全文获取类型
收费全文 | 239586篇 |
免费 | 6463篇 |
国内免费 | 1261篇 |
专业分类
耳鼻咽喉 | 1968篇 |
儿科学 | 8353篇 |
妇产科学 | 3982篇 |
基础医学 | 24182篇 |
口腔科学 | 2622篇 |
临床医学 | 20069篇 |
内科学 | 42090篇 |
皮肤病学 | 1477篇 |
神经病学 | 21313篇 |
特种医学 | 11426篇 |
外国民族医学 | 8篇 |
外科学 | 39052篇 |
综合类 | 6201篇 |
现状与发展 | 4篇 |
一般理论 | 35篇 |
预防医学 | 23149篇 |
眼科学 | 4117篇 |
药学 | 14824篇 |
18篇 | |
中国医学 | 1650篇 |
肿瘤学 | 20770篇 |
出版年
2023年 | 540篇 |
2022年 | 989篇 |
2021年 | 2209篇 |
2020年 | 1380篇 |
2019年 | 1846篇 |
2018年 | 23832篇 |
2017年 | 18857篇 |
2016年 | 20949篇 |
2015年 | 3039篇 |
2014年 | 3708篇 |
2013年 | 4099篇 |
2012年 | 11883篇 |
2011年 | 26089篇 |
2010年 | 21779篇 |
2009年 | 14011篇 |
2008年 | 23389篇 |
2007年 | 25849篇 |
2006年 | 4712篇 |
2005年 | 6073篇 |
2004年 | 6700篇 |
2003年 | 7599篇 |
2002年 | 5403篇 |
2001年 | 1129篇 |
2000年 | 1016篇 |
1999年 | 858篇 |
1998年 | 875篇 |
1997年 | 734篇 |
1996年 | 520篇 |
1995年 | 503篇 |
1994年 | 469篇 |
1993年 | 360篇 |
1992年 | 387篇 |
1991年 | 390篇 |
1990年 | 403篇 |
1989年 | 358篇 |
1988年 | 340篇 |
1987年 | 273篇 |
1986年 | 251篇 |
1985年 | 277篇 |
1984年 | 267篇 |
1983年 | 214篇 |
1982年 | 243篇 |
1981年 | 204篇 |
1980年 | 241篇 |
1979年 | 174篇 |
1978年 | 151篇 |
1977年 | 117篇 |
1976年 | 106篇 |
1974年 | 116篇 |
1973年 | 112篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
Colin W. BINNS Dawn GILCHRIST Beth WOODS Michael GRACEY Jane SCOTT Hannah SMITH 《Nutrition & Dietetics》2006,63(1):8-14
Objective: To document the breastfeeding practices of Aboriginal mothers delivering in Perth. Design and methods: A cohort of mothers was followed from the time of delivery for six months to obtain details of infant feeding practices. Subjects: A total of 455 mothers delivered during the study period and were asked to participate. A total of 425 mothers completed the initial questionnaire. Setting: The study was undertaken in six public hospitals in Perth, Western Australia. Data analyses: The data were analysed using spss . Breastfeeding duration was calculated using Kaplan–Meier survival analysis. Main outcome measures: Breastfeeding initiation and duration. Results: The mean age of the Aboriginal mothers was 21.8 years (range 14–39 years, SD 5.32) and the average gestational age was 38.3 weeks. Almost 50% of the mothers in the study delivered by Caesarean section. At discharge from hospital 89.4% (CI 86.6–92.1) of mothers were breastfeeding, declining to 58.8% (CI 53.5–64.1) at six months. When compared with non‐Aboriginal mothers, the Aboriginal breastfeeding rates were higher than the non‐Aboriginal average breastfeeding rates, but lower than the highest socioeconomic group. Conclusions: The breastfeeding rates of Aboriginal mothers are higher than for other Australians. This is despite the low maternal age and level of education and the high rates of low‐birth‐weight infants and Caesarean section among this population. The World Health Organization recommendation for infant feeding is exclusive breastfeeding until six months, but less than one‐third of Aboriginal mothers achieved this recommendation. 相似文献
62.
杨娅 Thomas Bartel Loredana Latina Guido Caspari 王新房 Raimund Erbel 《华中科技大学学报(医学英德文版)》2002,22(2):158-163
Coronary flow reserve (CFR) has been used toassess coronary microcirculation and epicardial coro-nary stenoses[1— 3 ] . CFR is defined as the ratio ofcoronary flow under maximal coronary vasodilatationto coronary flow under resting conditions[4 ] .Whenthe cross- sectional area of epicardial coronary arteriesis constant,coronary flow velocity (CFV) ratios areequal to volume flow ratios.The most common method used clinically formeasuring CFVR is intracoronary Doppler flow(ICD) analysis re… 相似文献
63.
64.
65.
Alex N. Bullock Julia Henckel Brian S. DeDecker Christopher M. Johnson Penka V. Nikolova Mark R. Proctor David P. Lane Alan R. Fersht 《Proceedings of the National Academy of Sciences of the United States of America》1997,94(26):14338-14342
Some 50% of human cancers are associated with mutations in the core domain of the tumor suppressor p53. Many mutations are thought just to destabilize the protein. To assess this and the possibility of rescue, we have set up a system to analyze the stability of the core domain and its mutants. The use of differential scanning calorimetry or spectroscopy to measure its melting temperature leads to irreversible denaturation and aggregation and so is useful as only a qualitative guide to stability. There are excellent two-state denaturation curves on the addition of urea that may be analyzed quantitatively. One Zn2+ ion remains tightly bound in the holo-form of p53 throughout the denaturation curve. The stability of wild type is 6.0 kcal (1 kcal = 4.18 kJ)/mol at 25°C and 9.8 kcal/mol at 10°C. The oncogenic mutants R175H, C242S, R248Q, R249S, and R273H are destabilized by 3.0, 2.9, 1.9, 1.9, and 0.4 kcal/mol, respectively. Under certain denaturing conditions, the wild-type domain forms an aggregate that is relatively highly fluorescent at 340 nm on excitation at 280 nm. The destabilized mutants give this fluorescence under milder denaturation conditions. 相似文献
66.
Management of sphenoid sinus cerebrospinal fluid rhinorrhea: making use of an extended approach to the sphenoid sinus. 总被引:2,自引:0,他引:2
Neelesh H Mehendale Bradley F Marple Brian Nussenbaum 《Otolaryngology--head and neck surgery》2002,126(2):147-153
OBJECTIVES: Specific information addressing the management of cerebrospinal fluid (CSF) fistulas that originate from within the sphenoid sinus remains scant. The objective of this study was to review the cause and management of CSF rhinorrhea arising from the sphenoid sinus. STUDY DESIGN AND SETTING: This is a retrospective chart review of 12 cases of CSF rhinorrhea arising from the sphenoid sinus that occurred in 11 patients. All patients were treated at a single institution between 1994 and 1999. RESULTS: All patients were managed surgically with sphenoid sinus fat obliteration using an endoscopic sublabial, transseptal approach. This approach was successful for all 12 cases, with median duration of follow-up of 18 months. CONCLUSIONS: Endoscopically assisted transseptal repair of CSF fistulas that originate within the sphenoid sinus offers an alternate approach to previously described methods of repair in this region. Advantages include wide access to the entire sphenoid sinus, improved access to laterally pneumatized regions within the sphenoid sinus, and rostral mucosal closure over the repair within the sinus. 相似文献
67.
68.
蒿甲醚引起小鼠体内日本血吸虫和曼氏血吸虫皮层变化1肖树华,沈炳贵,JackHORNER2,BrianACATTO3(中国预防医学科学院寄生虫病研究所,世界卫生组织疟疾、血吸虫病和丝虫病合作中心,上海200025,中国;2DepartmentofCli... 相似文献
69.
70.
The clinical, radiologic, and histopathologic findings of a case of bilateral dacryops is reported in a 49-year-old man. The patient presented with cystic masses located in superior lateral orbits and underwent bilateral excisions of these without any postoperative complications. 相似文献