全文获取类型
收费全文 | 8049篇 |
免费 | 514篇 |
国内免费 | 69篇 |
专业分类
耳鼻咽喉 | 60篇 |
儿科学 | 195篇 |
妇产科学 | 95篇 |
基础医学 | 1257篇 |
口腔科学 | 161篇 |
临床医学 | 553篇 |
内科学 | 1873篇 |
皮肤病学 | 199篇 |
神经病学 | 891篇 |
特种医学 | 285篇 |
外科学 | 917篇 |
综合类 | 18篇 |
预防医学 | 313篇 |
眼科学 | 229篇 |
药学 | 638篇 |
中国医学 | 59篇 |
肿瘤学 | 889篇 |
出版年
2023年 | 60篇 |
2022年 | 113篇 |
2021年 | 225篇 |
2020年 | 106篇 |
2019年 | 117篇 |
2018年 | 199篇 |
2017年 | 162篇 |
2016年 | 187篇 |
2015年 | 182篇 |
2014年 | 272篇 |
2013年 | 309篇 |
2012年 | 453篇 |
2011年 | 558篇 |
2010年 | 322篇 |
2009年 | 265篇 |
2008年 | 474篇 |
2007年 | 530篇 |
2006年 | 501篇 |
2005年 | 555篇 |
2004年 | 474篇 |
2003年 | 453篇 |
2002年 | 459篇 |
2001年 | 156篇 |
2000年 | 131篇 |
1999年 | 140篇 |
1998年 | 93篇 |
1997年 | 72篇 |
1996年 | 71篇 |
1995年 | 55篇 |
1994年 | 62篇 |
1993年 | 43篇 |
1992年 | 63篇 |
1991年 | 82篇 |
1990年 | 71篇 |
1989年 | 69篇 |
1988年 | 67篇 |
1987年 | 61篇 |
1986年 | 69篇 |
1985年 | 55篇 |
1984年 | 51篇 |
1983年 | 41篇 |
1982年 | 15篇 |
1981年 | 17篇 |
1980年 | 16篇 |
1979年 | 26篇 |
1978年 | 13篇 |
1977年 | 12篇 |
1976年 | 12篇 |
1973年 | 14篇 |
1969年 | 10篇 |
排序方式: 共有8632条查询结果,搜索用时 15 毫秒
31.
Yasuhiro Nakamura Tomohiko Sato Tatsuo Tanaka Toshihiko Kinjyo Akira Tanimura Kazuhiko Nagayama Toyohide Yanai Kozue Masaike Noriko Sibao 《Pathology international》1985,35(6):1495-1500
A case of glioblastoma arising in the pons of a 14-year-old boy in whom transsynaptic degeneration was found in the inferior olivary nucleus is reported. The tumor occupied most of the pons including the tegmental tract and invaded into the midbrain, medulla oblongata, cerebellar peduncles, thalamus, basal ganglia, and meninges. The right inferior olivary nucleus was devoid of the tumorous lesion, but many neurons were severely vacuolated. An im-munohistochemical study using glial fibrillary acidic protein (GFAP), neuron-specific enolase (NSE), and S-100 protein was performed. GFAP and S-100 protein were positive in the reactive glia of the nucleus and NSE gave a faint reaction in some degenerated neurons. These degenerative changes found in neurons of the inferior olivary nucleus were considered to be transsynaptic degeneration due to the destruction of the tegmental tract at the pons and of cerebellar peduncles by invasive pontine glioblastoma. ACTA PATHOL. JPN. 35: 1495–1500, 1985. 相似文献
32.
Annexin V and propidium iodide (PI) staining is a general technique for detecting apoptosis by flow-cytometry (FCM). The release of 2',7'-bis-(2-carboxyethyl)-5- (and-6)-carboxyfluorescein (BCECF), a non-lipophilic membrane-impermeable labeling dye, from the cytoplasm of target cells is an indicator of increased membrane permeability. This study aimed to devise a three-color FCM technique involving the BCECF-release parameter in addition to conventional Annexin V and PI staining for the analysis of target K562 cells undergoing cytotoxic/apoptotic processes mediated by natural killer (NK) cells. The results demonstrated the following step-wise process of membrane impairment: (1) initiation of Annexin V staining accompanied by increasing forward scatter (FSC) before BCECF-release, indicating membrane impairment without permeabilization by necrosis; (2) BCECF-release with decreasing FSC before PI influx; and (3) PI staining with the lowest FSC state. Therefore, the early stage of cytotoxicity/apoptosis conventionally defined by the flow-cytometric criteria of Annexin V staining before PI staining could be sub-divided into two stages before and after BCECF-release. Annexin-V staining in tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis was also initiated without BCECF-release. Although the underlying mechanism of the transition process from stage 1 to stage 2 is still unknown, this FCM technique should be a useful tool for differential assays of target cells regarding the sequential processes of NK-induced cytotoxicity. 相似文献
33.
Transcription factor Ets-1 mediates ischemia- and vascular endothelial growth factor-dependent retinal neovascularization 总被引:10,自引:0,他引:10 下载免费PDF全文
34.
Takasaki Y Kaneda K Matsushita M Yamada H Nawata M Matsudaira R Asano M Mineki R Shindo N Hashimoto H 《International immunology》2004,16(9):1295-1304
Using 2-dimensional electrophoresis and ion-pair chromatography, we have identified elements of proliferating cell nuclear antigen (PCNA) multiprotein complexes that are reactive to antibodies in sera from patients with systemic lupus erythematosus. Among the various elements of the complexes, a 37 kDa protein (PI 8.5) that specifically reacted with SLE sera, but not with sera from patients with other connective tissue diseases, was identified as glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Immunoblot analysis showed that SLE sera reactive with the 37 kDa protein specifically reacted with GAPDH, as did anti-GAPDH mAbs. The purified autoantibodies to GAPDH from lupus serum showed both nuclear speckled and cytoplasmic staining patterns in immunofluorescence on Hep-2 cells. In addition, enzyme-linked immunosorbent assay (ELISA) revealed the presence of anti-GAPDH autoantibodies in 47% of lupus patients. Longitudinal analysis of the reactivity of lupus sera to PCNA complexes showed the autoimmune response to spread from GAPDH to other elements of PCNA complexes, and the presence of anti-GAPDH antibodies was significantly correlated with increased levels of serum PCNA. Taken together, these findings suggest that GAPDH interacting with PCNA in association with its cellular function is a novel autoantigen recognized by lupus sera, and that GAPDH thus plays an important role in the induction of autoimmune responses against the PCNA complex. 相似文献
35.
Kado N Kitawaki J Koshiba H Ishihara H Kitaoka Y Teramoto M Honjo H 《Human reproduction (Oxford, England)》2003,18(4):715-720
BACKGROUND: The aim of this study was to investigate the relationships between the serum levels of soluble leptin receptor (SLEPR), and total, free and bound leptin, and the change in the serum SLEPR level during an IVF cycle. METHODS: Serum concentrations of leptin and SLEPR were measured in 50 Japanese women of reproductive age, and 20 patients participating in an IVF programme. The total leptin was fractionated into free and bound portions by gel filtration chromatography. RESULTS: The SLEPR level was negatively correlated with the body mass index (BMI) (r = -0.548, P < 0.0001), total leptin (r = -0.433, P < 0.0001), the percentage of free leptin (r = -0.732, P < 0.0001) and the absolute free leptin concentration (r = -0.506, P < 0.0001). The SLEPR level was positively correlated with the percentage of bound leptin (r = 0.730, P < 0.0001), whereas there was little variation in the absolute bound leptin concentration, regardless of the BMI or SLEPR concentration. During the IVF cycle, total and free leptin elevated during maximal ovarian stimulation, whereas there was no significant difference in the SLEPR concentration. CONCLUSIONS: The results demonstrate a skillful mechanism where a change in the serum SLEPR level regulates, in part, the biological activity of leptin in the circulation. 相似文献
36.
Steven F. Ziegler Karen K. Morella Dirk Anderson Noriko Kumaki Warren J. Leonard David Cosman Heinz Baumann 《European journal of immunology》1995,25(2):399-404
The interleukin (IL)-2 receptor γ chain has recently been shown to be a component of the IL-7 and IL-4 receptors. Using a transient transfection assay and the trans-activation of reporter gene constructs which are under the control of cytokine-responsive promoter elements, we have studied signal transduction through the IL-7 receptor (IL-7R). The reporter gene expression was not stimulated by receptors that contained the cytoplasmic domain of the IL-7R, either as intact IL-7R or as part of a chimeric receptor. However, co-expression of the IL-7R with the IL-2 receptor γ chain was able to stimulate gene activation. For maximal stimulation the intact cytoplasmic domains of each chain was required. 相似文献
37.
Iseki E Takayama N Furukawa Y Marui W Nakai T Miura S Uéda K Kosaka K 《Neuroscience letters》2002,325(3):211-215
The caudal part of the fastigial nucleus, or the fastigial oculomotor region (FOR), plays an important role in executing accurate saccades. Inactivation of a monkey FOR leads to dysmetric saccades. Currently available data suggest that the dysmetria could be described as a parametric, uniform change in saccadic gain or, alternatively, as a constant error in the specification of the saccadic goal. To discriminate between these two possibilities, we examined the effect of FOR inactivation in the monkey. After a unilateral injection of muscimol into the FOR, ipsiversive saccades overshot a target. Gains were similar for movements of different sizes. The overshoot increased proportionately with the target distance and had a very small constant component. The present study indicates that the hypermetria of ipsiversive saccades after inactivation of the monkey FOR is primarily due to a uniform gain increase for all sizes of saccades. 相似文献
38.
Effects of calcium on the conductance change of the end-plate membrane during the action of transmitter 总被引:12,自引:6,他引:12 下载免费PDF全文
Noriko Takeuchi 《The Journal of physiology》1963,167(1):141-155
39.
Ishiguro N Kanehisa H Miyatani M Masuo Y Fukunaga T 《European journal of applied physiology》2005,94(1-2):25-35
This study tested the hypothesis that, as compared to whole-body bioelectrical impedance (BI) analysis, segmental BI analysis can estimate lean body mass (LBM) more accurately in a population with a large difference in muscularity. In addition to whole-body BI, which determines impedance (Z) between the wrist and ankle, two segmental BI analyses which determine the Z value of every body segment in each of (1) the arms, legs and trunk (distal BI) and (2) the upper arms, upper legs and trunk (proximal BI) were applied to a group of 125 male athletes and 75 non-athletes. The subjects were divided into validation and cross-validation groups. Simple and multiple regression analyses were applied to (length)2/Z (BI index) values for the whole-body and each body segment, to develop the prediction equations of LBM measured using air-displacement plethysmography. In the validation group, the SE of estimation was similar in the whole-body (3.4 kg, 5.4%), distal (3.4 kg, 5.5%) and proximal BI (3.3 kg, 5.2%) analyses. However, the whole-body and distal BI analyses produced systematical errors in the estimates of LBM. Moreover, the residuals in the two methods significantly (P<0.05) correlated with the ratios of BI indices of the upper arms and upper legs to those of the arms and legs, respectively, calculated as variables approximating the relative development of lean tissues at the proximal area of limbs. On the other hand, the proximal BI analysis was validated and cross-validated. Thus, the accuracy of estimating LBM was similar in the whole-body and the two segmental BI analyses. However, the prediction equations derived from the use of the whole-body BI index and a combination of the arms, legs and trunk BI indices produced a systematical error relating to the difference between the limb segments in lean tissue development. 相似文献
40.