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951.
Nicodemus KK Kolachana BS Vakkalanka R Straub RE Giegling I Egan MF Rujescu D Weinberger DR 《Human genetics》2007,120(6):889-906
Catechol-O-methyltransferase (COMT) regulates dopamine degradation and is located in a genomic region that is deleted in a syndrome
associated with psychosis, making it a promising candidate gene for schizophrenia. COMT also has been shown to influence prefrontal
cortex processing efficiency. Prefrontal processing dysfunction is a common finding in schizophrenia, and a background of
inefficient processing may modulate the effect of other candidate genes. Using the NIMH sibling study (SS), a non-independent
case-control set, and an independent German (G) case-control set, we performed conditional/unconditional logistic regression
to test for epistasis between SNPs in COMT (rs2097603, Val158Met (rs4680), rs165599) and polymorphisms in other schizophrenia
susceptibility genes. Evidence for interaction was evaluated using a likelihood ratio test (LRT) between nested models. SNPs
in RGS4, G72, GRM3, and DISC1 showed evidence for significant statistical epistasis with COMT. A striking result was found
in RGS4: three of five SNPs showed a significant increase in risk [LRT P-values: 90387 = 0.05 (SS); SNP4 = 0.02 (SS), 0.02 (G); SNP18 = 0.04 (SS), 0.008 (G)] in interaction with COMT; main effects
for RGS4 SNPs were null. Significant results for SNP4 and SNP18 were also found in the German study. We were able to detect
statistical interaction between COMT and polymorphisms in candidate genes for schizophrenia, many of which had no significant
main effect. In addition, we were able to replicate other studies, including allelic directionality. The use of epistatic
models may improve replication of psychiatric candidate gene studies. 相似文献
952.
The extracellular alkaline protease in the supernatant of cell culture of the marine yeast Aureobasidium pullulans 10 was purified to homogeneity with a 2.1-fold increase in specific protease activity as compared to that in the supernatant
by ammonium sulfate fractionation, gel filtration chromatography (Sephadex™ G-75), and anion-exchange chromatography (DEAE
Sepharose Fast Flow). According to the sodium dodecyl sulfate-polyacrylamide gel electrophoresis data, the molecular mass
of the purified enzyme was estimated to be 32.0 kDa. The optimal pH and temperature of the purified enzyme were 9.0 and 45°C,
respectively. The enzyme was activated by Cu2+ (at a concentration of 1.0 mM) and Mn2+ and inhibited by Hg2+, Fe2+, Fe3+, Zn2+, and Co2+. The enzyme was strongly inhibited by phenylmethylsulfonyl fluoride, but weakly inhibited by EDTA, 1–10-phenanthroline, and
iodoacetic acid. The K
m and V
max values of the purified enzyme for casein were 0.25 mg/ml and 0.0286 μmol/min/mg of protein, respectively. After digestion
of shrimp protein, spirulina (Arthospira platensis) protein, proteins of marine yeast strains N3C (Yarrowia lipolytica) and YA03a (Hanseniaspora uvarum), milk protein, and casein with the purified alkaline protease, angiotensin I converting enzyme (ACE) inhibitory activities
of the resulting peptides reached 85.3%, 12.1%, 29.8%, 22.8%, 14.1%, and 15.5%, respectively, while the antioxidant activities
of these were 52.1%. 54.6%, 25.1%, 35%, 12.5%, and 24.2%, respectively, indicating that ACE inhibitory activity of the resulting
peptides from the shrimp protein and antioxidant activity of those produced from the spirulina protein were the highest, respectively.
These results suggest that the bioactive peptides produced by digestion of the shrimp protein with the purified alkaline protease
have potential applications in the food and pharmaceutical industries. 相似文献
953.
Feeding ecology of phocid seals and some walrus in the Alaskan and Canadian Arctic as determined by stomach contents and stable isotope analysis 总被引:1,自引:0,他引:1
Larissa-A. Dehn Gay G. Sheffield Erich H. Follmann Lawrence K. Duffy Dana L. Thomas Todd M. O’Hara 《Polar Biology》2007,30(2):167-181
Feeding habits of ringed (Phoca hispida), bearded (Erignathus barbatus), spotted (Phoca largha) and ribbon (Phoca fasciata) seals and walrus (Odobenus rosmarus) were studied using stomach contents and stable carbon and nitrogen isotopes. Bearded seals fed benthically, primarily crustaceans and mollusks. Both zooplankton and fish were significant prey for ringed seals, while fish was principal spotted seal prey. Few gastric contents were available from ribbon seals. δ15N was positively correlated with age in ribbon seals and δ13C was positively correlated with age in ringed and ribbon seals. δ15N was highest in spotted seals, in agreement with their fish-dominated diet. δ15N was not different between Alaskan-harvested ringed and bearded seals, while δ15N was lowest in ribbon seals and walrus. Carbon-13 was most enriched in bearded seals and walrus reflecting benthic ecosystem use. Canadian ringed seals were depleted in 13C compared to Alaskan pinnipeds, likely because of Beaufort Sea versus Chukchi and Bering seas influence. 相似文献
954.
955.
Comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) based on three-dimensional quantitative structure-activity relationship (3D-QSAR) studies were conducted on a series (44 compounds) of diaryloxy-methano-phenanthrene derivatives as potent antitubercular agents. The best predictions were obtained with a CoMFA standard model (q (2)=0.625, r (2)=0.994) and with CoMSIA combined steric, electrostatic, and hydrophobic fields (q (2)=0.486, r (2)=0.986). Both models were validated by a test set of seven compounds and gave satisfactory predictive r (2) values of 0.999 and 0.745, respectively. CoMFA and CoMSIA contour maps were used to analyze the structural features of the ligands to account for the activity in terms of positively contributing physicochemical properties: steric, electrostatic, and hydrophobic fields. The information obtained from CoMFA and CoMSIA 3-D contour maps can be used for further design of phenanthrene-based analogs as anti-TB agents. The resulting contour maps, produced by the best CoMFA and CoMSIA models, were used to identify the structural features relevant to the biological activity in this series of analogs. Further analysis of these interaction-field contour maps also showed a high level of internal consistency. This study suggests that introduction of bulky and highly electronegative groups on the basic amino side chain along with decreasing steric bulk and electronegativity on the phenanthrene ring might be suitable for designing better antitubercular agents. 相似文献
956.
The mechanism of cytotoxicity on liver carcinoma Bel-7402 cells induced by copper-1,10-phenanthroline, Cu(OP)2, has been studied. Cell viability and apoptotic rate were examined in cells treated with Cu(OP)2 or Cu2+ alone. It was found that the apoptosis induced by Cu(OP)2 could not be induced by Cu2+ or OP alone in our experimental conditions. Total copper content in cells was measured by atomic absorption spectrophotometry,
and the abnormal elevation of intracellular copper transported by lipophilic OP ligand may play the role of initial factor
in the apoptosis, which caused subsequent redox state changes in cells. Intracellular levels of reactive oxygen species (ROS)
were detected by fluorescent probe 2′,7′-dichlorofluorescein diacetate (DCFH-DA). Reduced (GSH) and total glutathione (GSSG + GSH)
were determined by High-performance liquid chromatography (HPLC) after derivatization, and the ratios of GSH/GSSG were subsequently
calculated. The overproduction of ROS and the decreased GSH/GSSG ratio were observed in cells which represented the occurrence
of oxidative stress in the apoptosis. Oxidative DNA damage was also found in cells treated with Cu(OP)2 in the early stage of the apoptosis, and it suggests that the activation of DNA repair system may be involved in the pathway
of the apoptosis induced by Cu(OP)2. 相似文献
957.
Staats CC Junges A Fitarelli M Furlaneto MC Vainstein MH Schrank A 《Applied microbiology and biotechnology》2007,76(4):945-950
The list of fungal species with known complete genome and/or expressed sequence tag collections is extending rapidly during
the last couple of years. Postgenomic gene function assignment is an obvious follow-up and depends on methodologies to test
gene function in vivo. One of such methods is the generation of null mutants via homologous recombination at the wild–type
loci by using inactivation cassettes. In this paper, the ability of Agrobacterium tumefaciens to genetically transform filamentous fungi was exploited to drive homologous recombination at the trp1 locus of the enthomopathogenic fungus Metarhizium anisopliae. The trp1 disruptants exhibited a clearly distinguishable phenotype from wild-type cells and were recovered with high efficiency of
homologous recombination (22%). The complementation of such mutants with the wild-type gene generates only transformants with
homologous integration. 相似文献
958.
Growing concentrations of N2O within the atmosphere have been accompanied by decreasing δ15N values, provoking the hypothesis of a global decline in the rate of N2O reduction relative to its production in soil. We estimate that the ratio of N2O produced to N2O reduced within the soil profile has declined by about 10–25% relative to its pre-industrial value. To a smaller extent,
a reduction in the uptake of atmospheric N2O at the soil surface relative to its emission could also have contributed to the reported isotopic signal. This calls for
a greater consideration of the process of N2O reduction in soil and its role in the global turnover of N2O. 相似文献
959.
This study investigated the enhanced crude oil biodegradability of Pseudomonas aeruginosa ZJU, a strain isolated from the Shengli oil field (Shandong Province, China), after preservation in a crude oil-containing
medium. This strain previously could not emulsify crude oil during preservation, but after switching to a subculture in a
glycerol medium for passages, it expressed increased biodegradation of crude oil within the first six passages and this biodegradation
sharply decreased after the seventh passage. It is noticed that about 70% of crude oil was degraded by Pseudomonas aeruginosa ZJU in the third passage while this biodegradability was less than 19% in the seventh passage. Similar to the trend on biodegradation
of crude oil, rhamnolipid production increased during the first six passages and later sharply decreased. Thus, it seems that
biodegradability was proportionally related to the rhamnolipid productivity in each passage in glycerol medium. Interestingly,
both rhamnolipid production and crude oil biodegradation were maintained if this strain was continuously preserved in crude
oil and could be retrieved if this strain was then re-preserved in crude oil-containing medium for seven days after the significant
decline in these two characteristics previously observed in the seventh passage. 相似文献
960.
Jennings BL Bell JD Hyodo S Toop T Donald JA 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2007,177(5):557-567
This study investigated vasodilator mechanisms in the dorsal aorta of the elephant fish, Callorhinchus milii, using anatomical and physiological approaches. Nitric oxide synthase could only be located in the perivascular nerve fibres
and not the endothelium of the dorsal aorta, using NADPH histochemistry and immunohistochemistry. In vitro organ bath experiments
demonstrated that a NO/soluble guanylyl cyclase (GC) system appeared to be absent in the vascular smooth muscle, since the
NO donors SNP (10−4 mol l−1) and SIN-1 (10−5 mol l−1) were without effect. Nicotine (3 × 10−4 mol l−1) mediated a vasodilation that was not affected by ODQ (10−5 mol l−1), l-NNA (10−4 mol l−1), indomethacin (10−5 mol l−1), or removal of the endothelium. In contrast, the voltage-gated sodium channel inhibitor, tetrodotoxin (10−5 mol l−1), significantly decreased the dilation induced by nicotine, suggesting that it contained a neural component. Pre-incubation
of the dorsal aorta with the calcitonin gene-related peptide (CGRP) receptor antagonist, CGRP8–37 (10−6 mol l−1) also caused a significant decrease in the nicotine-induced dilation. We propose that nicotine is mediating a neurally-derived
vasodilation in the dorsal aorta that is independent of NO, prostaglandins and the endothelium, and partly mediated by CGRP. 相似文献