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131.
Eubacterial isocitrate dehydrogenase with dual specificity for NAD and NADP from Rhodomicrobium vannielii 总被引:1,自引:0,他引:1
Abstract Cell-free extracts of the photosynthetic eubacterium Rhodomicrobium vannielii contained both NADP and NAD-linked isocitrate dehydrogenase activities. Apparent K m values of 12 μM for NADP, 0.75 mM for NAD, 9.3 μM for isocitrate (NADP utilising) and 8.2 μM for isocitrate (NAD utilising) were determined in such extracts. Four lines of evidence indicated that one enzyme was responsible for the two activities; (i) non-additivity of reaction rates in the presence of both NADP and NAD (ii) the presence of one band which stained for activity with both cofactors on non-denaturing polyacrylamide gels (iii) identical heat inactivation kinetics for both activities (iv) co-elution of both activities after ion-exchange and hydrophobic interaction chromatography. This is the first report of a eubacterial isocitrate dehydrogenase with dual cofactor specificity. 相似文献
132.
T P Haverty M Watanabe E G Neilson C J Kelly 《Journal of immunology (Baltimore, Md. : 1950)》1989,143(4):1133-1141
133.
Human papillomavirus type 48. 总被引:3,自引:1,他引:2
The cloning and partial characterization of the genome of human papillomavirus (HPV) type 48 is presented. Hybridization and short DNA sequence analyses permitted the alignment of the genome to the HPV genetic map. 相似文献
134.
Molecular genetic study of the frequency of monosomy 22q11 in DiGeorge syndrome 总被引:10,自引:2,他引:8 下载免费PDF全文
A. H. Carey D. Kelly S. Halford R. Wadey D. Wilson J. Goodship J. Burn T. Paul A. Sharkey J. Dumanski M. Nordenskjold R. Williamson P. J. Scambler 《American journal of human genetics》1992,51(5):964-970
It is well established that DiGeorge syndrome (DGS) may be associated with monosomy of 22q11-pter. More recently, DNA probes have been used to detect hemizygosity for this region in patients with no visible karyotypic abnormality. However, DGS has also been described in cases where the cytogenetic abnormality does not involve 22q11; for instance, four cases of 10p- have been reported. In this study we have prospectively analyzed patients, by using DNA markers from 22q11, to assess the frequency of 22q11 rearrangements in DGS. Twenty-one of 22 cases had demonstrable hemizygosity for 22q11. Cytogenetic analysis had identified interstitial deletion in 6 of 16 cases tested; in 6 other cases no karyotype was available. When these results are combined with those from our previous studies, 33 of 35 DGS patients had chromosome 22q11 deletions detectable by DNA probes. 相似文献
135.
Minimum qualifications for directors: DNA-based genetic-testing laboratories. DNA Testing Subcommittee, Quality Assurance Committee, Council of Regional Networks for Genetic Services. 下载免费PDF全文
136.
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138.
Catch and discards from experimental trawl and longline fishing in the deep water of the Rockall Trough 总被引:1,自引:0,他引:1
Comparative bottom trawl and longline surveys were carried out on two chartered commercial fishing vessels in the deep waters (350-1300 m) of the Rockall Trough, an area subjected to heavy commercial exploitation. The species composition, catch rates and length distributions from each survey were very different and reflected the fundamental difference in the two types of fishing operations. Bottom-trawled catches produced greater species diversity and higher discard rates. Longline catches produced larger specimens of teleost fish and were dominated by squalid shark. Trawl discards, expressed as kgs of discards per tonne of roundnose grenadier Coryphaenoides rupestris landed, were calculated for a broad range of the most abundant species taken in the catch. First estimates of total international discarding from deep-water trawling operations in the Rockall Trough area (7530 tonnes; 26.5 million individuals) were made by raising the discard rates using international grenadier landings for 1995. The outlook for the continued exploitation of the deep-water fish resource in the Rockall Trough and possible management options are discussed. 相似文献
139.
We used whole-cell patch-clamp recording techniques to investigate G protein-activated currents in cultured rat retinal pigment
epithelial (RPE) cells. Using 140 mm KCl intracellular and 130 mm NaCl extracellular solutions, rat RPE cells possessed both inward and outward K+ currents. Upon addition of the nonhydrolyzable guanine triphosphate analogue, guanosine-5′-O-(3-thiophosphate) (GTPγS, 0.1
mm), to the recording electrode, a nonspecific cation (NSC) current was elicited. The NSC current had a mean reversal potential
of +5.7 mV in 130 mm extracellular NaCl with Cs+-aspartate in the pipette, and was not affected by alterations in the extracellular Ca2+ or Cl− concentration. The GTPγS-activated current was found to be permeable to several monovalent cations (K+, Na+, choline, TRIS, and NMDG). Addition of fluoroaluminate, an activator of large molecular weight heterotrimeric GTP-binding
proteins (G proteins), to the intracellular recording solution activated the NSC current. The G protein involved was pertussis
toxin (PTX)-sensitive, since GTPγS failed to activate the NSC current in cells pretreated with PTX. Further investigation
of second messenger molecules suggested that activation of the NSC current was not affected by alterations in intracellular
Ca2+ or ATP. From these results, we conclude that a G protein-regulated NSC current is present in rat RPE cells. Activation of
the NSC current may sufficiently depolarize RPE cells to activate outward K+ currents. This would provide a mechanism by which these cells could rid themselves of accumulated K+.
Received: 25 January 1996/Revised: 24 April 1996 相似文献
140.
James H. Fitzpatrick Jr. Douglas Kintner †Mark Anderson †William M. Westler ‡Sherrie E. Emoto David D. Gilboe 《Journal of neurochemistry》1996,66(6):2612-2620
Abstract: The inorganic phosphate (Pi) NMR peak in brain has an irregular shape, which suggests that it represents more than a single homogeneous pool of Pi. To test the ability of the Marquardt-Levenberg (M-L) nonlinear curve fit algorithm software (Peak-Fit) to separate multiple peaks, locate peak centers, and estimate peak heights, we studied simulated Pi spectra with defined peak centers, areas, and signal-to-noise (S/N) ratios ranging from ∞ to 5.8. As the S/N ratio decreased below 15, the M-L algorithm located peak centers accurately when they were detected; however, small peaks tended to grow smaller and disappear, whereas the amplitudes of larger peaks increased. We developed an in vitro three-compartment model containing a mixture of Pi buffer, phosphocreatine, phosphate diester, and phosphate monoester (PME), portions of which were adjusted to three different pHs before addition of agar. Weighed samples of each buffered gel together with phospholipid extract and bone chips were placed in an NMR tube and covered with mineral oil. Following baseline correction, it was possible to separate the Pi peaks arising from the three compartments with different pH values if each peak made up 10–35% of total Pi area. In vivo, we identified the plasma compartment by intraarterial infusion of Pi. It was assumed that intracellular compartments contained high-energy phosphates and took up glucose. Based on these assumptions we subjected the brains to complete ischemia and observed that Pi compartments at pH 6.82, 6.92, 7.03, and 7.13 increased markedly in amplitude. If the brain cells took up and phosphorylated 2-deoxyglucose (2-DG), 2-DG-6-phosphate (2-DG-6-P) would appear in the PME portion of the spectrum ionized according to pHi. Four 2-DG-6-P peaks with calculated pH values of 6.86, 6.94, 7.04, and 7.15 did appear in the spectrum, thereby confirming that the four larger Pi peaks represented intracellular spaces. 相似文献