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531.
532.
Genetic Distances and Reconstruction of Phylogenetic Trees from Microsatellite DNA 总被引:16,自引:1,他引:15
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Recently many investigators have used microsatellite DNA loci for studying the evolutionary relationships of closely related populations or species, and some authors proposed new genetic distance measures for this purpose. However, the efficiencies of these distance measures in obtaining the correct tree topology remains unclear. We therefore investigated the probability of obtaining the correct topology (P(C)) for these new distances as well as traditional distance measures by using computer simulation. We used both the infinite-allele model (IAM) and the stepwise mutation model (SMM), which seem to be appropriate for classical markers and microsatellite loci, respectively. The results show that in both the IAM and SMM CAVALLI-SFORZA and EDWARDS'' chord distance (D(C)) and NEI et al.''s D(A) distance generally show higher P(C) values than other distance measures, whether the bottleneck effect exists or not. For estimating evolutionary times, however, NEI''s standard distance and GOLDSTEIN et al.''s (δ μ)(2) are more appropriate than other distances. Microsatellite DNA seems to be very useful for clarifying the evolutionary relationships of closely related populations. 相似文献
533.
Masatoshi Nei 《Genetics》1967,57(3):625-641
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535.
There are three different methods of estimating the number of nucleotide substitutions between a pair of species from amino acid sequence data, i.e. the Poisson correction method, random evolutionary hit method, and counting the actual but minimum number of nucleotide substitutions. In this paper the relationships among the estimates obtained by these methods are studied empirically. The results obtained indicate that there is a high correlation among these estimates and in practice any of the three methods may be used for constructing evolutionary trees or relating nucleotide substitutions to evolutionary time. The effects of varying rates of nucleotide substition among different sites on the Poisson correction and random evolutionary hit methods are also studied mathematically. It is shown that these two methods are quite insensitive to the variation of the rate of nucleotide substitution. 相似文献
536.
Masaaki?K. Sato Masaya Toda Naoki Inomata Hisataka Maruyama Yuko Okamatsu-Ogura Fumihito Arai Takahito Ono Akihiko Ishijima Yuichi Inoue 《Biophysical journal》2014,106(11):2458-2464
Mammalian cells must produce heat to maintain body temperature and support other biological activities. Methods to measure a cell’s thermogenic ability by inserting a thermometer into the cell or measuring the rate of oxygen consumption in a closed vessel can disturb its natural state. Here, we developed a noninvasive system for measuring a cell’s heat production with a bimaterial microcantilever. This method is suitable for investigating the heat-generating properties of cells in their native state, because changes in cell temperature can be measured from the bending of the microcantilever, without damaging the cell and restricting its supply of dissolved oxygen. Thus, we were able to measure increases in cell temperature of <1 K in a small number of murine brown adipocytes (n = 4–7 cells) stimulated with norepinephrine, and observed a slow increase in temperature over several hours. This long-term heat production suggests that, in addition to converting fatty acids into heat energy, brown adipocytes may also adjust protein expression to raise their own temperature, to generate more heat. We expect this bimaterial microcantilever system to prove useful for determining a cell’s state by measuring thermal characteristics. 相似文献
537.
Zhaotong Wang Takamasa Mizoguchi Takahito Kuribara Masaya Nakajima Mayuu Iwata Yuka Sakamoto Hiroyuki Nakamura Toshihiko Murayama Tetsuhiro Nemoto Motoyuki Itoh 《Open biology》2021,11(2)
Polypyrrole-based polyamides are used as sequence-specific DNA probes. However, their cellular uptake and distribution are affected by several factors and have not been extensively studied in vivo. Here, we generated a series of fluorescence-conjugated polypyrrole compounds and examined their cellular distribution using live zebrafish and cultured human cells. Among the evaluated compounds, Py3-FITC was able to visualize collagen-rich tissues, such as the jaw cartilage, opercle and bulbus arteriosus, in early-stage living zebrafish embryos. Then, we stained cultured human cells with Py3-FITC and found that the staining became more intense as the amount of collagen was increased. In addition, Py3-FITC-stained HR cells, which represent a type of ionocyte on the body surface of living zebrafish embryos. Py3-FITC has low toxicity, and collagen-rich tissues and ionocytes can be visualized when soaked in Py3-FITC solution. Therefore, Py3-FITC may be a useful live imaging tool for detecting changes in collagen-rich tissue and ionocytes, including their mammalian analogues, during both normal development and disease progression. 相似文献
538.
Kazuhiko TAKAMATSU Hiroyuki YAMASHITA Shigeru SATAKE Katsuyuki KAZUSA Hajime TABATA Takahito NISHIKATA 《Experimental Animals》2015,64(3):269-280
This study was conducted to examine any changes caused by feed restriction in dogs to
contribute to safety evaluation in toxicity studies. Two male 7-month-old beagle
dogs/group were fed 300 (control), 150 (50% of control), or 70 g/animal of diet daily (23%
of control) for 4 weeks. Effects of feed restriction, except for clinical signs, were
noted depending on the feed dosage in almost all examinations. The principal outcomes
were: decreased body weight and water consumption, ECG changes (decreased heart rate and
prolonged QTc), and hematopoietic and lymphopoietic suppression (decreased reticulocyte
ratio or white blood cell count in hematology, decreased nucleated cell count in bone
marrow, decreased erythroid parameters in myelography, and hypocellularity of bone marrow
and thymic atrophy in histopathology). In addition, some changes were noted in urinalysis
(decreased urine volume and sodium and potassium excretion), blood chemistry (decreased
ALP and inorganic phosphorus and increased creatinine), organ weights, and gastric
histopathology. These results provide important reference data for distinguishing the
primary effects of test compounds from secondary effects of decreased food consumption in
toxicity studies in beagle dogs. 相似文献
539.