全文获取类型
收费全文 | 72227篇 |
免费 | 4947篇 |
国内免费 | 201篇 |
专业分类
耳鼻咽喉 | 530篇 |
儿科学 | 2091篇 |
妇产科学 | 1166篇 |
基础医学 | 9881篇 |
口腔科学 | 1505篇 |
临床医学 | 7561篇 |
内科学 | 15424篇 |
皮肤病学 | 988篇 |
神经病学 | 6835篇 |
特种医学 | 2250篇 |
外国民族医学 | 1篇 |
外科学 | 10128篇 |
综合类 | 896篇 |
一般理论 | 72篇 |
预防医学 | 6446篇 |
眼科学 | 1739篇 |
药学 | 4976篇 |
1篇 | |
中国医学 | 80篇 |
肿瘤学 | 4805篇 |
出版年
2023年 | 378篇 |
2022年 | 525篇 |
2021年 | 1403篇 |
2020年 | 842篇 |
2019年 | 1368篇 |
2018年 | 1661篇 |
2017年 | 1239篇 |
2016年 | 1357篇 |
2015年 | 1588篇 |
2014年 | 2372篇 |
2013年 | 3224篇 |
2012年 | 5245篇 |
2011年 | 5378篇 |
2010年 | 3008篇 |
2009年 | 2675篇 |
2008年 | 4894篇 |
2007年 | 5357篇 |
2006年 | 5255篇 |
2005年 | 4980篇 |
2004年 | 4776篇 |
2003年 | 4327篇 |
2002年 | 4218篇 |
2001年 | 582篇 |
2000年 | 414篇 |
1999年 | 647篇 |
1998年 | 905篇 |
1997年 | 758篇 |
1996年 | 639篇 |
1995年 | 608篇 |
1994年 | 495篇 |
1993年 | 465篇 |
1992年 | 359篇 |
1991年 | 316篇 |
1990年 | 277篇 |
1989年 | 271篇 |
1988年 | 287篇 |
1987年 | 233篇 |
1986年 | 256篇 |
1985年 | 255篇 |
1984年 | 328篇 |
1983年 | 341篇 |
1982年 | 400篇 |
1981年 | 381篇 |
1980年 | 352篇 |
1979年 | 210篇 |
1978年 | 244篇 |
1977年 | 194篇 |
1976年 | 137篇 |
1975年 | 106篇 |
1974年 | 116篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
Zhenzhen Zhang Mark Garzotto Tomasz M. Beer Philippe Thuillier Stephen Lieberman Motomi Mori 《Nutrition and cancer》2016,68(8):1309-1319
Animal and human studies suggest fish oil and green tea may have protective effect on prostate cancer. Fatty acid synthase (FAS) has been hypothesized to be linked to chemoprotective effects of both compounds. This study evaluated the independent and joint effects of fish oil (FO) and green tea supplement (epigallocatechin-3-gallate, EGCG) on FAS and Ki-67 levels in prostate tissue. Through a double-blinded, randomized controlled trial with 2 × 2 factorial design, 89 men scheduled for repeat prostate biopsy following an initial negative prostate biopsy were randomized into either FO alone (1.9 g DHA + EPA/day), EGCG alone (600 mg/day), a combination of FO and EGCG, or placebo. We used linear mixed-effects models to test the differences of prostate tissue FAS and Ki-67 by immunohistochemistry between pre- and post-intervention within each group, as well as between treatment groups. Results did not show significant difference among treatment groups in pre-to-post-intervention changes of FAS (P = 0.69) or Ki-67 (P = 0.26). Comparing placebo group with any of the treatment groups, we did not find significant difference in FAS or Ki-67 changes (all P > 0.05). Results indicate FO or EGCG supplementation for a short duration may not be sufficient to produce biologically meaningful changes in FAS or Ki-67 levels in prostate tissue. 相似文献
3.
Erin C. Tully Jackson M. Gray Sherryl H. Goodman Stephen Nowicki Jr. 《Early child development and care》2016,186(12):1939-1951
Children who expect they can bring about good outcomes and avoid bad outcomes tend to experience more personal successes. Little is known about factors that contribute to these ‘control expectancies’. The purpose of the present study was to determine whether children's internal control expectancies occur in the context of parents’ internal control expectancies, low family strain, and high family cohesiveness and whether these factors are more strongly related to daughters’ than sons’ control expectancies. A community sample of 85 children aged 9–11 years and their parents (85 mothers; 63 fathers) completed rating scales. Fathers’ more internal control expectancies and mothers’ reports of fewer family strains were associated with daughters’ but not sons’ greater internal control expectancies, and greater family cohesiveness was related to both daughters’ and sons’ internal control orientations. These findings suggest that family factors may contribute to children's, particularly daughters’, development of internal control expectancies. 相似文献
4.
Edward J. Holland Walter O. Whitley Kenneth Sall Stephen S. Lane Aparna Raychaudhuri Steven Y. Zhang 《Current medical research and opinion》2016,32(10):1759-1765
Objective: Report efficacy findings from three clinical trials (one phase 2 and two phase 3 [OPUS-1, OPUS-2]) of lifitegrast ophthalmic solution 5.0% for treatment of dry eye disease (DED).Research design and methods: Three 84-day, randomized, double-masked, placebo-controlled trials. Adults (≥18 years) with DED were randomized (1:1) to lifitegrast 5.0% or matching placebo. Changes from baseline to day 84 in signs and symptoms of DED were analyzed.Main outcome measures: Phase 2, pre-specified endpoint: inferior corneal staining score (ICSS; 0–4); OPUS-1, coprimary endpoints: ICSS and visual-related function subscale (0–4 scale); OPUS-2, coprimary endpoints: ICSS and eye dryness score (EDS, VAS; 0–100).Results: Fifty-eight participants were randomized to lifitegrast 5.0% and 58 to placebo in the phase 2 trial; 293 to lifitegrast and 295 to placebo in OPUS-1; 358 to lifitegrast and 360 to placebo in OPUS-2. In participants with mild-to-moderate baseline DED symptomatology, lifitegrast improved ICSS versus placebo in the phase 2 study (treatment effect, 0.35; 95% CI, 0.05–0.65; p?=?0.0209) and OPUS-1 (effect, 0.24; 95% CI, 0.10–0.38; p?=?0.0007). Among more symptomatic participants (baseline EDS ≥40, recent artificial tear use), lifitegrast improved EDS versus placebo in a post hoc analysis of OPUS-1 (effect, 13.34; 95% CI, 2.35–24.33; nominal p?=?0.0178) and in OPUS-2 (effect, 12.61; 95% CI, 8.51–16.70; p?<?0.0001).Limitations: Trials were conducted over 12 weeks; efficacy beyond this period was not assessed.Conclusions: Across three trials, lifitegrast improved ICSS in participants with mild-to-moderate baseline symptomatology in two studies, and EDS in participants with moderate-to-severe baseline symptomatology in two studies. Based on the overall findings from these trials, lifitegrast shows promise as a new treatment option for signs and symptoms of DED. 相似文献
5.
6.
Henry Havel Gregory Finch Pamela Strode Marc Wolfgang Stephen Zale Iulian Bobe Hagop Youssoufian Matthew Peterson Maggie Liu 《The AAPS journal》2016,18(6):1373-1378
Advancing nanomedicines from concept to clinic requires integration of new science with traditional pharmaceutical development. The medical and commercial success of nanomedicines is greatly facilitated when those charged with developing nanomedicines are cognizant of the unique opportunities and technical challenges that these products present. These individuals must also be knowledgeable about the processes of clinical and product development, including regulatory considerations, to maximize the odds for successful product registration. This article outlines these topics with a goal to accelerate the combination of academic innovation with collaborative industrial scientists who understand pharmaceutical development and regulatory approval requirements—only together can they realize the full potential of nanomedicines for patients. 相似文献
7.
8.
9.
Bimal Bhindi Christine M. Lohse Phillip J. Schulte Ross J. Mason John C. Cheville Stephen A. Boorjian Bradley C. Leibovich R. Houston Thompson 《European urology》2019,75(5):766-772
Background
Partial nephrectomy (PN) is generally favored for cT1 tumors over radical nephrectomy (RN) when technically feasible. However, it can be unclear whether the additional risks of PN are worth the magnitude of renal function benefit.Objective
To develop preoperative tools to predict long-term estimated glomerular filtration rate (eGFR) beyond 30 d following PN and RN, separately.Design, setting, and participants
In this retrospective cohort study, patients who underwent RN or PN for a single nonmetastatic renal tumor between 1997 and 2014 at our institution were identified. Exclusion criteria were venous tumor thrombus and preoperative eGFR <15 ml/min/1.73 m2.Intervention
RN and PN.Outcome measurements and statistical analysis
Hierarchical generalized linear mixed-effect models with backward selection of candidate preoperative features were used to predict long-term eGFR following RN and PN, separately. Predictive ability was summarized using marginal , which ranges from 0 to 1, with higher values indicating increased predictive ability.Results and limitations
The analysis included 1152 patients (13 206 eGFR observations) who underwent RN and 1920 patients (18 652 eGFR observations) who underwent PN, with mean preoperative eGFRs of 66 ml/min/1.73 m2 (standard deviation [SD] = 18) and 72 ml/min/1.73 m2 (SD = 20), respectively. The model to predict eGFR after RN included age, diabetes, preoperative eGFR, preoperative proteinuria, tumor size, time from surgery, and an interaction between time from surgery and age (marginal ). The model to predict eGFR after PN included age, presence of a solitary kidney, diabetes, hypertension, preoperative eGFR, preoperative proteinuria, surgical approach, time from surgery, and interaction terms between time from surgery and age, diabetes, preoperative eGFR, and preoperative proteinuria (marginal ). Limitations include the lack of data on renal tumor complexity and the single-center design; generalizability needs to be confirmed in external cohorts.Conclusions
We developed preoperative tools to predict renal function outcomes following RN and PN. Pending validation, these tools should be helpful for patient counseling and clinical decision-making.Patient summary
We developed models to predict kidney function outcomes after partial and radical nephrectomy based on preoperative features. This should help clinicians during patient counseling and decision-making in the management of kidney tumors. 相似文献10.
Interaction effects between the 5‐hydroxy tryptamine transporter‐linked polymorphic region (5‐HTTLPR) genotype and family conflict on adolescent alcohol use and misuse 下载免费PDF全文