全文获取类型
收费全文 | 552704篇 |
免费 | 39973篇 |
国内免费 | 12862篇 |
专业分类
耳鼻咽喉 | 6020篇 |
儿科学 | 14421篇 |
妇产科学 | 7521篇 |
基础医学 | 38273篇 |
口腔科学 | 11818篇 |
临床医学 | 90245篇 |
内科学 | 84447篇 |
皮肤病学 | 5767篇 |
神经病学 | 22328篇 |
特种医学 | 19868篇 |
外国民族医学 | 32篇 |
外科学 | 63819篇 |
综合类 | 73534篇 |
现状与发展 | 40篇 |
一般理论 | 30篇 |
预防医学 | 50547篇 |
眼科学 | 6706篇 |
药学 | 52642篇 |
816篇 | |
中国医学 | 36076篇 |
肿瘤学 | 20589篇 |
出版年
2024年 | 1009篇 |
2023年 | 8055篇 |
2022年 | 12427篇 |
2021年 | 25025篇 |
2020年 | 21186篇 |
2019年 | 24460篇 |
2018年 | 19292篇 |
2017年 | 17979篇 |
2016年 | 19530篇 |
2015年 | 21625篇 |
2014年 | 41633篇 |
2013年 | 39949篇 |
2012年 | 39446篇 |
2011年 | 37692篇 |
2010年 | 32287篇 |
2009年 | 29831篇 |
2008年 | 27312篇 |
2007年 | 27617篇 |
2006年 | 23797篇 |
2005年 | 18442篇 |
2004年 | 12909篇 |
2003年 | 11189篇 |
2002年 | 9000篇 |
2001年 | 7603篇 |
2000年 | 6584篇 |
1999年 | 5352篇 |
1998年 | 5012篇 |
1997年 | 4492篇 |
1996年 | 3671篇 |
1995年 | 3455篇 |
1994年 | 3243篇 |
1993年 | 2672篇 |
1992年 | 2757篇 |
1991年 | 2378篇 |
1990年 | 2217篇 |
1989年 | 2128篇 |
1988年 | 1933篇 |
1987年 | 1749篇 |
1986年 | 1528篇 |
1985年 | 3490篇 |
1984年 | 3857篇 |
1983年 | 2559篇 |
1982年 | 3082篇 |
1981年 | 2514篇 |
1980年 | 2188篇 |
1979年 | 1911篇 |
1978年 | 1541篇 |
1977年 | 1339篇 |
1976年 | 1349篇 |
1975年 | 927篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Marike Gabrielson Mattias Hammarström Magnus Bäcklund Jenny Bergqvist Kristina Lång Ann H Rosendahl Signe Borgquist Roxanna Hellgren Kamila Czene Per Hall 《International journal of cancer. Journal international du cancer》2023,152(11):2362-2372
Tamoxifen prevents recurrence of breast cancer and is suggested for preventive risk-reducing therapy. Tamoxifen reduces mammographic density, a proxy for therapy response, but little is known about its effects in remodelling normal breast tissue. Our study, a substudy within the double-blinded dose-determination trial KARISMA, investigated tamoxifen-specific changes in breast tissue composition and histological markers in healthy women. We included 83 healthy women randomised to 6 months daily intake of 20, 10, 5, 2.5, 1 mg of tamoxifen or placebo. The groups were combined to “no dose” (0-1 mg), “low-dose” (2.5-5 mg) or “high-dose” (10-20 mg) of tamoxifen. Ultrasound-guided biopsies were collected before and after tamoxifen exposure. In each biopsy, epithelial, stromal and adipose tissues was quantified, and expression of epithelial and stromal Ki67, oestrogen receptor (ER) and progesterone receptor (PR) analysed. Mammographic density using STRATUS was measured at baseline and end-of-tamoxifen-exposure. We found that different doses of tamoxifen reduced mammographic density and glandular-epithelial area in premenopausal women and associated with reduced epithelium and increased adipose tissue. High-dose tamoxifen also decreased epithelial ER and PR expressions in premenopausal women. Premenopausal women with the greatest reduction in proliferation also had the greatest epithelial reduction. In postmenopausal women, high-dose tamoxifen decreased the epithelial area with no measurable density decrease. Tamoxifen at both low and high doses influences breast tissue composition and expression of histological markers in the normal breast. Our findings connect epithelial proliferation with tissue remodelling in premenopausal women and provide novel insights to understanding biological mechanisms of primary prevention with tamoxifen. 相似文献
52.
53.
《Research in social & administrative pharmacy》2022,18(9):3694-3698
In this paper, we argue that understanding and addressing the problem of poor-quality medical products requires a more interdisciplinary approach than has been evident to date. While prospective studies based on rigorous standardized methodologies are the gold standard for measuring the prevalence of poor-quality medical products and understanding their distribution nationally and internationally, they should be complemented by social science research to unpack the complex set of social, economic, and governance factors that underlie these patterns. In the following sections, we discuss specific examples of prospective quality surveys and of social science studies, highlighting the value of cross-sector partnerships in driving high-quality, policy-relevant research in this area. 相似文献
54.
目的 探讨鸟巢式护理模式在早产儿护理中的应用价值。方法 选取2016年6月—2020年5月本院收治的早产儿94例,采用随机数表法将其分为两组,每组各47例。对照组给予早产儿采取常规护理,观察组在早产儿常规护理上实施鸟巢式护理模式。比较两组临床效果、护理前后生长发育情况、肠胃功能及家属护理满意度。结果 观察组体温波动幅度低于对照组,睡眠时间长于对照组,血氧饱和度高于对照组,出暖箱时间短于对照组,差异有统计学意义(P<0.05)。护理前,两组头围、身高、体质量比较,差异无统计学意义(t=0.381,P=0.704、t=0.211,P=0.833、t=1.472,P=0.144);护理后2周,观察组头围(28.44±1.35)cm、身高(44.86±2.05)cm、体质量(2 336.93±12.47)g,高于对照组的(27.76±1.87)cm、(42.46±2.43)cm、(2 310.14±13.56)g,差异有统计学意义(t=2.021,P=0.046、t=5.175,P<0.001、t=9.970,P<0.001);观察组首次胎便时间、胎便转黄时间分别为(21.74±7.35)h、(58.91±12.44)h,短于对照组的(25.02±8.13)h、(63.87±13.74)h,排便次数及进奶量的增加分别为(5.67±1.32)次/d、(3.38±1.43)mL/d,高于对照组的(4.21±1.84)次/d、(2.13±0.27)mL/d,差异有统计学意义(t=2.052,P=0.043、t=4.420,P<0.001、t=2.205,P=0.030、t=5.889,P<0.001);观察组护理总满意度高于对照组,差异有统计学意义(P<0.05)。结论 鸟巢式护理模式可减少早产儿体温波动幅度,提供适宜的恒温环境,促进早产儿生长发育,效果确切,值得广泛应用。 相似文献
55.
目的研究慢阻肺急性加重期患者延迟就医与家庭动力学的相关性,希望能够为慢阻肺急性加重期患者拟定护理措施提供科学依据。方法选取2017年1月-2019年12月我院240例诊断为慢阻肺急性加重期的患者为研究对象。根据患者入院就医的时间进行分组,时间≥24h的延迟就医的患者为观察组,时间<24h的及时就医患者为对照组。结果两组患者在文化水平、家庭年收入、在职状态、医疗保险和婚姻状况和APACHEⅡ评分比较(P<0.05)。观察组患者疾病观念、个性化、系统逻辑和家庭氛围得分比对照组高(P<0.05)。Pearman的相关性分析结果显示:慢阻肺急性加重期患者延迟就医时间与各个层面分数以及家庭动力总分呈现负相关性(P<0.05)。应变量为延迟就医为应变量,患者的一般资料为自变量,经Logistic回归分析结果表明:延迟就医的影响因素为文化水平、家庭动力评分、职业状态、家庭收入、婚姻状况和APACHEⅡ评分。结论慢阻肺急性加重期患者家庭动力总分与疾病观念、个性化、系统逻辑和家庭氛围得分与延迟就医时间呈现负相关性,患者延迟就医的影响因素是家庭动力学评分。 相似文献
56.
57.
《Vaccine》2022,40(7):1001-1009
Vaccination guidelines for dogs and cats indicate that core vaccines (for dogs, rabies, distemper, adenovirus, parvovirus; for cats, feline parvovirus, herpes virus-1, calicivirus) are essential to maintain health, and that non-core vaccines be administered according to a clinician’s assessment of a pet’s risk of exposure and susceptibility to infection. A reliance on individual risk assessment introduces the potential for between-practice inconsistencies in non-core vaccine recommendations. A study was initiated to determine non-core vaccination rates of dogs (Leptospira, Borrelia burgdorferi, Bordetella bronchiseptica, canine influenza virus) and cats (feline leukemia virus) in patients current for core vaccines in veterinary practices across the United States. Transactional data for 5,531,866 dogs (1,670 practices) and 1,914,373 cats (1,661 practices) were retrieved from practice management systems for the period November 1, 2016 through January 1, 2020, deidentified and normalized. Non-core vaccination status was evaluated in 2,798,875 dogs and 788,772 cats that were core-vaccine current. Nationally, median clinic vaccination rates for dogs were highest for leptospirosis (70.5%) and B. bronchiseptica (68.7%), and much lower for canine influenza (4.8%). In Lyme-endemic states, the median clinic borreliosis vaccination rate was 51.8%. Feline leukemia median clinic vaccination rates were low for adult cats (34.6%) and for kittens and 1-year old cats (36.8%). Individual clinic vaccination rates ranged from 0 to 100% for leptospirosis, B. bronchiseptica and feline leukemia, 0–96% for canine influenza, and 0–94% for borreliosis. Wide variation in non-core vaccination rates between clinics in similar geographies indicates that factors other than disease risk are driving the use of non-core vaccines in pet dogs and cats, highlighting a need for veterinary practices to address gaps in patient protection. Failure to implement effective non-core vaccination strategies leaves susceptible dogs and cats unprotected against vaccine-preventable diseases. 相似文献
58.
《Gait & posture》2022
BackgroundAnteriorly-loaded walking is common in many occupations and may increase fall risk. Dynamic gait stability, defined by the Feasible Stability Region (FSR) theory, quantifies the kinematic relationship between the body’s center of mass (COM) and base of support (BOS). FSR-based dynamic gait stability has been used to evaluate the fall risk.Research questionHow does front load carriage affect dynamic gait stability, step length, and trunk angle among young adults during treadmill walking?MethodsIn this between-subject design study, 30 healthy young adults were evenly randomized into three load groups (0%, 10%, or 20% of body weight). Participants carried their assigned load while walking on a treadmill at a speed of 1.2 m/s. Body kinematics were collected during treadmill walking. Dynamic gait stability (the primary variable) was calculated for two gait events: touchdown and liftoff. Step length and trunk angle were measured as secondary variables. One-way analysis of variance was conducted to detect any group-related differences for all variables. Post-hoc analysis with Bonferroni correction was performed when main group differences were found.ResultsNo significant differences but medium to large effect sizes were found between groups for dynamic gait stability at touchdown (p = 0.194, η2 = 0.114) and liftoff (p = 0.122, η2 = 0.139). Trunk angle significantly increased (indicating backward lean) with the front load at touchdown (p < 0.001, η2 = 0.648) and liftoff (p < 0.001, η2 = 0.543). No significant between-group difference was found related to the step length (p = 0.344, η2 = 0.076).SignificanceCarrying a front load during walking significantly alters the trunk orientation and may change the COM-BOS kinematic relationship and, therefore, fall risk. The findings could inform the design of future studies focusing on the impact of anterior load carriage on fall risk during different locomotion. 相似文献
59.
60.