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21.
通过测定红细胞胞浆及膜中的PTPP活性,发现人正常血红细胞中胞浆PTPP活性约占红细胞PTPP总活性的70-80%,膜中只有约20-30%的PTPP活性。很多因素诸如:病变、PH值、温度、离子强度、细胞贮存时间以及药物等,对PTPP在胞浆与膜中的分布有影响。可以推测:膜上的PTPP能通过某种机制解离下来,进入胞浆;相反的过程,胞浆中的PTPP也能通过某种机制与膜结合。这种偶联与去偶联的具体机制及其生理功能还有待进一步探索。 相似文献
22.
Absence of a direct role for RNase HI in initiation of DNA replication at the oriC site on the Escherichia coli chromosome. 总被引:1,自引:0,他引:1 下载免费PDF全文
On the basis of the experiments carried out with rnhA224 mutants, we previously concluded that RNase HI is not essential for initiation of Escherichia coli chromosome replication at oriC (T. Kogoma, N.L. Subia, and K. von Meyenburg, Mol. Gen. Genet. 200:103-109, 1985). In light of the recent finding that rnhA224 is a UGA nonsense mutation which can be leaky in certain genetic backgrounds, we reexamined this conclusion with the use of rnhA339 (Null)::cat mutants. The possibility that recB+ is required for initiation at the alternative origins (oriKs) of replication in rnhA mutants was also tested. The results clearly indicated that RNase HI is not essential for oriC initiation and that recB+ is not required for initiation at oriK sites. 相似文献
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24.
Amino Acids - Protein arginine N-methyltransferases (PRMTs) have emerged as important actors in the eukaryotic stress response with implications in human disease, aging, and cell signaling.... 相似文献
25.
Xiang-yun Zhu 《Nordic Journal of Botany》2003,23(3):373-384
The pollen morphology of Gueldenstaedtia gansuensis. G. gracilis, G. henryi, G. monophylla. G. mutijlora, G. stenophylla. and G. verna and Tibetia liangshanensis, T. tongolensis, T. yadongensis. T. coelestis, and T yunnanensis are reported for the first time. The seed morphology of G. gracilis, G. maritima. G. monophylla, G. mutiflora, G. taihangensis, and G. verna and L coelestis, T. himalaica, T. yunnanensis, and T. yadongensis are firstly described here. In pollen morphology, the differences of pollen grains of Gueldenstaedtia and Tibetia are as follows: Gueldenstaedtia with pollen grains 3–colporate, psilate, and shapes spheroidal, sometimes subprolate, prolate or oblong; and Tibetia with pollen grains 3– and 4–colporate, perforate, shapes spheroidal, sometimes subprolate or prolate. These results, combined with the data of the basic chromosome number x=7 of Gueldenstaedtia and x=8 of Tibetia, support that the two genera should be recognized as two distinct genera, which are consistent with their morphological characters: Gueldenstaedtia with 2 upper lobes of calyx free, stipules free, adnate to petiole, and Tibetia with 2 upper lobes of calyx connate, stipules connate and opposite to leaves. In Tibetia, two types of pollen grains, 3– and 4–colporate pollen grains, are found. Regarding seed morphology: Gueldenstaedtia has circular depression, irregular circular depression or irregular circular reticulation on the surface; Tibetia has smooth surface. The differences in seed morphology of the two genera also support that they should be kept separate. The pollen morphology supports that G. gansuensis, G. gracilis, G. multiflora, G. stenophylla, and G. verna should be reduced into one species consistent with their morphological characteristics. The pollen grains of G. henryi are different from those of the other species in having wide colpi. 相似文献
26.
The type 1 insulin-like growth factor receptor (IGF-IR) and its docking protein, insulin receptor substrate-1 (IRS-1), play important roles in cell transformation, cell differentiation and aging. IRS-1 and other IRS proteins can, under certain conditions, localize to the nuclei of cells, where they undergo interactions with nuclear and nucleolar proteins. In this study, we confirm and extend these observations, demonstrating that IRS-1 is preferentially nuclear in growing cells. Differentiation and inhibition of ribosomal RNA synthesis cause subcellular redistribution of IRS-1 and other nuclear proteins to the cytoplasm. 相似文献
27.
Detection of Salmonella typhi by polymerase chain reaction 总被引:1,自引:0,他引:1
A rapid and sensitive method for detection of Salmonella typhi would help in preventing the spread of outbreaks and in clinical diagnosis. In order to develop unique PCR primers to detect Salm. typhi , ribosomal RNA genes from Salm. typhi (Rawlings) were cloned in pUC18. The resulting clone was confirmed by sequencing. The cloned DNA fragment contained the 5S, part of the 23S rRNA genes and the 5S-23S spacer region (EMBL/GenBank accession No. U04734).
It was expected that the 5S-23S spacer region is divergent unlike the highly conserved 23S+5S genes. This was confirmed by comparison with the rRNA gene sequences in the EMBL/GenBank database. A pair of PCR primers specific for Salm. typhi was obtained, based on this spacer region sequence. The specificity of this pair of primers was tested with 54 Salm. typhi strains (of 27 different phage types). All these Salm. typhi strains showed the positive 300 bp PCR product with this pair of primers. Six other Salmonella species as well as six other non- Salmonella bacteria were tested and none showed the 300 bp PCR product. The sensitivity of the detection level was 0·1 pg of pure Salm. typhi genomic DNA, or approximately 40 Salm. typhi cells in a spiked food sample. This pair of primers therefore has the potential for development into a diagnostic tool for the rapid diagnosis of typhoid fever. 相似文献
It was expected that the 5S-23S spacer region is divergent unlike the highly conserved 23S+5S genes. This was confirmed by comparison with the rRNA gene sequences in the EMBL/GenBank database. A pair of PCR primers specific for Salm. typhi was obtained, based on this spacer region sequence. The specificity of this pair of primers was tested with 54 Salm. typhi strains (of 27 different phage types). All these Salm. typhi strains showed the positive 300 bp PCR product with this pair of primers. Six other Salmonella species as well as six other non- Salmonella bacteria were tested and none showed the 300 bp PCR product. The sensitivity of the detection level was 0·1 pg of pure Salm. typhi genomic DNA, or approximately 40 Salm. typhi cells in a spiked food sample. This pair of primers therefore has the potential for development into a diagnostic tool for the rapid diagnosis of typhoid fever. 相似文献
28.
本文利用小鼠大脑机械损伤模型及体外培养的胶质细胞,采用同位素渗入法观察了细胞介素及其抗体对胶质细胞增生的影响。结果表明:体外培养时TNF-α在浓度为10~200u/ml培养液时均能促进胶质细胞增生(P<0.05),IL1-β在浓度为5~200u/ml培养液时能促进胶质细胞增生,TNF-α+IL1-β其促进胶质细胞增生作用更强烈,TNF-α抗体能完全阻断TNF-α的促增生作用,部分阻断TNF-α+IL1-β的促增生作用。在体实验时,IL1-β及TNF-α的作用与离体时相似,IL1-β及TNF-α亦能促进胶质细胞增生,二者共同作用时促细胞增生作用更强。以上结果提示,外源性TNF-α及IL1-β能促进中枢神经损伤后胶质细胞增生且具有协同作用。 相似文献
29.
黄精凝集素Ⅱ分子稳定性与生物学活性研究鲍锦库,曾仲奎,周红(四川大学生物系,成都,610064)本文在黄精凝集素Ⅱ纯化及性质研究的基础上,应用多种变性条件,研究其分子特性,同时对分子的巯基和色氨酸进行修饰,研究该凝集素分子保持其生物学活性与这些基团的... 相似文献
30.
Abstract The present paper deals with a new species Habrophlebiodes zijinensis sp. nov. collected in Nanjing, Jiangsu Povince, China. 相似文献