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381.
M Maroli  C Khoury  G Manilla 《Parassitologia》1992,34(1-3):103-107
Haemaphysalis (Alloceraea) inermis Birula specimens have been collected in a woody land of Manziana in the province of Rome. This is the first report in Latium region and suggests the presence of autochthonous populations of the species in Central Italy since no exotic fauna has been introduced in the past in the area studied. The role of H. inermis on the transmission of pathogens for humans and animals is discussed.  相似文献   
382.
Lithostratigraphy of the Triassic in Jordan   总被引:1,自引:0,他引:1  
The Triassic sequence of Jordan east of the Rift-valley consists of an over 1000 m thick sequence of sedimentary rocks. These sediments were deposited near the shore, either under terrestrial conditions within the intertidal range just offshore, or under saline conditions in a sabkha lagoonal environment. Nine formations are described: Um Irna (80 m), Ma'in (40 m), Dardun (60 m), Ain Musa (80 m), Hisban (35 m), Mukheiris (90 m), Iraq al Amir (170 m), Um Tina (260 m), Abu Ruweis (200 m). With the exception of large parts of the Um Tina and the Abu Ruweis Formations all other formations are exposed along the NE coast of the Dead Sea and the deep wadis just E and NE of it. Each formation is defined by a type section. The sedimentary rocks are intruded by dykes and sills composed of diabase and gabbro of uniform composition and older than Upper Jurassic in age. Comparison of Triassic rocks from the west side of the Rift (DRUCKMAN 1974, 1977) indicates that the facies and thickness of Jordanian Triassic rocks as well as the northernmost limit of intrusive rocks can only be fitted with those of the central Negev. A relative movement of the Abrabian block against Palestine-Sinai of at least 100 km along the Rift is probable (BANDEL 1981).  相似文献   
383.
Analysis of mouse cDNA clones has led to the identification of a class I (H-2)-related gene that encodes a truncated transplantation-like antigen. Unlike the products of the class I genes (H-2K, H-2D, and H2-L), which are synthesized and displayed on the surface of all cells, the class I-related gene product is expressed only in liver cells and is secreted. The region of the secreted molecule corresponding to the extracellular domain of the membrane-bound class I antigens shows unusual amino acid substitutions at positions otherwise invariably conserved. There is also loss of a glycosylation site that is used in all class I antigens. Within the region corresponding to the transmembrane domain are multiple nonconservative substitutions of hydrophobic residues, alterations that render the encoded protein incapable of inserting into the plasma membrane. Toward the end of the same domain, the polypeptide chain terminates abruptly and thus lacks the intracellular domain present on all class I antigens. A candidate for this secreted molecule, detected using various heteroantisera against class I antigens, has been identified. A potential role for this serum protein in mediating active tolerance is discussed.  相似文献   
384.

Background  

The immune system behaves like a complex, dynamic network with interacting elements including leukocytes, cytokines, and chemokines. While the immune system is broadly distributed, leukocytes must communicate effectively to respond to a pathological challenge. The Basic Immune Simulator 2010 contains agents representing leukocytes and tissue cells, signals representing cytokines, chemokines, and pathogens, and virtual spaces representing organ tissue, lymphoid tissue, and blood. Agents interact dynamically in the compartments in response to infection of the virtual tissue. Agent behavior is imposed by logical rules derived from the scientific literature. The model captured the agent-to-agent contact history, and from this the network topology and the interactions resulting in successful versus failed viral clearance were identified. This model served to integrate existing knowledge and allowed us to examine the immune response from a novel perspective directed at exploiting complex dynamics, ultimately for the design of therapeutic interventions.  相似文献   
385.
J A Small  G A Scangos  L Cork  G Jay  G Khoury 《Cell》1986,46(1):13-18
Transgenic mice containing the early region of human papovavirus JC were produced. Some of these mice exhibited a shaking disorder similar to the previously described mutant mice jimpy or quaking. Neuropathological analysis indicated a dysmyelination in the central nervous system, but not the peripheral nervous system. A high level of JCV T-antigen mRNA was present in the brains of the mice exhibiting the myelin disorder. JC virus is associated in humans with a degenerative demyelinating disease: progressive multifocal leukoencephalopathy. The JCV-containing transgenic mice may therefore provide an animal model for studying this disease.  相似文献   
386.
The genes for the classical transplantation antigens are unique in that they belong to a multigene family of which each member is represented by a large number of alleles. Since all of these genes are highly related in sequence, it has been difficult to study the expression of individual members of this complex gene family. Based upon our initial suggestion that the 3' noncoding regions of these genes may be useful in identifying mRNA molecules transcribed from different loci, we have compared a large number of sequences from different inbred mouse strains and have been able to assign each of these sequences without ambiguity into distinct allelic series. Such accurate assignment has afforded the opportunity to compare the coding regions of these highly homologous genes and has led to the identification of sequences which are apparently unique to specific genes in the family. Synthetic oligonucleotides corresponding to each of the locus-specific unique regions have been used successfully to type a panel of cDNA sequences, as well as to quantitate the relative amounts of mRNA transcribed from distinct loci. The availability of these specific coding probes will allow the analysis of individual genes and their specific expression without interference from other highly homologous sequences in this multigene family.  相似文献   
387.
The relationship between sporulation temperature and spore killing temperature is described.Bacillus subtilis YB886, grown and sporulated at 25°, 30°, 37°, and 45°C, produced spores having D90 values of 63.5, 76.3, 89.0, and 106 min respectively. In addition, the vegetative cells of this strain also demonstrated resistance to heat killing when grown at elevated temperatures (D50 of 26.6, 32.5, 39.0, and >50 min for cells grown at 25°, 30°, 37°, and 45°C). A transposon-generated mutant of strain YB886, designated as BUL786, which is missing a heat shock-induced protein (97 kDa) (Qoronfleh MW and Streips UN, BBRC, 138:526–532, 1986 and FEMS 1987), was tested for thermotolerance under similar conditions. The cells failed to respond to growth at high temperature by producing heat-resistant spores or vegetative cells. For strain BUL786 the D90 of spores generated at 20°, 25°, 30°, 37°, and 45°C was 9.4, 11.3, 12.8, 14.1, and 20 min, respectively. Similarly, the D50 of vegetative cells was 15, 16.8, 17.8, 19.0, and 22.3 min when the cells were grown at 20°, 25°, 30°, 37°, and 45°C. Also, sporulation of YB886 cells in the presence of cadmium chloride increased the D90 values for the resulting spores (5µM CdCl2 resulted in a D90 of 160 min). Strain BUL786 failed to produce spores with any elevated D90 when grown in the presence of CdCl2.  相似文献   
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