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排序方式: 共有576条查询结果,搜索用时 15 毫秒
1.
Segregation analysis of 1885 DMD families: significant departure from the expected proportion of sporadic cases 总被引:3,自引:3,他引:0
G. Barbujani A. Russo G. A. Danieli A. W. J. Spiegler J. Borkowska I. Hausmanova Petrusewicz 《Human genetics》1990,84(6):522-526
Summary The proportion of sporadic cases of Duchenne muscular dystrophy has been estimated by classical segregation analysis in a pooled sample of 1885 sibships from 7 different countries. A significant departure from the theoretical expectations based on mutation-selection equilibrium is observed (segregation frequency = 0.439 ± 0.017; frequency of sporadic cases = 0.229 ± 0.026, at the maximum likelihood). The occurrence of germinal mosaicism in some of the mothers of Duchenne cases may account for this peculiar finding, although a possible role of inequality of mutation rates in the two sexes cannot be ruled out. 相似文献
2.
Diatom communities of acidic mountain streams in Poland 总被引:1,自引:0,他引:1
A comparison has been made of the species composition of diatom communities developing in acidic Polish mountain streams which flow over calcium-poor substrates: sandstones in the Silesian Beskid (section of the Western Carpathians), the witokrzyskie Mts, and over granite in the Karkonosze range (in the Sudetic Mts). The number of taxa and diversity of the diatom assemblages decreased along a decreasing pH gradient. The correlation between pH and the number of taxa was positive and significant (r
2 = 0.69, p < 0.005). A small number of species (< 20) and low diversity were found in the communities developing in strongly acidic streams such as in the witokrzyskie Mts with pH 4.1–5.2, and in the Silesian Beskid with pH 3.5–4.0. In the stream of the Karkonosze Mts, with pH 5.2–6.0, the communities were characterized by their greater number of species and higher diversity.Acidobiontic and acidophilous diatoms were generally dominant. The pH-indiferent forms were less abundant, and their proportion increased above pH 5.0. Eunotia exigua, E. paludosa var. trinacria, E. tenella and Pinnularia subcapitata dominated in streams with the lowest pH, while E. exigua, E. sudetica and Achnanthes kryophila predominated in a stream with water pH above 5.2. Eunotia exigua, a common acidobiontic species was present in all the examined communities, and was a strong dominant in waters of pH 5.0. A corresponding decrease in abundance of E. exigua was observed with an increase in pH. 相似文献
3.
Janina Kaczanowska Leonora Wychowaniec Marek Ostrowski 《Development genes and evolution》1982,191(5):325-330
Summary An easy and sensitive method is reported here for testing the similarities of individual patterns by photographically transforming maps of these patterns to given, deductively chosen conventions involving constant distances between selected reference points. A cumulative map is produced by loading all landmarks from a set of individual maps on to one sheet of paper. The use of various a priori conventions results in variable cumulative maps, which are then optically transformed on an analog digital converter, with additional input for optical picture processing. The densitometrical maps thus obtained may be compared as to the cumulative degree of areas of maximal and minimal density of landmarks. The best conventions are those that yield the map with the most contrast.Maps of spatial patterns of the sites of contractile vacuole pore (CVP) primordia in an early stage of divisional morphogenesis of the ciliateChilodonella steini were compared after four different transformations and adjustments of the same set of individual maps. The best focusing of the sites of CVP differentiation was achieved by use of the postoral axis, defined by the center of the oral apparatus and the posterior end of the cell as the scaling parameter. The composite domain map obtained by optical transformation of this cumulative map could distinguish the specific CVP territories observed in earlier work (Kaczanowska 1981). These results confirm earlier findings that indicated the site of the oral apparatus is an important reference point in CVP primordia positioning. They also strongly suggest the existence of an overriding scaling factor governing the positioning of sites of differentiation in both dimensions of the developmental field. The method of superposition and scaling of pattern maps is generally applicable to situations in which pattern elements appear at discrete points on a flat surface. 相似文献
4.
A range of phenolic compounds were found in leaves of three cotton species. Water and nutrient stress (sulfur deficiency) both caused a significant decrease in phenolic content. Possible interpretations of the observed phenomena are given. 相似文献
5.
Ratajczak Mariusz Z. Adamiak Mateusz Bujko Kamila Thapa Arjun Pensato Valentina Kucia Magda Ratajczak Janina Ulrich Henning 《Purinergic signalling》2020,16(2):153-166
Purinergic Signalling - Bone marrow (BM) as an active hematopoietic organ is highly sensitive to changes in body microenvironments and responds to external physical stimuli from the surrounding... 相似文献
6.
Faisan Joseph P. Luhan Ma. Rovilla J. Sibonga Rema C. Mateo Jonalyn P. Ferriols Victor Marco Emmanuel N. Brakel Janina Ward Georgia M. Ross Stuart Bass David Stentiford Grant D. Brodie Juliet Hurtado Anicia Q. 《Journal of applied phycology》2021,33(4):2391-2405
Journal of Applied Phycology - Farmed eucheumatoids are the top aquaculture commodity in the Philippines, contributing more than 60% of total national aquaculture production by volume. Despite... 相似文献
7.
Sandra M. Miltsch Jürgen Krücken Janina Demeler Sabrina Ramünke Achim Harder Georg von Samson-Himmelstjerna 《Parasitology international》2013,62(6):591-598
Due to the increasing development of anthelmintic resistance in nematodes worldwide, it is important to search for anthelmintic compounds with new modes of action and also to investigate the possibility to combine compounds with possible synergistic effects. There might also be the chance to take advantage of the fact that nematode populations which have developed resistance against one anthelmintic class might respond hypersusceptibly to another drug class. The aim of this study was to investigate responses of Caenorhabditis elegans populations with mutations in neuro-muscular ion channels to different anthelmintic classes. Furthermore, potential synergistic effects between two anthelmintic compounds from different classes, i.e. emodepside and tribendimidine, were studied. Although there was neither a synergistic nor an antagonistic effect between emodepside and tribendimidine, other types of interactions could be identified. The C. elegans GABAA-receptor (GABAA-R) unc-49 mutants, showing decreased emodepside susceptibility, were more susceptible to tribendimidine than wild-type C. elegans. In contrast, the reverse phenomenon – hypersusceptibility to emodepside in tribendimidine resistant acetylcholine-receptor (AChR) loss of function mutants – was not observed. Moreover, the slo-1 mutant strain (completely emodepside resistant) also showed hypersusceptibility to piperazine. Interestingly, neither the GABAA-R unc-49 mutants nor the AChR mutants showed decreased susceptibility against piperazine, although there were some studies that indicated an involvement of GABAA-R or AChR in the piperazine mode of action. In conclusion, the present study provides evidence suggesting that interactions between commercially available anthelmintic drugs with different modes of action might be a relatively common phenomenon but this has to be carefully worked out for each anthelmintic and each anthelmintic drug combination. Moreover, results obtained in C. elegans will have to be confirmed using parasitic nematodes in the future. 相似文献
8.
Barbara Stopa Anna Jagusiak Leszek Konieczny Barbara Piekarska Janina Rybarska Grzegorz Zemanek Marcin Król Piotr Piwowar Irena Roterman 《Journal of molecular modeling》2013,19(11):4731-4740
Congo red dye as well as other eagerly self-assembling organic molecules which form rod-like or ribbon-like supramolecular structures in water solutions, appears to represent a new class of protein ligands with possible wide-ranging medical applications. Such molecules associate with proteins as integral clusters and preferentially penetrate into areas of low molecular stability. Abnormal, partly unfolded proteins are the main binding target for such ligands, while well packed molecules are generally inaccessible. Of particular interest is the observation that local susceptibility for binding supramolecular ligands may be promoted in some proteins as a consequence of function-derived structural changes, and that such complexation may alter the activity profile of target proteins. Examples are presented in this paper. 相似文献
9.
While uniparental transmission of mtDNA is widespread and dominating in eukaryotes leaving mutation as the major source of genotypic diversity, recently, biparental inheritance of mitochondrial genes has been demonstrated in reciprocal crosses of Pelargonium zonale and P. inquinans. The thereby arising heteroplasmy carries the potential for recombination between mtDNAs of different descent, i.e. between the parental mitochondrial genomes. We have analyzed these Pelargonium hybrids for mitochondrial intergenomic recombination events by examining differences in DNA blot hybridization patterns of the mitochondrial genes atp1 and cob. Further investigation of these genes and their flanking regions using nucleotide sequence polymorphisms and PCR revealed DNA segments in the progeny, which contained both P. zonale and P. inquinans sequences suggesting an intergenomic recombination in hybrids of Pelargonium. This turns Pelargonium into an interesting subject for studies of recombination and evolutionary dynamics of mitochondrial genomes. 相似文献