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81.
Abstract. We describe two new species of Blepharoneura (Diptera: Tephritidae) from Venezuela and Trinidad and redescribe Blepharoneura atomaria (Fabricius), comb.n. Each of the morphologically similar sympatric species feeds on a different tissue of Gurania spinulosa Cogn. (Cucurbitaceae): seeds ( B.manchesteri , sp.n.), male flowers ( B.atomaria ), and female flowers ( B.perkinsi , sp.n.). With the help of elementary school children and teachers we developed new methods for detecting and describing wing patterns. We present frequency distributions of character states and describe a denticulate area within the distiphallus that may function as a holdfast. For each species we provide notes on the ecology and behaviour of larvae and adults.  相似文献   
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PRIVATIZATION AND JUST HEALTHCARE   总被引:2,自引:0,他引:2  
ALLEN BUCHANAN 《Bioethics》1995,9(3):220-239
When advocates of insurance-privatization consider whether private insurance-dominated systems achieve justice at all, they tend to rely on an incomplete set of criteria for a just healthcare system. They also mistakenly assume that it is enough to show that justice is in principle achievable within a private insurance-dominated system. This essay offers a more complete set of criteria for a just healthcare system. It then argues that the motivational assumptions needed to make insurance-privatization at all plausible (on grounds of choice, efficiency, and quality of care) are inconsistent with the motivational assumptions needed to show that in practice a private insurance-dominated system will achieve justice. A private insurance-dominated system can be expected to satisfy the criteria for just healthcare only if (a) there is extensive and effective regulation to constrain the normal competitive behavior of private insurers or if (b) generous public funds are provided to fill the gaps in access left by the private insurance market. Yet the assumptions about the motivations and abilities of the public, regulators, and public officials needed to satisfy conditions (a) or (b) contradict the privatization advocate's explanations of how privatization will maximize efficiency, choice, and quality of care  相似文献   
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Involvement of different cellular investments of the amphibian ovarian follicle wall in the ovulatory process, progesterone production, and oocyte maturation was investigated. Following microdissection, to selectively remove one or more layers (surface epithelium, theca, follicle cells) of the follicle wall, dissected and undirected ovarian follicles were treated with frog pituitary homogenate (FPH) or progesterone. Intact follicles ovulated in response to pituitary homogenate and this was associated with contractions of the follicle wall. Ovulation and follicular contractions were not observed following removal of the surface epithelium without removing the thecal layer. Oocyte maturation occured in response to FPH following removal of the surface epithelium alone or together with the theca, but not in the absence of the follicle cells. Intact follicles were most responsive to FPH with respect to progesterone production, and removal of all somatic cells from oocytes obliterated FPH stimulated progesterone production. Oocytes, regardless of wether any or all follicular wall layers were removed, matured but did not ovulate following exposure to progesterone. The results suggest that the surface epithelium, but not the theca, is required for FPH-induced extrusion (ovulation) of the oocyte from ovarian follicle wall. Additionally, the somatic tissue rather than the oocyte appears to be the cells producing progesterone following FPH treatment. The results indicate that separate cellular layers (individually and/or as a result of interactions) of the follicle wall carry out different functions during follicular differentiation and mediation of ovulation. Data provide functional evidence for a role of the surface epithelium in controlling the process of ovulation and follicular contraction.  相似文献   
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ABSTRACT. Parasitic dinoflagellates of the genus Amoebophrya play important roles in the ecology of estuaries and open ocean environments. Little is known of the cell and molecular biology of Amoebophrya , but the genus is intermediate on phylogenetic trees between apicomplexans and typical dinophycean dinoflagellates. Here, we constructed four cDNA libraries, from different stages after infecting the host, Karlodinium veneficum , with Amoebophrya sp. These libraries were used to generate 898 expressed sequence tags (ESTs), with sequences attributed to either the host or parasite, based on AT bias, codon usage, and occurrence during infection. Overall, 209 sequences were attributable to the parasite and 685 to the host. The 50 putative parasite sequences with good protein matches in GenBank were used to find the same protein from host ESTs. For 26 genes, both host and parasite sequences were identified, of which 20 encoded ribosomal proteins. PCR for seven predicted parasite and two host genes were used to confirm attributions. The most common host and parasite ESTs were compared to see if multiple gene copies were present. The host plastocyanin gene had multiple sequence variants, but parasite rps 27 a contained only one polymorphism, likely due to an amplification error. Amplification, cloning, and sequencing of five parasite protein-coding genes suggested that the parasite has a single sequence for each gene, but three host genes were found to have multiple variants. The genome of Amoebophrya sp. infecting K. veneficum appears to have an organization more similar to other eukaryotes than to the tandem gene arrangements found in dinoflagellates.  相似文献   
88.
Local host plant specialization in an insect herbivore may be caused by numerous factors, including host-specific natural enemy pressures or a local lack of suitable host-plant choices that are available elsewhere in its range. Such local specialization or "ecological monophagy', for whatever reason, may reflect reduced ability to behaviourally accept or physiologically utilize other allopatric hosts that are naturally used elsewhere by the species. We tested this feeding specialization hypothesis using the Tasmanian subspecies of Macleay's swallowtail butterfly, Graphium macleayanum moggana (Papilionidae), which uses only a single host-plant species, Antherosperma moschatum (southern sassafras, of the Monlmiaceae). Further north, this same butterfly species (G. m. macleayanum) uses at least 13 host-plant species from seven genera and four families (Lauraceae, Rutaceae, Winteraceae, and Monlmiaceae). Our larval feeding assays with G. m. moggana from Tasmania showed that certain Magnoliaceae and Lauraceae could support some larval growth to pupation. However, such growth was slower and survival was lower than observed on their normal southern sassafras host (Monimiaceae). We also found that toxicity of particular plant species varied tremendously within plant families (for both the Magnoliceae and the Monlmiaceae).  相似文献   
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Louse flies, also known as deer keds (Lipoptena mazamae Rondani), infest cervids such as white‐tailed deer, Odocoileus virginianus and vector pathogens such as Anaplasma and Bartonella schoenbuchensis to cattle and humans, respectively. The population genetic structure of 30 L. mazamae collected from white‐tailed deer in four regions of Arkansas, U.S.A., designated by county boundaries, was examined using DNA sequences of a 259‐bp region of the mitochondrial DNA rRNA 16S gene. Of the 259 nucleotide characters, 33 were variable and 6 haplotypes were identified. Two haplotypes occurred only once (haplotype 3 and 4), whereas two other haplotypes occurred in 43% (haplotype 1 in two regions) and 40% (haplotype 6 in three regions) of the samples. Phylogenetic relationships of the six L. mazamae haplotypes were constructed with other Hippoboscid and Glossinid samples and two clades resulted. Clade 1 was located in the north and western Ozarks whereas clade 2 was found in the northern and eastern Ozarks. Results from the present study indicate that Lipoptena may be a polyphyletic genus; consequently, more research into genetic variation within this genus is necessary.  相似文献   
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