全文获取类型
收费全文 | 4735篇 |
免费 | 221篇 |
国内免费 | 29篇 |
专业分类
耳鼻咽喉 | 26篇 |
儿科学 | 106篇 |
妇产科学 | 60篇 |
基础医学 | 663篇 |
口腔科学 | 163篇 |
临床医学 | 290篇 |
内科学 | 1023篇 |
皮肤病学 | 114篇 |
神经病学 | 369篇 |
特种医学 | 209篇 |
外科学 | 645篇 |
综合类 | 20篇 |
预防医学 | 200篇 |
眼科学 | 92篇 |
药学 | 459篇 |
中国医学 | 49篇 |
肿瘤学 | 497篇 |
出版年
2023年 | 29篇 |
2022年 | 57篇 |
2021年 | 76篇 |
2020年 | 60篇 |
2019年 | 54篇 |
2018年 | 92篇 |
2017年 | 79篇 |
2016年 | 79篇 |
2015年 | 86篇 |
2014年 | 112篇 |
2013年 | 169篇 |
2012年 | 268篇 |
2011年 | 315篇 |
2010年 | 142篇 |
2009年 | 145篇 |
2008年 | 242篇 |
2007年 | 314篇 |
2006年 | 302篇 |
2005年 | 287篇 |
2004年 | 293篇 |
2003年 | 230篇 |
2002年 | 247篇 |
2001年 | 97篇 |
2000年 | 95篇 |
1999年 | 77篇 |
1998年 | 65篇 |
1997年 | 49篇 |
1996年 | 41篇 |
1995年 | 43篇 |
1994年 | 45篇 |
1993年 | 37篇 |
1992年 | 64篇 |
1991年 | 60篇 |
1990年 | 50篇 |
1989年 | 64篇 |
1988年 | 63篇 |
1987年 | 74篇 |
1986年 | 57篇 |
1985年 | 38篇 |
1984年 | 36篇 |
1983年 | 40篇 |
1982年 | 22篇 |
1981年 | 16篇 |
1980年 | 22篇 |
1979年 | 25篇 |
1978年 | 18篇 |
1977年 | 11篇 |
1973年 | 15篇 |
1971年 | 14篇 |
1970年 | 15篇 |
排序方式: 共有4985条查询结果,搜索用时 15 毫秒
41.
The cells from 5 cases of non-lymphocytic leukemia were investigated by immunoelectron microscopy using an anti-granulocyte antibody, clone 1G10 (New England Nuclear), to clarify the nature of immature leukemic cells. Reaction products on the surface of the leukemic cells were composed of two layers, an inner translucent and an outer dense granular zone. Although non-leukemic cells of the granulocytic series in various stages of maturation between promyelocytes and neutrophils were all positive for the antigen-antibody reaction, non-neoplastic monocytes and lymphocytes were all negative. Using this method, it was possible to diagnose the undifferentiated leukemic cells that were negative for myeloperoxidase. Furthermore, the results of our present study suggest the possibility that the antibody 1G10 may be useful for distinguishing granulocytic cells from cells of monocytic lineage. 相似文献
42.
S. Oh-ishi Takako Kizaki Tomomi Ookawara Koji Toshinai Shukoh Haga Fujio Karasawa Tetsuo Satoh Naokazu Nagata L. L. Ji Hideki Ohno 《Pflügers Archiv : European journal of physiology》1998,435(6):767-774
The aim of the current study was to elucidate the synergism of dietary calcium restriction and exhaustive exercise in the
antioxidant enzyme system of rat soleus muscle, and to investigate the involvement of neutrophils in exercise-induced muscle
damage. Forty-eight male Wistar rats were assigned to the following groups: control (C) or calcium-restricted [1 month (1 M)
or 3 months (3 M)]. Each group was subdivided into acutely exercised or non-exercised groups. Soleus muscle from each rat
was analysed to determine the levels of antioxidant enzymes [Mn-superoxide dismutase (SOD), Cu,Zn-SOD, glutathione peroxidase
(GPX), and catalase (CAT)]. Dietary calcium restriction resulted in calcium deficiency and upregulated the antioxidant enzymes
examined except GPX. Conversely, exhaustive exercise significantly decreased GPX and CAT, but not SODs activities in the calcium-restricted
(1 M and/or 3 M) rats. Contents of immunoreactive Mn-SOD and Cu,Zn-SOD were only increased in the 3 M rats. During calcium
restriction, the mRNA expression of both forms of SOD showed initial upregulation, followed by downregulation. Exhaustive
exercise significantly increased the mRNA expressions only in the 3 M rats. Moreover, exhaustive exercise markedly increased
myeloperoxidase activity in soleus muscles from the 1 M and 3 M rats compared with the C rats, and significantly enhanced
the ability of neutrophils to generate superoxide in the 3 M rats. The results demonstrate that dietary calcium restriction
upregulates certain antioxidant enzyme activities in rat soleus muscle, indicating an enhanced resistance to potential increases
in intracellular reactive oxygen species. The results also suggest that exhaustive exercise may cause oxidative damage in
soleus muscle of calcium-deficient rats through the activation of neutrophils.
Received: 4 August 1997 / Received after revision: 29 September 1997 / Accepted: 26 November 1997 相似文献
43.
Takuya Kishimoto Ting-Ting Liu Hiroyasu Hatakeyama Tomomi Nemoto Noriko Takahashi Haruo Kasai 《The Journal of physiology》2005,568(3):905-915
We investigated exocytosis of PC12 cells using two-photon excitation imaging and extracellular polar tracers (TEP imaging) at the basal region of PC12 cells adjacent to the glass cover slip. TEPIQ (two-photon extracellular polar-tracer imaging-based quantification) analysis revealed that most exocytosis was mediated by large dense-core vesicles (LVs) with a mean diameter of 220 nm, and that exocytosis of LVs occurred slowly with a mean latency of ∼7 s even though exocytosis was induced with large increases in cytosolic Ca2 + concentration by uncaging of a caged-Ca2 + compound. We also found that 97% of exocytic LVs remained poised at the plasma membrane, 72% maintained their fusion pores in an open conformation for more than 30 s, and 76% triggered sequential compound exocytosis of vesicles that were located deeper in the cytosol. Sequential compound exocytosis by PC12 cells was confirmed by electron microscopic investigation with photoconversion of diaminobenzidine by FM1-43 (a polar membrane tracer). Our data suggest that pre-stimulus docking of LVs to the plasma membrane does not necessarily hasten the fusion reaction, while docking and resulting stability of exocytic LVs facilitates sequential compound exocytosis, and thereby allowing mobilization of deep vesicles. 相似文献
44.
Masumi Takano-Maruyama Yoshiro Ohara Kunihiko Asakura Takako Okuwa 《Journal of neuroinflammation》2006,3(1):19-8
Theiler's murine encephalomyelitis virus (TMEV) is divided into two subgroups on the basis of their different biological activities.
GDVII subgroup strains produce fatal poliomyelitis in mice without virus persistence or demyelination. In contrast, TO subgroup
strains induce demyelinating disease with virus persistence in the spinal cords of weanling mice. Two proteins, whose open
reading frames are located in the N-terminus of the polyprotein, recently have been reported to be important for TMEV biological
activities. One is leader (L) protein and is processed from the most N-terminus of the polyprotein; its function is still
unknown. Although the homology of capsid proteins between DA (a representative strain of TO subgroup) and GDVII strains is
over 94% at the amino acid level, that of L shows only 85%. Therefore, L is thought to be a key protein for the subgroup-specific
biological activities of TMEV. Various studies have demonstrated that L plays important roles in the escape of virus from
host immune defenses in the early stage of infection. The second protein is a 17–18 kDa protein, L*, which is synthesized
out-of-frame with the polyprotein. Only TO subgroup strains produce L* since GDVII subgroup strains have an ACG rather than
AUG at the initiation site and therefore do not synthesize L*. 'Loss and gain of function' experiments demonstrate that L*
is essential for virus growth in macrophages, a target cell for TMEV persistence. L* also has been demonstrated to be necessary
for TMEV persistence and demyelination. Further analysis of L and L* will help elucidate the pathomechanism(s) of TMEV-induced
demyelinating disease. 相似文献
45.
Tanimoto Y Hayakawa T Nemoto K 《Journal of biomedical materials research. Part B, Applied biomaterials》2005,72(2):310-315
The aim of this study was to investigate the extent of polymerization (Ep) in terms of polymerization rate of UDMA/TEGDMA resin mixtures and its composite resin, by using a differential scanning calorimeter (DSC) technique employing a photopolymerization apparatus. The resin mixtures used in this study consisted of urethane dimethacrylate (UDMA) as a base monomer and triethyleneglycol dimethacrylate (TEGDMA) as a low viscosity monomer. The concentration of TEGDMA in the mixed monomer was varied to 0, 20, 40, 60, 80, and 100 mol %. Additionally, using a base monomer consisting of 60 mol % UDMA and 40 mol % TEGDMA, four kinds of composites with silica filler of 0, 20, 40, 60, and 70 wt %, were prepared in this study. The general reaction profile and Ep values were obtained from the DSC curves. Increasing the concentration of TEGDMA resulted in a decrease in the viscosity of the UDMA/TEGDMA mixture, a delay in the time to maximum polymerization rate, and an increase in the Ep values of the resin mixtures. Furthermore, Ep values decreased with increasing filler content between 0 and 60 wt % but did not decrease further between 60 and 70 wt %. 相似文献
46.
G protein modulation of voltage-sensitive muscarinic receptor signalling in mouse pancreatic acinar cells 总被引:2,自引:0,他引:2
Ong BH Ohsaga A Sato K Oshiro T Shirato K Maruyama Y 《Pflügers Archiv : European journal of physiology》2001,441(5):604-610
Submaximal stimulation of mouse pancreatic acinar cells by acetylcholine (ACh) generates periodic Ca2+ responses sensitive to the membrane potential. Monitoring the muscarinic Ca2+ responses using patch-clamp whole-cell current recordings, we examined the mechanism of guanine nucleotide-binding protein (G protein)-receptor interaction in terms of the membrane potential. The lowest ACh concentration able to elicit consistent repetitive spikes was 50 nM, in the presence of which hyperpolarization increased and depolarization decreased the spike frequency. The saturating concentration was 10 microM, this induced a sustained response insensitive to voltage. Internal guanosine 5'-tri- and diphosphates (GTP, GDP) depressed and potentiated the voltage sensitivity, respectively, but not for the response to a saturating ACh concentration (10 microM). Internal guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS) abolished the voltage sensitivity. The results indicate that the ACh-induced Ca2+ response is sensitive to the membrane potential and that a close linkage exists between voltage sensitivity and the G protein association/dissociation cycle in the muscarinic receptor. 相似文献
47.
11q trisomy detected by fluorescence in situ hybridization 总被引:1,自引:0,他引:1
Takako Takano Yasuko Yamanouchi Shoko Kawashima Masatsune Date Shintaro Hashira Mitsushiro Kida Toshiaki Abe Yutaka Nakahori Yasuo Nakagome 《Clinical genetics》1993,44(6):324-328
Takano T, Yamanouchi Y, Kawashima S, Date M, Hashira S, Kida M, Abe T, Nakahori Y, Nakagome Y. 11q trisomy detected by fluorescence in situ hybridization. Clin Genet 1993: 44: 324–328. © Munksgaard, 1993 A patient with psychomotor developmental delay, multiple minor anomalies, congenital heart disease and left inguinal hernia is reported. His karyotype was 45,X/46,X,+mar (3 : 37 cells), and the marker chromosome was identified as t(Y;11) (q12;q14?) using fluorescence in situ hybridization and fluorescent chromosome painting. He was diagnosed as mosaic for de novo 11q trisomy. 相似文献
48.
Heat and water vapour transfer of protective clothing systems in a cold environment,measured with a newly developed sweating thermal manikin 总被引:1,自引:0,他引:1
Fukazawa T Lee G Matsuoka T Kano K Tochihara Y 《European journal of applied physiology》2004,92(6):645-648
A moveable sweating thermal manikin has recently been developed. Thermal and water-vapour resistances of three kinds of cold-protective clothing ensembles, laminated with polytetrafluoroethylene, polyurethane and without a laminate were measured, with the aid of the manikin in a cold environment of 5°C with a relative humidity of 70% and an air velocity of around 1.5 m s–1. Two sweating rates of 65 and 130 g m–2 h–1 were employed. Supplied heat fluxes in both of the sweat rates ranged from 350 W m–2 to 400 W m–2. To maintain a comfortable condition, the skin wettedness (w) (mean weighted value) had to be kept at 0.6. The measurements obtained from the manikin when testing the three ensembles were w=0.3 (approximately) for the low sweat rate and w0.6 for the high sweat rate, irrespective of the property differences among the ensembles. In addition, the condensation in the ensembles in comparison with those calculated from an analytical equation is discussed. Condensation mass fluxes in the ensembles obtained byexperiment and those from the calculation agreed sufficiently well. Thus, distribution of the condensation in the ensembles was estimated using the equation. 相似文献
49.
Spectral imaging fluorescence microscopy 总被引:2,自引:0,他引:2
Haraguchi T Shimi T Koujin T Hashiguchi N Hiraoka Y 《Genes to cells : devoted to molecular & cellular mechanisms》2002,7(9):881-887
The spectral resolution of fluorescence microscope images in living cells is achieved by using a confocal laser scanning microscope equipped with grating optics. This capability of temporal and spectral resolution is especially useful for detecting spectral changes of a fluorescent dye; for example, those associated with fluorescence resonance energy transfer (FRET). Using the spectral imaging fluorescence microscope system, it is also possible to resolve emitted signals from fluorescent dyes that have spectra largely overlapping with each other, such as fluorescein isothiocyanate (FITC) and green fluorescent protein (GFP). 相似文献
50.
Bibek Dutta Taichi Asami Tohru Imatomi Kento Igarashi Kento Nagata Tomomi Watanabe-Asaka Takako Yasuda Shoji Oda Manfred Shartl Hiroshi Mitani 《Journal of radiation research》2021,62(1):12
Transgenic expression in medaka of the Xiphophorus oncogene xmrk, under a pigment cell specific mitf promoter, induces hyperpigmentation and pigment cell tumors. In this study, we crossed the Hd-rR and HNI inbred strains because complete genome information is readily available for molecular and genetic analysis. We prepared an Hd-rR (p53+/−, p53−/−) and Hd-rR HNI hybrid (p53+/−) fish-based xmrk model system to study the progression of pigment cells from hyperpigmentation to malignant tumors on different genetic backgrounds. In all strains examined, most of the initial hyperpigmentation occurred in the posterior region. On the Hd-rR background, mitf:xmrk-induced tumorigenesis was less frequent in p53+/− fish than in p53−/− fish. The incidence of hyperpigmentation was more frequent in Hd-rR/HNI hybrids than in Hd-rR homozygotes; however, the frequency of malignant tumors was low, which suggested the presence of a tumor suppressor in HNI genetic background fish. The effects on tumorigenesis in xmrk-transgenic immature medaka of a single 1.3 Gy irradiation was assessed by quantifying tumor progression over 4 consecutive months. The results demonstrate that irradiation has a different level of suppressive effect on the frequency of hyperpigmentation in purebred Hd-rR compared with hybrids. 相似文献