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181.
A quantitative analysis of C3 binding to O-antigen capsule, lipopolysaccharide, and outer membrane protein of E. coli 0111B4 总被引:10,自引:0,他引:10
K A Joiner R Goldman M Schmetz M Berger C H Hammer M M Frank L Leive 《Journal of immunology (Baltimore, Md. : 1950)》1984,132(1):369-375
The binding of serum C3 to the O-antigen capsule (OAg Cap), lipopolysaccharide (LPS), and outer membrane proteins (OMP) of Escherichia coli 0111B4 was examined. Bacteria were intrinsically labeled with [3H] or [14C]galactose (*gal) in the OAg Cap and LPS moieties or with [14C]leucine (*leu) to label proteins. Organisms were then incubated in serum containing differentially labeled C3, the above fractions were separated, and the proportion of each binding to a column containing anti-C3 was measured. The OAg Cap fraction bound 72 to 82% of the C3, which bound to E. coli 0111B4 during incubation in absorbed 10% pooled normal human serum (10% PNHS) or absorbed 40% C8-deficient serum (C8D). This distribution did not change when the organism was presensitized with immune IgG before serum incubation. A total of 2.93% +/- 0.48 of OAg Cap and 0.52% +/- 0.16 of LPS *gal bound specifically to Sepharose-containing antibodies to C3 (A:C3-Seph) after incubation in 10% PNHS; these values increased to 10.1% +/- 4.5 and 1.8% +/- 0.3, respectively, when C3 deposition was increased fourfold by incubation in 40% C8D. When encapsulated E. coli 0111B4 was incubated in 10% PNHS containing biotinylated C3, specific attachment of OAg Cap *gal to avidin-Sepharose was demonstrated in 1% sodium dodecyl sulfate (SDS), and complete release of bound *gal but not C3 occurred with 1 M NH2OH. When a mutant of E. coli 0111B4 lacking OAg Cap was incubated in 40% C8D, the outer membrane (OM) bound 85% of C3. Five percent of OM *gal from the unencapsulated organism bound to A:C3-Seph in 0.05% SDS, indicating that the fraction of LPS molecules with bound C3 increased threefold in the absence of OAg Cap. OAg Cap does not contain protein, and no net specific binding of *leu from OAg Cap fractions to A:C3 was detectable; 2.4 to 3.6% of OM *leu bound to A:C3-Seph. Immunoprecipitation of 82.9% of OAg Cap *gal with antisera that were directed to E. coli 0111B4 was associated with co-precipitation of 69.5% of C3 in the capsular fraction. Therefore, the majority of C3 bound to E. coli 0111B4 was covalently attached to OAg Cap and LPS. As corroboration of experiments with whole bacteria, purified OAg Cap and purified LPS consumed C3 when incubated in serum in the fluid phase. These results are the first to evaluate the acceptor site for C3 deposition on a Gram-negative organism incubated in serum, and show that LPS, OAg Cap, and OMP are all major acceptor sites for C3 in nonimmune serum. 相似文献
182.
183.
The scrotal myocutaneous flap 总被引:2,自引:0,他引:2
M A Mendez-Fernandez C Hollan D H Frank J C Fisher 《Plastic and reconstructive surgery》1986,78(5):676-678
The scrotum is a thermoregulatory, well-vascularized structure formed by skin and nonstriated muscle with unique elastic properties. This makes it an ideal source of tissue coverage for problem wounds in its vicinity. Two patients in which scrotal musculocutaneous flaps were used are reported: one, a paraplegic, with a recurrent ischioperineal decubitus ulcer, and another with an ulcer of the penis with exposed Dacron graft previously placed to treat Peyronie's disease. After reviewing the anatomy of the scrotum and the existent literature, we studied scrotal vascularity in a fresh specimen by transillumination. Based on our experience, we conclude that this flap is easy to perform, reliable, and very useful for wounds around the perineal region. 相似文献
184.
Hierarchical selection theory and sex ratios I. General solutions for structured populations 总被引:4,自引:0,他引:4
Steven A. Frank 《Theoretical population biology》1986,29(3):312-342
Models of sex-ratio evolution in structured populations are derived with G.R. Price's covariance form for the hierarchical analysis of natural selection (1970, Nature 227, 520-521). Previous work on competition among related males for mates (local mate competition), competition among related females for a limiting resource (local resource competition), inbreeding, group selection, and asymmetry of genetic inheritance between males and females, are subsumed under a general formulation for sex-ratio biases in structured populations. I found that the evolutionarily stable strategy sex ratio (males:females) for diploids is 1 - rho m:1 - rho f, where rho m is the regression coefficient of relatedness of the controlling genotypes on males competing for mates, rho f is the regression of controlling genotypes on females that compete for a fixed, limiting resource, and there is no inbreeding. For inbreeding and no competition among females, the evolutionarily stable strategy is 1 - rho m:1 + rho mf, where rho mf is the regression of controlling genotypes on females' mates. 相似文献
185.
Indomethacin inhibits thrombin-, but not thyroxin-stimulated resorption of fetal rat limb bones 总被引:2,自引:0,他引:2
The bone-resorbing effects of thrombin and thyroxin, two agents that stimulate resorption in neonatal mouse calvaria by prostaglandin-dependent mechanisms, were examined in cultures of fetal rat limb bones. Thrombin produced maximal resorption in the limb bone cultures at a concentration of 100 U/ml when bones were cultured in BGJ supplemented with 1 mg/ml bovine serum albumin. The effects of thrombin were partially inhibited by 0.5 and 10 uM indomethacin. Thrombin failed to elicit resorption when the limb bones were cultured in DMEM with 15% horse serum. Thyroxin stimulated the resorption of limb bones in both BGJ-albumin and DMEM-serum media. Resorption was elicited by thyroxin concentrations of 10 nM-10 uM. 30 uM thyroxin failed to stimulate resorption. The dose-response curve to thyroxin was shallow, and the agent did not produce maximal resorption. The bone-resorbing effects of thyroxin were not affected by 0.5 or 10 uM indomethacin. 相似文献
186.
Jacques Hille Frank Verheggen Peter Roelvink Henk Franssen Ab van Kammen Pim Zabel 《Plant molecular biology》1986,7(3):171-176
Summary Plant cells are sensitive to the antibiotic bleomycin, a DNA damaging glycopeptide. A bleomycin resistance determinant, located on transposon Tn5 and functional in bacteria, has been cloned in a plant expression vector and introduced into Nicotiana plumbaginifolia using Agrobacterium tumefaciens. The expression of this determinant in plant cells confers resistance to bleomycin and allows selection of transformed plant cells. 相似文献
187.
J A Van Kuik R A Hoffmann J H G M Mutsaers H Van Halbeek J P Kamerling J F G Vliegenthart 《Glycoconjugate journal》1986,3(1):27-34
The 500-MHz1H-NMR characteristics of theN-linked carbohydrate chain Man1-6[Xyl1-2]Man1-4GlcNAc1-4[Fuc1-3]GlcNAc1-NAsn of the proteolytic enzyme bromelain (EC 3.4.22.4) from pineapple stem were determined for the oligosaccharide-alditol and the glycopeptide, obtained by hydrazinolysis and Pronase digestion, respectively. The1H-NMR structural-reporter-groups of the (1–3)-linked fucose residue form unique sets of data for the alditol as well as for the glycopeptide. 相似文献
188.
Toxoplasmosis is caused by the parasite Toxoplasma gondii. It is acquired from undercooked meat or from food or fomites contaminated by cat feces. The disease can be transmitted to the fetus only during maternal parasitemia, which is associated with primary infection. Extrapolation from current data suggests that there are 140 to 1400 cases of congenital toxoplasmosis per year in Canada and that 70 to 280 of the infants are severely affected at birth; many of the others suffer sequelae later in life. Serologic diagnosis of primary infection in the mother is quite sensitive and specific. Diagnosis in the infant is more difficult and may take several months. Prenatal treatment of the woman and postnatal treatment of the infant are hampered by the lack of proven efficacy as well as ethical and compliance problems. Preventive serologic screening and prophylaxis have the same drawbacks. Educating young women to avoid infection is an inexpensive, low-risk intervention that would be the preferred preventive strategy if it could be shown to be effective. Immunization may prove to be the most cost-effective method of preventing congenital toxoplasmosis if a safe and effective vaccine is developed. 相似文献
189.
Association between coated vesicles and microtubules 总被引:3,自引:0,他引:3
In this study, a possible functional association between microtubules and coated vesicles is described. We have found that our preparations of microtubules contained coated vesicles in quantities of usually above 10%. These coated vesicles were identified both by immunological methods using anticoat antibodies and by electron microscopy of negatively stained specimens. In the immune replica, two components of coated vesicles, i.e., heavy (clathrin) and light chains, were recognized as constituents of the preparations. In the electron microscope, it was found that coated vesicles were attached predominantly along the length of microtubules. Furthermore, projections from the microtubules to the triskelion centers of the clathrin lattice were identified and thus seem to serve as linkers between the cytoskeletal structure of the organelle. A similar type of association was detected in tissue culture cells; bridges between coated vesicles and microtubules were clearly identified by electron microscopy of thin sections. 相似文献
190.
Intracellular microelectrode studies were conducted to investigate the actions of the partial agonist-antagonist nalorphine at an opiate receptor on functional frog skeletal muscle fiber membranes. In high bath concentrations (greater than or equal to 10(-4) M), nalorphine alone produces agonist actions similar to the "full" opiate agonists. These actions were (i) to depress both the sodium and potassium (gNa and gK) conductance increases due to electrical stimulation by a nonspecific local anestheticlike mechanism and (ii) to depress gNa by a specific opiate receptor mediated mechanism. In a much lower bath concentration (1 X 10(-8) M) nalorphine acts to antagonize the specific opiate receptor mediated depression of gNa produced by the "full" agonist meperidine. Thus in this preparation nalorphine, "the partial antagonist," has the same actions as naloxone, which is often considered to be a full antagonist. The quantitative differences observed in the effects of these two opiate antagonists are discussed. 相似文献