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71.
72.
Alexandrova LA Jasko MV Belobritskaya EE Chudinov AV Mityaeva ON Nasedkina TV Zasedatelev AS Kukhanova MK 《Bioconjugate chemistry》2007,18(3):886-893
A simple and convenient method for incorporation of fluorescent or ligand groups into 3'-termini of DNA fragments is proposed. A set of triphosphoric acid monoesters bearing fluorescent groups or biotin attached to the triphosphate fragment through linkers of different lengths and structures was synthesized. All the compounds were substrates for calf thymus terminal deoxynucleotidyltransferase and were used for incorporation of marker groups into 3'-termini of DNA fragments. The compounds were successfully applied for DNA labeling during post-PCR target preparation for microarray analysis. 相似文献
73.
74.
75.
Loredana R Barbara D Annamaria L Stefania T Maria MC Silvana F Piero A Marina P 《Molecular reproduction and development》2003,66(1):54-59
In the present paper we investigated the role played by apoptosis during oogenesis in the cartilaginous fish Torpedo marmorata. TEM, TUNEL and immunohistochemical techniques were employed to specifically reveal morphological and biochemical hallmarks of apoptosis in specimens from birth to sexual maturity. Data obtained demonstrate that apoptosis occurs in prefollicular oocyte selection, in maintaining the homeostasis of granulosa in healthy growing oocyte and in resorbing atretic follicles. In this respect, the involvement of apoptosis in Torpedo marmorata oogenesis closely parallels that found in mammals, thus confirming that strategies of germ cell selection among vertebrates have been evolutionarily preserved. 相似文献
76.
The Helicobacter pylori VacA cytotoxin activates RBL-2H3 cells by inducing cytosolic calcium oscillations 总被引:2,自引:0,他引:2
de Bernard M Cappon A Pancotto L Ruggiero P Rivera J Del Giudice G Montecucco C 《Cellular microbiology》2005,7(2):191-198
Helicobacter pylori causes an acute inflammatory response followed by chronic infection of the human gastric mucosa. Identification of the bacterial molecules endowed with a pro-inflammatory activity is essential to a molecular understanding of the pathogenesis of H. pylori associated diseases. The vacuolating cytotoxin A (VacA) induces mast cells to release pro-inflammatory cytokines. Here, we show that VacA activates the mast cell line RBL-2H3 by rapidly inducing an oscillation of the level of cytosolic calcium with exocytosis of secretory granules. Cytosolic calcium derives mainly from intracellular stores. VacA also stimulates a calcium-dependent production of pro-inflammatory cytokines, including tumour necrosis factor alpha (TNF-alpha). These observations indicate that VacA may act as a pro-inflammatory factor of H. pylori at very early stages of the innate immune response. 相似文献
77.
Yong?Zhu Pierre-Edouard?Fournier Marina?Eremeeva Didier?RaoultEmail author 《BMC microbiology》2005,5(1):11
Background
Rickettsiae closely related to the Malish strain, the reference Rickettsia conorii strain, include Indian tick typhus rickettsia (ITTR), Israeli spotted fever rickettsia (ISFR), and Astrakhan fever rickettsia (AFR). Although closely related genotypically, they are distinct serotypically. Using multilocus sequence typing (MLST), we have recently found that distinct serotypes may not always represent distinct species within the Rickettsia genus. We investigated the possibility of classifying rickettsiae closely related to R. conorii as R. conorii subspecies as proposed by the ad hoc committee on reconciliation of approaches to bacterial systematics. For this, we first estimated their genotypic variability by using MLST including the sequencing of 5 genes, of 31 rickettsial isolates closely related to R. conorii strain Malish, 1 ITTR isolate, 2 isolates and 3 tick amplicons of AFR, and 2 ISFR isolates. Then, we selected a representative of each MLST genotype and used multi-spacer typing (MST) and mouse serotyping to estimate their degree of taxonomic relatedness. 相似文献78.
Luciana Mollo Marina C. M. Martins Vanessa Fátima Oliveira Catarina C. Nievola Rita de Cássia L. Figueiredo-Ribeiro 《Plant Cell, Tissue and Organ Culture》2011,107(1):141-149
The imperial bromeliad Alcantarea imperialis grows naturally on rocky outcrops (‘inselbergs’) in regions where daily temperatures vary from 5 to 40°C. As carbohydrate
metabolism is altered in response to cold, it could lead to reprogramming of the metabolic machinery including the increase
in levels of metabolites that function as osmolytes, compatible solutes, or energy sources in order to maintain plant homeostasis.
The aim of this study was to evaluate the effects of different temperatures on plant growth and non-structural carbohydrates
in plants of A. imperialis adapted to low temperature. Seedlings of A. imperialis were grown in vitro under a 12-h photoperiod with four different day/night temperature cycles: 5/5°C, 15/15°C, 15/30°C (dark/light)
and 30/30°C. Plants were also cultivated at 26°C in ex vitro conditions for comparison. The results showed an inverse relationship
between temperature and germination time and no differences in the percentage of germination. Plants maintained for 9 months
at 15°C presented a reduced number of leaves and roots, and a dry mass four times lower than plants grown at 30°C. Sugar content
was higher in plants grown at 15°C than at 30°C. However, the highest amount of total sugar was found in plants growing under
warm day/cold night conditions. Myo-inositol, glucose, fructose and sucrose were found predominantly under high temperatures, while under low temperatures,
sucrose was apparently replaced by trehalose, raffinose and stachyose. Starch content was highest in plants grown under high
temperatures. The lowest starch content was detected under low temperatures, suggesting its conversion into soluble carbohydrates
to protect the plants against cold. These results indicated that low temperature retarded growth of A. imperialis and increased sugar levels, mainly trehalose, thus suggesting that these sugar compounds could be involved in cold tolerance. 相似文献
79.
Isolation and characterization of biologically active murine interleukin-1 alpha derived from expression of a synthetic gene in Escherichia coli 总被引:3,自引:0,他引:3
G O Daumy J M Merenda A S McColl G C Andrews A E Franke K F Geoghegan I G Otterness 《Biochimica et biophysica acta》1989,998(1):32-42
A murine interleukin-1 alpha (mIL-1 alpha) gene coding for amino acids 115 to 270 of the precursor protein (Lomedico, P.T., Gubler, U., Hellmann, C.P., Dukovich, M., Giri, J.G., Pan, Y.E., Collier, K., Semionow, R., Chua, A.O. and Mizel, S.B. (1984) Nature 312, 458-462) was chemically synthesized and expressed in Escherichia coli. mIL-1 alpha, in the form of insoluble inclusion bodies, accounted for approx. 30% of total cellular protein produced by the recombinant strain. A simple isolation protocol was developed in which inclusion body material was first solubilized in 3 M guanidine hydrochloride, and the mIL-1 alpha was then simultaneously purified and allowed to fold to its active conformation by dialysis against distilled water. This procedure yielded pure, biologically active mIL-1 alpha with 41% recovery of the mIL-1 alpha present in the guanidine hydrochloride extract. The purified preparation had the expected amino acid composition, a molar absorptivity of 28,200 M-1.cm-1 and a pI of 5.2. No methionyl-mIL-1 alpha was detected by N-terminal sequence analysis, and the endotoxin level was less than 10 pg per micrograms of mIL-1 alpha. The specific biological activity was 3.10(7) units/mg in a co-mitogenic thymocyte proliferation assay. In addition to full-length mIL-1 alpha, the preparation contained N-terminally truncated mIL-1 alpha species (mainly des-4 and des-6 amino acid forms). The truncated species were isolated and found to have the same biological activity as the complete polypeptide. Thus, the active fragment of mIL-1 alpha appears to consist of a proteinase-sensitive N-terminal region which is not essential for activity, and a proteinase-resistant core which harbors the essential determinants of its cytokine function. 相似文献
80.
While investigating dinoflagellate cyst assemblages in surface sediments of the Gulfs of Naples and Salerno (Mediterranean Sea), we found a new calcareous resting cyst. This cyst has a round to oval body surrounded by a thick mineral layer, which gives it the shape of a Napoleon hat, with a flat, oval face bearing the archeopyle and a convex keel on the opposite side. The cyst shape is variable in both natural samples and clonal cultures. The organic membrane underlying the calcareous covering is resistant to acetolysis, thus demonstrating the presence of sporopolleninlike material. The cyst germinated into a motile stage having the same morphological features and thecal plate pattern as Peridinium tyrrhenicum Balech. We believe the validity of the genus Pentapharsodinium Indelicato & Loeblich should be accepted. Based on the comparative examination of the species we collected and of a similar species, Pentapharsodinium trachodium Indelicato & Loeblich, we propose Pentapharsodinium tyrrhenicum as a new combination for Peridinium tyrrhenicum. The genus Pentapharsodinium also includes P. dalei Indelicato & Loeblich (= Peridinium faeroense Dale), which produces spiny, organic-walled cysts. The presence of species forming calcareous cysts and species producing noncalcareous cysts in the same genus raises questions about maintaining the family Calciodinellaceae. This family should only include calcareous cyst-forming peridinioids, in order to maintain a unified system of classification of fossil and recent dinoflagellates. 相似文献