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1.
We describe practical, effective, office-based methods for physicians to use to assist patients to stop smoking that do not require special training or support personnel. Brief counseling achieves smoking cessation in a small percent of well patients but is more effective in patients with smoking-related illnesses or abnormal laboratory test results. Routine prescribing of nicotine gum without participation by the patient in a smoking-cessation program does not increase smoking cessation, and we do not recommend it. The prevention of smoking relapse can probably be enhanced by scheduling follow-up office visits after the patient has quit. Failure to quit on initial attempts should not discourage physicians and patients, since most successful abstainers usually must make several attempts to quit. We outline for physicians two approaches, one brief and one more intensive, to help patients stop smoking. 相似文献
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Cell yields were determined for two bacterial soil isolants grown aerobically in minimal media on a variety of synthetic organic compounds. 1-Dodecanol, benzoic acid, phenylacetic acid, phenylglyoxylic acid, and diethylene, triethylene, and tetraethylene glycols were tested. Two “biochemicals,” succinate and acetate, were also tested for comparison. Yields were calculated on the basis of grams of cells obtained per mole of substrate utilized, gram atom of carbon utilized, mole of oxygen consumed, and equivalent of “available electrons” in the substrates. This latter value appears to be nearly constant at 3 g of cells per equivalent of “available electrons.” Yields predicted on this basis for other bacteria and for yeasts on other substrates are in fair agreement with reported values. 相似文献
4.
Krešimir Begović Jonathan S. Schurman Marek Svitok Jakob Pavlin Thomas Langbehn Kristyna Svobodová Martin Mikoláš Pavel Janda Michal Synek William Marchand Lucie Vitková Daniel Kozák Ondrej Vostarek Vojtech Čada Radek Bače Miroslav Svoboda 《Global Change Biology》2023,29(1):143-164
In a world of accelerating changes in environmental conditions driving tree growth, tradeoffs between tree growth rate and longevity could curtail the abundance of large old trees (LOTs), with potentially dire consequences for biodiversity and carbon storage. However, the influence of tree-level tradeoffs on forest structure at landscape scales will also depend on disturbances, which shape tree size and age distribution, and on whether LOTs can benefit from improved growing conditions due to climate warming. We analyzed temporal and spatial variation in radial growth patterns from ~5000 Norway spruce (Picea abies [L.] H. Karst) live and dead trees from the Western Carpathian primary spruce forest stands. We applied mixed-linear modeling to quantify the importance of LOT growth histories and stand dynamics (i.e., competition and disturbance factors) on lifespan. Finally, we assessed regional synchronization in radial growth variability over the 20th century, and modeled the effects of stand dynamics and climate on LOTs recent growth trends. Tree age varied considerably among forest stands, implying an important role of disturbance as an age constraint. Slow juvenile growth and longer period of suppressed growth prolonged tree lifespan, while increasing disturbance severity and shorter time since last disturbance decreased it. The highest age was not achieved only by trees with continuous slow growth, but those with slow juvenile growth followed by subsequent growth releases. Growth trend analysis demonstrated an increase in absolute growth rates in response to climate warming, with late summer temperatures driving the recent growth trend. Contrary to our expectation that LOTs would eventually exhibit declining growth rates, the oldest LOTs (>400 years) continuously increase growth throughout their lives, indicating a high phenotypic plasticity of LOTs for increasing biomass, and a strong carbon sink role of primary spruce forests under rising temperatures, intensifying droughts, and increasing bark beetle outbreaks. 相似文献
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Cell migration and growth are essential components of the development of multicellular organisms. The role of various cues
in directing cell migration is widespread, in particular, the role of signals in the environment in the control of cell motility
and directional guidance. In many cases, especially in developmental biology, growth of the domain also plays a large role
in the distribution of cells and, in some cases, cell or signal distribution may actually drive domain growth. There is an
almost ubiquitous use of partial differential equations (PDEs) for modelling the time evolution of cellular density and environmental
cues. In the last 20 years, a lot of attention has been devoted to connecting macroscopic PDEs with more detailed microscopic
models of cellular motility, including models of directional sensing and signal transduction pathways. However, domain growth
is largely omitted in the literature. In this paper, individual-based models describing cell movement and domain growth are
studied, and correspondence with a macroscopic-level PDE describing the evolution of cell density is demonstrated. The individual-based
models are formulated in terms of random walkers on a lattice. Domain growth provides an extra mathematical challenge by making
the lattice size variable over time. A reaction–diffusion master equation formalism is generalised to the case of growing
lattices and used in the derivation of the macroscopic PDEs. 相似文献
7.
Yulin Song Vincent Hervé Renate Radek Fabienne Pfeiffer Hao Zheng Andreas Brune 《Environmental microbiology》2021,23(8):4228-4245
Spirochetes of the genus Treponema are surprisingly abundant in termite guts, where they play an important role in reductive acetogenesis. Although they occur in all termites investigated, their evolutionary origin is obscure. Here, we isolated the first representative of ‘termite gut treponemes’ from cockroaches, the closest relatives of termites. Phylogenomic analysis revealed that Breznakiella homolactica gen. nov. sp. nov. represents the most basal lineage of the highly diverse ‘termite cluster I', a deep-branching sister group of Treponemataceae (fam. ‘Termitinemataceae’) that was present already in the cockroach ancestor of termites and subsequently coevolved with its host. Breznakiella homolactica is obligately anaerobic and catalyses the homolactic fermentation of both hexoses and pentoses. Resting cells produced acetate in the presence of oxygen. Genome analysis revealed the presence of pyruvate oxidase and catalase, and a cryptic potential for the formation of acetate, ethanol, formate, CO2 and H2 - the fermentation products of termite gut isolates. Genes encoding key enzymes of reductive acetogenesis, however, are absent, confirming the hypothesis that the ancestral metabolism of the cluster was fermentative, and that the capacity for acetogenesis from H2 plus CO2 - the most intriguing property among termite gut treponemes - was acquired by lateral gene transfer. 相似文献
8.
Finds of fossil wood with bivalve wood borings (Teredolites clavatus and T. longissimus) occur in various facies and presumed sedimentary settings of the platform, shallow-marine Bohemian Crectaceous Basin. The basin comprises areas with sandy-dominated sediments, with marl and clay-dominated sediments, areas with predominat sandy-marly rocks, and finally areas dominated by calcareous nearshore sediments. Teredolites clavatus is common in fossil wood of sandstones, originating in beach or deltaic settings; marl and clay-dominated rock frequently bear wood fragments densely bored by Teredolites longissimus. When accompanied by evidence of marine environments as body fossils, glauconite or typical trace fossils, most of the wood fragments are bored. The presence/absence of borings in wood fragments can be considered the most reliable and easily useable criterion of distinction of marine settings in sandy sediments of the margin of the Bohemian Cretaceous Basin. 相似文献
9.
Karel Pomeisl Květoslava Horská Radek Pohl Jiří Blažek Marcela Krečmerová 《Nucleosides, nucleotides & nucleic acids》2013,32(3):159-171
A series of new monophosphates of 1-[2-(phosphonomethoxy)alkyl]thymines, such as PMPTp, 3-MeO-PMPTp, HPMPTp, and FPMPTp, were synthesized and tested for their ability to inhibit human thymidine phosphorylase. Kinetic measurements of enzyme activity were performed using thymidine and inorganic phosphate as the substrates. The data show that some monophosphates provide a considerable increase of the multisubstrate inhibitory effect. The highest inhibitory potency was found with (R)-FPMPTp 4c (K i dT = 4.09 ± 0.47 μM, K i(Pi) = 2.13 ± 0.29 μM) and (R) 3-MeO-PMPTp 4d (K i dT = 5.78 ± 0.71 μM, K i(Pi) = 2.71 ± 0.37 μM). 相似文献
10.
Lubomir Prochazka Stepan Koudelka Lan-Feng Dong Jan Stursa Jacob Goodwin Jiri Neca Josef Slavik Miroslav Ciganek Josef Masek Katarina Kluckova Maria Nguyen Jaroslav Turanek Jiri Neuzil 《Apoptosis : an international journal on programmed cell death》2013,18(3):286-299
α-Tocopheryl succinate (α-TOS) is a promising anti-cancer agent due to its selectivity for cancer cells. It is important to understand whether long-term exposure of tumour cells to the agent will render them resistant to the treatment. Exposure of the non-small cell lung carcinoma H1299 cells to escalating doses of α-TOS made them resistant to the agent due to the upregulation of the ABCA1 protein, which caused its efflux. Full susceptibility of the cells to α-TOS was restored by knocking down the ABCA1 protein. Similar resistance including ABCA1 gene upregulation was observed in the A549 lung cancer cells exposed to α-TOS. The resistance of the cells to α-TOS was overcome by its mitochondrially targeted analogue, MitoVES, that is taken up on the basis of the membrane potential, bypassing the enhanced expression of the ABCA1 protein. The in vitro results were replicated in mouse models of tumours derived from parental and resistant H1299 cells. We conclude that long-term exposure of cancer cells to α-TOS causes their resistance to the drug, which can be overcome by its mitochondrially targeted counterpart. This finding should be taken into consideration when planning clinical trials with vitamin E analogues. 相似文献