全文获取类型
收费全文 | 3810篇 |
免费 | 218篇 |
国内免费 | 16篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 101篇 |
妇产科学 | 60篇 |
基础医学 | 456篇 |
口腔科学 | 188篇 |
临床医学 | 299篇 |
内科学 | 943篇 |
皮肤病学 | 52篇 |
神经病学 | 349篇 |
特种医学 | 68篇 |
外科学 | 534篇 |
综合类 | 36篇 |
一般理论 | 1篇 |
预防医学 | 302篇 |
眼科学 | 46篇 |
药学 | 204篇 |
中国医学 | 17篇 |
肿瘤学 | 363篇 |
出版年
2024年 | 3篇 |
2023年 | 16篇 |
2022年 | 45篇 |
2021年 | 106篇 |
2020年 | 72篇 |
2019年 | 131篇 |
2018年 | 131篇 |
2017年 | 68篇 |
2016年 | 61篇 |
2015年 | 99篇 |
2014年 | 136篇 |
2013年 | 160篇 |
2012年 | 309篇 |
2011年 | 312篇 |
2010年 | 157篇 |
2009年 | 152篇 |
2008年 | 284篇 |
2007年 | 274篇 |
2006年 | 291篇 |
2005年 | 276篇 |
2004年 | 238篇 |
2003年 | 189篇 |
2002年 | 187篇 |
2001年 | 17篇 |
2000年 | 26篇 |
1999年 | 29篇 |
1998年 | 28篇 |
1997年 | 24篇 |
1996年 | 21篇 |
1995年 | 29篇 |
1994年 | 18篇 |
1993年 | 21篇 |
1992年 | 18篇 |
1991年 | 10篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1984年 | 7篇 |
1983年 | 11篇 |
1982年 | 5篇 |
1981年 | 13篇 |
1980年 | 7篇 |
1975年 | 2篇 |
1973年 | 5篇 |
1972年 | 2篇 |
1971年 | 3篇 |
1970年 | 2篇 |
排序方式: 共有4044条查询结果,搜索用时 15 毫秒
121.
122.
First characterization of fluoroquinolone resistance in Streptococcus suis 总被引:5,自引:0,他引:5
下载免费PDF全文
![点击此处可从《Antimicrobial agents and chemotherapy》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Escudero JA San Millan A Catalan A de la Campa AG Rivero E Lopez G Dominguez L Moreno MA Gonzalez-Zorn B 《Antimicrobial agents and chemotherapy》2007,51(2):777-782
We have identified and sequenced the genes encoding the quinolone-resistance determining region (QRDR) of ParC and GyrA in fluoroquinolone-susceptible and -resistant Streptococcus suis clinical isolates. Resistance is the consequence of single point mutations in the QRDRs of ParC and GyrA and is not due to clonal spread of resistant strains or horizontal gene transfer with other bacteria. 相似文献
123.
124.
In Vitro Activities of Ketolide HMR 3647, Macrolides, and Clindamycin against Coryneform Bacteria 总被引:3,自引:2,他引:3
下载免费PDF全文
![点击此处可从《Antimicrobial agents and chemotherapy》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Luis Martínez-Martínez Alvaro Pascual Ana Isabel Surez Evelio J. Perea 《Antimicrobial agents and chemotherapy》1998,42(12):3290-3292
The in vitro activity of ketolide HMR 3647 against coryneform bacteria isolated from clinical samples was evaluated. Except against Corynebacterium jeikeium and C. urealyticum, HMR 3647 showed high activity against Corynebacterium spp., being more active than 14- and 16-membered macrolides, azithromycin, or clindamycin. HMR 3647 also had high in vitro activity against Brevibacterium spp. and Listeria monocytogenes. 相似文献
125.
A Cantafora A Di Biase D Alvaro M Angelico M Marin A F Attili 《Clinica chimica acta; international journal of clinical chemistry》1983,134(3):281-295
In this paper we propose a novel, rapid and simple high-performance liquid chromatographic (HPLC) method for the identification and quantitation of individual phosphatidylcholine (PC) molecular species from natural mixtures. To overcome difficulties deriving from the lack of adequate standards and from the variability of the responses to UV spectrophotometric detectors currently used in HPLC analysis, we first fractionated and quantitated the major molecular species of a commercial egg PC by means of a preparative column. The identification of PC molecular species was confirmed by gas-liquid chromatographic analysis of fatty acids. We employed the fractions recovered from preparative HPLC to determine the detector calibration factors of the individual molecular species separated using an analytical, high-speed, reversed-phase HPLC column. The proposed method seems to be adequate for the analysis of PC from many biological sources. Its application to the analysis of human hepatic and gallbladder biliary PC is shown. 相似文献
126.
Ohad Ronen K. Thomas Robbins Kerry D. Olsen Ashok R. Shaha Gregory W. Randolph Iain J. Nixon Mark E. Zafereo Dana M. Hartl Luiz P. Kowalski Juan P. Rodrigo Andrs Coca‐Pelaz Antti A. Mkitie Vincent Vander Poorten Alvaro Sanabria Peter Angelos Alessandra Rinaldo Alfio Ferlito 《Head & neck》2020,42(10):3061-3071
Recent modifications in the management of well‐differentiated thyroid cancer have resulted in significant alterations in clinical approach. Utilizing a series of preoperative and postoperative risk factors involving both the patient and the disease pathology, we offer the term “staged thyroidectomy” to help organize these risk factors for patients and the endocrine team to optimize management. This approach is intended to incorporate our latest nuanced understanding of certain endocrine pathology and may serve to optimize patient outcomes. 相似文献
127.
128.
Alvaro Baik Cho M.D. Ph.D. Renata Gregorio Paulos M.D. Marcelo Rosa de Resende M.D. Ph.D. Leandro Yoshinobu Kiyohara M.D. Luiz Sorrenti M.D. Teng Hsiang Wei M.D. Ph.D. Raul Bolliger Neto M.D. Rames Mattar Júnior M.D. Ph.D. 《Microsurgery》2014,34(7):511-515
The purpose of this study was to observe whether the results of the median nerve fascicle transfer to the biceps are equivalent to the classical ulnar nerve fascicle transfer, in terms of elbow flexion strength and donor nerve morbidity. Twenty‐five consecutive patients were operated between March 2007 and July 2013. The patients were divided into two groups. In Group 1 (n = 8), the patients received an ulnar nerve fascicle transfer to the biceps motor branch. In Group 2 (n = 15), the patients received a median nerve fascicle transfer to the biceps motor branch. Two patients with follow‐up less than six months were excluded. Both groups were similar regarding age (P = 0.070), interval of injury (P = 0.185), and follow‐up period (P = 0.477). Elbow flexion against gravity was achieved in 7 of 8 (87.5%) patients in Group 1, versus 14 of 15 (93.3%) patients in Group 2 (P = 1.000). The level of injury (C5‐C6 or C5‐C7) did not affect anti‐gravity elbow flexion recovery in both the groups (P = 1.000). It was concluded that the median nerve fascicle transfer to the biceps is as good as the ulnar nerve fascicle transfer, even in C5‐C7 injuries. © 2014 Wiley Periodicals, Inc. Microsurgery 34:511–515, 2014. 相似文献
129.
Yichen Zhong Alvaro Mu?oz George J. Schwartz Bradley A. Warady Susan L. Furth Alison G. Abraham 《Journal of the American Society of Nephrology : JASN》2014,25(5):913-917
GFR decline in patients with CKD has been widely approximated using linear models, but this linearity assumption is not well validated. We conducted a matched case-control study in children from the Chronic Kidney Disease in Children (CKiD) cohort ages 1–16 years with mild to moderate CKD to assess whether GFR decline follows a nonlinear trajectory as CKD approaches ESRD. Children (n=125) who initiated RRT (cases) during follow-up were individually matched by CKD stage at baseline and glomerular/nonglomerular diagnosis with children (n=125) who remained RRT-free when the corresponding case initiated RRT (controls). GFR trajectories were compared using log-linear and piecewise log-linear mixed effects models adjusted for baseline characteristics. From study entry to 18 months before RRT, GFR declined 7% faster among cases compared with controls. However, GFR declined 26% faster among cases compared with controls (P<0.001) during the 18 months before RRT. Nonlinearity in the rate of kidney function loss, which was shown in this cohort, may preclude accurate clinical prediction of the timing of RRT and adequate patient preparation. This study should prompt the characterization of predictive factors that may contribute to an acceleration of kidney function decline.GFR is a key measurement of kidney function, and the degree of GFR decline over time is a reflection of the severity of CKD progression. GFR decline has been approximated as linear or log-linear in most analyses of progression, an assumption that has been consistent with available data.1–4 However, many studies rely on relatively short follow-up periods and few repeated measures. Given the convenience of assuming a linear GFR trajectory, which results from the ease of modeling and interpreting linear slopes, few studies have sought to validate the linearity assumption and explore the possibility of nonlinear GFR decline. However, nonlinearity in GFR decline has been observed in some epidemiologic studies,5–7 and the implications on the risk for adverse outcomes have generated interest.8 A CKD cohort study in France found that about one half of its patients experienced nonlinear GFR decline during the last year before dialysis.5 A study by Li et al.9 used a flexible approach to model nonlinearity in GFR trajectories. Li et al.9 found evidence of nonlinear GFR trajectory behavior in adult patients with CKD, and furthermore, the probability of having nonlinear features in an individual trajectory was associated with known risk factors for CKD progression. O’Hare et al.10 found several distinct nonlinear patterns of GFR decline in the 2 years before dialysis initiation in Veterans Affairs patients.Clinical strategies and subsequent patient response to care could potentially benefit from new insights into the variable paths of progression in patients with CKD.10,11 The question of whether characterizing the nonlinearity in the GFR trajectory can assist the identification of risk groups for outcomes, such as ESRD, remains unexplored. The implications on future outcomes of an increased rate of GFR decline could inform clinical decisions about screening frequencies, treatment, or preparation for RRT.The Chronic Kidney Disease in Children (CKiD) study is an ongoing cohort study of children with CKD who, at baseline, had an eGFR between 30 and 90 ml/min per 1.73 m3 and were ages 1–16 years. An end point of the study is RRT defined as transplant or dialysis. To determine whether trajectories of GFR accelerate before RRT, we nested a case-control study, in which cases were children observed to have received RRT and controls were children with CKD who remained RRT-free at the time when the corresponding case initiated RRT.There were 147 children who experienced RRT during follow-up. Each case was matched individually to an eligible control at the time of the case occurrence. The matching factors included baseline CKD stage, glomerular/nonglomerular diagnosis, and, through design, the amount of follow-up time from study entry. Matching was done without replacement, and 22 cases were excluded from the analyses, because no appropriate control was available. We used a random sequence to determine the order of matching. The analysis was, thus, based on 125 matched case-control pairs. Demographic and clinical characteristics of cases and controls at baseline are shown in Characteristics Cases (n=125) Controls (n=125) Age, yr 12.64 (9.23–14.53) 12.33 (8.71–14.74) Sex (girls), N (%) 38 (30.4) 57 (45.6) Race (nonwhite), N (%) 51 (40.8) 36 (28.8) Urine protein/creatinine ratio 1.74 (0.48–4.04) 0.60 (0.26–1.76) Proteinuria, N (%) 0.2≤protein/creatinine ratio<2 56 (46.7) 71 (59.7) Protein/creatinine ratio≥2 51 (42.5) 23 (19.3) Baseline GFRa 32.21 (26.43–39.64) 35.77 (27.86–43.78) Glomerular diagnosis, N (%)a 47 (37.6) 47 (37.6)