全文获取类型
收费全文 | 2651篇 |
免费 | 129篇 |
国内免费 | 2篇 |
出版年
2023年 | 9篇 |
2022年 | 7篇 |
2021年 | 55篇 |
2020年 | 29篇 |
2019年 | 36篇 |
2018年 | 72篇 |
2017年 | 56篇 |
2016年 | 75篇 |
2015年 | 112篇 |
2014年 | 147篇 |
2013年 | 177篇 |
2012年 | 190篇 |
2011年 | 199篇 |
2010年 | 113篇 |
2009年 | 97篇 |
2008年 | 203篇 |
2007年 | 181篇 |
2006年 | 190篇 |
2005年 | 155篇 |
2004年 | 130篇 |
2003年 | 131篇 |
2002年 | 123篇 |
2001年 | 22篇 |
2000年 | 18篇 |
1999年 | 16篇 |
1998年 | 14篇 |
1997年 | 16篇 |
1996年 | 11篇 |
1995年 | 9篇 |
1994年 | 9篇 |
1993年 | 11篇 |
1992年 | 7篇 |
1991年 | 9篇 |
1990年 | 4篇 |
1989年 | 8篇 |
1988年 | 9篇 |
1987年 | 8篇 |
1986年 | 10篇 |
1985年 | 7篇 |
1984年 | 10篇 |
1983年 | 7篇 |
1982年 | 8篇 |
1981年 | 8篇 |
1979年 | 9篇 |
1978年 | 11篇 |
1975年 | 11篇 |
1974年 | 7篇 |
1973年 | 7篇 |
1972年 | 4篇 |
1970年 | 3篇 |
排序方式: 共有2782条查询结果,搜索用时 288 毫秒
101.
Fujarewicz K Kimmel M Lipniacki T Swierniak A 《IEEE/ACM transactions on computational biology and bioinformatics / IEEE, ACM》2007,4(3):322-335
The paper concerns the problem of fitting mathematical models of cell signaling pathways. Such models frequently take the form of sets of nonlinear ordinary differential equations. While the model is continuous in time, the performance index used in the fitting procedure involves measurements taken at discrete time moments. Adjoint sensitivity analysis is a tool which can be used for finding the gradient of a performance index in the space of parameters of the model. In the paper, a structural formulation of adjoint sensitivity analysis called the generalized backpropagation through time (GBPTT) is used. The method is especially suited for hybrid, continuous-discrete time systems. As an example, we use the mathematical model NF-kappaB of the regulatory module, which plays a major role in the innate immune response in animals. 相似文献
102.
Karhánek D Kacer P Kuzma M Splíchalová J Cervený L 《Journal of molecular modeling》2007,13(9):1009-1016
Theoretical investigation of Pt(0)-olefin organometallic complexes containing tertiary phosphine ligands was focused on the
strength of platinum-olefin electronic interaction. DFT theoretical study of electronic effects in a substantial number of
ethylene derivatives was evaluated in terms of the Pt-olefin binding energy using MP2 correlation theory. Organometallics
bearing coordinated olefins with general formula (R1R2C = CR3R4)Pt(PH3)2 [R = various substituents] had been selected, including olefins containing both electron-donor substituents as well as electron-withdrawing
groups. The stability of the corresponding complexes increases with a strengthening electron-withdrawal ability of the olefin
substituents.
Figure Representation of (CH2 = CHR)Pt(PPh3)2 and the stability chart 相似文献
103.
We analysed 16 populations of Dactylorhiza majalis subsp. majalis from northern Poland, simultaneously utilizing both morphological and molecular data. Genetic differentiation was examined using five microsatellite loci, and morphological variation was assessed for 23 characters. At the species level, our results showed a moderate level of genetic diversity (A = 6.00; Ae = 1.86; Ho = 0.387; FIS = 0.139) which varied between the studied populations (A = 2.60–4.20; Ae = 1.68–2.39; Ho = 0.270–0.523; FIS = ?0.064–0.355). A significant excess of homozygotes was detected in five population, while excess of heterozygotes was observed in four populations, but the latter values were statistically insignificant. Moderate, but clear between population genetic differentiation was found (FST = 0.101; p < 0.001). Considering pairwise‐FST and number of migrants among populations, we recognized three population groups (I, II, III), where the first could be further divided into two subgroups (Ia, Ib). These three groups differed with respect to gene flow values (Nm = 0.39–1.12). The highest number of migrants per generation was noticed among populations of subgroup Ia (8.58), indicative of a central panmictic population with free gene flow surrounded by peripatric local populations (Ib) with more limited gene flow. Geographic isolation, habitat fragmentation and limited seed dispersal are inferred to have caused limitations to gene flow among the three indicated population groups. There was a significant correlation between the morphological and genetic distance matrices. A weak but significant pattern of isolation by distance was also observed (r = 0.351; p < 0.05). 相似文献
104.
Kieliszek Marek Błażejak Stanisław Bzducha-Wróbel Anna Kot Anna M. 《Biological trace element research》2019,187(1):328-328
Biological Trace Element Research - The authors forgot to include the following information in Materials and Methods. 相似文献
105.
Marzec-Wróblewska Urszula Kamiński Piotr Łakota Paweł Szymański Marek Wasilow Karolina Ludwikowski Grzegorz Jerzak Leszek Stuczyński Tomasz Woźniak Alina Buciński Adam 《Biological trace element research》2019,188(2):251-260
Biological Trace Element Research - We analyzed cobalt (Co), chromium (Cr), and lead (Pb) concentrations in human semen and catalase CAT activity in seminal plasma and the effects of their... 相似文献
106.
Litvín Radek Bína David Herbstová Miroslava Pazderník Marek Kotabová Eva Gardian Zdenko Trtílek Martin Prášil Ondřej Vácha František 《Photosynthesis research》2019,142(2):137-151
Photosynthesis Research - Survival of phototrophic organisms depends on their ability to collect and convert enough light energy to support their metabolism. Phototrophs can extend their absorption... 相似文献
107.
Zivcak Marek Brestic Marian Botyanszka Lenka Chen Yang-Er Allakhverdiev Suleyman I. 《Photosynthesis research》2019,139(1-3):239-251
Photosynthesis Research - In our experiments, we examined high light responses and photosynthetic capacity of chlorophyll-less isogenic mutant lines of hexaploid bread wheat (Triticum aestivum L.)... 相似文献
108.
Wimmer G Dedík L Michal M Mudríková A Durisová M 《Bulletin of mathematical biology》1999,61(2):365-377
Properties of two of the stochastic circulatory models theoretically introduced by Smith et al., 1997, Bull. Math. Biol. 59, 1–22 were investigated. The models assumed the gamma distribution of the cycle time under either the geometric or Poisson
elimination scheme. The reason for selecting these models was the fact that the probability density functions of the residence
time of these models are formally similar to those of the Bateman and gamma-like function models, i.e., the two common deterministic
models. Using published data, the analytical forms of the probability density functions of the residence time and the distributions
of the simulated values of the residence time were determined on the basis of the deterministic models and the stochastic
circulatory models, respectively. The Kolmogorov-Smirnov test revealed that even for 1000 xenobiotic particles, i.e., a relatively
small number if the particles imply drug molecules, the probability density functions of the residence time based on the deterministic
models closely matched the distributions of the simulated values of the residence time obtained on the basis of the stochastic
circulatory models, provided that parameters of the latter models fulfilled selected conditions. 相似文献
109.
Rhizomelic chondrodysplasia punctata (RCDP) is a lethal autosomal recessive disease correspondingto complementation group 11 (CG 11), the second most common of the thirteen CGs of peroxisomalbiogenesis disorders (PBDs). RCDP is characterized by proximal limb shortening, severely disturbedendochondrial bone formation, and mental retardation, but there is an absence of the neuronal migrationdefect found in the other PBDs. Plasmalogen biosynthesis and phytanic acid oxidation are deficient, butvery long chain fatty acid (VLCFA) oxidation is normal. At the cellular level, RCDP is unique in thatthe biogenesis of most peroxisomal proteins is normal, but a specific subset of at least four, and maybemore, peroxisomal matrix proteins fail to be imported from the cytosol. In this review, we discuss recentadvances in understanding RCDP, most prominently the cloning of the affected gene, PEX7,and identification of PEX7 mutations in RCDP patients. Human PEX7 wasidentified by virtue of its sequence similarity to its Saccharomyces cerevisiae ortholog, whichhad previously been shown to encode Pex7p, an import receptor for type 2 peroxisomal targetingsequences (PTS2). Normal human PEX7 expression rescues the cellular defects in culturedRCDP cells, and cDNA sequence analysis has identified a variety of PEX7 mutations in RCDP patients,including a deletion of 100 nucleotides, probably due to a splice site mutation, and a prevalent nonsensemutation which results in loss of the carboxyterminal 32 amino acids. Identification of RCDP as a PTS2import disorder explains the observation that several, but not all, peroxisomal matrix proteins aremistargeted in this disease; three of the four proteins deficient in RCDP have now been shown to bePTS2-targeted. 相似文献
110.
The effect of temperature on mechanical unfolding of proteins is studied using a Go-like model with a realistic contact map and Lennard-Jones contact interactions. The behavior of the I27 domain of titin and its serial repeats is contrasted to that of simple secondary structures. In all cases, thermal fluctuations accelerate the unraveling process, decreasing the unfolding force nearly linearly at low temperatures. However, differences in bonding geometry lead to different sensitivity to temperature and different changes in the unfolding pattern. Due to its special native-state geometry, titin is much more thermally and elastically stable than the secondary structures. At low temperatures, serial repeats of titin show a parallel unfolding of all domains to an intermediate state, followed by serial unfolding of the domains. At high temperatures, all domains unfold simultaneously, and the unfolding distance decreases monotonically with the contact order, that is, the sequence distance between the amino acids that form the native contact. 相似文献