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云南省哀牢山中山湿性常绿阔叶林萌生现象的初步研究 总被引:14,自引:1,他引:14
在森林树木受到人为或自然破坏以后,残留植物体的萌生是一个普遍存在的现象。据Kauffman〔1〕和Khan〔2〕等人在热带地区的研究,通过萌生形成的植株与通过种子萌发形成的植株相比,前者具有更快的生长速度,而且通过其原有的强大根系,能更有效地利用土壤中的养分资源,同时对环境也具有更强的适应能力。这些都构成了萌生植株在生长上的优势,使其在种群竞争中处于有利的地位。由此可见,萌生过程在植被恢复和自然更新中起到了重要的作用。近年来,关于植被萌生的研究在国外已得到越来越多的重视〔3~8〕,而在国内至今还未见到这方面的正式报道。… 相似文献
116.
Qun Li Zhiyuan Han Navleen Singh Berta Terr Ryann M. Fame Uzayr Arif Thomas D. Page Tasneem Zahran Ahmed Abdeltawab Yuan Huang Ping Cao Jun Wang Hao Lu Hart G. W. Lidov Kameswaran Surendran Lizhao Wu James Q. Virga Ying-Tao Zhao Ulrich Schüller Robert J. Wechsler-Reya Maria K. Lehtinen Sudipto Roy Zhongmin Liu Travis H. Stracker Haotian Zhao 《Cell death and differentiation》2022,29(8):1596
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Accumulation of protein and starch in grain is a key process determining grain yield and quality in wheat. Under drought or waterlogging, endogenous plant hormone levels will change and may have an impact on the yield and quality of wheat. In a greenhouse experiment, four winter wheat (Triticum aestivum L.) varieties differing in grain protein content, Heimai 76, Wanmai 38, Yangmai 10 and Yangmai 9, were subjected to drought (SRWC = 4550%, DR), waterlogging (WL) and moderate water supply (SRWC = 7580%, CK), beginning from 4 days post-anthesis (DPA) to maturity. On the 10 (grain enlargement stage) and 20 (grain filling stage) DPA, endogenous abscisic acid (ABA), gibberellins (GA1+3), indole-3-acetic acid (IAA) and zeatin riboside (ZR) were determined in sink and source organs of wheat plants by enzyme linked immunosorbent assay (ELISA). The patterns of hormonal changes were similar in four varieties. The ABA levels were much higher under DR and WL than under CK. Compared with CK, GA1+3 levels in whole-plant under DR and WL changed a little at 10 DPA, but markedly decreased under DR and WL at 20 DPA. Changes of endogenous IAA level under DR and WL exhibited a complicated pattern, depending on organs and growth stages. Particularly at the 20 DPA, the mean levels of IAA in roots, leaves and grains decreased significantly under DR and WL. In comparison with CK, ZR levels in all organs significantly decreased under DR and WL at both stages. The correlation analyses between yields and contents of starch and protein in grains and levels and ratios of four hormones in source and sink organs indicated that the changes in yield and content of grain starch and protein under DR and WL were associated with the reduced IAA, ZR and GA1+3 levels and elevated ABA level in plants, especially in grains. It was proposed that the changed levels of endogenous hormones under post-anthesis DR and WL might indirectly affect protein and starch accumulation in grains by influencing the regulatory enzymes and processes. 相似文献
118.
Yanyi Liu Michael Clark Qifeng Zhang Danmei Yu Dawei Liu Jun Liu Guozhong Cao 《Liver Transplantation》2011,1(2):194-202
Nanostructured V2O5 thin films have been prepared by means of cathodic deposition from an aqueous solution made from V2O5 and H2O2 directly on fluorine‐doped tin oxide coated (FTO) glasses followed by annealing at 500°C in air, and studied as film electrodes for lithium ion batteries. XPS results show that the as‐deposited films contained 15% V4+, however after annealing all the vanadium is oxidized to V5+. The crystallinity, surface morphology, and microstructures of the films have been investigated by means of XRD, SEM, and AFM. The V2O5 thin film electrodes show excellent electrochemical properties as cathodes for lithium ion intercalation: a high initial discharge capacity of 402 mA h g?1 and 240 mA h g?1 is retained after over 200 cycles with a discharging rate of 200 mA g?1 (1.3 C). The specific energy density is calculated as 900 W h kg?1 for the 1st cycle and 723 W h kg?1 for the 180th cycle when the films are tested at 200 mA g?1 (1.3 C). When discharge/charge is carried out at a high current density of 10.5 A g?1 (70 C), the thin film electrodes retain a good discharge capacity of 120 mA h g?1, and the specific power density is over 28 kW kg?1. 相似文献
119.
Copy-Number Mutations on Chromosome 17q24.2-q24.3 in Congenital Generalized Hypertrichosis Terminalis with or without Gingival Hyperplasia 总被引:1,自引:0,他引:1
Miao Sun Ning Li Wu Dong Qing Liu Guang He Xin Li Yang Luo Dan Lv Dai Zhang Chaoxia Lu Lihua Cao W.H. Irwin McLean Ming-Rong Wang Lin He Wilson H.Y. Lo 《American journal of human genetics》2009,84(6):807-813
Congenital generalized hypertrichosis terminalis (CGHT) is a rare condition characterized by universal excessive growth of pigmented terminal hairs and often accompanied with gingival hyperplasia. In the present study, we describe three Han Chinese families with autosomal-dominant CGHT and a sporadic case with extreme CGHT and gingival hyperplasia. We first did a genome-wide linkage scan in a large four-generation family. Our parametric multipoint linkage analysis revealed a genetic locus for CGHT on chromosome 17q24.2-q24.3. Further two-point linkage and haplotyping with microsatellite markers from the same chromosome region confirmed the genetic mapping and showed in all the families a microdeletion within the critical region that was present in all affected individuals but not in unaffected family members. We then carried out copy-number analysis with the Affymetrix Genome-Wide Human SNP Array 6.0 and detected genomic microdeletions of different sizes and with different breakpoints in the three families. We validated these microdeletions by real-time quantitative PCR and confirmed their perfect cosegregation with the disease phenotype in the three families. In the sporadic case, however, we found a de novo microduplication. Two-color interphase FISH analysis demonstrated that the duplication was inverted. These copy-number variations (CNVs) shared a common genomic region in which CNV is not reported in the public database and was not detected in our 434 unrelated Han Chinese normal controls. Thus, pathogenic copy-number mutations on 17q24.2-q24.3 are responsible for CGHT with or without gingival hyperplasia. Our work identifies CGHT as a genomic disorder. 相似文献
120.
Verstreken P Koh TW Schulze KL Zhai RG Hiesinger PR Zhou Y Mehta SQ Cao Y Roos J Bellen HJ 《Neuron》2003,40(4):733-748
We describe the isolation and characterization of Drosophila synaptojanin (synj) mutants. synj encodes a phosphatidylinositol phosphatase involved in clathrin-mediated endocytosis. We show that Synj is specifically localized to presynaptic terminals and is associated with synaptic vesicles. The electrophysiological and ultrastructural defects observed in synj mutants are strikingly similar to those found in endophilin mutants, and Synj and Endo colocalize and interact biochemically. Moreover, synj; endo double mutant synaptic terminals exhibit properties that are very similar to terminals of each single mutant, and overexpression of Endophilin can partially rescue the functional defects in partial loss-of-function synj mutants. Interestingly, Synj is mislocalized and destabilized at synapses devoid of Endophilin, suggesting that Endophilin recruits and stabilizes Synj on newly formed vesicles to promote vesicle uncoating. Our data also provide further evidence that kiss-and-run is able to maintain neurotransmitter release when synapses are not extensively challenged. 相似文献