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991.
Salek RM Pears MR Cooper JD Mitchison HM Pearce DA Mortishire-Smith RJ Griffin JL 《Journal of biomolecular NMR》2011,49(3-4):175-184
The Neuronal Ceroid Lipofuscinoses (NCL) are a group of fatal inherited neurodegenerative diseases in humans distinguished by a common clinical pathology, characterized by the accumulation of storage body material in cells and gross brain atrophy. In this study, metabolic changes in three NCL mouse models were examined looking for pathways correlated with neurodegeneration. Two mouse models; motor neuron degeneration (mnd) mouse and a variant model of late infantile NCL, termed the neuronal ceroid lipofuscinosis (nclf) mouse were investigated experimentally. Both models exhibit a characteristic accumulation of autofluorescent lipopigment in neuronal and non neuronal cells. The NMR profiles derived from extracts of the cortex and cerebellum from mnd and nclf mice were distinguished according to disease/wildtype status. In particular, a perturbation in glutamine and glutamate metabolism, and a decrease in γ-amino butyric acid (GABA) in the cerebellum and cortices of mnd (adolescent mice) and nclf mice relative to wildtype at all ages were detected. Our results were compared to the Cln3 mouse model of NCL. The metabolism of mnd mice resembled older (6?month) Cln3 mice, where the disease is relatively advanced, while the metabolism of nclf mice was more akin to younger (1-2?months) Cln3 mice, where the disease is in its early stages of progression. Overall, our results allowed the identification of metabolic traits common to all NCL subtypes for the three animal models. 相似文献
992.
Michael A. Gorycki 《Biotechnic & histochemistry》1989,64(4):197-199
The design and properties of a rigid, box-like device to be placed on the knife stage of a Porter-Blum MT-2 ultramicrotome are described. This “superstage” acts as a hand and tool rest, and a wind screen for the knife boat. The superstage easily permits tight rafts of ultrathin sections to be centrally located on grids. Additionally, it aids in placing 1 μm thick sections at the same relative location on glass slides to facilitate their examination in the light microscope. 相似文献
993.
Fatty-acid synthesis has been measured in vivo with3H2O in cafeteria-fed rats exhibiting diet-induced thermogenesis. Synthesis was decreased in brown adipose tissue, the liver, white adipose tissue, and the carcass of the cafeteria-fed animals compared to rats fed the normal stock diet. Whole-body synthesis was also decreased in the cafeteria-fed group. Diet-induced thermogenesis, in contrast to cold-induced non-shivering thermogenesis does not lead to increased fatty-acid synthesis and this is presumably due to the inhibitory effects on lipogenesis of the high dietary fat intake characteristic of cafeteria diets. The results also indicate that the energy cost of body fat deposition in cafeteria-fed rats is lower than in animals fed a low-fat/high-carbohydrate stock diet. 相似文献
994.
Conservation of rice genetic resources: the role of the International Rice Genebank at IRRI 总被引:1,自引:0,他引:1
Rice genetic resources, comprising landrace varieties, modern and obsolete varieties, genetic stocks, breeding lines, and the wild rices, are the basis of world food security. The International Rice Genebank at the International Rice Research Institute in the Philippines conserves the largest and most diverse collection of rice germplasm. The facilities of the genebank ensure the long-term preservation of this important diversity. In field research, factors that affect long-term viability of rice seeds have been identified, leading to the introduction of modified practices for germplasm multiplication and regeneration. The value of conserved germplasm can be assessed in terms of useful traits for rice breeding and the economic impact that germplasm utilization has on rice production and productivity. The application of molecular markers is changing perspectives on germplasm management. International policies affecting access to and use of rice germplasm are discussed. 相似文献
995.
996.
997.
Molecular analysis of Gaucher disease: distribution of eight mutations and the complete gene deletion in 27 patients from Germany 总被引:2,自引:0,他引:2
P. le Coutre A. Demina Ernest Beutler Michael Beck P. E. Petrides 《Human genetics》1997,99(6):816-821
Gaucher disease is the most common lysosomal storage disease with a high prevalence in the Ashkenazi Jewish population but
it is also present in other populations. The presence of eight mutations (1226G, 1448C, IVS2+1, 84GG, 1504T, 1604T, 1342C
and 1297T) and the complete deletion of the β-glucocerebrosidase gene was investigated in 25 unrelated non-Jewish patients
with Gaucher’s disease in Germany. In the Jewish population, three of these mutations account for more than 90% of all mutated
alleles. In addition, relatives of two patients were included in our study. Restriction fragment length polymorphism analysis
and sequencing of PCR products obtained from DNA of peripheral blood leukocytes was performed for mutation analysis. Gene
deletion was detected by comparison of radioactively labelled PCR fragments of both the functional β-glucocerebrosidase gene
and the pseudogene. Among the unrelated patients, 50 alleles were investigated and the mutations identified in 35 alleles
(70%), whereas 15 alleles (30%) remained unidentified. The most prevalent mutation in our group of patients was the 1226G
(370Asn→Ser) mutation, accounting for 18 alleles (36%), followed by the 1448C (444Leu→Pro) mutation, that was found in 12 alleles (24%). A complete gene deletion was present in two alleles (4%). The IVS1+2 (splicing
mutation), the 1504T (463Arg→Cys) as well as the 1342C (409Asp→His) mutations were each present in one allele (2%). None of the alleles carried the 84GG (frameshift), 1604A (496Arg→His) or the 1297T (394Val→Leu) mutation. This distribution is different from the Ashkenazi Jewish population but is similar to other Caucasian groups like
the Spanish and Portuguese populations. Our results confirm the variability of mutation patterns in Gaucher patients of different
ethnic origin. All patients were divided into nine groups according to their genotype and their clinical status was related
to the individual genotype. Genotype/phenotype characteristics of the 1226G, 1448C, and 1342C mutations of previous studies
were confirmed by our results.
Received: 19 November 1996 / Revised: 29 January 1997 相似文献
998.
Josée Harel Linda Duplessis Jeffrey S. Kahn Michael S. DuBow 《Archives of microbiology》1990,154(1):67-72
The 37,000 bp double-stranded DNA genome of bacteriophage Mu behaves as a plaque-forming transposable element of Escherichia coli. We have defined the cis-acting DNA sequences required in vivo for transposition and packaging of the viral genome by monitoring the transposition and maturation of Mu DNA-containing pSC101 and pBR322 plasmids with an induced helper Mu prophage to provide the trans-acting functions. We found that nucleotides 1 to 54 of the Mu left end define an essential domain for transposition, and that sequences between nucleotides 126 and 203, and between 203 and 1,699, define two auxiliary domains that stimulate transposition in vivo. At the right extremity, the essential sequences for transposition require not more than the first 62 base pairs (bp), although the presence of sequences between 63 and 117 bp from the right end increases the transposition frequency about 15-fold in our system. Finally, we have delineated the pac recognition site for DNA maturation to nucleotides 32 to 54 of the Mu left end which reside inside of the first transposase binding site (L1) located between nucleotides 1–30. Thus, the transposase binding site and packaging domains of bacteriophage Mu DNA can be separated into two well-defined regions which do not appear to overlap.Abbreviations
attL
attachment site left
-
attR
attachment site right
- bp
base pairs
- Kb
kilobase pair
- nt
nucleotide
- Pu
Purine
- Py
pyrimidine
- Tn
transposable element
State University of New York, Downstate Medical Center, Brooklyn, NY 11204 USA 相似文献
999.
1000.
Brockmeier U Caspers M Freudl R Jockwer A Noll T Eggert T 《Journal of molecular biology》2006,362(3):393-402
Efficient protein secretion is very important in biotechnology as it provides active and stable enzymes, which are an essential prerequisite for successful biocatalysis. Therefore, optimizing enzyme-producing bacterial strains is a major challenge in the field of biotechnology and protein production. In this study, the Gram-positive model bacterium Bacillus subtilis was optimized for heterologous protein secretion using a novel approach. Two lipolytic enzymes, cutinase from Fusarium solani pisi and a cytoplasmatic esterase of metagenomic origin, were chosen as reporters for heterologous protein secretion. In a systematic screening approach, all naturally occurring (non-lipoprotein) Sec-type signal peptides (SPs) from B. subtilis were characterized for their potential in heterologous protein secretion. Surprisingly, optimal SPs in cutinase secretion were inefficient in esterase secretion and vice versa, indicating the importance of an optimal fit between the SP and the respective mature part of the desired secretion target proteins. These results highlight the need for individually optimal signal peptides for every heterologous secretion target. Therefore, the SP library generated in this study represents a powerful tool for secretion optimization in Gram-positive expression hosts. 相似文献