arm of chromosome 2. The deletions were also used to order known visible loci located near Adh.--The vital loci near Adh were also investigated. A total of 109 lethal mutations were generated with EMS and 33 of these, localized within a region defined by the overlap of two of the deletions, were found to belong to 13 complementation groups. If one includes three other loci known to belong there (el, Adh and Sco) a total of 16 complemetation groups have been identified in the region close to Adh. 相似文献