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2.
Interference with viral infection by defective RNA replicase.   总被引:16,自引:6,他引:10  
RNA-dependent RNA and DNA polymerases have a conserved segment, Tyr-X-Asp-Asp (G. Karmer and P. Argos, Nucleic Acids Res. 12:7269-7282, 1984). To investigate the function of this segment, we changed the Gly residue at position 357 in the conserved sequence Tyr-356-Gly-357-Asp-358-Asp-359 of the replicase of RNA coliphage Q beta to Ala, Ser, Pro, Met, or Val and examined the replicase activity in vivo. Cells carrying the variant plasmids lost the replicase activity and severely inhibited the proliferation of phage Q beta (group III) and related phage SP (group IV) by suppressing phage RNA synthesis. In contrast, substitution of the Gly residue at 390 showed only a slight inhibitory effect, although replicase activity was also lost. These results suggest that the cells harboring an altered replicase at the conserved segment can interfere specifically with the wild-type phage and different but related phage infections.  相似文献   
3.
Two new proteins with apparent molecular masses of 53 kDa and 190 kDa have been identified in both sarcoplasmic reticulum and human blood platelets using a monoclonal antibody, FII1b5. The sarcoplasmic reticulum FII1b5 antigens were present in the terminal cisternae fraction, but were absent from light sarcoplasmic reticulum. The platelet and skeletal muscle proteins were not sensitive to digestion with endoglycosidase H under conditions that removed carbohydrate from the 53 kDa glycoprotein in sarcoplasmic reticulum or GPIIIa in platelet microsomes and did not bind 45Ca in a nitrocellulose overlay calcium-binding assay. These results distinguished the FII1b5 antigens from the 53 kDa glycoprotein and calsequestrin of sarcoplasmic reticulum. The 190 kDa platelet and sarcoplasmic reticulum proteins were extracted from membranes with high concentrations of NaCl, indicating that the high molecular mass FII1b5 antigens are peripherally associated with the bilayers. In contrast, the platelet and muscle 53 kDa proteins remained membrane-bound in the presence of high salt concentrations, suggesting that they are integral proteins.  相似文献   
4.
The tumor-infiltrating lymphocytes (TILs) were cultured with interleukin 2 (IL-2) to induce the activated killer cells possessing autologous tumor-killing activity, and analysed their cell surface phenotypes and assessed anti-tumor killing activity. Furthermore, the activated TILs were transferred into 7 patients adoptively resulting in complete remission in a patient with pancreatic cancer and partial remission in another patient with gastric cancer.The cytotoxic activities of activated TILs at 3 weeks-incubation was 72 ± 15, 42 ± 26, 27 ± 21 and 25 ± 15% against K562, Daudi, KATO-III and autologous tumor, respectively. The negative selection method, indicated that the killer cells recognizing autologous tumor cells consisted of CD4- or CD8-positive T lymphocytes and CD16- or CD56-positive natural killer cells. The activated TILs could not only lyse cultured tumor cell lines, but also autologous tumor cells.  相似文献   
5.
Summary The distribution and development of serotonin-and RFamide-like immunoreactivities in the nervous system of Chaetognatha, Paraspadella gotoi, were examined in whole-mount preparations. In adults, a single serotonin-like immunoreactive (5HTLI) neuron and numerous RFamide-like immunoreactive (RFaLI) neurons were found in the central nervous system. Based on the structure of the fins, hooks, and eyes, seven postembryonic developmental stages were recognized. The most obvious features of the stages are: stage 1, newly hatched young; stage 2, elongation of a continuous lateral tail fin; stage 3, separation of the lateral and tail fins; stage 4, appearance of hooks; stage 5, pigmentation of eyes, stage 6, attachment by tail adhesive fins; stage 7, prey capture. Stage 1 did not show any immunoreactivity. The 5HTLI neuron first appeared at stage 4 and its axonal pathway became similar to the adult at stage 6. On the other hand, the RFaLI neurons appeared at stage 3 in the ventral ganglion. Some of their somata disappeared at stage 5 and the neuronal architecture resembled the adult at stage 7 although the RFaLI neurons in the cerebral ganglion were complete at the juvenile stage.We are sad to announce that Dr. M. Yoshida died on 29 October 1988  相似文献   
6.
Synaptosomes isolated from the rat cerebral cortex were mixed with sonicated phospholipid vesicles and subjected to freezing-thawing to acquire giant proteoliposomes. Membranes of these giant proteoliposome could thus be studied using patch-clamp techniques. Single-channel currents were measured with the inside-out patch of the membrane, in KCl solutions. Three different potassium channels were detected and unit conductances were 15.1, 28.6 and 91.0 pS, respectively, in a symmetrical 150 mM KCl solution. All these channels are more permeable to potassium than to sodium ions, the permeability ratio being about 2:1. Tetraethylammonium ions blocked these channels. The gating of these potassium channels is independent of the membrane potential, Presumably, these channels play a role in the resting membrane potential of presynaptic nerve terminals.  相似文献   
7.
The complete nucleotide sequence of the group II RNA coliphage GA   总被引:14,自引:0,他引:14  
The complete nucleotide sequence of the RNA coliphage GA, a group II phage, is presented. The entire genome comprises 3466 bases. Three large open reading frames were identified, which correspond to the maturation protein gene (390 amino acids), the coat protein gene (129 amino acids) and the replicase beta-subunit protein gene (531 amino acids). In addition, untranslated regions occur at the 5' (135 bases) and 3' (122 bases) ends of the molecule. Two intercistronic untranslated regions occur between the cistrons for the maturation and coat proteins, and between the coat and beta-subunit proteins. We have compared the nucleotide sequence of GA RNA with the published sequence of MS2 RNA, and show that they are related. The comparative structures of two important regulatory regions are presented; the coat protein binding site which is involved in translational repression of the replicase beta-subunit protein gene, and a hairpin in a region proximal to the lysis protein gene.  相似文献   
8.
The structural relationships of S-II, S-II', and S-I(b) stimulatory proteins of RNA polymerase II purified from Ehrlich ascites tumor cells were investigated. From analysis of the amino acid compositions and tryptic peptide maps of these proteins labeled with radioiodinated Bolton-Hunter reagent, it was concluded that S-I(b) is a part of S-II located at either the amino- or carboxyl-terminal and that only this region mainly contains radioiodinatable amino acid residues when labeled using 125I. On chymotryptic digestion, S-II was cleaved to 21- and 18-kDa fragments in the presence of DNA. The 21-kDa fragment was found to be sufficient for stimulation of RNA polymerase II. It was suggested that S-II' is formed by phosphorylation of S-II in the domain containing the 18-kDa fragment.  相似文献   
9.
In the process of live-vaccine immunization of Salmonella enteritidis infection in mice, the relation between the number of bacteria in the organs of mice and their protecting effect was studied. Treatment with antibiotics was used to control the number of immunizing bacteria in the tissues. Mice, which were infected with 10(-5) mg (1,000 mouse MLD) of virulent S. enteritidis and treated with kanamycin simultaneously, acquired high antilethal resistance against infection with the same organisms. However, the administration of large amounts of kanamycin, which caused a rapid decrease in bacterial numbers in the organs of infected mice, was incapable of conferring immunity. This indicated the necessity of persistence of live bacteria in the host for the production of immunity. A large number of microorganisms were maintained for 53 weeks in a diffusion chamber inserted into the mouse abdominal cavity. The mice implanted with diffusion chambers containing large numbers of virulent S. enteritidis did not acquire antilethal resistance against infection with the same organisms, although agglutinins against S. enteritidis were observed in these mice. Agglutinin was also found in the fluid contained in diffusion chambers inserted into mice immunized with a killed vaccine of S. enteritidis. This indicated that antibody penetrated the membrane filter of diffusion chambers from outside to inside and vice versa. From these results, it is suggested that contact of live microorganisms with the host cell is necessary for conferring postinfective immunity in salmonellosis.  相似文献   
10.
A cell-associated antibody was detected in the peritoneal mononuclear phagocytes (referred to as monocytes) of mice hyperimmunized with live vaccine of Salmonella enteritidis, by use of immune transfer and immune adherence hemagglutination techniques. The cellular antibody inhibited the growth of a virulent strain of S. enteritidis with the aid of complement and lysozyme on nutrient agar plates. This type of bactericidal antibody could not be detected in the monocytes of mice immunized with killed vaccine of S. enteritidis. The antibody extracted from the peritoneal monocytes of mice hyperimmunized with live vaccine was identified as a macroglobulin by ultracentrifugal analysis.  相似文献   
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