全文获取类型
收费全文 | 20082篇 |
免费 | 1121篇 |
国内免费 | 94篇 |
专业分类
耳鼻咽喉 | 163篇 |
儿科学 | 491篇 |
妇产科学 | 488篇 |
基础医学 | 2846篇 |
口腔科学 | 358篇 |
临床医学 | 1833篇 |
内科学 | 4675篇 |
皮肤病学 | 570篇 |
神经病学 | 1666篇 |
特种医学 | 410篇 |
外国民族医学 | 18篇 |
外科学 | 2087篇 |
综合类 | 102篇 |
一般理论 | 11篇 |
预防医学 | 2074篇 |
眼科学 | 466篇 |
药学 | 1388篇 |
中国医学 | 78篇 |
肿瘤学 | 1573篇 |
出版年
2024年 | 19篇 |
2023年 | 161篇 |
2022年 | 349篇 |
2021年 | 654篇 |
2020年 | 347篇 |
2019年 | 591篇 |
2018年 | 635篇 |
2017年 | 424篇 |
2016年 | 423篇 |
2015年 | 559篇 |
2014年 | 796篇 |
2013年 | 1073篇 |
2012年 | 1521篇 |
2011年 | 1703篇 |
2010年 | 919篇 |
2009年 | 761篇 |
2008年 | 1335篇 |
2007年 | 1346篇 |
2006年 | 1263篇 |
2005年 | 1232篇 |
2004年 | 1075篇 |
2003年 | 1002篇 |
2002年 | 931篇 |
2001年 | 241篇 |
2000年 | 206篇 |
1999年 | 204篇 |
1998年 | 163篇 |
1997年 | 131篇 |
1996年 | 94篇 |
1995年 | 94篇 |
1994年 | 86篇 |
1993年 | 77篇 |
1992年 | 81篇 |
1991年 | 81篇 |
1990年 | 72篇 |
1989年 | 72篇 |
1988年 | 78篇 |
1987年 | 39篇 |
1986年 | 61篇 |
1985年 | 43篇 |
1984年 | 34篇 |
1983年 | 34篇 |
1982年 | 25篇 |
1981年 | 23篇 |
1980年 | 24篇 |
1979年 | 33篇 |
1978年 | 18篇 |
1977年 | 17篇 |
1974年 | 18篇 |
1972年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
Diana Guaya Hernn Cobos Jhulissa Camacho Carmen Milena Lpez Csar Valderrama Jos Luis Cortina 《Materials》2022,15(15)
Hydrothermally synthesized Linde type A (LTA) and faujasite X (FAU-X) zeolites are low-cost and environmentally benign inorganic carriers for environmental applications. In this study, (oxy)hydroxides were incorporated onto LTA and FAU-X zeolites to promote the phosphate adsorption. The performance of LTA-Fe and FAU-X-Fe was evaluated through batch adsorption assays. A complete evaluation was performed to recover phosphate from synthetic wastewater. The effect of pH, concentration, equilibrium, and kinetic parameters on phosphate adsorption and its further reuse in sorption–desorption cycles were evaluated. LTA-Fe and FAU-X-Fe are effective for adsorption of phosphate at neutral (e.g., pH 7.0 ± 0.2) and in a broad range of phosphate concentrations. Higher ratios of adsorption capacities were obtained by synthetic zeolites enriched with iron in comparison to their parent forms. The phosphate adsorption occurred through hydrogen bonding and complexation reactions between protonated iron hydroxyl groups and phosphate anions. The phosphate monolayer adsorption was followed by diffusion through the internal pores and 80% of the equilibrium adsorption was reached within 50 min. The LTA-Fe and FAU-X-Fe can be used for phosphate recovery from wastewater treatment plants. The use of LTA-Fe and FAU-X-Fe in a tertiary wastewater treatment stage could allow to reduce the phosphate–phosphorous content, reaching the regulatory levels (equal 1 mg L−1 total phosphorous). The phosphate adsorption using LTA-Fe and FAU-X-Fe does not require pH adjustment, and it is endothermic. The reusability of both iron zeolites is limited, and they can be finally disposed for soil amendment applications. 相似文献
103.
Adina Frum Carmen Maximiliana Dobrea Luca Liviu Rus Lidia-Ioana Virchea Claudiu Morgovan Adriana Aurelia Chis Anca Maria Arseniu Anca Butuca Felicia Gabriela Gligor Laura Gratiela Vicas Ovidiu Tita Cecilia Georgescu 《Nutrients》2022,14(15)
Grape pomace and berries represent natural sources of phytochemicals that can increase the quality of life of consumers by contributing to the prevention of chronic diseases; thus, the development of a dietary supplement was necessary. The raw material (r.m.) used for the development of the dietary supplement consisted of dried and powdered bilberries (Vaccinium myrtillus L.), red currants (Ribes rubrum L.), and red fermented pomaces (Vitis vinifera L.) from Feteasca Neagra and Cabernet Sauvignon cultivars. The particle size distribution, powder flow, total phenolic content (TPC), HPLC-DAD phenolic profile assessment, and radical scavenging assay (RSA) were employed for the analysis of the raw material. After encapsulation, the average mass and uniformity of mass, the disintegration, and the uniformity of content for the obtained capsules were performed to obtain a high-quality dietary supplement. All the assays performed complied to the compendial requirements and the TPC was determined at 9.07 ± 0.25 mg gallic acid equivalents/g r.m. and RSA at 48.32 ± 0.74%. The highest quantities of phenolic compounds determined were 333.7 ± 0.50 µg/g r.m. for chlorogenic acid, followed by rutin, ferulic acid, and (+)-catechin with 198.9 ± 1.60 µg/g r.m., 179.8 ± 0.90 µg/g r.m. and 118.7 ± 0.75 µg/g r.m., respectively. The results of this study can be used for the manufacturing and assessing of pilot scale-up capsule batches and thinking of quality assurance, we recommend that the industrial batch extracts should be standardized in polyphenols, and the manufacturing process should be validated. 相似文献
104.
The new cembrane diterpenes leptodienone A (2) and leptodienone B (3) and the known compounds lopholide, lophodiol B, lophodione, and lophotoxin (1) have been isolated from the gorgonian Leptogorgia laxa collected in the Gulf of California. The structures of the new metabolites have been established by spectroscopic techniques. The in vitro cytotoxicity of the new compounds has been tested against three human tumor cell lines. 相似文献
105.
106.
Simon-Bouy B Taillandier A Fauvert D Brun-Heath I Serre JL Armengod CG Bialer MG Mathieu M Cousin J Chitayat D Liebelt J Feldman B Gérard-Blanluet M Körtge-Jung S King C Laivuori H Le Merrer M Mehta S Jern C Sharif S Prieur F Gillessen-Kaesbach G Zankl A Mornet E 《Prenatal diagnosis》2008,28(11):993-998
OBJECTIVE: We studied hypophosphatasia (HP) mutations in 19 cases prenatally detected by ultrasonography without familial history of HP. We correlated the mutations with the reported ultrasound signs, and discussed genetic counseling with regard to the particular dominantly inherited prenatal benign form of HP. METHOD: The coding sequence of the tissue nonspecific alkaline phosphatase (TNSALP) gene was analyzed by DNA sequencing, and 3D modeling was used to locate the mutated amino acids with regard to the functional domains of TNSALP. RESULTS: Although reported ultrasound signs were heterogeneous, two mutated alleles were found in 18 of the 19 cases studied, indicating recessive transmission of the disease. Functional domains of TNSALP were affected by 74% of missense mutations. In all the cases, including one with only a heterozygous mutation, molecular, biological, and familial data do not corroborate the hypothesis of prenatal benign HP. The mutation c.1133A>T observed in the prenatal benign form of HP and common in USA was not found in this series. CONCLUSION: The results point out the prenatally detectable allelic heterogeneity of HP. The nature of the detected mutations and the evidence of recessive inheritance do not support these cases being affected with prenatal benign HP. 相似文献
107.
M. Rut Aguiar Couto Rita Vidal HernándezMontserrat González Rodríguez Antonio López PortelaAlfonso Otero Valenzuela 《Progresos de Obstetricia y Ginecología》2008
Objectives
To evaluate the utility and effectiveness of hysteroscopic retrieval of intrauterine devices (IUDs) in early pregnancy.Subjects and methods
We followed-up four pregnant women with IUDs with retracted tails removed by hysteroscopy before 10 weeks of pregnancy from 2003 to 2005.Results
After hysteroscopy, pregnancy course was successful in three women, without complications that could be attributed to the procedure. There was one abortion due to rupture of fetal membranes at 15 weeks’ gestation.Conclusions
The application of hysteroscopy in pregnancy has always been limited. In all patients, a possible optic nerve lesion in the fetus should be evaluated. This technique should not be performed after the 10th week of pregnancy. In most patients, pregnancy continues without complications after IDU removal. 相似文献108.
Encarnación Arriaza Peso M. del Carmen Arévalo PáezM. Ángeles Grandas Alonso Tomás Olleros Izard 《Progresos de Obstetricia y Ginecología》2008
Objective
To evaluate the safety and efficacy of a standardized isopropanolic extract of Cimicifuga racemosa (CR) (Remifemin®) in the treatment of climacteric symptoms.Material and method
We performed a multicenter observational prospective study in 483 postmenopausal women (natural menopause) between April and August 2004. In all patients, the presence and intensity (mild, moderate, severe) of hot flashes, sweating, irritability, nervousness, and depression were registered in a questionnaire administered at the beginning of treatment and 3 months later. The patients received 40 mg/day of CR for 12 weeks. Symptoms were evaluated before and after treatment. The statistical analysis was performed using the chi-squared test.Results
Tolerance was excellent with no treatment withdrawals due to adverse effects. Efficacy was considered good by most of the clinicians. Of the 483 patients enrolled, 471 attended the second visit (the 12 women not attending the second visit were included in the group of women showing no improvement). Of the 483 women with hot flashes, 77% improved. The intensity of hot flashes was reduced in 85%, 76% and 64% of the patients with severe, moderate, and mild symptoms, respectively. The symptoms showing greatest improvement were hot flashes and sweating: sweating improved in 78% (severe 85%, moderate 81% mild 65%). Rates of improvement were over 70% for psychic symptoms: irritability (severe 77%, moderate 72%, mild 43%), depression (severe 78%, moderate 64%, mild 51%) and insomnia (severe 78%, moderate 69%, mild 49%).Conclusions
CM (40 mg/day) is a safe and effective alternative for the treatment of climacteric symptoms in women who cannot or do not wish to receive hormone replacement therapy. 相似文献109.