全文获取类型
收费全文 | 53664篇 |
免费 | 3646篇 |
国内免费 | 204篇 |
专业分类
耳鼻咽喉 | 549篇 |
儿科学 | 1461篇 |
妇产科学 | 930篇 |
基础医学 | 7065篇 |
口腔科学 | 1373篇 |
临床医学 | 5284篇 |
内科学 | 10956篇 |
皮肤病学 | 770篇 |
神经病学 | 5262篇 |
特种医学 | 2869篇 |
外国民族医学 | 6篇 |
外科学 | 7830篇 |
综合类 | 620篇 |
一般理论 | 40篇 |
预防医学 | 4321篇 |
眼科学 | 1233篇 |
药学 | 3425篇 |
中国医学 | 76篇 |
肿瘤学 | 3444篇 |
出版年
2023年 | 202篇 |
2021年 | 855篇 |
2020年 | 661篇 |
2019年 | 878篇 |
2018年 | 1029篇 |
2017年 | 861篇 |
2016年 | 1004篇 |
2015年 | 1114篇 |
2014年 | 1550篇 |
2013年 | 2239篇 |
2012年 | 3339篇 |
2011年 | 3479篇 |
2010年 | 2010篇 |
2009年 | 1831篇 |
2008年 | 3308篇 |
2007年 | 3388篇 |
2006年 | 3326篇 |
2005年 | 3268篇 |
2004年 | 3066篇 |
2003年 | 2989篇 |
2002年 | 2832篇 |
2001年 | 820篇 |
2000年 | 746篇 |
1999年 | 820篇 |
1998年 | 682篇 |
1997年 | 529篇 |
1996年 | 494篇 |
1995年 | 458篇 |
1994年 | 370篇 |
1993年 | 353篇 |
1992年 | 502篇 |
1991年 | 464篇 |
1990年 | 430篇 |
1989年 | 474篇 |
1988年 | 402篇 |
1987年 | 424篇 |
1986年 | 388篇 |
1985年 | 373篇 |
1984年 | 371篇 |
1983年 | 341篇 |
1982年 | 346篇 |
1981年 | 326篇 |
1980年 | 283篇 |
1979年 | 273篇 |
1978年 | 263篇 |
1977年 | 222篇 |
1976年 | 188篇 |
1975年 | 197篇 |
1974年 | 197篇 |
1972年 | 173篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
951.
Carola Eriksson Margareta Larsson Agneta Skoog Svanberg Tanja Tydén 《Upsala journal of medical sciences》2013,118(2):122-129
Background Different reasons influence the current low birth-rate and the postponement of the birth of the first child throughout Europe. The aim of this study was to explore how highly educated women and men in Sweden reflect on fertility and postponed parenthood.Methods We interviewed women (n = 22) and men (n = 18) who had started their professional careers and still had no children. Data were analysed with qualitative content analysis.Results Fertility was perceived as an unconsidered capacity, sometimes unpredictable, and different for women and men, but nevertheless taken for granted. The participants were of the opinion that fertility could be restored by assisted reproductive technologies or replaced by alternatives to a biological child. Postponed parenthood was described as an adaptation to societal changes and current discourses about parenthood as well as a consequence of a contemporary lifestyle with many competing priorities.Conclusion Highly educated young women and men in contemporary Sweden have competing priorities when planning and setting goals for their lives, and having children is one of them. They describe fertility as an imperceptible and retrievable capacity and postponed parenthood as a rational adaptation to changes in society. These findings suggest that increased information about the limitations of human reproduction is needed, but also that societal support for younger parents is of utmost importance. 相似文献
952.
953.
Epidermal tumors belong to the most frequent type of neoplasms, and tumor‐associated accumulation of mast cells (MCs) has first been observed more than a century ago. Therefore, MCs have been implicated in tumor development and growth; however, the results regarding the role of MC in cutaneous de novo carcinogenesis are still controversially discussed. Here, we subjected MC‐deficient KitW/KitW?v mice to chemical skin carcinogenesis. Tumors were induced using the carcinogen 7,12‐dimethylbenz[a]‐anthracene and subsequent treatment with the tumor promoter 12‐tetradecanoyl‐phorbol‐13‐acetat. The treatment resulted in pronounced inflammatory cell infiltrates that were diminished in MC‐deficient animals. Unexpectedly, tumor development and growth was significantly increased in MC‐deficient KitW/KitW?v mice. The repair of their MC deficiency by local adoptive transfer of MCs normalized tumor incidence and growth. The recruitment of skin‐infiltrating immune cells, particularly of F4/80+ monocytes, Gr‐1+ granulocytes, B220+ B cells and CD8+ T lymphocytes, to sites of tumor development was, in part, also controlled by MCs. Recent evidence indicated the importance of local antitumor tissue immunity which prevents tumor development. These findings suggest a critical role for MCs in mediating these host antitumor immune responses in the skin. 相似文献
954.
955.
956.
957.
958.
Frank Zongo Christophe Ribuot Ahcène Boumendjel Innocent Guissou 《Fundamental & clinical pharmacology》2014,28(3):323-330
Waltheria indica is used in traditional pharmacopeia in Burkina Faso for the treatment of asthma and conditions of inflammation. To evaluate its pharmacological properties and isolate the active compounds, a study through a bioguided phytochemical approach was conducted. This search was guided by a two‐level investigation. First, we evaluated the impact of various fractions on the activity of enzymes involved in smooth muscle contraction (PDE4A1α) and inflammatory processes (PLA2, 5‐LOX). Second, we investigated the inhibitory effect of fractions on isolated rat trachea. The initial hydroalcoholic extract from roots of W. indica (HA), n‐hexane fraction (F1), dichloromethane fraction (F2), ethyl acetate fraction (F3), residuary fraction (F4) reduced enzyme activity of PDE4A1α (inhibition of 22–42% at 50 μg/mL), 5‐LOX (60–80% at 10 μg/mL), and PLA2 (42–94% at 100 μg/mL). On isolated rat trachea, only HA, F3, and fractions obtained from F3 by chromatography on silica gel column, using dichloromethane/methanol, dose dependently inhibited contraction induced by acetylcholine. IC50 was 1051 μg/mL for HA and comprised between 181 and 477 μg/mL for F3 and its fractions. The most active fractions were purified and led to the identification of (‐)‐epicatechin. (‐)‐epicatechin from W. indica dose dependently inhibited PLA2 (IC50 = 154.7 μm ) and 5‐LOX (IC50 = 15.8 μm ). In conclusion, both inhibition of PDE4A1α, 5‐LOX, and PLA2 activities and rat trachea relaxation by W. indica validate its use in traditional management of asthma and other conditions of inflammation. These effects should be, at least in part, attributed to the presence of (‐)‐epicatechin in roots of W. indica. 相似文献
959.
960.