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971.
972.
P P Morgan 《CMAJ》1986,134(3):209-210
The classic site for paracentesis in generalized ascites is in the left lower quadrant of the abdomen at a position equivalent to McBurney''s point. Its use has an average success rate of 58%, depending on the amount of liquid. To assess the efficacy of paracentesis at this site and to establish the ideal site for blind puncture, we studied 27 consecutive patients with ascites detected by abdominal ultrasonography. The amount of ascites was graded from 1 to 4. Free fluid had accumulated mostly in the perihepatic region, then around the bladder and in the right paracolic gutter, and finally in the left flank. In six of the eight patients in whom fluid was found in the left or right flank, air-filled bowel loops were observed between the abdominal wall and the fluid, in the expected path of a blind puncture. These findings suggest that the safety and efficacy of paracentesis would be greatly improved by ultrasonographic guidance. 相似文献
973.
Transcriptomics reveal transgenerational effects in purple sea urchin embryos: Adult acclimation to upwelling conditions alters the response of their progeny to differential pCO2 levels 下载免费PDF全文
Juliet M. Wong Kevin M. Johnson Morgan W. Kelly Gretchen E. Hofmann 《Molecular ecology》2018,27(5):1120-1137
974.
975.
Juliana Tarquini Néstor Toledo Leopoldo H. Soibelzon Cecilia C. Morgan 《Historical Biology》2018,30(4):496-506
Procyonidae were the first northern placental carnivorans that reached the Neotropics. They are represented by two extinct genera: ?Cyonasua and ?Chapalmalania (late Miocene – early Pleistocene). Postcranial elements are only known for ?Cyonasua and related taxa (?Parahyaenodon argentinus and ?Tetraprothomo argentinus). To obtain highly reliable allometric equations for body mass estimations of fossil procyonids, we performed least squares regressions (multiple and bivariate lineal models) using 51 postcranial linear measurements. The extant sample included 124 taxa corresponding to nine families of Carnivora, with body mass data from the literature. We obtained about 63 equations from diverse combinations of postcranial measurements; 14 of them were selected using several reliability indexes as criteria. Our results show that body masses calculated for ?Cyonasua range between 12.63 and 28.45 kg, ?P. argentinus was estimated at 14.41 kg, while ?T. argentinus at 25.31 kg. Thus, the body mass of ?Cyonasua would have been at least twice as high as the mean of the extant procyonid Procyon cancrivorus. ?Cyonasua was probably able to fend off predators and quite capable of climbing slowly on thick-enough branches. Other palaeoecological and palaeobiological inferences are discussed. 相似文献
976.
The evolution of self-fertilization in perennials 总被引:6,自引:0,他引:6
Abstract Many plants are perennials, but studies of self-fertilization do not usually include features of perennial life histories. We therefore develop models that include selfing, a simple form of perenniality, adult inbreeding depression, and an adult survivorship cost to seed production. Our analysis shows that inbreeding depression in adults diminishes the genetic transmission advantage associated with selfing, especially in long-lived perennials that experience inbreeding depression over many seasons. Perennials also pay a cost when selfing increases total seed set at the expense of future survivorship and reproduction. Such life-history considerations shed new light on the generalization that annuals self-fertilize more than perennials. Past research suggested reproductive assurance as an explanation for this association, but common modes of selfing offer equal reproductive assurance to annuals and perennials. Instead, perennials may avoid selfing because of adult inbreeding depression and the cost to future survivorship and reproduction. 相似文献
977.
Manganese metabolism is impaired in the Belgrade laboratory rat 总被引:4,自引:0,他引:4
Anita C. G. Chua Evan H. Morgan 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(5):361-369
Homozygous Belgrade rats have a hypochromic anaemia due to impaired iron transport across the cell membrane of immature erythroid
cells. This study aimed at investigating whether there are also abnormalities of Mn metabolism in erythroid and other types
of cells. The experiments were performed with homozygous (b/b) and heterozygous (+/b) Belgrade rats and Wistar rats and included
measurements of Mn uptake by reticulocytes in vitro, Mn absorption from in situ closed loops of the duodenum, and plasma clearance
and uptake by several organs after intravenous injection of radioactive Mn bound to transferrin (Tf ) or mixed with serum.
Similar measurements were made with 59Fe-labelled Fe in several of the experiments. Mn uptake by reticulocytes and absorption from the duodenum was impaired in
b/b rats compared with +/b or Wistar rats. The plasma clearance of Mn-Tf was much slower than Mn-serum, but both were faster
than the clearance of Fe-Tf. Uptake of 54Mn by the kidneys, brain and femurs was less in b/b than Wistar or +/b rats, but uptake by the liver was greater in b/b rats.
Similar differences were found for 59Fe uptake by kidneys, brain and femurs but 59Fe uptake by the liver was also impaired in the liver. It is concluded that the genetic abnormality present in b/b rats affects
Mn metabolism as well as Fe metabolism and that Mn and Fe share similar transport mechanisms in the cells of erythroid tissue,
duodenal mucosa, kidney and blood-brain barrier.
Accepted: 20 February 1997 相似文献
978.
Metallothionein is a ubiquitous low molecular weight metalloprotein with powerful protective properties against oxygen radical-mediated
cytotoxicity associated with inflammatory processes. In rheumatoid arthritis, the inflammatory damage to the synovium appears
to be mediated by free radicals released by the high concentration of neutrophils found in the synovial fluid of the inflamed
joint. Synovial tissue obtained during routine surgery on rheumatoid and non-rheumatoid joints was subjected to an indirect
immunoperoxidase protocol for the immunolocalization of metallothionein using mouse monoclonal anti-metallothionein antibody
E9, reactive against the two major isoforms of mammalian metallothionein. A layer of large dendritic-like cells situated subsynovially
in the rheumatoid synovium stained very positively for the metalloprotein, both cytoplasmically and in their nuclei. These
cells were not found in non-rheumatoid osteoarthritic or in undamaged synovial tissue associated with traumatic joint injury.
An attempt was made to investigate their lineage using a series of antibody markers against epithelial cells, endothelial
cells, smooth muscle, mesothelial cells, fibroblasts, neutrophils, dermal dendrocytes, macrophages, low and high molecular
weight cytokeratin as well as a cell proliferation marker. From our results, it is suggested that these metallothionein-positive
cells are probably myofibroblasts similar to the highly motile cells present in granulation tissue. They may originate from
perivascular areas of synovium and their movement into the inflamed synovium may reflect the cytoprotective role of metallothionein
acting as a free radical scavenger against oxidative damage 相似文献
979.
980.
J.A.W. Morgan V. Kuntzelmann S. Tavernor M.A. Ousley & C. Winstanley 《Journal of applied microbiology》1997,83(6):665-670
Strains of Xenorhabdus nematophilus and Photorhabdus luminescens were genetically marked with kanamycin resistance and the xylE gene to aid theirdetection in water and soil. Following release in river water, cells declined to undetectable levelsin 6 d. In sterile river water, this decline was enhanced with cells detectable for only 2 d. In sterileMilli-Q purified water, the decline was slower than in either sterile or non-sterile river water.Survival in soil was also restricted with cells only detectable for 7 d. These experiments indicatedthat both X. nematophilus and P. luminescens have limited survival orcompetitive abilities in these environments. The faster decline of populations in sterile river waterwas unexpected, and the possible formation of specialized survival stages was investigated. Insterile water, a non-culturable but viable population of cells was detected, indicating that cellsmay survive longer than anticipated in the environment and remain undetectable using standardmicrobiological methods. The implications of this work to the use of these strains in biologicalcontrol and the release of genetically-modified micro-organisms is discussed. 相似文献