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991.
A. de Raucourt D. Girard Y. Prigent P. Boyaval 《Applied microbiology and biotechnology》1989,30(5):528-534
Summary An off-line parameter estimation method has been developed to predict the dynamic behaviour of a continuous lactose fermentation system. The model used is an unstructured model taking into account cell growth, substrate consumption, and metabolite production (lactic acid). This method, based on the Hooke-Jeeves non-linear-programming technique, results in a good estimation of the biological parameters of the model, and so gives a better understanding of the different phenomena involved in lactose fermentation.Nomenclature
Cp, Cs, Cz, Dp, Ds, Dz
coefficients in system (A)
-
Fe
bioreactor influent flow rate (1/h)
-
I
current in the ED unit (A)
-
J
lactate flux in the ED unit (g/h)
-
Kd
mortality constant (h-1)
-
Kp
product inhibition constant (g/l)
-
Ks
strbstrate saturation constant (g/l)
-
P
0
product concentration in the bioreactor (g/l)
-
P
1
product concentration in the D tank (g/l)
-
P
0r
estimation of P
0 (g/l)
-
Q
0
retentate flow rate (UF influent) (1/h)
-
Q
1
permeate flow rate (1/h)
-
Q
22
cell bleed flow rate (1/h)
-
Q
3
recycling flow rate in the ED (influent) (1/h)
-
Se
substrate concentration in the influent (g/l)
-
S
0
supstrate concentration in the bioreactor (g/l)
-
S
1
substrate concentration in tank D (g/l)
-
S
0r
estimation of S
0 (g/l)
-
t
time (h)
-
V
0
fermentation broth volume (1)
-
V
1
tank D volume (1)
-
X
0
biomass concentration in the bioreactor (g/l)
-
Y
P/S
(=1/Y
S/P) lactic acid yield coefficient (g lactic acid/g lactose consumed)
-
Y
X/S
(=1/Y
S/X) cell yield coefficient (g cells produced/g lactose consumed)
-
Y
X/Z
(=1/Y
Z/X) second cell yield coefficient (g cells produced/g nitrogen consumed)
-
Y
x, Y
m
input mathematical parameters of the linear system (M
2)
-
Ze
nitrogen concentration in the influent (g/l)
-
Z
0
nitrogen concentration in the bioreactor (g/l)
-
Z
1
nitrogen concentration in tank D (g/l)
-
Z
0r
estimation of Z
0 (g/l)
- ,
constants of the Luedeking and Piret's model
-
specific growth rate (h-1)
- max
maximum specific growth rate (h-1) 相似文献
992.
Calcitonin gene-related peptide (CGRP) in normotensive and spontaneously hypertensive rats 总被引:2,自引:0,他引:2
With the techniques of specific radioimmunoassay and gel filtration it was found that CGRP was distributed in various tissues of normotensive (WKY) and spontaneously hypertensive rats (SHR) with the highest concentration in the lumbar spinal cord (1197 +/- 94.8 pg/mg tissue) and the lowest in the auricle (15.0 +/- 2.1 pg/mg tissue). In comparison with WKY, CGRP concentration in the plasma was decreased and in the abdominal aorta and hypothalamus was increased in SHR. Gel filtration revealed only one major CGRP molecular form in the tissues. In addition, CGRP reduced the mean arterial pressure (MAP) in SHR in a dose-dependent manner. These data suggest that CGRP may play an important role in the pathogenesis of hypertension and its possible therapy. 相似文献
993.
Seven benign and four malignant mixed tumors of the salivary gland, biopsied using fine-needle aspiration, were analyzed using digital image analysis. Mean nuclear form factor, perimeter, and area were significantly increased in malignant cases. Better separation between diagnostic categories, however, was achieved by utilizing the coefficient of variation (CV) within a case rather than mean value. Form factor CV alone divided cases into nonoverlapping diagnostic categories. This quantitative analog of "pleomorphism" provided a useful marker for malignancy in mixed tumors. 相似文献
994.
IgG from antiserum against endogenous mammalian FMRF-NH2-related peptides augments morphine- and stress-induced analgesia in mice 总被引:2,自引:1,他引:1
Two mammalian FMRF-NH2-like peptides have been isolated from bovine brain; an octapeptide with the structure Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2 (F-8-F-NH2) and an octadecapeptide, Ala-Gly-Glu-Gly-Leu-Ser-Ser-Pro-Phe-Trp-Ser-Leu-Ala-Ala-Pro-Gln-Arg-Phe- NH2 (A-18-F-NH2). In the present study determinations were made of the effects of intracerebroventricular administration of IgG prepared from antisera raised against these peptides on nociception and morphine- and immobilization-induced opioid analgesia in mice. Both F-8-F-NH2-IgG and A-18-F-NH2-IgG antisera increased nociception (thermal response latency) and significantly augmented morphine- and immobilization-induced analgesia in a naloxone reversible manner, with F-8-F-NH2-IgG antisera having a greater effect than A-18-F-NH2-IgG antisera. These results provide further evidence that mammalian FMRF-NH2-like peptides function as endogenous opiate antagonists and have a role in the mediation of antinociception. 相似文献
995.
Neurotensin immunoreactivity in the central nucleus of the rat amygdala: an ultrastructural approach
Neurotensin (NT) was demonstrated in the central nucleus of the rat amygdala (CNA) using a modification of the avidin-biotin complex immunohistochemical technique. Electron-dense reaction product (particles were 15-25 nm in diameter) was localized in perikarya, dendrites, axons, and axon terminals. It was found also associated with profiles of rough endoplasmic reticulum, mitochondria, microtubules, and small agranular as well as large granular vesicles. In distal dendrites, the reaction product was associated with microtubules, vesicles, and postsynaptic densities. Axon terminals of three types formed synaptic contracts with NT-immunoreactive neurons in the CNA: one was characterized by numerous round or oval agranular vesicles, the second by numerous pleomorphic vesicles, and the third by agranular vesicles that were loosely distributed and pleomorphic. All three types formed symmetric axosomatic and asymmetric axodendritic contacts. NT-immunoreactive axon terminals containing small round agranular vesicles stood out clearly from the intermingling profiles of immunonegative structures. We found numerous glomeruli, each consisting of a central NT-immunoreactive dendrite surrounded by all three types of axon terminals. We observed that some NT-immunoreactive terminals formed symmetric axoaxonal contacts with each other, providing evidence for the presence of local NT-to-NT circuits, whereas many others synapsed with axon terminals devoid of NT immunoreactivity. 相似文献
996.
C. Y. Boquien G. Corrieu M. J. Desmazeaud 《Applied microbiology and biotechnology》1989,30(4):402-407
Summary
Streptococcus cremoris AM2 is characterized by an aminopeptidase and Leuconostoc lactis CNRZ 1091 by an -galactosidase and a citrate lyase. These strains were grown in pure or mixed cultures, in presence or absence of citrate (15 mM) and at controlled or uncontrolled pH. Cell populations and the activities of the enzymes were measured during microbial growth. Linear correlations were established between the population of S. cremoris AM2 and aminopeptidase activity, and between that of L. lactis CNRZ 1091 and the activities of -galactosidase and citrate lyase. These correlations held regardless of whether the culture was pure or mixed and if the pH was controlled or not. The presence of citrate did not change citrate lyase and aminopeptidase activities, but inhibited the synthesis of the -galactosidase and not its activity. The linear relationships permit the determination of bacterial populations in less than 2 h without counting but by measuring enzyme activities. 相似文献
997.
A Jacquet T Kleinschmidt A G Schnek Y Looze G Braunitzer 《Biological chemistry Hoppe-Seyler》1989,370(5):425-434
The amino-acid sequence of chymopapain is presented. It was isolated from the latex of the fruits from the tropical species Carica papaya L. and is, besides papain and papaya proteinase omega, the third thiol proteinase from this source. The primary structure contains 218 amino-acid residues. It was deduced from sequence analysis of the native enzyme and of peptides obtained by tryptic, chymotryptic, peptic, thermolysinolytic and mild acidic hydrolysis. Out of a total of eight cysteine residues, six are involved in the formation of three disulfide bonds, the location of which has been established with the help of peptic and thermolysinolytic peptides and fragments, obtained by mild acidic hydrolysis. Chymopapain shares 126 identical amino-acid residues (58%) with papain and 141 (65%) with papaya proteinase omega, including the three disulfide bridges and the free cysteine in position 25, required for activity. Except some amino-acid residues in the substrate-binding site, all residues involved in the catalytic mechanism are conserved. The homology between papaya proteinases is discussed. 相似文献
998.
A F Bobkova A S Gol'dshte?nKaftanova E N Dobrov I G Atabekov 《Molekuliarnaia genetika, mikrobiologiia i virusologiia》1989,(2):35-41
Antigenic properties of intact potato virus X (PVX) particles and of PVX coat protein (CP) preparations were compared using different modifications of ELISA test. In the competitive ELISA test (reaction in solution) antibodies to intact virus react much stronger with PVX than with CP while antibodies to CP react much stronger with CP than with PVX. In the direct ELISA test (reaction on the solid support) the difference in reactions of antiCP antibodies with PVX and CP is eliminated while the one in reactions of antiPVX antibodies with these antigens remains. No difference was registered in reactivity of PVX absorbed directly on polystyrene or on immunoglobulin-coated wells (sandwich ELISA) to antiCP antibodies. 相似文献
999.
V V Cherny M Paulitschke M V Simonova E Hessel V S Ermakov YuASokolov D Lerche V S Markin 《General physiology and biophysics》1989,8(1):23-37
The action of the antiviral drug rimantadine on the structure of bilayer lipid membranes (BLM) and RBC membranes was investigated. Structural changes in BLM were recorded by ionophore conductivity changes and by changes in the third harmonic of capacity current signal due to lateral compression of BLM in an electric field. It was shown that the adsorption of rimantadine on BLM results in an increase in ionophore mobility in bilayer membranes of dioleolyllecithin (DOL) and common lipids of bovine brain (CL) and in a decrease in those of azolectin (A). Relative changes in the third harmonic signal also depend on the membrane composition and have different signs. The results may be explained by the rimantadine action on the lipid bilayer structure: "rigidification" of A-membranes and "fluidization" of BLM from DOL and CL. Structural reorganization of RBC membranes as investigated by the ability of the cells to enter a micropipette (inner diameter greater than or equal to 3 microns) thereby undergoing deformation. It was shown that rimantadine influences RBC deformability due to drug induced inhomogenous mechanical membrane properties. Also, rimantadine accelerated the process of artificially induced aggregation of erythrocytes. The relation of the effects on artificial and biological membranes, and the structural changes in the lipid phase of membrane are discussed. 相似文献
1000.
K Y Yeh M Yeh P R Holt 《Biology of the cell / under the auspices of the European Cell Biology Organization》1989,65(2):139-150
The cell cycle phase that mediates the induction of intestinal sucrase-isomaltase (SI) expression by glucocorticoids was investigated by measuring migration rates of 3H-DNA-labeled and of SI-containing epithelial cells by autoradiography and indirect immunofluorescent staining after simultaneous administration of [3H]thymidine and cortisone to 12-d-old rat pups. By 24 and 48 h, lead 3H-DNA-labeled cells had migrated 7.8 and 12.4 cell positions higher on the villus than lead cells expressing SI. Cell migration rates from 12 to 24 h and 24 to 48 h were 0.68 and 0.97 cell position/h. Thus, commitment to SI expression occurred in cells 11.5-12.8 h after the S phase, which is calculated to be in the G1 phase. To determine whether committed cells need to replicate to express SI, cell differentiation was examined in primary cultures of crypt cells originating from corticosterone-treated rats. About two-thirds of cultured cells were retarded in the S phase after plating, as judged by no increase of DNA labeling indices, no change in epithelial cell number, and the absence of mitosis (less than 0.01%). The proportion of cells expressing SI increased from 0 to 6-8% between 12 and 24 h, and reached 48% 48 h after plating on collagen-coated dishes. SI expression did not occur in cells plated on glass or plastic surfaces. Pulse labeling with [35S]methionine confirmed that de novo synthesis of SI occurred in cell cultures. Thus, additional cell cycling of committed cells occurring in vivo is not obligatory for the expression of SI. 相似文献