全文获取类型
收费全文 | 4673篇 |
免费 | 162篇 |
国内免费 | 36篇 |
专业分类
耳鼻咽喉 | 23篇 |
儿科学 | 86篇 |
妇产科学 | 69篇 |
基础医学 | 610篇 |
口腔科学 | 72篇 |
临床医学 | 265篇 |
内科学 | 1165篇 |
皮肤病学 | 54篇 |
神经病学 | 361篇 |
特种医学 | 202篇 |
外科学 | 900篇 |
综合类 | 34篇 |
预防医学 | 101篇 |
眼科学 | 185篇 |
药学 | 239篇 |
中国医学 | 8篇 |
肿瘤学 | 497篇 |
出版年
2023年 | 19篇 |
2022年 | 48篇 |
2021年 | 96篇 |
2020年 | 46篇 |
2019年 | 68篇 |
2018年 | 76篇 |
2017年 | 65篇 |
2016年 | 98篇 |
2015年 | 103篇 |
2014年 | 139篇 |
2013年 | 182篇 |
2012年 | 291篇 |
2011年 | 305篇 |
2010年 | 144篇 |
2009年 | 136篇 |
2008年 | 267篇 |
2007年 | 297篇 |
2006年 | 261篇 |
2005年 | 292篇 |
2004年 | 293篇 |
2003年 | 286篇 |
2002年 | 296篇 |
2001年 | 56篇 |
2000年 | 65篇 |
1999年 | 95篇 |
1998年 | 64篇 |
1997年 | 68篇 |
1996年 | 59篇 |
1995年 | 61篇 |
1994年 | 57篇 |
1993年 | 62篇 |
1992年 | 43篇 |
1991年 | 42篇 |
1990年 | 29篇 |
1989年 | 33篇 |
1988年 | 24篇 |
1987年 | 24篇 |
1986年 | 25篇 |
1985年 | 20篇 |
1984年 | 17篇 |
1983年 | 26篇 |
1982年 | 19篇 |
1981年 | 20篇 |
1980年 | 17篇 |
1979年 | 10篇 |
1978年 | 17篇 |
1977年 | 11篇 |
1976年 | 12篇 |
1974年 | 13篇 |
1971年 | 8篇 |
排序方式: 共有4871条查询结果,搜索用时 31 毫秒
51.
52.
Carcinosarcoma of the uterine corpus containing endolymphatic stromal myosis (ESM) is extremely rare. This report describes the light- and electron-microscopic findings of ESM coexisting with adenocarcinoma of the uterus in a 58-year-old female. The polypoid tumor originated from the fundus uteri and filled the uterine cavity. In addition to papillary and medullary acinous adenocarcinoma at the apex of the polypoid mass, the major portion of the tumor specimen was composed of cells resembling endometrial stromal cells that infiltrated the myometrium and lymphatic channels, and a diagnosis of ESM was made due to the relative cell uniformity, rare mitoses, and the presence of invasive growth. There have been few reports on the ultra-structure of ESM and endometrial stromal sarcoma, and there are no reports on the ultrastructural difference between these tumors. In addition to the ultrastructural observations of our case, the electron-microscopic findings of previous reports are discussed. 相似文献
53.
Iwao Nakayama Shiro Noguchi Hiroto Yamashita Nobuo Murakami Akira Moriuchi Shigeo Yokoyama Yuichi Mochizuki Akito Noguchi 《Pathology international》1983,33(6):1139-1150
An electron microscopic immunohistochemical localization of thyroglobulin (TG) using PAP methods has been made in 15 cases of cold follicular adenoma. All cases of follicular adenoma showed organ specific functions such as synthesis, storage, reabsorption, and hydrolysis of thyroglobulin except for an area composed of follicular cells with trabecular arrangement. Immuno-reaction product for TG was precisely demonstrated in follicular lumina, subapical vesicles and reabsorbed colloid droplets. The reaction product observed in the follicular lumen was clearly demarcated from the cytoplasm of the follicular cells by the apical plasma membrane. The subapical vesicles ranging approximately from 50 mμ to 300 mμ in diameter were rarely observed in follicular adenoma and some of them fused with the reabsorbed colloid droplets. The reabsorbed colloid droplets usually had the intense reaction product and hydrolyzed colloid droplets had a vacuole containing floccular low electron dense materials. There is no reaction product in rough endoplasmic reticulum and Golgi complexes. 相似文献
54.
Kurose T Okumura Y Sato S Yamamoto Y Akaki S Takeda Y Kanazawa S Ando A Date H Shimizu N Hiraki Y 《Acta medica Okayama》2004,58(1):7-15
We evaluated the respiratory functions of patients with pulmonary emphysema who underwent lung volume reduction surgery (LVRS) by the mean transit time (MTT) with Xe-133 lung ventilation scintigraphy, forced expiration volume in 1 sec (FEV1.0), residual volume (RV), distance walked in 6 min (6-min walk), and the Hugh-Jones classification (H-J classification) before and after LVRS. In 69 patients with pulmonary emphysema (62 men, 7 women; age range, 47-75 years; mean age, 65.4 years +/- 6.1, preoperative H-J classification, III (two were II)-V) who underwent LVRS, all preoperative and postoperative parameters (MTT 3 weeks after LVRS and the others 3 months after LVRS) were judged statistically by the Wilcoxon signed-ranks test and Odds ratio. Every postoperative parameter was improved with a significant difference (P < 0.05) compared to preoperative parameters. MTT at 3 weeks after LVRS was not associated with %FEV1.0 and the H-J classification at 3 months after LVRS, but was associated with RV and a 6-min walk at 3 months after LVRS. MTT was useful for the clinical evalution of aerobic capability after LVRS. 相似文献
55.
Jun-ichi Kadokawa Yoshitaka Matsumura Shiro Kobayashi 《Macromolecular chemistry and physics.》1994,195(11):3689-3698
This paper describes a new ring-opening-closing alternating copolymerization (ROCAC) of 2-methyl-2-oxazoline (five-membered cyclic imino ether, 1 ) with N-methyldiacrylamide ( 2 ). The reaction of a 1 : 1 monomer feed ratio proceeded without any added catalyst to give an alternating copolymer 3 having two structural units formed by ring-opening and ring-closing (cyclization). The structure of copolymer 3 was determined by 1H, 13C NMR, and IR spectroscopies. The extent of cyclization was at most 65%. The copolymerization was reasonably explained by a mechanism of propagation via zwitterion intermediates. 相似文献
56.
Flavonoids such as luteolin, fisetin and apigenin are inhibitors of interleukin-4 and interleukin-13 production by activated human basophils 总被引:2,自引:0,他引:2
Hirano T Higa S Arimitsu J Naka T Shima Y Ohshima S Fujimoto M Yamadori T Kawase I Tanaka T 《International archives of allergy and immunology》2004,134(2):135-140
BACKGROUND: We have previously shown that fisetin, a flavonol, inhibits IL-4 and IL-13 synthesis by allergen- or anti-IgE-antibody-stimulated basophils. This time, we investigated the inhibition of IL-4 and IL-13 production by basophils by other flavonoids and attempted to determine the fundamental structure of flavonoids related to inhibition. We additionally investigated whether flavonoids suppress leukotriene C4 synthesis by basophils and IL-4 synthesis by T cells in response to anti-CD3 antibody. METHODS: Highly purified peripheral basophils were stimulated for 12 h with anti-IgE antibody alone or anti-IgE antibody plus IL-3 in the presence of various concentrations of 18 different kinds of flavones and flavonols. IL-4 and IL-13 concentrations in the supernatants were then measured. Leukotriene C4 synthesis was also measured after basophils were stimulated for 1 h in the presence of flavonoids. Regarding the inhibitory activity of flavonoids on IL-4 synthesis by T cells, peripheral blood mononuclear cells were cultured with flavonoids in anti-CD3-antibody-bound plates for 2 days. RESULTS: Luteolin, fisetin and apigenin were found to be the strongest inhibitors of both IL-4 and IL-13 production by basophils but did not affect leukotriene C4 synthesis. At higher concentrations, these flavonoids suppressed IL-4 production by T cells. Based on a hierarchy of inhibitory activity, the basic structure for IL-4 inhibition by basophils was determined. CONCLUSIONS: Due to the inhibitory activity of flavonoids on IL-4 and IL-13 synthesis, it can be expected that the intake of flavonoids, depending on the quantity and quality, may ameliorate allergic symptoms or prevent the onset of allergic diseases. 相似文献
57.
Naoko Tanda Shiro Mori Masato Nose Tetsuo Saito Shi-Taek Song Atsushi Sato Teiichi Teshima 《Pathology international》1996,46(9):639-645
The expression of -GlcNAcβ1–6Man-(β1–6) branched oligosaccharides In carcinoma cells has been considered to influence their metastatic potentials. In the present paper, the lectin histochemistry of oral squamous cell carcinomas obtained in biopsy from 34 patients with Phaseolus vulgaris leukoagglutinin (L-PHA), which potentially binds to N-glycosidic carbohydrates with β1–6 linked lactosamin antennae, was studied in order to analyze the relationship between their staining patterns and metastases. The L-PHA-binding oligosaccharides of the carcinomas were expressed on the cell surface in the following patterns: (i) all cells were positive for the staining ('positive'); (ii) some cells were positive but the rest of the carcinoma cells were negative ('weakly positive'); and (iii) all were negative ('negative'). Statistical analysis revealed that the incidence of the metastasis to regional lymph nodes in the 'positive' cases was significantly higher than that in the 'negative' cases. Moreover, the number of the CD14 positive cells including macrophages in the Stroma adjacent to the cardnomas in the 'positive' cases was less than that in the 'negative' or 'weakly positive' cases. The expression of L-PHA-binding oligosaccharides in oral squamous cell carcinoma may be responsible for their metastatic potential to regional lymph nodes, possibly Including their ability to escape macrophage recognition. 相似文献
58.
In analyzing repeated measurements from randomized controlled trials with mixed‐effects models, it is important to carefully examine the conventional normality assumption regarding the random‐effects distribution and its dependence on treatment allocation in order to avoid biased estimation and correctly interpret the estimated random‐effects distribution. In this article, we propose the use of a gradient function method in modeling with the different random‐effects distributions depending on the treatment allocation. This method can be effective for considering in advance whether a proper fit requires a model that allows dependence of the random‐effects distribution on covariates, or for finding the subpopulations in the random effects. 相似文献
59.
Akt/PKB activation in gastric carcinomas correlates with clinicopathologic variables and prognosis 总被引:23,自引:0,他引:23
Nam SY Lee HS Jung GA Choi J Cho SJ Kim MK Kim WH Lee BL 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2003,111(12):1105-1113
Akt/protein kinase B (PKB) plays an important role in cell survival. However, the role of Akt in the biology of gastric cancer has not been well studied. We sought to investigate the expression of Akt or phosphorylated Akt (pAkt) in human gastric carcinomas and to analyze the relationship between Akt or pAkt and the clinicopathologic parameters. The expressions of Akt and pAkt were evaluated immunohistochemically in 311 gastric carcinomas using the tissue array method. Akt expression was detected in 74% of the tumors and pAkt expression in 78%. pAkt was highly expressed in the early stage of pTNM (p=0.011). We also found an inverse association between pAkt and lymphatic invasion (p=0.01) or lymph node metastasis (p=0.008). pAkt expression was significantly correlated with a higher survival in patients with stage I carcinomas (p=0.0003). Interestingly, combined evaluation revealed that the group with pAkt-positive and lymph node-negative carcinomas showed a better prognosis than the other groups (p<0.0001). In addition, pAkt was shown to correlate positively with APC (p=0.002) and Smad4 (p<0.0001) expression. These findings suggest that pAkt expression may help to predict the clinical outcome of gastric cancer patients. 相似文献
60.
Haruyasu Yamaguchi Koji Ishiguro Shiro Sugihara Yoichi Nakazato Takeshi Kawarabayashi Xiaoyan Sun Shunsaku Hirai 《Acta neuropathologica》1994,88(5):413-419
The localization of apolipoprotein E (ApoE) has been examined immunohistochemically in the autopsied brains of middle-aged and old-aged control subjects, with and without amyloid protein (A) deposits, and of Alzheimer's disease patients. Senile plaques were consistently labeled with ApoE antiserum even in the very early stage of senile plaque formation seen in the fifth decade. In the cerebellar molecular layer, small dots of ApoE immunoreactivity, which were prominent in the Alzheimer's disease subjects, were observed in addition to immunoreactivity in diffuse plaques. ApoE antisera labeled all of the extracellular neurofibrillary tangles (NFT), whereas only a small minority of extracellular NFT were positive for A. A punctate pattern of ApoE immunoreactivity was seen at the media of the meningeal vessels lacking amyloid, when senile plaques were present in the nearby cortex. In the early stage of amyloid angiopathy, the distribution of ApoE immunoreactivity was much more extensive than that of A positivity. These findings suggest that ApoE accumulates in the early stage of senile plaque formation and, furthermore, that ApoE accumulation precedes A deposition in extracellular NFT and amyloid angiopathy. 相似文献