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191.
Artificial endosperm of Cleopatra tangerine zygotic embryos: a model for somatic embryo encapsulation 总被引:1,自引:0,他引:1
Nieves Nadina Lorenzo Jose C. Blanco Maria de los A. González Justo Peralta Hipólito Hernández Martha Santos Ramón Concepción Oscar Borroto Carlos G. Borroto Eduviges Tapia Raúl Martinez Marcos E. Fundora Zaida González Alfredo 《Plant Cell, Tissue and Organ Culture》1998,54(2):77-83
Synthetic seed technology may be of value in breeding programs and allow the propagation of many elite genotype-derived plants
in a short time. In this work, a range of artificial endosperm treatments of Cleopatra tangerine zygotic embryos were evaluated
for suitability for encapsulation of somatic embryos. Different complexing ions in the form of alginate capsules, zeolite
as an ion exchanger and the relationship between capsule-nutrient gel on germination of zygotic embryos, were evaluated. Artificial
endosperm assays showed that abscisic acid (1 μM) and mannitol (0.25 M) delayed germination and conversion of zygotic embryos,
whereas amino acid supplements (proline, glutamic acid and arginine) accelerated the conversion process. An artificial endosperm
was used to encapsulate somatic and zygotic embryos. After encapsulation, zygotic embryos germinated after four days of culture
while somatic embryos germinated asynchronously after 20 days. Somatic embryo-derived plantlets showed greater vigour than
zygotic embryo-derived plantlets. Results showed that this artificial endosperm is adequate for Cleopatra tangerine somatic
embryo germination and conversion into plants.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
192.
193.
Martha P. Brown Dimitri Toptygin K. B. Lee Theresa Animashaun R. C. Hughes Y. C. Lee Ludwig Brand 《Journal of Protein Chemistry》1998,17(2):149-159
The plant lectin Tetracarbidium conophorum agglutinin II binds to glycoproteins and glycopeptides in a structurally specific manner [Animashaun et al., (1994) Glycoconjugate J.
11, 299–303]. We have characterized the steady-state and time-resolved fluorescence of the tryptophan residues of this lectin. The fluorescence (ex = 295 nm, em = 350 nm) decay is complex and can be described by four decay times with the following values: 1 = 7.4nsec, 1 = 0.22; 2 = 2.9 nsec, 2 = 0.25; 3 = l.0 nsec, 3 = 0.34; 4 = 0.2 nsec, 4 = 0.18. The addition of a biantennary glycopeptide
to the lectin results in a quench and an 8 nm blue shift of the emission spectrum. The effect is saturable, and is described by an association constant of 1.8×105 M–1. The tryptophan fluorescence of Tetracarbidium conophorum agglutinin II may therefore be utilized to characterize thermodynamically the binding interactions between this lectin and complex glycoprotein. 相似文献
194.
William Vernier Wesley Chong David Rewolinski Samantha Greasley Thomas Pauly Morena Shaw Dac Dinh Rose Ann Ferre Seiji Nukui Martha Ornelas Eric Reyner 《Bioorganic & medicinal chemistry》2010,18(9):3307-3319
A novel series of potent thioether benzenesulfonamide inhibitors of carbonic anhydrases II and IV was discovered using structure-based drug design. Synthesis, structure–activity relationship, and optimization of physicochemical properties are described. Low nanomolar potency was achieved, and selected compounds with improved thermodynamic solubility showed promising in vitro inhibition of carbonic anhydrase activity in rabbit iris ciliary body homogenate. 相似文献
195.
Gloria Puerto Lina Erazo Maira Wintaco Claudia Castro Wellman Ribón Martha Inírida Guerrero 《PloS one》2015,10(6)
Introduction
Tuberculosis (TB) remains a primary public health problem worldwide. The number of multidrug-resistant tuberculosis (MDR TB) cases has increased in recent years in Colombia. Knowledge of M. tuberculosis genotypes defined by spoligotyping can help determine the circulation of genotypes that must be controlled to prevent the spread of TB.Objective
To describe the genotypes of M. tuberculosis using spoligotyping in resistant and drug-sensitive isolates and their possible associations with susceptibility to first-line drugs.Methods
An analytical observational study was conducted that included 741 isolates of M. tuberculosis from patients. The isolates originated from 31 departments and were obtained by systematic surveillance between 1999 and 2012.Results
In total 61.94% of the isolates were resistant to 1 or more drugs, and 147 isolates were MDR. In total, 170 genotypes were found in the population structure of Colombian M. tuberculosis isolates. The isolates were mainly represented by four families: LAM (39.9%), Haarlem (19%), Orphan (17%) and T (9%). The SIT42 (LAM 9) was the most common genotype and contained 24.7% of the isolates, followed by the genotypes SIT62 (Haarlem1), SIT53 (T1), and SIT50 (H3). A high clustering of isolates was evident with 79.8% of the isolates classified into 32 groups. The Beijing family was associated with resistant isolates, whereas the Haarlem and T families were associated with sensitive isolates. The Haarlem family was also associated with grouped isolates (p = 0.031).Conclusions
A high proportion (approximately 80%) of isolates was found in clusters; these clusters were not associated with resistance to first-line drugs. The Beijing family was associated with drug resistance, whereas the T and Haarlem families were associated with susceptibility in the Colombian isolates studied. 相似文献196.
197.
198.
Nazneen N. Dewji S. Jonathan Singer Eliezer Masliah Edward Rockenstein Mihyun Kim Martha Harber Taylor Horwood 《PloS one》2015,10(4)
β-Amyloid (Aβ) accumulation in the brain is widely accepted to be critical to the development of Alzheimer’s disease (AD). Current efforts at reducing toxic Aβ40 or 42 have largely focused on modulating γ-secretase activity to produce shorter, less toxic Aβ, while attempting to spare other secretase functions. In this paper we provide data that offer the potential for a new approach for the treatment of AD. The method is based on our previous findings that the production of Aβ from the interaction between the β-amyloid precursor protein (APP) and Presenilin (PS), as part of the γ-secretase complex, in cell culture is largely inhibited if the entire water-soluble NH2-terminal domain of PS is first added to the culture. Here we demonstrate that two small, non-overlapping water-soluble peptides from the PS-1 NH2-terminal domain can substantially and specifically inhibit the production of total Aβ as well as Aβ40 and 42 in vitro and in vivo in the brains of APP transgenic mice. These results suggest that the inhibitory activity of the entire amino terminal domain of PS-1 on Aβ production is largely focused in a few smaller sequences within that domain. Using biolayer interferometry and confocal microscopy we provide evidence that peptides effective in reducing Aβ give a strong, specific and biologically relevant binding with the purified ectodomain of APP 695. Finally, we demonstrate that the reduction of Aβ by the peptides does not affect the catalytic activities of β- or γ-secretase, or the level of APP. P4 and P8 are the first reported protein site-specific small peptides to reduce Aβ production in model systems of AD. These peptides and their derivatives offer new potential drug candidates for the treatment of AD. 相似文献
199.
Martha L. Carvour Jerald P. Harms Charles F. Lynch Randall R. Mayer Jeffery L. Meier Dawei Liu James C. Torner 《PloS one》2015,10(6)
Objectives
Neurologic complications of human immunodeficiency virus (HIV) infection and acquired immune deficiency syndrome (AIDS) frequently lead to disability or death in affected patients. The aim of this study was to determine whether survival patterns differ between men and women with HIV/AIDS-related neurologic disease (neuro-AIDS).Methods
Retrospective cohort data from a statewide surveillance database for HIV/AIDS were used to characterize survival following an HIV/AIDS-related neurologic diagnosis for men and women with one or more of the following conditions: cryptococcosis, toxoplasmosis, primary central nervous system lymphoma, progressive multifocal leukoencephalopathy, and HIV-associated dementia. A second, non-independent cohort was formed using university-based cases to confirm and extend the findings from the statewide data. Kaplan-Meier analysis was used to compare the survival experiences for men and women in the cohorts. Cox regression was employed to characterize survival while controlling for potential confounders in the study population.Results
Women (n=27) had significantly poorer outcomes than men (n=198) in the statewide cohort (adjusted hazard ratio=2.31, 95% CI: 1.22 to 4.35), and a similar, non-significant trend was observed among university-based cases (n=17 women, 154 men). Secondary analyses suggested that this difference persisted over the course of the AIDS epidemic and was not attributable to differential antiretroviral therapy responses among men and women.Conclusions
The survival disadvantage of women compared to men should be confirmed and the mechanisms underlying this disparity elucidated. If this relationship is confirmed, targeted clinical and public health efforts might be directed towards screening, treatment, and support for women affected by neuro-AIDS. 相似文献200.