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71.
用硫酸铵分段盐析及DEAE-Sephadex A-50、羟磷灰石和CM纤维素等多种柱层析方法,从正常小鼠肝浸液中分离纯化出一种免疫抑制蛋白质(LISP)。在体外用微量该蛋白质就能强烈抑制小鼠T、B淋巴细胞对促有丝分裂原和同种异型抗原的增生反应。纯化的蛋白质在聚丙烯酰胺凝胶电泳(PACE)和等电聚焦(IEF)鉴定时均显示为一条区带,其等电点(pI)值在7.5—7.8范围。沉降系数利S_(20),w为5.39。Sephadex G-100凝胶层析测得LISP的分子量为78,000道尔顿。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)提示LISP是由二个相同的亚基组成,亚基分子量为38,500道尔顿。LISP是一种既非糖蛋白又非脂蛋白的碱性蛋白质,对它的氨基酸组成也作了分析。 相似文献
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Sixty depressed patients and 52 normal controls completed three selfreport inventories: the Symptom Checklist-90 (SCL-90), the Beck Depression Inventory (BDI) and a new Verbal Style Investigation Schedule (VESIS) developed by the first author. The VESIS uses 16 key emotional and physical terms from Western inventories and identified the words and phrases most commonly used by Chinese patients to express these feeling states. Chinese subjects commonly used the key term itself for only 3 or the 16 key terms; they usually preferred to use other words or phrases to express the feeling state. We categorized these Chinese expressions into four styles of verbal expression: Psychological, Somatic, Neutral (i.e., a mixture of psychological and somatic) and Deficient (i.e., lack of expression because of denial or suppression). Three of the 12 key emotional terms of the VESIS (depressed, fearful, and anxiousness) were more commonly expressed in a somatic or neutral mode than the other key emotional terms. The key terms suicidal interest and being punished were more commonly expressed in a deficient style than other key emotional terms. The somatic factor score of the SCL-90 was not correlated with increased somatic expression of emotional states; thus patients who have multiple somatic complaints are not more likely to express emotions somatically. The hypothesis of somatization is discussed in light of this study. 相似文献
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Molecular cloning of a human gene that regulates chromosome condensation and is essential for cell proliferation. 总被引:19,自引:3,他引:16
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The tsBN2 cell line, a temperature-sensitive (ts) mutant of baby hamster kidney cell line BHK21/13, seems to possess a mutation in the gene that controls initiation of chromosome condensation. At the nonpermissive temperature (39.5 degrees C), the chromatin of tsBN2 cells is prematurely condensed, and the cells die. Using tsBN2 cells as a recipient of DNA-mediated gene transfer, we investigated a human gene that is responsible for regulation of chromosome condensation and cell proliferation. We found that the human gene complementing the tsBN2 mutation resides in the area of the 40- to 50-kilobase HindIII fragment, derived from HeLa cells. Based on this finding, we initiated cloning of a human gene complementing the tsBN2 mutation. From lambda and cosmid libraries carrying partial digests of DNA from the secondary transformants, the 41.8-kilobase HindIII fragment containing the human DNA was isolated. The cloned human DNA was conserved in ts+ transformants through primary and secondary transfections. Two cosmid clones convert the ts- phenotype of tsBN2 cells to ts+ with more than 100 times a higher efficiency, compared with cases of transfection with total human DNA. Thus, the cloned DNA fragments contain an active human gene that complements the tsBN2 mutation. 相似文献
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Although acute alterations in Ca2+ fluxes may mediate the skeletal responses to certain humoral agents, the processes subserving those fluxes are not well understood. We have sought evidence for Ca2+-dependent ATPase activity in isolated osteoblast-like cells maintained in primary culture. Two Ca2+-dependent ATPase components were found in a plasma membrane fraction: a high affinity component (half-saturation constant for Ca2+ of 280 nM, of 13.5 nmol/mg per min) and a low affinity component, which was in reality a divalent cation ATPase, since Mg2+ could replace Ca2+ without loss of activity. The high affinity component exhibited a pH optimum of 7.2 and required Mg2+ for full activity. It was unaffected by potassium or sodium chloride, ouabain or sodium azide, but was inhibited by lanthanum and by the calmodulin antagonist trifluoperazine. This component was prevalent in a subcellular fraction which was also enriched in 5′-nucleotidase and adenylate cyclase activities, suggesting the plasma membrane as its principal location. Osteosarcoma cells, known to resemble osteoblasts in their biological characteristics and responses to bone-seeking hormones, contained similar ATPase activities. Inclusion of purified calmodulin in the assay system caused small non-reproducible increases in the Ca2+-dependent ATPase activity of EGTA-washed membranes. Marked, consistent calmodulin stimulation was demonstrated in membranes exposed previously to trifluoperazine and then washed in trifluoperazine-free buffer. These results indicate the presence of a high affinity, calmodulin-sensitive Ca2+-dependent ATPase in osteoblast-like bone cells. As one determinant of Ca2+ fluxes in bone cells, this enzyme may participate in the hormonal regulation of bone cell function. 相似文献
80.
Cytosine residues of poly(C) and heat-denatured calf thymus DNA were transformed into 5,6-dihydrouracil-6-sulfonate (U(SO−3)) residues by treatment with bisulfite. The poly(U(SO−3)2, C3) and poly(U(SO−3)9, C1) prepared did not form inter-base binding with either poly(A) or poly(I) as judged by the absence of hypochromicity in ultraviolet absorbance. U(SO−3) residues in the DNA inactivated it to serve as template for E.coli DNA polymerase I, while the template activity was restored by conversion of the U(SO−3) residues into U. 相似文献