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951.
Interactions between a symmetrical minor groove binding compound and DNA oligonucleotides: 1H and 19F NMR studies 总被引:1,自引:0,他引:1
A H Wang S Cottens P B Dervan J P Yesinowski G A van der Marel J H van Boom 《Journal of biomolecular structure & dynamics》1989,7(1):101-117
High-resolution NMR techniques (proton and 19F) have been used to study the interactions between several DNA oligonucleotides with varying length of AT base pairs and the synthetic pyrrole-containing compound (P1-F4S-P1), which has properties similar to the DNA minor groove binding drug distamycin A. When this two-fold symmetrical DNA binding molecule is added to the self-complementary DNA oligomers, the resulting complex exhibits an NMR spectrum without any doubling of individual resonances, consistent with a two-fold symmetry of the complex. This is in contrast to all other complexes studied so far. The minimum length of an AT stretch for specific ligand binding is judged to be greater than 4 base pairs. Inter-molecular proton nuclear Overhauser effects between the ligand molecule and a DNA dodecamer d(CGCAAATTTGCG) provide evidence that P1-F4S-P1 binds DNA in the minor groove and interacts with the middle AT base pairs. The presence of a specific interaction between P1-F4S-P1 and DNA is conclusively demonstrated by 19F NMR studies, in which four previously chemically equivalent fluorine nuclei in the free molecule become two non-equivalent pairs (yielding an AB quartet pattern) upon the binding of P1-F4S-P1 to DNA duplex. A sequence-dependent binding behavior of P1-F4S-P1 is evident by comparing the 19F NMR spectra of the complexes between P1-F4S-P1 and two different but related DNA dodecamers, d(CGCAAATTTGCG) and d(CGCTTTAAAGCG). P1-F4S-P1 binds more strongly to the former dodecamer with an association constant of approximately 1 X 10(3) M-1. 相似文献
952.
Definition of subchromosomal intervals around the myotonic dystrophy gene region at 19q 总被引:18,自引:0,他引:18
D Schonk M Coerwinkel-Driessen I van Dalen F Oerlemans B Smeets J Schepens T Hulsebos D Cockburn Y Boyd M Davis 《Genomics》1989,4(3):384-396
The localization to 19q of the gene causing myotonic dystrophy (DM) has been defined more precisely by refinement of the physical location of several linked markers. A somatic cell hybrid mapping panel from cells with t(1;19), t(12;19), and t(X;19) translocation products was constructed to define five different intervals across 19q. In addition, we have derived a series of cell hybrids by irradiation of a der(19)-only hybrid to further subdivide the cen-q13.1 region. Using an array of 36 cloned genes, anonymous DNAs, and enzyme markers, we have tested the location of the panel breakpoints and refined the regional assignment of several of these markers. All markers tightly linked to DM are localized mainly within 19q13.2, thus suggesting that the DM gene is also close to this region. 相似文献
953.
Analysis of molecular deletions with cDNA probes in patients with Duchenne and Becker muscular dystrophies 总被引:2,自引:0,他引:2
H Gilgenkrantz J Chelly M Lambert D Récan J C Barbot G J van Ommen J C Kaplan 《Genomics》1989,5(3):574-580
In the course of a systematic survey of DMD and BMD patients with intronic probes and with cDNA probes covering three-fourths of the coding sequence, 45 molecular deletions within the DMD gene were investigated. Forty-two percent of the breakpoints were located in the intronic sequence containing probe P20, whereas the other deletions were widespread around the more proximal part of the gene. Most of the BMD deletions were in the P20 region. Pulsed field gel electrophoresis was used to determine the size of some deletions and allowed us to estimate the physical distance between the intronic probes JBir and P20. The reading frame was checked in 11 cases with proximal deletions and found to be disrupted in 6 of 7 DMD patients, in 1 intermediate case, and, unexpectedly, in 3 BMD patients. 相似文献
954.
J P Nap C van de Wiel H P Spaink M Moerman M van den Heuvel M A Djordjevic A A van Lammeren A van Kammen T Bisseling 《Molecular plant-microbe interactions : MPMI》1989,2(2):53-63
The role of the Rhizobium nod genes in the induction of nodulin gene expression was examined by analyzing nodules formed on vetch roots by bacterial strains containing only the nod region. Introduction of an 11-kb cloned nod region of the R. leguminosarum sym plasmid pRL1JI into sym plasmid-cured rhizobia conferred on the recipient strains the ability to induce nodules in which all nodulin genes were expressed. This proves that from the sym plasmid only the nod region is involved in the induction of nodulin gene expression. A transconjugant of Agrobacterium carrying the same nod region induces nodules in which only early nodulin gene expression is detected. Thus, the nod region is essential for the induction of early nodulin gene expression. In this case, nodule cytology may indicate that a defense response of the plant interferes with the induction of late nodulin gene expression. Indirect evidence is presented that indeed the Rhizobium nod genes are also in some way involved in the induction of the expression of late noduling genes. The combination between histological data and pattern of nodulin gene expression furthermore reveals a correlation between nodule structure and nodulin gene expression. This correlation may aid in speculations about the functions of nodulins. 相似文献
955.
Attenuation of neurotoxicity following anoxia or glutamate receptor activation in EGF- and hippocampal extract-treated neuronal cultures 总被引:1,自引:0,他引:1
Neurotoxicity following anoxia or glutamate receptor activation was studied in primary neuronal cultures grown in serum-free, chemically defined CDM R12 medium. Exposure to 1 mM KCN, 0.5 mM kainic acid and 0.5 mM N-methyl-D-aspartate led to progressive neuronal degeneration. This damage was quantified by measuring lactate dehydrogenase released in the culture medium. The toxic effects were observed early during the development of the neuronal culture (from 4 days in vitro on) and seemed to be neuron-specific since astrocyte cultures were not affected. Chronic treatment of the neuronal cultures with epidermal growth factor at 10 ng/ml and hippocampal extract at dil. 1/833 (w/v) induced morphological alterations, increased beta-adrenergic receptor coupled adenylate cyclase activity, increased level of total lactate dehydrogenase activity in the case of epidermal growth factor-treated cultures, and attenuation of lactate dehydrogenase release following exposure to KCN or glutamate receptor agonists. The alterations observed are probably due to the proliferation and differentiation of glial cells in these treated cultures. This suggests that glial cells protect neurons in vitro from degeneration induced by anoxia or glutamate receptor activation. 相似文献
956.
Cores were collected from dominant pondcypress trees growing in a swamp that had received sewage effluent for 7 yr and a nearby control swamp to determine the combined effects of changes in nutrient supply and hydrologic regime on tree growth. The cores were used to measure two indices of tree growth: basal area increment (BAI) and relative basal area increment (RBAI, which accounts for differences in growth due to the size of teh tree) between 1970–1983 while one swamp remained untreated and the other received weekly additions of sewage effluent from 1974–1981. Throughout the whole period, the mean BAI and RBAI of pond-cypress trees in the untreated swamp remained unchanged, ranging between 5.55–6.38 cm2 yr–1 and 1.09–1.27% yr–1, respectively. In contrast, trees in the treated swamp increased their BAI approximately two-fold from 7.40 cm2 yr–1 prior to treatment to 14.83 cm2 yr–1 after the onset of treatment and maintained this rate of growth in the 2 yr period after cessation of treatment. Relative basal area increment showed a similar response, but the proportional increase due to treatment was less (1.5-fold factor) than for BAI. The response of pondcypress trees to the sewage effluent differed depending upon whether the trees were located in the deep or shallow water zones. Trees in the deep zone of the treated swamp had lower BAIs and RBAIs than those in the shallow zone during the treatment period, whereas in pre- and post-treatment periods growth indices were equal in both zones. No significant differences in growth between deep and shallow zones were observed during all three time periods in the control swamp. 相似文献
957.
In this study we have established culture conditions that allow the preferential and rapid expansion of either T cell receptor (TCR)+/CD3+16- T lymphocytes or TCR-/CD3-16+ natural killer (NK) cells, or the non-selective outgrowth of both subsets. Optimal proliferation of lymphocytes was obtained using a combination of irradiated allogeneic peripheral blood lymphocytes (PBL) and irradiated Epstein Barr virus (EBV) transformed lymphoblastoid B cell lines (B-LCL). Addition of 1 microgram/ml leucoagglutinin to the culture medium induced a preferential outgrowth of TCR+/CD3+16- T lymphocytes. The proportion of TCR-/CD3-16+ NK cells was decreased to 5% or less, although still a 2000-fold multiplication of TCR-/CD3-16+ NK cells was obtained at day 13. Without leucoagglutinin a 1000-fold increase of about 70% pure TCR-/CD3-16+ NK cells was obtained at day 13. Intermediate concentrations of leucoagglutinin (0.1-0.3 micrograms/ml) resulted in a non-selective expansion of both NK cells and T cells. Irrespective whether leucoagglutinin was added or not, the number of TCR+/CD3+8+ lymphocytes increased more rapidly relative to the TCR+/CD3+4+ lymphocytes resulting in an increased TCR+/CD3+8+ population size. Also under limiting dilution conditions leucoagglutinin increased the frequency of proliferating cells. In contrast to the preferential outgrowth of TCR+/CD3+8+ lymphocytes in bulk cultures, approximately 80% of the clones generated was TCR+/CD3+4+, demonstrating a growth promoting effect of TCR+/CD3+4+ lymphocytes on TCR+/CD3+8+ lymphocytes in PBL bulk cultures. 相似文献
958.
W E Mesker M J Eysackers M C Ouwerkerk-van Velzen A M van Driel-Kulker J S Ploem 《Analytical cellular pathology》1989,1(2):87-95
Two techniques are described to enhance the detection of low frequency aneuploid cells in automated cell analysis. One method concerns a cell preparation technique; the other is focused on specific cell selection at the measurement level. The cell preparation method has been designed to select and process the tumour areas in paraffin blocks and can be used for image as well as for flow cytometry. The technique uses incident fluorescence microscopy for visual inspection of the surface of the fluorescently stained tissue block to select the specific tumour parts. Using image cytometry, it is shown that in tissue sections with very small tumour foci and many normal cells, aneuploidy could only be detected after enrichment of the cell sample with the specifically selected areas. The cell selection at the measurement level is directed towards detection of low frequency aneuploid cells on microscope slides using the specific capacities of LEYTAS (Leyden Television Analysis System). With this system, cells of interest can be selected by means of minimum size and intensity thresholds. In addition to measurement of the total cell population, all cells above a minimum DNA value can thus be specifically selected and measured. The advantage of both enrichment techniques is the possibility to detect and measure aneuploid cell lines in cases where normal, diploid cells dominate the paraffin tissue. 相似文献
959.
Peter Schröder 《Trees - Structure and Function》1989,3(1):38-44
Summary A gas transport system based upon the physico-chemical effect of thermo-osmosis of gases in described for the black alder, Alnus glutinosa (L.) Gaertn. Air is transported through the alder's stem to the roots, thus improving O2 supply to respiring tissues of the root system. The gas transport system is investigated by means of a tracer gas technique (11% ethane in air, v/v). Gas transport depends on any source of radiant heat generating a temperature difference between the tree's stems and the atmosphere. The amount of gas transported in leafless trees is four times higher than the amount of gas reaching the roots by gas diffusion. Two-thirds of the gas is transported in the wood, only one-third in the bark. Intercellular spaces inside the porous lenticels of the bark are responsible for this kind of gas transport. Their diameters are estimated by the effusion rates of different tracer gases to be in the range of 1 m. 相似文献
960.
Structural characterization of tatiopterin, a novel pterin isolated from Methanogenium tationis 总被引:3,自引:0,他引:3
P C Raemakers-Franken F G Voncken J Korteland J T Keltjens C van der Drift G D Vogels 《BioFactors (Oxford, England)》1989,2(2):117-122
Cofactor extracts of Methanogenium tationis were screened for the presence of pterin-derivatives. Methanopterin, sarcinapterin and 7-methylpterin were absent, while 2-amino-4-hydroxy-pteridine and another blue fluorescent compound with a pterin spectrum were detected. The latter pterin was purified by ion exchange and reversed-phase column chromatography. The structure of this compound was elucidated by combining spectrophotometry, amino acid analysis and 1H-NMR spectroscopy. The pterin, which we named tatiopterin, was identified as an aspartyl derivative of sarcinapterin with a 7-proton instead of a 7-methyl group in the pterin moiety. The IUPAC name is: N-[-1'-(2'-amino-4'-hydroxy-7'-proton-6'-pteridinyl)ethyl]-4- [2',3',4',5'-tetrahydroxypent-1'-yl(5'----1')O-alpha- ribofuranosyl-5'-phosphoric acid]aniline, in which the phosphate group is esterified with alpha-hydroxyglutarylglutamylaspartic acid. 相似文献