全文获取类型
收费全文 | 871篇 |
免费 | 98篇 |
国内免费 | 1篇 |
出版年
2023年 | 4篇 |
2021年 | 14篇 |
2020年 | 23篇 |
2019年 | 43篇 |
2018年 | 35篇 |
2017年 | 8篇 |
2016年 | 17篇 |
2015年 | 18篇 |
2014年 | 36篇 |
2013年 | 46篇 |
2012年 | 49篇 |
2011年 | 33篇 |
2010年 | 31篇 |
2009年 | 18篇 |
2008年 | 40篇 |
2007年 | 36篇 |
2006年 | 31篇 |
2005年 | 33篇 |
2004年 | 14篇 |
2003年 | 25篇 |
2002年 | 23篇 |
2001年 | 26篇 |
2000年 | 22篇 |
1999年 | 21篇 |
1998年 | 24篇 |
1997年 | 9篇 |
1996年 | 26篇 |
1995年 | 22篇 |
1994年 | 12篇 |
1993年 | 16篇 |
1992年 | 16篇 |
1991年 | 12篇 |
1990年 | 12篇 |
1989年 | 17篇 |
1988年 | 8篇 |
1987年 | 11篇 |
1986年 | 11篇 |
1985年 | 9篇 |
1984年 | 12篇 |
1983年 | 10篇 |
1982年 | 5篇 |
1981年 | 9篇 |
1980年 | 6篇 |
1979年 | 16篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1974年 | 7篇 |
1973年 | 5篇 |
1972年 | 4篇 |
1939年 | 4篇 |
排序方式: 共有970条查询结果,搜索用时 78 毫秒
1.
A case of chromomycosis in which hyperthermia proved effective is reported. The patient was a 56-year-old male bean curd maker who, without any previous history of minor trauma, developed on the extensor side of the left upper arm an eczematous lesion that underwent gradual radial expansion. The lesion showed a well-defined, 7×10 cm infiltrated erythematous plaque with the central area healed and, at the upper and lower borders, adherent scales and crusts on the surface. Histological examination revealed granulomatous changes in the dermis, as well as sclerotic cells within giant cells and microabscesses. On culturing,Fonsecaea pedrosoi was isolated. The patient was treated with disposable chemical pocket warmers, which were secured over the lesion with a rather tight elastic bandage, so that they kept the affected area warm for 24 hours a day. After a month of such hyperthermic treatment, the erythema and infiltration had decreased considerably, and microscopic examination and culture of the crusts both yielded negative results. Examination of biopsy specimens of the lesion after the third month showed that it had cicatrized. The treatment was stopped after 4 months, and no relapse occurred. We also summarize the published results of local hyperthermic treatment of chromomycosis in Japan. 相似文献
2.
3.
Cheng Qian MD Danqi Chang MD Hang Li MD Yanggan Wang 《Journal of cellular biochemistry》2019,120(5):7771-7777
Heart failure (HF) remains a common complication after acute ST-segment elevation myocardial infarction (STEMI). Here, we aim to identify critical genes related to the developed HF in patients with STEMI using bioinformatics analysis. The microarray data of GSE59867, including peripheral blood samples from nine patients with post-infarct HF and eight patients without post-infarct HF, were downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) between HF and non-HF groups were screened by LIMMA package. Functional enrichment analyses of DEGs were conducted, followed by construction of a protein-protein interaction (PPI) network. The dynamic messenger RNA (mRNA) level of the hub genes during the follow-up was analyzed to further elucidate their role in HF development. A total of 58 upregulated and 75 downregulated DEGs were screen out. They were mainly enriched in biological processes about inflammatory response, extracellular matrix organization, response to cAMP, immune response, and positive regulation of cytosolic calcium ion concentration. Pathway analysis revealed that the DEGs were also involved in hematopoietic cell lineage, pathways in cancer, and extracellular matrix-receptor interaction. In the PPI network consisting of 58 nodes and 72 interactions, CXCL8 (degree = 15), THBS1 (degree = 8), FOS (degree = 7), and ITGA2B (degree = 6) were identified as the hub genes. In the comparison of patients with and without post-infarct HF, the mRNA level of these hub genes were all higher within 30 days but reached similar at 6 months after STEMI. In conclusion, CXCL8, THBS1, FOS, and ITGA2B may play important roles in the development of HF after acute STEMI. 相似文献
4.
U. Behrens N. Fedoroff A. Laird M. Müller-Neumann P. Starlinger J. Yoder 《Molecular & general genetics : MGG》1984,194(1-2):346-347
Summary The cloning of the controlling element Ac from the wx-m7 allele of Zea mays is described. The cloned fragment carries a 4.3 kb insertion that by restriction analysis is indistinguishable from the Ac insertion in Ac wx-m9. It is located approximately 2.5 kb upstream of the Ac wx-m9 insertion.
Offprint requests to: P. Starlinger 相似文献
5.
The application of culture-dependent studies to quantify Fe-metabolizing microorganisms from the environment is a necessity, as there are so far no universal functional marker genes for application in culture-independent studies. Media composition can vary between studies, therefore, we determined the effects of three different growth media on the quantification (MPNs) and identity (via cloning and sequencing of dominant DGGE bands) of nitrate-reducing Fe(II)-oxidizers and lactate- or acetate-oxidizing Fe(III)-reducers from a lacustrine sediment: low sulphate freshwater medium (FWM), sterile filtered bicarbonate-buffered lake water (BLW) and a mixture of both (MIX). We consistently found fewer cells in the BLW than in the FWM and the MIX. The DGGE banding patterns of the microbial communities enriched in different media types clustered together according to the e? donor and acceptor couples and not according to the medium used. Thus, although the medium composition significantly influenced the quantification and thereby conclusions on the abundance and potential significance of the targeted group within the ecosystem, biodiversity assessments through enrichment cultures were less influenced by the medium, but instead were affected by the type and concentration of the e? donor/acceptor. 相似文献
6.
7.
A cancer microenvironment generates strong hydrogen bond network system by the positive feedback loops supporting cancer complexity and robustness. Such network functions through the AKT locus generating high entropic energy supporting cancer metastatic robustness. Charged lepton particle muon follows the rule of Bragg effect during a collision with hydrogen network in cancer cells. Muon beam dismantles hydrogen bond network in cancer by the muon-catalyzed fusion, leading to apoptosis of cancer cells. Muon induces cumulative energy appearance on the hydrogen bond network in a cancer cell with its fast decay to an electron and two neutrinos. Thus, muon beam, muonic atom, muon neutrino shower, and electrons simultaneously cause fast neutralization of the AKT hydrogen bond network by the conversion of hydrogen into deuterium or helium, inactivating the hydrogen bond networks and inducing failure of cancer complexity and robustness with the disappearance of a malignant phenotype. 相似文献
8.
9.
Zusammenfassung Die Pylorusanhänge (P. A.) von Asterias rubens L. wurden licht- und elektronenmikroskopisch untersucht. — Die Wandung der P. A. gliedert sich in eine hohe Epithelschicht, in deren basalen Abschnitten zahlreiche Nervenfasern verlaufen, eine bindegewebige Basallamelle und ein Coelomepithel, dessen Zellen eine lockere Lage von glatten Muskelzellen und Axonen bedecken.Die Zellen des Epithels der P. A. sind mit einem dichten, gleichmäßig ausgebildeten Bürstensaum ausgestattet, ferner mit je einer langen, mit einer Wimperwurzel verbundenen Cilie (9+2-Typus), die sich in die Lichtung der Caeca erhebt. Die Wimperwurzeln besitzen eine periodische Gliederung. Vereinzelte Epithelzellen tragen ein plumperes, unregelmäßig gestaltetes Geäst von Mikrovilli. Die bereits lichtmikroskopisch wahrnehmbare zarte Streifung der Zellapices beruht auf dem Vorhandensein von parallelisierten Mikrotubuli. Starke Vesikulation der Saumzellen und das Vorhandensein pinozytotischer Bläschen an der Basis der Mikrovilli ist als Ausdruck lebhafter resorptiver Tätigkeit des Epithels der P. A. anzusehen. Vor allem in den basalen Abschnitten der Epithelzellen liegen kugelige Lipideinschlüsse, in anderen Zellen Mukopolysaccharidgranula. An der Oberfläche der Epithelzellen werden Mukopolysaccharide ausgestoßen, teilweise in Form zusammengesinterter, unregelmäßig gestalteter Bildungen. Das morphologische Äquivalent der von anderen Autoren beschriebenen sog. Zymogenkörnchen konnte mit Sicherheit nicht ermittelt werden. Intraepitheliale Sinneszellen wurden nicht beobachtet.Die nackten Axone innerhalb des Epithels der P. A. lagern sich den Basalteilen der Saumzellen an, bilden jedoch mit ihnen keine typischen, d. h. durch Membranverdickungen ausgezeichneten Synapsen. Ihr Axoplasma enthält außer Neurotubuli Bläschen mit massendichtem Inhalt, die Granula aminerger oder peptiderger Nervenfasern ähneln. Möglicherweise sind bei Asterias Nervenfasern jeweils verschiedenen Inhalts ausgebildet, da Profile von Axonen mit kleineren (1000–1200 Å Durchmesser) und größeren Granula (1200–1600 Å) nachzuweisen sind. Das Vorkommen von Ergastoplasmastrukturen und Golgimembranen in den Axonen sowie die Abschnürung von Vesikeln mit massendichtem Inhalt vom Golgiapparat spricht für eine Entstehung von Elementargranula in der Peripherie der entsprechenden Neurone. Das Bild synaptischer Bläschen kann durch entleerte Elementargranula vorgetäuscht werden.Die glatten Muskelzellen unter dem Coelomepithel stehen mit Nervenendigungen, die dense-cored vesicles enthalten, in Berührung, doch sind Synapsen mit Membranverdickungen, wie sie bei den Vertebraten angetroffen werden, nicht ausgebildet.
Summary The pyloric ceca (p. c.) of the starfish, Asterias rubens L., are investigated light- and electronmicroscopically.The wall of the p. c. consists of 1. a high columnar epithelium the basal part of which is permeated by many axons, 2. a basal lamina, 3. a loose layer of smooth muscle cells intermingled with thin nerve fibres, and 4. the coelomic epithelium. Intraepithelial sensory elements are lacking in the epithelium.The epithelial cells of the p. c. are provided with a very well developed brush border built up by microvilli of equal length and diameter. In addition each cell bears a long cilium (9 + 2 pattern) connected with a periodically structured rootlet. Only single cells are characterized by a more or less irregular seam of plump ramified microvilli. The parallel orientation of microtubules in the apical parts of the cells causes the striation already to be observed under the light microscope.The intense vesiculation of the cytoplasm and the occurrence of many pinocytotic invaginations on the basis of the brush border is considered to be the equivalent of the high absorption activity of the epithelial cells.Spheroidal lipid inclusions, mucopolysaccharide granules and large masses of unknown nature are embedded in the cytoplasm of the epithelial cells. Irregularly shaped mucopolysaccharide substances are extruded into the lumen of the p. c. The occurrence of so-called zymogen granules has not been observed in our material.The intraepithelial axons are closely attached to the basal parts of the epithelial cells without forming typical synapses with membrane thickenings. Apart from neurotubules, the axoplasm of these tiny fibres contains dense-cored vesicles (diameter 1000–1200 Å, 1200–1600 Å) resembling the elementary granules of aminergic and peptidergic nerve fibres. The presence of ergastoplasmic structures and Golgi membranes within the axoplasm and the gemmation of dense-cored vesicles from the Golgi apparatus speaks in favour of a peripheral elaboration of elementary granules in the axons of the starfish.The smooth muscle cells covered by the coelomic epithelium of the p. c. are in contact with axonal terminals containing dense-cored and empty vesicles. Typical synaptic structures as described for vertebrates apparently do not exist in the starfish.相似文献
10.
Eight Danish Holstein cows were milked with a 1-mm thick specially designed soft liner on their right rear teat and a standard
liner mounted under extra high tension on their left rear teat. Four of the animals were overmilked for 5 min. Rear teats
were subjected to ultrasound examination on the first day and to infrared thermography on the second day. Teats were submersed
in ethanol 20 min post-milking on the second day. Ultrasonography measurements showed that teat canal length increased by
30–41% during milking. Twenty minutes after milking, teats milked with modified standard liners still had elongated teat canals
while teats milked with the soft liner were normalized. Overmilking tended to increase teat wall thickness. Approximately
80% of variability in teat canal length, from before teat preparation to after milking, could be explained by changes during
teat preparation. Thermography indicated a general drop in teat temperature during teat preparation. Teat temperature increased
during milking and continued to increase until the ethanol challenge induced a significant drop. Temperatures approached pre-challenge
rather than pre-milking temperatures within 10 minutes after challenge. Teat temperatures were dependent on type of liner.
Mid-teat temperatures post-challenge relative to pre-teat preparation were dependent on overmilking. Thermography and ultrasound
were considered useful methods to indirectly and non invasively evaluate teat tissue integrity. 相似文献