全文获取类型
收费全文 | 2740568篇 |
免费 | 197111篇 |
国内免费 | 7847篇 |
学科分类
医药卫生 | 2945526篇 |
出版年
2021年 | 22524篇 |
2019年 | 23559篇 |
2018年 | 34855篇 |
2017年 | 26234篇 |
2016年 | 29831篇 |
2015年 | 33563篇 |
2014年 | 44680篇 |
2013年 | 67116篇 |
2012年 | 92383篇 |
2011年 | 96770篇 |
2010年 | 56962篇 |
2009年 | 53537篇 |
2008年 | 89429篇 |
2007年 | 95029篇 |
2006年 | 95714篇 |
2005年 | 91863篇 |
2004年 | 88097篇 |
2003年 | 84671篇 |
2002年 | 81443篇 |
2001年 | 131046篇 |
2000年 | 134058篇 |
1999年 | 112955篇 |
1998年 | 31753篇 |
1997年 | 28370篇 |
1996年 | 28629篇 |
1995年 | 27766篇 |
1994年 | 25412篇 |
1993年 | 23735篇 |
1992年 | 86787篇 |
1991年 | 83031篇 |
1990年 | 80130篇 |
1989年 | 77297篇 |
1988年 | 70683篇 |
1987年 | 69108篇 |
1986年 | 64566篇 |
1985年 | 61501篇 |
1984年 | 45716篇 |
1983年 | 38558篇 |
1982年 | 22811篇 |
1981年 | 20236篇 |
1979年 | 39634篇 |
1978年 | 27905篇 |
1977年 | 23685篇 |
1976年 | 21823篇 |
1975年 | 23271篇 |
1974年 | 27392篇 |
1973年 | 25996篇 |
1972年 | 24354篇 |
1971年 | 22522篇 |
1970年 | 20755篇 |
排序方式: 共有10000条查询结果,搜索用时 313 毫秒
71.
72.
73.
Michael Staehler Peter J. Goebell Lothar Müller Till-Oliver Emde Natalie Wetzel Lisa Kruggel Martina Jänicke Norbert Marschner the RCC-Registry Group 《International journal of cancer. Journal international du cancer》2020,146(5):1307-1315
Non-clear cell renal cell carcinoma is a very rare malignancy that includes several histological subtypes. Each subtype may need to be addressed separately regarding prognosis and treatment; however, no Phase III clinical trial data exist. Thus, treatment recommendations for patients with non-clear cell metastatic RCC (mRCC) remain unclear. We present first prospective data on choice of first- and second-line treatment in routine practice and outcome of patients with papillary mRCC. From the prospective German clinical cohort study (RCC-Registry), 99 patients with papillary mRCC treated with systemic first-line therapy between December 2007 and May 2017 were included. Prospectively enrolled patients who had started first-line treatment until May 15, 2016, were included into the outcome analyses (n = 82). Treatment was similar to therapies used for clear cell mRCC and consisted of tyrosine kinase inhibitors, mechanistic target of rapamycin inhibitors and recently checkpoint inhibitors. Median progression-free survival from start of first-line treatment was 5.4 months (95% confidence interval [CI], 4.1–9.2) and median overall survival was 12.0 months (95% CI, 8.1–20.0). At data cutoff, 73% of the patients died, 6% were still observed, 12% were lost to follow-up, and 9% were alive at the end of the individual 3-year observation period. Despite the lack of prospective Phase III evidence in patients with papillary mRCC, our real-world data reveal effectiveness of systemic clear cell mRCC therapy in papillary mRCC. The prognosis seems to be inferior for papillary compared to clear cell mRCC. Further studies are needed to identify drivers of effectiveness of systemic therapy for papillary mRCC. 相似文献
74.
Niamh M. Kelly Jessica V. Keane Rachel B. Gallimore Debra Bick Rachel M. Tribe 《Maternal & child nutrition》2020,16(2)
There is evidence that caesarean section delivery can impact on neonatal weight loss and weight gain patterns in the first 5 days of life. We conducted an integrative systematic review to examine the association of mode of delivery on early neonatal weight loss. Pubmed, Cumulative Index to Nursing and Allied Health Literature, Web of Science, Excerpta Medica dataBASE, and Medical Literature Analysis and Retrieval System Online were searched for relevant papers published before June 2019. Reference lists from the relevant papers were then backwards and forwards searched. As neonatal weight loss was reported in different formats, a meta‐analysis could not be carried out. Most studies did not distinguish between elective and emergency caesarean sections or instrumental and nonassisted vaginal deliveries. Seven papers were included. All papers except one found that caesarean section was associated with higher weight loss in the early days of life. Two papers presented data from studies on babies followed up to 1 month. One study found that on day 25, babies born by caesarean section had significantly higher weight gain than those born vaginally, while another found that by day 28, babies born vaginally gained more weight per day (11.9 g/kg/day) than those born by caesarean section (10.9 g/kg/day; p = .02). Overall, infants born by caesarean section lost more weight than those born vaginally, but due to the small number of studies included, more are needed to look at this difference and why it may occur. This discrepancy in weight between the two groups may be corrected over time, but future studies will need larger sample sizes and longer follow‐up periods to examine this. 相似文献
75.
76.
77.
78.
Martin R. Späth Malte P. Bartram Nicolàs Palacio-Escat K. Johanna R. Hoyer Cedric Debes Fatih Demir Christina B. Schroeter Amrei M. Mandel Franziska Grundmann Giuliano Ciarimboli Andreas Beyer Jayachandran N. Kizhakkedathu Susanne Brodesser Heike Göbel Jan U. Becker Thomas Benzing Bernhard Schermer Martin Höhne Markus M. Rinschen 《Kidney international》2019,95(2):333-349
79.
Elizabeth D. Krebs Robert B. Hawkins J. Hunter Mehaffey Clifford E. Fonner Alan M. Speir Mohammed A. Quader Jeffrey B. Rich Leora T. Yarboro Nicholas R. Teman Gorav Ailawadi 《The Journal of thoracic and cardiovascular surgery》2019,157(4):1533-1542.e2
Objectives
Expedient extubation after cardiac surgery has been associated with improved outcomes, leading to postoperative extubation frequently during overnight hours. However, recent evidence in a mixed medical-surgical intensive care unit population demonstrated worse outcomes with overnight extubation. This study investigated the impact of overnight extubation in a statewide, multicenter Society of Thoracic Surgeons database.Methods
Records from 39,812 patients undergoing coronary artery bypass grafting or valve operations (2008-2016) and extubated within 24 hours were stratified according to extubation time between 06:00 and 18:00 (day) or between 18:00 and 6:00 (overnight). Outcomes including reintubation, mortality, and composite morbidity-mortality were evaluated using hierarchical regression models adjusted for Society of Thoracic Surgeons predictive risk scores. To further analyze extubation during the night, a subanalysis stratified patients into 3 groups: 06:00 to 18:00, 18:00 to 24:00, and 24:00 to 06:00.Results
A total of 20,758 patients were extubated overnight (52.1%) and were slightly older (median age 66 vs 65 years, P < .001) with a longer duration of ventilation (4 vs 7 hours, P < .001). Day and overnight extubation were associated with equivalent operative mortality (1.7% vs 1.7%, P = .880), reintubation (3.7% vs 3.4%, P = .141), and composite morbidity-mortality (8.2% vs 8.0%, P = .314). After risk adjustment, overnight extubation was not associated with any difference in reintubation, mortality, or composite morbidity-mortality. On subanalysis, those extubated between 24:00 and 06:00 exhibited increased composite morbidity-mortality (odds ratio, 1.18; P = .001) but no difference in reintubation or mortality.Conclusions
Extubation overnight was not associated with increased mortality or reintubation. These results suggest that in the appropriate clinical setting, it is safe to routinely extubate cardiac surgery patients overnight. 相似文献80.
Ángel Becerra Héctor Trujillo Lucía Valencia Aurelio Rodríguez‐Pérez 《Brazilian Journal of Anesthesiology》2019,69(2):200-203