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241.
242.
Peter W. Andrews Edward Nudelman Sen-Itiroh Hakomori Bruce A. Fenderson 《Differentiation; research in biological diversity》1990,43(2):131-138
NTERA-2 cl.D1 human embryonal carcinoma (EC) cells were induced to differentiate by either bromodeoxyuridine (BUdR) or hexamethylene bisacetamide (HMBA), and also by retinoic acid. Following exposure to each of these inducers, the globoseries glycolipid antigens stage-specific embryonic antigens -3 and -4 (SSEA-3 and -4) and the glycoprotein antigen TRA-1-60, all characteristic of the human EC cell surface, underwent a marked reduction in expression within about 7 days. At the same time, the lactoseries glycolipid antigen SSEA-1, and ganglioseries antigens A2B5 (GT3) and ME311 (9-0-acetyl GD3) were induced in BUdR- and retinoic acid-treated cells. However, these antigens did not appear during the first 7-14 days of HMBA-induced differentiation. The observations of cell surface antigen expression were paralleled by analysis of glycolipids isolated from the cells by thin-layer chromatography. This analysis, in which the new monoclonal antibodies VINIS-56 and VIN-2PB-22 were included, also revealed expression of gangliosides GD3 and GD2 in all differentiated cultures, albeit at much lower levels following HMBA exposure than following retinoic acid or BUdR-exposure. Further, disialylparagloboside was detected in retinoic acid and BUdR-induced, but not HMBA-induced, cultures. Taken with morphological observations, the results suggest that HMBA induces differentiation of NTERA-2 cl.D1 EC cells along a pathway distinct from the pathway(s) induced by retinoic acid and BUdR. 相似文献
243.
Extracellular matrix influences hormone and protein production by human chorionic villi 总被引:4,自引:0,他引:4
Summary Increasing evidence confirms that the extracellular matrix greatly influences cell behaviour and function. Collagen and fibrin are in contact with trophoblast throughout pregnancy. To investigate whether these two matrices influence hormon production by the trophoblast, explants from first-trimester chorionic villi were cultured for up to 30 days either a) in medium with agitation, b) embedded in type-I collagen (three-dimensional gels), or c) embedded in fibrin (three-dimensional gels). The supernatant culture medium was changed every 48 h and tested by radioimmunoassay for hCG, progesterone and pregnancy-associated plasma protein A. In addition, after 3, 7, 15, and 30 days of culture villi were fixed and studied by light and electron microscopy. Embedding in the extracellular matrix showed higher and longer-lasting production rates of all measured products and superior structural preservation as compared to cultures with agitation. Collagen matrix proved to be superior to fibrin. As established by several tests, this difference was neither due to thrombin used to polymerize fibrinogen, nor to differences in the diffusion rates through the two different matrices used. We conclude that extracellular matrix, particularly collagen, influences the synthesis of trophoblastic products. Embedding of the villous explants in three-dimensional gels constitutes a new method for long-term cultures of chorionic villi.This study was presented at the workshop Placental-and decidual-specific protein synthesis and secretion: regulation, role and interaction, Zemun, Belgrade, Yugoslavia, 19–20 May, 1988 (Bischof and Castellucci 1988; see also J. Aplin 1989), and at the 11th Rochester Trophoblast Conference, Rochester, N.Y. USA, 9–12 October 1988 (Castellucci et al. 1988) 相似文献
244.
Competition from native soil rhizobia is likely to be an important factor limiting Phaseolus vulgaris L. inoculant response in Latin America. We used UMR 1116, a nod
+ fix– natural mutant of Rhizobium leguminosarum bv phaseoli strain CC511, as a reference strain to study competition for nodulation sites in this species. When P. vulgaris cv Carioca was planted in soils containing different proportions of UMR 1116 and the effective and competitive strain UMR 1899, UMR 1116 occupied more than 50% of the nodules at all inoculant ratios tested, though increasing the proportion of UMR 1899 in the inoculant did enhance the number and percentage of effective nodules and plant dry weight. Sixty two strains of bean rhizobia were tested in competition with UMR 1116. An inoculant ratio of 1:1 was used, with all strains applied to the soil rather than to seeds. Strains varied in the number and percentage of effective nodules produced in competition with UMR 1116, and in plant dry weight, and there was a strong correlation between variation in each of these traits and plant N accumulation. Seven of the strains (UMR 1073, 1084, 1102, 1125, 1165, 1378 and 1384) were identified as both superior in competitive ability and active in N2 fixation. Site of placement of the inoculant and ambient temperature influenced strain response.Journal paper 16736, Agricultural Experiment Station, University of Minnesota, St. Paul, MN 55108, USA 相似文献
245.
Peter Bräunig 《Cell and tissue research》1990,260(1):95-108
Summary The nervus corporis cardiaci III (NCC III) of the locust Locust migratoria was investigated with intracellular and extracellular cobalt staining techniques in order to elucidate the morphology of neurons within the suboesophageal ganglion, which send axons into this nerve. Six neurons have many features in common with the dorsal, unpaired, median (DUM) neurons of thoracic and abdominal ganglia. Three other cells have cell bodies contralateral to their axons (contralateral neuron 1–3; CN 1–3). Two of these neurons (CN2 and CN3) appear to degenerate after imaginal ecdysis. CN3 innervates pharyngeal dilator muscles via its anterior axon in the NCC III, and a neck muscle via an additional posterior axon within the intersegmental nerve between the suboesophageal and prothoracic ganglia. A large cell with a ventral posterior cell body is located close to the sagittal plane of the ganglion (ventral, posterior, median neuron; VPMN). Staining of the NCC III towards the periphery reveals that the branching pattern of this nerve is extremely variable. It innervates the retrocerebral glandular complex, the antennal heart and pharyngeal dilator muscles, and has a connection to the frontal ganglion.Abbreviations
AH
antennal heart
-
AN
antennal nerves
-
AO
aorta
-
AV
antennal vessel
-
CA
corpus allatum
-
CC
corpus cardiacum
-
CN1, CN2, CN3
contralateral neuron 1–3
-
DIT
dorsal intermediate tract
-
DMT
dorsal median tract
-
DUM
dorsal, unpaired, median
-
FC
frontal connective
-
FG
frontal ganglion
-
HG
hypocerebral ganglion
-
LDT
lateral dorsal tract
-
LMN, LSN
labral motor and sensory nerves
-
LN+FC
common root of labral nerves and frontal connective
-
LO
lateral ocellus
-
MDT
median dorsal tract
-
MDVR
ventral root of mandibular nerve
-
MVT
median ventral tract
-
NCA I, II
nervus corporis allati I, II
-
NCC I, II, III
nervus corporis cardiaci I, III
-
NR
nervus recurrens
-
NTD
nervus tegumentarius dorsalis
-
N8
nerve 8 of SOG
-
OE
oesophagus
-
OEN
oesophageal nerve
-
PH
pharynx
-
SOG
suboesophageal ganglion
-
T
tentorium
-
TVN
tritocerebral ventral nerve
-
VLT
ventral lateral tract
-
VIT
ventral intermediate tract
-
VMT
ventral median tract
-
VPMN
ventral, posterior, median neuron
-
1–7
peripheral nerves of the SOG
-
36, 37, 40–45
pharyngeal dilator muscles 相似文献
246.
Aurelio Serrano Patricia Giménez Siegfried Scherer Peter Böger 《Archives of microbiology》1990,153(6):614-618
The in situ location of the electron carrier protein cytochrome C
553 (cyt c
553) has been investigated in both vegetative cells and heterocysts of the cyanobacterium Anabaena variabilis ATCC 29413 using the antibody-gold technique, carried out as a post-ernbedding immunoelectron microscopy procedure. When using a rabbit polyclonal anti-cyt c
553 specific antiserum an intense labelling, associated mainly with the cell periphery (cytoplasmic membrane and periplasmic area), was seen in both heterocysts and vegetative cells. The selective release of most of the cellular cyt c
553 during a Tris-EDTA treatment confirms a periplasmic localization of this protein in A. variabilis. The results indicate that most of cyt c
553 is located in the periplasmic space. The roles ascribed to this protein in both respiration and photosynthesis in cyanobacteria are discussed.Abbreviations Cyt c
553
cytochrome c
553
- PBS
phosphate buffered saline (20 mM sodium phosphate, 0.9% NaCl, pH 7.4)
- PMSF
phenylmethylsulfonyl fluoride
Recipient of a Research Fellowship of the Alexander von Humboldt Foundation (Bonn, FRG) for a leave to the University of Konstanz. 相似文献
247.
R-banding and nonisotopic in situ hybridization: precise localization of the human type II collagen gene (COL2A1) 总被引:17,自引:4,他引:13
Ei-ichi Takahashi Tada-aki Hori Peter O'Connell Mark Leppert Ray White 《Human genetics》1990,86(1):14-16
Summary A new mapping system, based on nonisotopic in situ hybridization combined with fluorescent staining of replicated prometaphase R-bands, is described. Replication of the bands is achieved by treatment of thymidinesynchronized cells with bromodeoxyuridine. The human COL2A1 gene was mapped to band 12q13.11–q13.12 in this manner, to illustrate the potential of the technique for improving the precision of chromosomal mapping and physical ordering of genes. 相似文献
248.
Martin Poot Julia Koehler Peter S. Rabinovitch Holger Hoehn Jean H. Priest 《Human genetics》1990,84(3):258-262
Summary BrdU-Hoechst flow cytometry was used to investigate the effects of DNA hypomethylation, induced by treatment with 5-azacytidine (5AC), on cell proliferation. When human fibroblast-like cells derived from skin and amniotic fluid were exposed to 5AC during three successive cell cycles, their clone-forming ability was diminished after removal of the drug. Treated cells were rendered quiescent by culture with low serum in the absence of the drug. Upon serum stimulation, they showed a diminished fraction of proliferating cells, which exhibited a prolonged transit through the S and G2 phase of the cell cycle, and a permanent arrest within the G2 compartment. This pattern of disturbed cell proliferation may in part explain the changes in replication banding pattern reported in the literature. Cytogenetic analysis of 5AC-treated cells revealed numerous endomitoses and tetraploid metaphases indicating a disturbed chromosome cycle in association with these cell kinetic perturbations. 相似文献
249.
Roger V. Lebo Lee A. Anderson Salvatore DiMauro Eric Lynch Peter Hwang Robert Fletterick 《Human genetics》1990,86(1):17-24
Summary When probes throughout the McArdle disease (myophosphorylase) gene region were used to search for DNA polymorphisms, only an MspI polymorphism was found in 94 enzyme-probe combinations. Along with an insertion/deletion polymorphism more 3 to the gene locus, these polymorphisms will be informative in 75% of at-risk patients. These results contrast strikingly to the six polymorphic sites detected in 15 enzyme-probe combinations in the homologous Her's disease (liver phosphorylase) gene region. This single MspI polymorphic site includes a CpG sequence of known increased mutability suggesting that DNA regions with rare polymorphisms will have most polymorphic sites at sequences with enhanced mutability. Fluorescence in situ hybridization sublocalized this gene to proximal band 11q13, establishing a point of cross-reference between the physical and genetic maps. 相似文献
250.
Fragile×expression and×inactivation 总被引:1,自引:0,他引:1
Summary The inactive fragile×chromosomes of a 47,fra(X),fra(X),Y male with a typical fragile×phenotype were successfully separated from the active homologues by means of somatic cell hybridization. It was shown by FUdR-induction and caffein-posttreatment that the separated inactive×chromosomes expressed their fragile sites and that the presence of an active mutated \sxchromosome was not a prerequisite for fragile X expression. The fragility seems to be an intrinsic property of the individual fragile site. This result is in favour of the classical concept that the fragile site at Xq27.3 has a primary pathogenetic function in this syndrome, although the fragility itself could represent a secondary phenomenon related to an unknown alteration of the DNA in this chromosome region. It is also concluded that inactivation of the fragile\sxchromosome in females is not responsible for either false negative fragile\sxfindings or the observation of fragile\sxnegative colonies isolated from fragile\sxpositive fibroblasts in heterozygotes. 相似文献