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121.
Drosophila adult structures derive from imaginal discs, which are sacs with apposed epithelial sheets, the disc proper (DP) and the peripodial epithelium (PE). The Drosophila TGF-beta family member decapentaplegic (dpp) contributes to the development of adult structures through expression in all imaginal discs, driven by enhancers from the 3' cis-regulatory region of the gene. In the eye/antennal disc, there is 3' directed dpp expression in both the DP and PE associated with cell proliferation and eye formation. Here, we analyze a new class of dpp cis-regulatory mutations, which specifically disrupt a previously unknown region of dpp expression, controlled by enhancers in the 5' regulatory region of the gene and limited to the PE of eye/antennal discs. These are the first described Drosophila mutations that act by solely disrupting PE gene expression. The mutants display defects in the ventral adult head and alter peripodial but not DP expression of known dpp targets. However, apoptosis is observed in the underlying DP, suggesting that this peripodial dpp signaling source supports cell survival in the DP. 相似文献
122.
123.
Blackstock R Buchanan KL Cherniak R Mitchell TG Wong B Bartiss A Jackson L Murphy JW 《Mycopathologia》1999,147(1):1-11
Two isolates of Cryptococcus neoformans were previously described as being highly divergent in their level of capsule synthesis in vivo and in their virulence for mice. The highly virulent isolate (NU-2) produced more capsule than a weakly virulent isolate (184A) in vitro under tissue culture conditions and in vivo. This investigation was done to determine if there were differences between the two isolates in other factors that might also contribute to virulence. Growth rate was not a factor as NU-2 grew more slowly than 184A. Based on PCR fingerprinting the two isolates were genetically different providing an opportunity to examine differences in multiple virulence traits. Quantitative analysis revealed that NU-2 expressed significantly more melanin and mannitol than did 184A. Although the isolates expressed the same capsular chemotype, NU-2 produced an additional structure reporter group (SRG)under tissue culture conditions that was not present when grown in glucose salts/urea/basal medium (GSU).Capsular polysaccharide SRGs of 184A were unaffected by shifting the growth conditions from GSU to tissue culture conditions. Our results suggest that pathogenesis of a C. neoformans strain is dictated by the quantitative expression of the strain's combined virulence traits. Regulators of the expression of these genes may be playing key roles in virulence.This revised version was published online in October 2005 with corrections to the Cover Date. 相似文献
124.
Mass spectrometry comparative screening was used to identify ovarian regulatory peptides involved in the successive steps of egg-laying in the cuttlefish Sepia officinalis. The peptide content of full-grown oocytes (FGO) was compared with that of oocyte-conditioned medium, which resulted in the detection of peptides that were present in both samples. These peptides, which are suspected of being released by the oocyte in the genital tract, were submitted to a structural analysis. This strategy led to the characterization of a new ovarian regulatory peptide (EISLDKD) able to inhibit the contractions of the whole female genital tract and of the main nidamental glands (MNG). As EISLDKD appeared to be the first regulatory peptide directly involved, at physiological concentrations, in the secretion of the egg capsule by the main nidamental glands, it was named SepCRP for Sepia Capsule Releasing Peptide. Mass spectrometry analysis clearly demonstrated that SepCRP was expressed during vitellogenesis by the ovarian follicles and released by the FGO in the lumen of the female genital tract. In association with the ovarian 5-HT, SepCRP would be responsible for the storage of FGO to avoid the spawning of unfertilized oocytes before mating. Released by the distal oviduct in the mantle cavity, SepCRP probably in association with a cocktail of ovarian regulatory factors targets the MNG to regulate the egg capsule secretion. Thus, the ovary appeared to be one of the main sources of regulatory peptides involved in the successive steps of egg-laying in the cephalopod mollusk S. officinalis. 相似文献
125.
The droplet breakup technique with an immiscible liquid coflowing stream was investigated for the preparation of mammalian cell-enclosing subsieve-sized capsules of less than 100 microm in diameter. The major parts of the droplet generation device were a needle of several hundred micrometers in diameter for extruding the cell-suspending sodium alginate aqueous solution and a tubule of 2.5 mm in diameter through which the extruded alginate solution flowed into ambient immiscible liquid paraffin. The needle was positioned upstream in the vicinity of the coaxial tubule. The droplet diameter of the viscous sodium alginate aqueous solution could be controlled from several dozen to several hundred micrometers by changing the velocities of the inner and ambient fluids and the diameter of the needle. By utilizing a 300-microm diameter needle, CHO-K1 cell-enclosing droplets of 48 +/- 8 microm in diameter were obtained by extruding a cell-suspending sodium alginate solution at a velocity of 1.2 cm/sec into the ambient liquid paraffin flowing at a velocity of 23.5 cm/sec. The breakup process did not influence the viability of the enclosed cells, since more than 95% of the CHO-K1 cells remained alive after the enclosing process. 相似文献
126.
Distinguishing the contributions of the perichondrium, cartilage, and vascular endothelium to skeletal development 总被引:4,自引:0,他引:4
During the initiation of endochondral ossification three events occur that are inextricably linked in time and space: chondrocytes undergo terminal differentiation and cell death, the skeletal vascular endothelium invades the hypertrophic cartilage matrix, and osteoblasts differentiate and begin to deposit a bony matrix. These developmental programs implicate three tissues, the cartilage, the perichondrium, and the vascular endothelium. Due to their intimate associations, the interactions among these three tissues are exceedingly difficult to distinguish and elucidate. We developed an ex vivo system to unlink the processes initiating endochondral ossification and establish more precisely the cellular and molecular contributions of the three tissues involved. In this ex vivo system, the renal capsule of adult mice was used as a host environment to grow skeletal elements. We first used a genetic strategy to follow the fate of cells derived from the perichondrium and from the vasculature. We found that the perichondrium, but not the host vasculature, is the source of both trabecular and cortical osteoblasts. Endothelial cells residing within the perichondrium are the first cells to participate in the invasion of the hypertrophic cartilage matrix, followed by endothelial cells derived from the host environment. We then combined these lineage analyses with a series of tissue manipulations to address how the absence of the perichondrium or the vascular endothelium affected skeletal development. We show that although the perichondrium influences the rate of chondrocytes maturation and hypertrophy, it is not essential for chondrocytes to undergo late hypertrophy. The perichondrium is crucial for the proper invasion of blood vessels into the hypertrophic cartilage and both the perichondrium and the vasculature are essential for endochondral ossification. Collectively, these studies clarify further the contributions of the cartilage, perichondrium, and vascular endothelium to long bone development. 相似文献
127.
C. Dolinski G. Borgonie R. Schnabel James G. Baldwin 《Development genes and evolution》1998,208(9):495-503
Bacterial feeding nematodes in the order Rhabditida including Zeldia punctata (Cephalobidae) and Caenorhabditis elegans (Rhabditidae) differ profoundly in the buccal capsule parts and associated cells. We carried out a range of tests to determine
which buccal capsule parts and cells are evolutionarily homologous between the representative species of the two families.
Tests included reconstruction of the buccal capsule and procorpus with transmission electron microscopy (TEM), nuclei position
and morphology using 4,6-diamidino-2-phenylindole (DAPI) staining, and cell lineage using four dimensional (4D) microscopy.
The lining of the buccal capsule of Z. punctata and additional Cephalobidae includes four sets of muscular radial cells, ma, mb, mc and md, in contrast to C. elegans and additional Rhabditidae, which has two sets of epithelial cells (e1, e3) and two sets of muscle cells (m1, m2). Cell lineage
of a nematode closely related to Z. punctata, Cephalobus cubaensis, supports the hypothesis that in cephalobids the e1 and e3 cells become hypodermal cells or are programmed to die. Our findings
contradict all previous hypotheses of buccal capsule homology, and suggest instead that ma and mb in Z. punctata are homologous to m1 and m2 in C. elegans respectively. We also hypothesize that ma and mb could be homologous to primary and secondary sets of stylet-protractor muscle
cells in the plant parasitic Tylenchida.
Received: 24 March 1998 / Accepted: 24 July 1998 相似文献
128.
W. O. C. Symondson 《BioControl》1994,39(3-4):323-333
Previous work has shown thatAbax parallelepipedus Piller &; Mitterpacher preys upon slugs in the field, and can be effectively employed to control slugs in polythene tunnels. To be a viable biological control agent this carabid must also be amenable to mass culturing. Manipulation of the substrate ensured that eggs were laid in soil capsules, but deposited in peat, facilitating collection and monitoring. Up to 570 eggs per beetle were laid at 20°C. No cannibalism was exhibited at any stage by this species. Larvae were reared intensively in batches and fed ad libitum on live earthworms, eliminating the need for regular feeding and the removal of decaying food. Rearing experiments were undertaken under a number of different temperature regimes. At constant 20°C it was found that growth was arrested in some 2nd instar larvae for long periods. Co-ordinated changes between 2nd and 3rd instar stages were induced by reduction of the temperature to 14°C between days 24–31 from hatching. The complete life cycle, from newly laid egg to adult beetle, could be reduced to less than 110 days. Mortality was greatest at the late 3rd instar and pre-pupal stages, and possible reasons for this are discussed. 相似文献
129.
摘要 目的:探讨益肺胶囊联合乌美溴铵维兰特罗吸入粉雾剂对慢性阻塞性肺疾病(COPD)疾病稳定期患者肺功能、细胞免疫功能和血清碱性成纤维细胞生长因子(bFGF)、沉默信息调节因子1(SIRT1)的影响。方法:纳入我院2021年3月~2022年6月期间收治的COPD稳定期患者104例,按照随机数字表法分为对照组(乌美溴铵维兰特罗吸入粉雾剂治疗,n=52)和观察组(益肺胶囊联合乌美溴铵维兰特罗吸入粉雾剂治疗,n=52)。对比两组临床症状恢复时间、6 min步行试验(6MWT)和COPD评估测试(CAT)评分、肺功能[第1秒用力呼气容积(FEV1)、用力肺活量(FVC)、每分钟最大通气量(MVV)]、细胞免疫功能和血清bFGF、SIRT1水平,观察两组不良反应发生情况。结果:与对照组相比,观察组的肺啰音、咳嗽、咯痰消失时间缩短(P<0.05)。与对照组相比,观察组治疗14 d后6MWT更远,CAT评分更低(P<0.05)。与对照组相比,观察组治疗14 d后FVC、FEV1、MVV更高(P<0.05)。与对照组相比,观察组治疗14 d后CD3+、CD4+、CD4+/CD8+更高,CD8+更低(P<0.05)。与对照组相比,观察组治疗14 d后bFGF更低,SIRT1更高(P<0.05)。两组不良反应总发生率组间对比无差异(P>0.05)。结论:益肺胶囊联合乌美溴铵维兰特罗吸入粉雾剂有助于调节COPD稳定期患者血清bFGF、SIRT1水平,改善肺功能和细胞免疫功能。 相似文献
130.
A synergistic Hawaiian (GVH) and a nonsynergistic Oregonian (GVO) strain of a granulosis virus (GV) infect the armyworm, Pseudaletia unipuncta. The protein components of the enveloped virions and of the capsule (inclusion body) were compared between the two strains. When the enveloped virions of both strains were analyzed by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, the protein patterns were similar except for minor peaks in the higher molecular weight region. On the other hand, the capsule proteins differed between the two strains when examined with immunoelectrophoresis and SDS-polyacrylamide gel electrophoresis. The capsule proteins of GVH were composed of two major proteins, one a structural protein and the other the protein of the synergistic factor. The capsule protein of GVO, however, had only the structural protein. The rocket immunoelectrophoresis and affinity chromatography indicated that the structural proteins of the two strains were partially dissimilar. The molecular weight of the structural protein of GVO was 29,100 ± 500 and that of GVH was 28,700 ± 500. The amount of synergistic factor in a GVH capsule was about 5% of the dissolved capsule components. 相似文献