全文获取类型
收费全文 | 2400445篇 |
免费 | 201133篇 |
国内免费 | 6457篇 |
专业分类
耳鼻咽喉 | 34648篇 |
儿科学 | 73092篇 |
妇产科学 | 63266篇 |
基础医学 | 338263篇 |
口腔科学 | 68099篇 |
临床医学 | 219374篇 |
内科学 | 472294篇 |
皮肤病学 | 48374篇 |
神经病学 | 202253篇 |
特种医学 | 97096篇 |
外国民族医学 | 903篇 |
外科学 | 363046篇 |
综合类 | 61632篇 |
现状与发展 | 10篇 |
一般理论 | 983篇 |
预防医学 | 192591篇 |
眼科学 | 56296篇 |
药学 | 180808篇 |
29篇 | |
中国医学 | 6340篇 |
肿瘤学 | 128638篇 |
出版年
2018年 | 25305篇 |
2017年 | 19890篇 |
2016年 | 21603篇 |
2015年 | 24689篇 |
2014年 | 35431篇 |
2013年 | 52488篇 |
2012年 | 71132篇 |
2011年 | 74794篇 |
2010年 | 44078篇 |
2009年 | 42141篇 |
2008年 | 70388篇 |
2007年 | 74690篇 |
2006年 | 75516篇 |
2005年 | 73529篇 |
2004年 | 70384篇 |
2003年 | 68013篇 |
2002年 | 67132篇 |
2001年 | 113106篇 |
2000年 | 117106篇 |
1999年 | 98956篇 |
1998年 | 28294篇 |
1997年 | 25917篇 |
1996年 | 25747篇 |
1995年 | 24915篇 |
1994年 | 23407篇 |
1993年 | 21727篇 |
1992年 | 79571篇 |
1991年 | 76558篇 |
1990年 | 73694篇 |
1989年 | 70952篇 |
1988年 | 65959篇 |
1987年 | 64874篇 |
1986年 | 61391篇 |
1985年 | 58449篇 |
1984年 | 44246篇 |
1983年 | 37689篇 |
1982年 | 22891篇 |
1981年 | 20341篇 |
1979年 | 41310篇 |
1978年 | 28990篇 |
1977年 | 24349篇 |
1976年 | 22836篇 |
1975年 | 23967篇 |
1974年 | 29644篇 |
1973年 | 28046篇 |
1972年 | 26230篇 |
1971年 | 24156篇 |
1970年 | 22755篇 |
1969年 | 21089篇 |
1968年 | 19136篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
191.
O. Morris M. Fairclough J. Grigg C. Prenant A. McMahon 《Journal of labelled compounds & radiopharmaceuticals》2019,62(1):4-23
Affinity peptide and protein‐ (APP) based radiotracers are an increasingly popular class of radiotracer in positron emission tomography (PET), which was once dominated by the use of small molecule radiotracers. Radiolabelled monoclonal antibodies (mAbs) are important examples of APPs, yet a preference for smaller APPs, which exhibit fast pharmacokinetics and permit rapid PET aided diagnosis, has become apparent. 18F exhibits favourable physical characteristics for APP radiolabelling and has been described as an ideal PET radionuclide. Notwithstanding, 18F radiolabelling of APP is challenging, and this is echoed in the literature where a number of diverse approaches have been adopted. This review seeks to assess and compare the approaches taken to 18F APP radiolabelling with the intention of highlighting trends within this expanding field. Generic themes have emerged in the literature, namely the use of mild radiolabelling conditions, a preference of site‐specific methodologies with an impetus for short, automated procedures which produce high‐yielding [18F]APPs. 相似文献
192.
193.
194.
Eloise R. Galligan Lindsey Fix Sameera Husain Philip Zachariah Darrell J. Yamashiro Christine T. Lauren 《Journal of cutaneous pathology》2019,46(2):159-161
We report a case of disseminated Trichosporon asahii in a patient on systemic antifungal therapy who presented with multiple cutaneous nodules suggestive of fungal infection. Histologic features resembled neutrophilic eccrine hidradenitis but staining with periodic acid‐Schiff and Gomori methenamine silver confirmed the clinical diagnosis. This case highlights the importance of maintaining suspicion for trichosporonosis and contextualizing histologic findings within the underlying clinical picture. 相似文献
195.
196.
B. Siska I. Machac P. Dolecek J. Martiska 《Pharmaceutical development and technology》2019,24(1):80-88
Rheological behaviour of pharmaceutical semisolid preparations significantly affects manufacturing process, administration, stability, homogeneity of incorporated drug, accuracy of dosing, adhesion in the place of application, drug release, and resulting therapeutic effect of the product. We performed test of consistency by penetrometry, rotational, oscillation and creep tests, and squeeze and tack tests of model samples to introduce methods suitable for characterization and comparison of semisolids in practice. Penetrometry is a simple method allowing sorting the semisolids to low and high stress-resistant materials but deficient for rheological characterization of semisolids. Value of yield stress, generally considered to be appropriate feature of semisolids, is significantly influenced by the method of testing and the way of evaluation. The hysteresis loops of model semisolids revealed incomplete thixotropy, therefore, three-step thixotropy test was employed. Semisolids showed nonlinear response in the creep phase of tests and partial recovery of structure by storing energy in the recovery phase. Squeeze and tack tests seem to be convenient ways for comparison of semisolids. Our study can contribute to a better understanding of different flow behaviour of semisolids given by different physicochemical properties of excipients and can bring useful approaches to evaluation and comparison of semisolids in practice. 相似文献
197.
198.
Rian M. Hasson Kayla A. Fay Joseph D. Phillips Timothy M. Millington David J. Finley 《American journal of surgery》2021,221(4):725-730
BackgroundRural populations face many health disadvantages compared to urban areas. There is a critical need to better understand the current lung cancer screening landscape in these communities to identify targeted areas to improve the impact of this proven tool.MethodsData from the County Health Rankings of New Hampshire and Vermont was reviewed for population density, distribution of adult smokers, and level of education compared to the distribution of Lung Cancer Screening Facilities throughout these two states.ResultsScreening programs in southern counties of Vermont with lower levels of education have decreased access. In New Hampshire, there are no programs within 30 miles of the areas with the largest distribution of smokers, and decreased access in some areas with the lowest levels of education.ConclusionsImproving equitable access to high-quality screening services in rural regions and the creation of targeted interventions to address decreased access in areas of high tobacco use and low education is vital to decreasing the incidence of latestage presentations of lung cancer within these populations. 相似文献
199.
Michael W. Manning Yi-Ju Li Dean Linder John C. Haney Yi-Hung Wu Mihai V. Podgoreanu Madhav Swaminathan Jacob N. Schroder Carmelo A. Milano Ian J. Welsby Mark Stafford-Smith Kamrouz Ghadimi 《Journal of cardiothoracic and vascular anesthesia》2021,35(5):1310-1318
- Download : Download high-res image (215KB)
- Download : Download full-size image
200.
Shylo R. Johnson Dennis Slate Kathleen M. Nelson Amy J. Davis Samual A. Mills John T. Forbes Kurt C. VerCauteren Amy T. Gilbert Richard B. Chipman 《Viruses》2021,13(2)
Since the 1990s, oral rabies vaccination (ORV) has been used successfully to halt the westward spread of the raccoon rabies virus (RV) variant from the eastern continental USA. Elimination of raccoon RV from the eastern USA has proven challenging across targeted raccoon (Procyon lotor) and striped skunk (Mephitis mephitis) populations impacted by raccoon RV. Field trial evaluations of the Ontario Rabies Vaccine Bait (ONRAB) were initiated to expand ORV products available to meet the rabies management goal of raccoon RV elimination. This study describes the continuation of a 2011 trial in West Virginia. Our objective was to evaluate raccoon and skunk response to ORV occurring in West Virginia for an additional two years (2012–2013) at 75 baits/km2 followed by three years (2014–2016) of evaluation at 300 baits/km2. We measured the change in rabies virus-neutralizing antibody (RVNA) seroprevalence in targeted wildlife populations by comparing levels pre- and post-ORV during each year of study. The increase in bait density from 75/km2 to 300/km2 corresponded to an increase in average post-ORV seroprevalence for raccoon and skunk populations. Raccoon population RVNA levels increased from 53% (300/565, 95% CI: 50–57%) to 82.0% (596/727, 95% CI: 79–85%) during this study, and skunk population RVNA levels increased from 11% (8/72, 95% CI: 6–20%) to 39% (51/130, 95% CI: 31–48%). The RVNA seroprevalence pre-ORV demonstrated an increasing trend across study years for both bait densities and species, indicating that multiple years of ORV may be necessary to achieve and maintain RVNA seroprevalence in target wildlife populations for the control and elimination of raccoon RV in the eastern USA. 相似文献