全文获取类型
收费全文 | 224677篇 |
免费 | 17909篇 |
国内免费 | 5575篇 |
专业分类
耳鼻咽喉 | 1829篇 |
儿科学 | 3342篇 |
妇产科学 | 3235篇 |
基础医学 | 26811篇 |
口腔科学 | 4361篇 |
临床医学 | 18899篇 |
内科学 | 34808篇 |
皮肤病学 | 2975篇 |
神经病学 | 13698篇 |
特种医学 | 7167篇 |
外国民族医学 | 2篇 |
外科学 | 18981篇 |
综合类 | 31541篇 |
现状与发展 | 31篇 |
一般理论 | 11篇 |
预防医学 | 17543篇 |
眼科学 | 2645篇 |
药学 | 29408篇 |
91篇 | |
中国医学 | 16652篇 |
肿瘤学 | 14131篇 |
出版年
2024年 | 434篇 |
2023年 | 3186篇 |
2022年 | 5289篇 |
2021年 | 9653篇 |
2020年 | 8153篇 |
2019年 | 7996篇 |
2018年 | 7876篇 |
2017年 | 8715篇 |
2016年 | 8929篇 |
2015年 | 8517篇 |
2014年 | 10354篇 |
2013年 | 14755篇 |
2012年 | 11750篇 |
2011年 | 13864篇 |
2010年 | 9156篇 |
2009年 | 9058篇 |
2008年 | 10363篇 |
2007年 | 11481篇 |
2006年 | 10723篇 |
2005年 | 9822篇 |
2004年 | 8324篇 |
2003年 | 7433篇 |
2002年 | 5980篇 |
2001年 | 5363篇 |
2000年 | 4477篇 |
1999年 | 3745篇 |
1998年 | 2945篇 |
1997年 | 3055篇 |
1996年 | 2799篇 |
1995年 | 2469篇 |
1994年 | 2374篇 |
1993年 | 1998篇 |
1992年 | 1794篇 |
1991年 | 1674篇 |
1990年 | 1439篇 |
1989年 | 1191篇 |
1988年 | 1125篇 |
1987年 | 1022篇 |
1986年 | 946篇 |
1985年 | 1371篇 |
1984年 | 1093篇 |
1983年 | 827篇 |
1982年 | 858篇 |
1981年 | 732篇 |
1980年 | 662篇 |
1979年 | 519篇 |
1978年 | 343篇 |
1977年 | 298篇 |
1976年 | 274篇 |
1975年 | 198篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
201.
202.
Abdelhadi Lahoum Nasserdine Sabaou Christian Bijani Noureddine Bouras Frédéric Pont Selma P. Snini Florence Mathieu 《Saudi Pharmaceutical Journal》2019,27(1):56-65
The actinobacterium strain ABH26 closely related to Saccharothrix xinjiangensis, isolated from an Algerian Saharan soil sample, exhibited highly antagonist activity against Gram-positive bacteria, yeasts and filamentous fungi. Its ability to produce antimicrobial compounds was investigated using several solid culture media. The highest antimicrobial activity was obtained on Bennett medium. The antibiotics secreted by strain ABH26 on Bennett medium were extracted by methanol and purified by reverse-phase HPLC using a C18 column. The chemical structures of the compounds were determined after spectroscopic (1H NMR, 13C NMR, 1H-1H COSY and 1H-13C HMBC spectra), and spectrometric (mass spectrum) analyses. Two new cyanogriside antibiotics named cyanogriside I (1) and cyanogriside J (2), were characterized along with three known caerulomycins, caerulomycin A (3), caerulomycin F (4) and caerulomycinonitrile (5). This is the first report of cyanogrisides and caerulomycins production by a member of the Saccharothrix genus. The minimum inhibitory concentrations (MIC) of these antibiotics were determined against pathogenic microorganisms. 相似文献
203.
《Journal of Clinical Orthopaedics and Trauma》2019,10(2):380-386
Additive manufacturing is a rapidly emerging technology which is being successfully implemented in the various field of medicine as well as in orthopaedics, where it has applications in reducing cartilage defects and treatments of bones. The technology helps through systematic collection of information about the shape of the "defects" and precise fabrication of complex 3D constructs such as cartilage, heart valve, trachea, myocardial bone tissue and blood vessels. In this paper, a large number of the relevant research papers on the additive manufacturing and its application in medical specifically orthopaedics are identified through Scopus had been studied using Bibliometric analysis and application analysis is undertaken. The bibliometric analysis shows that there is an increasing trend in the research reports on additive manufacturing applications in the field of orthopaedics. Discussions are on using technological advancement like scanning techniques and various challenges of the orthopaedic being met by additive manufacturing technology. For patient-specific orthopaedic applications, these techniques incorporate clinical practice and use for effective planning. 3D printed models printed by this technology are accepted for orthopaedic surgery such as revision of lumbar discectomy, pelvic surgery and large scapular osteochondroma. The applications of additive manufacturing in orthopaedics will experience a rapid translation in future. An orthopaedic surgeon can convert need/idea into a reality by using computer-aided design (CAD) software, analysis software to facilitate the manufacturing. Thus, AM provides a comprehensive opportunity to manufacture orthopaedic implantable medical devices. 相似文献
204.
《European journal of surgical oncology》2021,47(12):3105-3112
BackgroundDetails of perioperative outcomes and survival after gastric cancer surgery in prior transplant recipients have received minimal research attention.MethodsWe performed an observational cohort study using the database of 20,147 gastric cancer patients who underwent gastrectomy at a single gastric cancer center in Korea. Forty-one solid organ recipients [kidney (n = 35), liver (n = 5), or heart (n = 1)] were matched with 205 controls using propensity score matching.ResultsOperation time, blood loss, and postoperative pain were similar between groups. Short-term complication rates were similar between transplantation and control groups (22.0% vs. 20.1%, P = 0.777). Transplantation group patients with stage 1 gastric cancer experienced no recurrence, while those with stage 2/3 cancer had significantly higher recurrence risk compared to the controls (P = 0.049). For patients with stage 1 cancer, the transplantation group had a significantly higher rate of non-gastric cancer-related deaths compared to the controls (19.2% vs. 1.4%, P = 0.001). For those with stage 2/3 cancer, significantly lower proportion of the transplantation group received adjuvant chemotherapy compared to the control group (26.7% vs. 80.3%, P < 0.001). The transplantation group had a higher (albeit not statistically significant) rate of gastric cancer-related deaths compared to the controls (40.0% vs. 18.0%, P = 0.087).ConclusionTransplant recipients and non-transplant recipients exhibited similar perioperative and short-term outcomes after gastric cancer surgery. From long-term outcome analyses, we suggest active surveillance for non-gastric cancer-related deaths in patients with early gastric cancer, as well as strict oncologic care in patients with advanced cancer, as effective strategies for transplant recipients. 相似文献
205.
206.
207.
《Obstetrics, Gynaecology and Reproductive Medicine》2020,30(10):315-320
The incidence of obesity in the UK is increasing, meaning more women booking for antenatal care are obese. Obesity poses many additional risks to the mother and fetus during pregnancy, labour and the puerperium. Care of obese women should aim to reduce these risks. This article will discuss the risks associated with obesity in pregnancy and the management of obese women, from preconception through to completion of the postnatal period. 相似文献
208.
OBJECTIVES: To assess the effectiveness and safety of additional bedtime H2‐receptor antagonists (H2RAs) in suppressing nocturnal gastric acid breakthrough (NAB) via a systematic review. METHODS: Eligible trials were identified by searching the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library Issue 2, 2004), MEDLINE (January 1966–June 2004), EMBASE (January 1980–June 2004) and CINAHL (January 1982–June 2004). Additional hand‐searching was conducted on the proceedings of correlated conferences, eight important Chinese journals and references of all included trials. All randomized controlled trials evaluating H2RAs for the control of NAB were eligible for inclusion. The systematic review was conducted using methods recommended by The Cochrane Collaboration. RESULTS: Only two randomized crossover studies, comprising 32 participants, met the inclusion criteria. Because the design, dosage and duration of the treatments were different between the studies, it was not possible to conduct meta‐analysis. There were no consistent conclusions found between the two included studies in evaluating H2RAs for the control of NAB. CONCLUSIONS: No implications for practice at this stage can be concluded. Appropriately designed large‐scale randomized controlled trials with long‐term follow up are needed to determine the effects of additional bedtime H2RAs in suppressing NAB. 相似文献
209.
《Journal of labelled compounds & radiopharmaceuticals》2006,49(4):339-343
Condensation of thiourea 1 with diethyl malonate 2 in the presence of sodium methoxide furnished 4,6‐dihydroxy‐2‐mercaptopyrimidine 3 . Compound 3 on methylation with diazomethane followed by oxidation with H5IO6/CrO3 in ethyl acetate gave 4,6‐dimethoxy‐2‐methylsulphonylpyrimidine 5 . Compound 5 on condensation with 2‐mercapto‐6‐chlorobenzoic acid in the presence of a phase transfer catalyst, tetrabutylammonium bromide and sodium carbonate gave the title compound – pyrithiobac‐sodium 6 with an overall yield of > 35% starting from thiourea. Following the above standardized procedure, using [14C]‐thiourea in lieu of thiourea, 14C labelled product 6 , was synthesized with an overall radiochemical yield > 30% (with respect to [14C]‐thiourea) for further evaluations of environmental fate of 6 , in soils and plants. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
210.
盐酸氟西汀对抑郁症模型小鼠神经肽Y表达的研究 总被引:3,自引:0,他引:3
目的 探讨盐酸氟西汀对慢性应激抑郁症模型小鼠下丘脑神经肽Y(NPY)的表达影响。方法 采用旷场试验(Open-Field)法,比较抑郁症模型小鼠与正常对照组行为学改变方面的差异。将慢性应激抑郁症小鼠模型随机分成盐酸氟西汀和阿米替林治疗组、模型对照组,同时设立空白对照组,利用半定量逆转录.聚合酶联反应(RT-PCR)法、细胞酶联免疫法和蛋白免疫印迹(Western-blot)技术,比较试验组小鼠下丘脑NPY的表达变化。结果 (1)与正常组比较,模型组在总路程缩短、活动斑数减少和体重增加幅度下降等方面具有显著性差异。(2)与正常组比较,抑郁症模型组下丘脑NPY的mRNA表迭下降。(3)经过3周的治疗,盐酸氟西汀组和阿米替林组小鼠下丘脑NPY的mRNA及蛋白表达没有明显差别,但是两组的表达结果显著高于模型对照组,与空白对照组的结果接近。结论 脑内NPY的mRNA及蛋白的表达增加可能是盐酸氟西汀治疗抑郁症小鼠的机制之一。 相似文献