全文获取类型
收费全文 | 1742090篇 |
免费 | 127332篇 |
国内免费 | 4238篇 |
专业分类
耳鼻咽喉 | 22565篇 |
儿科学 | 56743篇 |
妇产科学 | 47097篇 |
基础医学 | 247542篇 |
口腔科学 | 49761篇 |
临床医学 | 156067篇 |
内科学 | 343048篇 |
皮肤病学 | 39822篇 |
神经病学 | 135007篇 |
特种医学 | 65822篇 |
外国民族医学 | 243篇 |
外科学 | 263912篇 |
综合类 | 39698篇 |
现状与发展 | 4篇 |
一般理论 | 557篇 |
预防医学 | 127263篇 |
眼科学 | 41542篇 |
药学 | 127170篇 |
51篇 | |
中国医学 | 4804篇 |
肿瘤学 | 104942篇 |
出版年
2021年 | 14316篇 |
2019年 | 14570篇 |
2018年 | 21186篇 |
2017年 | 16104篇 |
2016年 | 17706篇 |
2015年 | 20417篇 |
2014年 | 28094篇 |
2013年 | 40179篇 |
2012年 | 55971篇 |
2011年 | 58771篇 |
2010年 | 34794篇 |
2009年 | 32395篇 |
2008年 | 54068篇 |
2007年 | 57329篇 |
2006年 | 57568篇 |
2005年 | 54832篇 |
2004年 | 52762篇 |
2003年 | 50083篇 |
2002年 | 48100篇 |
2001年 | 92509篇 |
2000年 | 94294篇 |
1999年 | 77623篇 |
1998年 | 20116篇 |
1997年 | 17581篇 |
1996年 | 17669篇 |
1995年 | 16987篇 |
1994年 | 15543篇 |
1993年 | 14262篇 |
1992年 | 57850篇 |
1991年 | 55656篇 |
1990年 | 53333篇 |
1989年 | 51134篇 |
1988年 | 46512篇 |
1987年 | 45279篇 |
1986年 | 42548篇 |
1985年 | 40307篇 |
1984年 | 29628篇 |
1983年 | 25163篇 |
1982年 | 14102篇 |
1979年 | 25819篇 |
1978年 | 17799篇 |
1977年 | 15092篇 |
1976年 | 14028篇 |
1975年 | 14736篇 |
1974年 | 17820篇 |
1973年 | 17156篇 |
1972年 | 15839篇 |
1971年 | 14614篇 |
1970年 | 13580篇 |
1969年 | 12627篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
Sofosbuvir and velpatasvir with or without voxilaprevir in direct‐acting antiviral‐naïve chronic hepatitis C: patient‐reported outcomes from POLARIS 2 and 3 下载免费PDF全文
103.
104.
Serum pepsinogen 1 and anti‐Helicobacter pylori IgG antibodies as predictors of gastric cancer risk in Finnish males 下载免费PDF全文
105.
106.
Lisa Daniels Rachael W. Taylor Sheila M. Williams Rosalind S. Gibson Samir Samman Benjamin J. Wheeler Barry J. Taylor Elizabeth A. Fleming Nicola K. Hartley Anne-Louise M. Heath 《Journal of the Academy of Nutrition and Dietetics》2018,118(6):1006-1016.e1
Background
Little is known about zinc intakes and status during complementary feeding. This is particularly true for baby-led approaches, which encourage infants to feed themselves from the start of complementary feeding, although self-feeding may restrict the intake of zinc-rich foods.Objective
To determine the zinc intakes, sources, and biochemical zinc status of infants following Baby-Led Introduction to SolidS (BLISS), a modified version of Baby-Led Weaning (BLW), compared with traditional spoon-feeding.Design
Secondary analysis of the BLISS randomized controlled trial.Participants/setting
Between 2012 and 2014, 206 community-based participants from Dunedin, New Zealand were randomized to a Control or BLISS group.Intervention
BLISS participants received eight study visits (antenatal to 9 months) providing education and support regarding BLISS (ie, infant self-feeding from 6 months with modifications to address concerns about iron, choking, and growth).Main outcome measures
Dietary zinc intakes at 7 and 12 months (weighed 3-day diet records) and zinc status at 12 months (plasma zinc concentration).Statistical analyses performed
Regression analyses were used to investigate differences in dietary intakes and zinc status by group, adjusted for maternal education and parity and infant age and sex.Results
There were no significant differences in zinc intakes between BLISS and Control infants at 7 (median: 3.5 vs 3.5 mg/day; P=0.42) or 12 (4.4 vs 4.4 mg/day; P=0.86) months. Complementary food groups contributing the most zinc at 7 months were “vegetables” for Control infants, and “breads and cereals” for BLISS infants, then “dairy” for both groups at 12 months. There was no significant difference in mean±standard deviation plasma zinc concentration between the Control (62.8±9.8 μg/dL [9.6±1.5 μmol/L]) and BLISS (62.8±10.5 μg/dL [9.6±1.6 μmol/L]) groups (P=0.75).Conclusions
BLISS infants achieved similar zinc intake and status to Control infants. However, the BLISS intervention was modified to increase iron intake, which may have improved zinc intake, so these results should not be generalized to infants following unmodified BLW. 相似文献107.
Lindsey Haynes-Maslow Lauri Andress Stephanie Jilcott Pitts Isabel Osborne Barbara Baquero Lisa Bailey-Davis Carmen Byker-Shanks Bailey Houghtaling Jane Kolodinsky Brian K. Lo Emily H. Morgan Emily Piltch Elaine Prewitt Rebecca A. Seguin Alice S. Ammerman 《Journal of the Academy of Nutrition and Dietetics》2018,118(9):1664-1672
Background
In 2016, the US Department of Agriculture (USDA)’s Supplemental Nutrition Assistance Program (SNAP) Retailer Rule proposed several changes for SNAP-authorized retailers, including: requiring retailers to have at least 85% of their food sales come from items that are not cooked or heated on site before or after purchase; requiring stores to stock seven varieties of qualifying foods from four staple food groups; requiring stores to carry perishable foods in three of the four staple groups; requiring stores to carry six units of qualifying foods at all times (depth of stock); disqualifying multiple ingredient foods and accessory foods from counting toward depth of stock requirements.Objectives
To better understand arguments used to support or oppose the USDA’s proposed rule that all SNAP-authorized retailers carry more nutritious foods.Design
We conducted a qualitative content analysis of a random sample of public comments posted to the US Federal Register (a publicly available database) in response to the USDA’s proposed rule.Participants/setting
A random sample of 20% of all public comments submitted by individuals and organizations to the US Federal Register were analyzed (n=303) for this study.Results
Three main themes were discussed: 1) arguments used in opposition to the rule; 2) arguments used in support of the rule; and 3) facilitators to assist stores in implementing the rule. Some of the subthemes included focusing on definitions used in the rule, reduced food access caused by stores leaving the SNAP program, lack of space and equipment for healthy foods, and the potential for increasing healthy food access.Conclusions
Nutrition and dietetics practitioners may be tasked with working with stores to implement healthy changes. Nutrition and dietetics practitioners must understand the role that the USDA has in food policy. In addition, understanding how federal food policy influences the environments in which dietetics professionals’ clients are making food choices is important. 相似文献108.
CAM2038, FluidCrystal injection depot, is an extended release formulation of buprenorphine given subcutaneously every 1 week (Q1W) or every 4 weeks (Q4W). The purpose of this research was to predict the magnitude of drug-drug interaction (DDI) after coadministration of a strong CYP3A4 inducer or inhibitor using physiologically based pharmacokinetic (PBPK) modeling. A PBPK model was developed for CAM2038 based on the previously published buprenorphine PBPK model after intravenous and sublingual administration and the PK profiles after subcutaneous administration of CAM2038 from 2 phase I clinical trials. The strong CYP3A4 inhibitor ketoconazole was predicted to increase the buprenorphine exposure by 35% for the Q1W formulation and 34% for Q4W formulation, respectively. Also, the strong CYP3A4 inducer rifampin was predicted to decrease the buprenorphine exposure by 26% for both the Q1W and Q4W formulations. The results provided insight into the potential DDI effect for CAM2038 and suggested a lack of clinically meaningful DDI when CAM2038 is coadministered with CYP3A4 inhibitor or inducer. Therefore, no dose adjustment is required when CAM2038 is coadministered with CYP3A4 perpetrators. 相似文献
109.
Lisa A. McConnachie Loren M. Kinman Josefin Koehn John C. Kraft Sarah Lane Wonsok Lee Ann C. Collier Rodney J.Y. Ho 《Journal of pharmaceutical sciences》2018,107(7):1787-1790
Daily oral antiretroviral therapy regimens produce limited drug exposure in tissues where residual HIV persists and suffer from poor patient adherence and disparate drug kinetics, which all negatively impact outcomes. To address this, we developed a tissue- and cell-targeted long-acting 4-in-1 nanosuspension composed of lopinavir (LPV), ritonavir, tenofovir (TFV), and lamivudine (3TC). In 4 macaques dosed subcutaneously, drug levels over 5 weeks in plasma, lymph node mononuclear cells (LNMCs), and peripheral blood mononuclear cells (PBMCs) were analyzed by liquid chromatography–tandem mass spectrometry. Plasma and PBMC levels of the active drugs (LPV, TFV, and 3TC) were sustained for 5 weeks; PBMC exposures to LPV, ritonavir, and 3TC were 12-, 16-, 42-fold higher than those in plasma. Apparent T1/2z of LPV, TFV, and 3TC were 219.1, 63.1, and 136.3 h in plasma; 1045.7, 105.9, and 127.7 h in PBMCs. At day 8, LPV, TFV, and 3TC levels in LNMCs were 4.1-, 5.0-, and 1.9-fold higher than in those in PBMCs and much higher than in plasma. Therefore, 1 dose of a 4-drug nanosuspension exhibited persistent drug levels in LNMCs, PBMCs, and plasma for 5 weeks. With interspecies scaling and dose adjustment, this 4-in-1 HIV drug-combination could be a long-acting treatment with the potential to target residual virus in tissues and improve patient adherence. 相似文献
110.
Ashaben Patel Vineet Gupta John Hickey Nancy S. Nightlinger Richard S. Rogers Christine Siska Sangeeta B. Joshi Michael S. Seaman David B. Volkin Bruce A. Kerwin 《Journal of pharmaceutical sciences》2018,107(12):3032-3046
In this study, we investigated analytical challenges associated with the formulation of 2 anti-HIV broadly neutralizing antibodies (bnAbs), 3BNC117 and PGT121, both separately at 100 mg/mL and together at 50 mg/mL each. The bnAb formulations were characterized for relative solubility and conformational stability followed by accelerated and real-time stability studies. Although the bnAbs were stable during 4°C storage, incubation at 40°C differentiated their stability profiles. Specific concentration-dependent aggregation rates at 30°C and 40°C were measured by size exclusion chromatography for the individual bnAbs with the mixture showing intermediate behavior. Interestingly, although the relative ratio of the 2 bnAbs remained constant at 4°C, the ratio of 3BNC117 to PGT121 increased in the dimer that formed during storage at 40°C. A mass spectrometry-based multiattribute method, identified and quantified differences in modifications of the Fab regions for each bnAb within the mixture including clipping, oxidation, deamidation, and isomerization sites. Each bnAb showed slight differences in the levels and sites of lysine residue glycations. Together, these data demonstrate the ability to differentiate degradation products from individual antibodies within the bnAb mixture, and that degradation rates are influenced not only by the individual bnAb concentrations but also by the mixture concentration. 相似文献