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251.
Summary A random sample of seedlings representing high, medium and poor vigour was studied for tuber colour, tuber shape, eye depth, tuber cracking, tuber yield per plant, average tuber weight and number of tubers per plant in four successive generations (F1, F1, F1C2, and F1C3). Based on the performance of vigour groups in various generations and inter-generation correlation coefficients, we propose a procedure for the elimination of unproductive genotypes early in the breeding programme. The data indicates that seedlings of poor vigour can be discarded at the seedling stage prior to transplantation in the field. The rejection of clones on the basis of tuber colour, tuber shape, eye depth and tuber cracking can also be initiated at the seedling stage. For tuber yield and average tuber weight a negative selection (rejection of poor phenotypes) is suggested from the first clonal generation and for number of tubers, from second clonal generation, until statistically sound replicated trials can be conducted for carrying out positive selection.  相似文献   
252.
253.
Sodium ion batteries have attracted much attention in recent years, due to the higher abundance and lower cost of sodium, as an alternative to lithium ion batteries. However, a major challenge is their lower energy density. In this work, we report a novel multi‐electron cathode material, KVOPO4, for sodium ion batteries. Due to the unique polyhedral framework, the V3+ ? V4+ ? V5+ redox couple was for the first time fully activated by sodium ions in a vanadyl phosphate phase. The KVOPO4 based cathode delivered reversible multiple sodium (i.e. maximum 1.66 Na+ per formula unit) storage capability, which leads to a high specific capacity of 235 Ah kg?1. Combining an average voltage of 2.56 V vs. Na/Na+, a high practical energy density of over 600 Wh kg?1 was achieved, the highest yet reported for any sodium cathode material. The cathode exhibits a very small volume change upon cycling (1.4% for 0.64 sodium and 8.0% for 1.66 sodium ions). Density functional theory (DFT) calculations indicate that the KVOPO4 framework is a 3D ionic conductor with a reasonably, low Na+ migration energy barrier of ≈450 meV, in line with the good rate capability obtained.  相似文献   
254.
The present study was designed to evaluate the effect of P. aeruginosa on reproductive potential of male mice via a series of in vitro and in vivo experiments. In vitro studies involved sperm parameters, Mg2+ATPase activity and acrosome status. In vivo study employed male mice which in the right vas deferens received 20?μl of either PBS (Group I) or 104 cfu of P. aeruginosa (Group II). The animals were sacrificed on day 3, 7 and 14 and various parameters viz. body weight, TSI (%), bacterial load, spermiogram {i.e. sperm count, motility (%), viability (%) and morphology}, lipid peroxidation and tissue histopathology were evaluated. The results revealed that cell free supernatant of P. aeruginosa resulted in reduced motility, viability, Mg2+dependent ATPase activity and premature acrosomal loss of mouse spermatozoa in vitro. In vivo study showed that in comparison to group I, group II revealed significant alterations in all the parameters on all the days of sacrifice. Further, when reproductive organs of right and left side of mice in group II were compared, the right side demonstrated more devastating effects in terms of altered TSI (%) of testis and cauda epididymis, higher bacterial counts, azoospermia, increased malondialdehyde levels and severe inflammation in tissue histopathology in comparison to left side where bacteria disseminated in reduced numbers, thereby, resulting in insignificant changes in TSI (%), spermiogram, malondialdehyde levels and tissue histology. This study demonstrates that the colonization of P. aeruginosa in male genital tract could be a risk factor for fertility.  相似文献   
255.
256.
We synthesized a library of aminopyrazole analogs to systematically explore the hydrophobic pocket adjacent to the hinge region and the solvent exposed region of cyclin dependent kinases. Structure-activity relationship studies identified an optimal substitution for the hydrophobic pocket and analog 24 as a potent and selective CDK2/5 inhibitor.  相似文献   
257.
Nodulation is the first, and quantitatively predominant, cellular defense reaction to bacterial infection in insects and other invertebrates. Inhibition of eicosanoid biosynthesis in true armyworms, Pseudaletia unipuncta, and black cutworms, Agrotis ipsilon, immediately prior to intrahemocoelic injections with heat-killed preparations of the bacterium, Serratia marcescens, severely impaired the nodulation response. Five eicosanoid biosynthesis inhibitors, including dexamethasone (a phospholipase A(2) inhibitor), indomethacin, ibuprofen (cyclooxygenase inhibitors), phenidone (dual lipoxygenase/cyclooxygenase inhibitor) and eicosatetraynoic acid (an arachidonic acid analog that inhibits all arachidonic acid metabolism) severely reduced nodulation in infected insects. The dexamethasone effects were reversed by treating true armyworms with arachidonic acid immediately after infection. In addition to these pharmacological findings, we demonstrate that an eicosanoid biosynthesis system is present in these insects. Arachidonic acid is present in fat body phospholipids at about 0.4% of total phospholipid fatty acids. Fat body expressed a phospholipase A(2) that can hydrolyze arachidonic acid from the sn-2 position of cellular phospholipids. Fat body preparations were competent to biosynthesize prostaglandins, of which PGE(2) was the major product. These findings support the hypothesis that eicosanoids mediate cellular immune reactions in insects.  相似文献   
258.
Anin vitrosystem has been employed to study the apoptotic mechanisms in the AK-5 tumor which is a spontaneously regressing rat histiocytoma. Cytosolic extracts of tumor cells primed for apoptosis using dexamethasone and immune serum from tumor-regressing animals were able to induce apoptosis in intact nuclei and reproduce the classical morphological and biochemical features typical of apoptotic cells. The cleavage of lamin A and PARP to signature fragments by these extracts and the inhibition of the same using peptide inhibitors signify the pivotal role of ICE and ICE-related proteases in apoptosis. Lamin A cleavage was insensitive to YVAD but PARP cleavage was blocked by both YVAD and DEVD. Cell extracts derived from cells overexpressing theBcl-2gene andNedd-2antisense gene, respectively, failed to induce apoptosis in exogenously added nuclei, suggesting thatBcl-2gene product is downregulating a key event in apoptotic cascade. The study also demonstrates the coherent action of different ICE-related proteases in apoptosis and their functional redundancy. This system may prove useful for analyzing complex molecular mechanisms underlying apoptosis in tumor cells.  相似文献   
259.

Purpose

Distance-to-target (DTT) methods are weighting methods aimed at assessing the distance of an existing situation from a desired state (the target). Weighting factors in DTT methods could be based on calculation which is performed on normalization factors (NFs) developed for life cycle assessment (LCA). At present, some DTT weighting sets have been developed. However, there is no DTT weighting set assessing the distance of EU domestic impacts from the desired state set by EU binding or non-binding policy targets (e.g., those related to the “Climate and Energy Package” and the “Roadmap to a Resource Efficient Europe”).

Methods

In the present work, a methodology to derive target references from policy-based targets in 2020 (TRs2020), both binding (A) and non-binding (B), is presented. Resulting target factors and DTT weighting factors are then compared to the current normalisation factors (based on 2010 normalization references). The resulting weighting factor (WF) sets are presented and discussed in light of their use for decision support in policy and business contexts. We applied the WF sets to characterization results to an example (the EU energy mix process) aiming at illustrating key differences and effects on the results.

Results and discussion

The three reference sets (NRs2010, TRs2020A, and TRs2020B) show, in some impact categories, a relatively small difference. WFs referred to set A and set B result to be quite similar, with the only exception of water depletion impact category, for which a very relevant change is foreseen when considering the effect of the non-binding target of limiting the abstraction of water resource to 20 % of the available renewable water resources. This is mainly due to the higher difficulty in deriving quantitative targets from non-binding strategies and policies rather than from binding ones.

Conclusions

The resulting weighting sets present strengths and limitations. The translation of policy targets into quantitative modifications to the baseline inventories appeared to be not a straightforward task, due to several reasons discussed in the paper (e.g., not all the policy targets are expressed in quantitative terms or can be translated into quantitative reductions and modifications of the elementary flows in the existing baseline inventories). Aiming at improving the effectiveness in supporting policies, further development of the methodology may be the integration with other DTT approaches such those based on carrying capacity, developed to integrate Earth’s carrying capacity concept and planetary boundaries.
  相似文献   
260.
Hematopoietic stem cells (HSCs) are capable of giving rise to all blood cell lineages throughout adulthood, and the generation of engraftable HSCs from human pluripotent stem cells is a major goal for regenerative medicine. Here, we describe a functional genome‐wide RNAi screen to identify genes required for the differentiation of embryonic stem cell (ESC) into hematopoietic stem/progenitor cells (HSPCs) in vitro. We report the discovery of novel genes important for the endothelial‐to‐hematopoietic transition and subsequently for HSPC specification. High‐throughput sequencing and bioinformatic analyses identified twelve groups of genes, including a set of 351 novel genes required for HSPC specification. As in vivo proof of concept, four of these genes, Ap2a1, Mettl22, Lrsam1, and Hal, are selected for validation, confirmed to be essential for HSPC development in zebrafish and for maintenance of human HSCs. Taken together, our results not only identify a number of novel regulatory genes and pathways essential for HSPC development but also serve as valuable resource for directed differentiation of therapy grade HSPCs using human pluripotent stem cells.  相似文献   
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