全文获取类型
收费全文 | 11847篇 |
免费 | 717篇 |
国内免费 | 215篇 |
专业分类
耳鼻咽喉 | 672篇 |
儿科学 | 125篇 |
妇产科学 | 92篇 |
基础医学 | 2144篇 |
口腔科学 | 1399篇 |
临床医学 | 841篇 |
内科学 | 904篇 |
皮肤病学 | 240篇 |
神经病学 | 525篇 |
特种医学 | 598篇 |
外国民族医学 | 4篇 |
外科学 | 1227篇 |
综合类 | 1439篇 |
现状与发展 | 1篇 |
预防医学 | 207篇 |
眼科学 | 675篇 |
药学 | 610篇 |
8篇 | |
中国医学 | 267篇 |
肿瘤学 | 801篇 |
出版年
2024年 | 18篇 |
2023年 | 123篇 |
2022年 | 224篇 |
2021年 | 377篇 |
2020年 | 334篇 |
2019年 | 307篇 |
2018年 | 330篇 |
2017年 | 316篇 |
2016年 | 316篇 |
2015年 | 353篇 |
2014年 | 597篇 |
2013年 | 596篇 |
2012年 | 588篇 |
2011年 | 593篇 |
2010年 | 583篇 |
2009年 | 542篇 |
2008年 | 546篇 |
2007年 | 520篇 |
2006年 | 489篇 |
2005年 | 440篇 |
2004年 | 400篇 |
2003年 | 366篇 |
2002年 | 294篇 |
2001年 | 305篇 |
2000年 | 253篇 |
1999年 | 271篇 |
1998年 | 227篇 |
1997年 | 240篇 |
1996年 | 225篇 |
1995年 | 180篇 |
1994年 | 167篇 |
1993年 | 161篇 |
1992年 | 144篇 |
1991年 | 149篇 |
1990年 | 123篇 |
1989年 | 134篇 |
1988年 | 105篇 |
1987年 | 84篇 |
1986年 | 91篇 |
1985年 | 92篇 |
1984年 | 101篇 |
1983年 | 44篇 |
1982年 | 73篇 |
1981年 | 77篇 |
1980年 | 70篇 |
1979年 | 43篇 |
1978年 | 42篇 |
1977年 | 31篇 |
1976年 | 29篇 |
1975年 | 22篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Inside the lactating breast: the latest anatomy research 总被引:1,自引:0,他引:1
Geddes DT 《Journal of Midwifery & Women's Health》2007,52(6):556-563
Although it is well recognized that a thorough understanding of the anatomy of an organ is essential to enable assessment of any abnormalities in that organ, there has been little investigation of the anatomy of the normal lactating breast since Sir Astley Cooper performed detailed dissections of the anatomy of the breast more than 160 years ago. Many mothers recognize that breast milk provides the ultimate nutrition and protection for the infant; however, a significant proportion of women experience difficulties breastfeeding, some of which lead to weaning the infant. Recently, a small number of studies have focused on the gross anatomy of the breast, and have found that the ductal system is comprised of fewer numbers of main ducts than previously thought. In addition, the ducts are compressible and do not contain large amounts of milk, the amount of fatty tissue in the breast is variable, and a proportion is situated within the glandular tissue. These findings add to our understanding of both the physiology and pathology of the lactating breast. 相似文献
82.
大鼠颌下腺切除对CCl4所致肝损伤修复的影响 总被引:1,自引:0,他引:1
实验大鼠分为颌下切除+CCl4组,假手术+CCl4对照组及正常对照组,结果假手术+CCl4第2d时Ⅲ带细胞轻度受损,第4d、8d时受损面积略大,第12d时大部分细胞恢复,而颌下腺切除+CCl4组则损伤明显,第8d时胞质极度稀疏,12d时大部分细胞尚未恢复,与假手术组比较,该组Feulgen反应略弱,PAS反应减弱,第4~8d时较明显,G-6-P,SDH活性均减弱。结果表明颌下腺切除导致内源性表皮生 相似文献
83.
Clear-cell lesions of the parotid gland are uncommon but when studied by fine-needle aspiration may result in a clinically important but cytologically difficult differential diagnosis. Clear-cell lesions involving the parotid include acinic cell neoplasm, clear cell oncocytoma, mucoepidermoid carcinoma, primary clear-cell carcinoma, epithelial-myoepithelial carcinoma, and metastatic renal cell carcinoma. Accurate diagnosis is achieved by assessment of nuclear features, other cell populations present, and clinical data including radiographic studies. 相似文献
84.
Hidemi Kaname Toshio Yoshihara Yuji Yaku Tetsuo Ishii 《Medical Electron Microscopy》1993,26(2):99-104
Primary squamous cell carcinoma of the submandibular gland is a rare tumor. In this report, the histological and ultrastructural
features of a case of primary squamous cell carcinoma arising in the left submandibular gland is presented. Light microscopically,
the tumor consisted of well differentiated keratinizing squamous cell nests. Ultrastructurally, the tumor cells were oval
or spindle-shaped, and several tumor cells had intracytoplasmic desmosome-like structures, resembling intercellular desmosomes.
The majority of the tumor cells contained a large number of intermediate filaments (tonofilaments). Intercellular desmosomes
were well developed. No secretory granules were found. These ultrastructural features may enable us to distinguish primary
squamous cell carcinoma from mucoepidermoid carcinoma which is often misdiagnosed as squamous cell carcinoma. 相似文献
85.
A. Awad P. Govitrapong Y. Hama M. Hegazy M. Ebadi 《Journal of neural transmission (Vienna, Austria : 1996)》1989,76(2):129-144
Summary The high concentration of zinc in the bovine pineal gland prompted us to investigate the existence of a zinc-binding protein in this organ. In this study, we report that the subcellular distribution of zinc in the bovine pineal gland is nonuniform, with the crude nuclear, mitochondrial, microsomal, and supernatant fractions having 0.264±0.038, 0.160±0.019, 0.130±0.016, and 0.287±0.010 g zinc/mg protein, respectively. Furthermore, gel filtration studies using Sephadex G-75 and a 105,000 g supernatant fraction revealed two zinc binding protein peaks that bind 1.7 and 3.7 g Zn++/mg protein, respectively. Furthermore, purification of the protein peak with an elution volume (ve/vo) of 2.06 on anion exchange chromatography (DEAE-A 25) yielded a single protein peak which binds 10 g zinc/mg protein. The comparative high performance liquid Chromatographic (HPLC) profiles of the zinc-induced hepatic metallothionein isoform I (retention time=17.39 min) and of the bovine pineal metallothionein-like protein isoform I (retention time=17.49 min) are similar. Since zinc is a potent inhibitor of sulfhydryl-containing enzymes and receptor sites, we investigated the effects of zinc and found that it inhibited the binding of [3H]glutamate (IC 50=80 M) and of [3H]spiroperidol (IC 50=0.6 mM) to the pineal membranes. The results of these studies are interpreted to indicate that the bovine pineal gland possesses an active and dynamic zinc homeostatic mechanism, whose precise function(s) remain(s) to be delineated. 相似文献
86.
Milan Elleder 《Virchows Archiv : an international journal of pathology》1992,421(4):351-354
Summary Lysosomal storage inclusions were observed in skin eccrine gland secretory and myoepithelial cells in three cases of Krabbe's disease. In addition to storage there were numerous degenerative changes, occasionally resulting in cell necrosis. These findings suggest a generalized nature of the storage process in this lysosomal enzymopathy and point to high galactocerebroside turnover in eccrine gland epithelium. This knowledge may be of value in the biopsy diagnosis of Krabbe's disease. 相似文献
87.
汗腺癌病理分级的预后意义 总被引:3,自引:0,他引:3
目的:探讨汗腺癌不同病理组织学分级对复发和转移及预后的影响。方法:参照Bloom-Richardson乳腺癌分级标准对105例汗腺癌进行分级,并探讨其与复发、转移和预后间的关系。结果:在105例汗腺癌中,属分化型者42例,属低分化型者63例,两者复发率、多次复发率、区域淋巴结转移率和远处转移率及死亡率比较,提示在多次复发、远处转移方面差异有显著性,在预后方面差异非常显著。结论:将汗腺癌按腺管形成多少、核的多形性和核分裂数进行病理组织学分级,对选择治疗、估计预后具有很大的指导意义 相似文献
88.
Gerald R. Buzzell Armando Menndez-Pelez Roger A. Hoffman Carmen Rodríguez Isaac Antolin 《Anatomical record (Hoboken, N.J. : 2007)》1994,240(1):52-58
Background: The porphyrin concentrations of the Harderian glands of Syrian hamsters show marked sexual differences, with male levels being much lower than those of females. Porphyrinogenesis is inhibited by androgens, so orchidectomy leads to elevated male porphyrin concentrations; however, a number of other procedures (some of which also lower androgen levels) prevent this. We studied the effects of short-day photoperiods and melatonin on Harderian porphyrin concentrations. Methods: Intact, castrated, or pinealectomized hamsters of both sexes were exposed to long-day or short-day photoperiods. Intact or castrated hamsters were given melatonin injections in the morning or the afternoon, or were given beeswax pellets containing melatonin. After a variable period, Harderian glands were dissected and porphyrins were measured. Results: Prolonged short-day exposure (13 weeks) led to increased Harderian porphyrin concentrations and this rise was prevented by pinealectomy. The rise in Harderian porphyrins following short-day exposure was small, compared with that following castration. Short-day photoperiods also prevented the rise in porphyrin levels associated with castration and this effect was prevented by removal of the pineal. Melatonin injections, whether given in the morning or in the afternoon, had no effect on Harderian porphyrin concentration of castrated male hamsters. Continuous release melatonin pellets reduced the postcastrational rise in porphyrin levels in one experiment, while having no effect in another. In female hamster, neither short photoperiods nor melatonin pellets influenced Harderian porphyrin concentrations. Conclusions: These results suggested that a factor from the pineal gland helps maintain the low levels of porphyrin which are characteristic of male Harderian glands, despite the decrease in androgen levels which typically results from exposure to short days. Morning and afternoon injections of melatonin and continuous release melatonin pellets failed to resolve the question of whether this pineal factor is melatonin. Our results demonstrated that low male and high female porphyrin levels are maintained in Syrian hamsters, despite seasonal variations in the hormonal milieu, suggesting that these sexual differences are important for the (still unestablished) function of the Harderian glands in this species. © 1994 Wiley-Liss, Inc. 相似文献
89.
N. Tsuchikame Y. Ishimaru S. Ohshima M. Takahashi 《Virchows Archiv : an international journal of pathology》1993,422(4):337-340
We report three cases of fundic gland polyposis in the stomach identified in three patients who were related. Grossly the numerous polyps covered an area limited to the body and fundus of the stomach, no polyps were found in the antrum, duodenum, colon, or rectum, and histologically, the gastric lesions consisted of numerous hamartomatous polyps, characterized by proliferation of the fundic and cystic glands. The gastric lesions were identified in families without polyposis coli. This type of fundic gland polyposis has never been documented before in the literature. 相似文献
90.