全文获取类型
收费全文 | 4328篇 |
免费 | 215篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 97篇 |
儿科学 | 131篇 |
妇产科学 | 156篇 |
基础医学 | 443篇 |
口腔科学 | 121篇 |
临床医学 | 312篇 |
内科学 | 925篇 |
皮肤病学 | 74篇 |
神经病学 | 211篇 |
特种医学 | 74篇 |
外科学 | 928篇 |
综合类 | 116篇 |
一般理论 | 3篇 |
预防医学 | 292篇 |
眼科学 | 110篇 |
药学 | 355篇 |
中国医学 | 23篇 |
肿瘤学 | 194篇 |
出版年
2023年 | 52篇 |
2022年 | 123篇 |
2021年 | 186篇 |
2020年 | 118篇 |
2019年 | 143篇 |
2018年 | 177篇 |
2017年 | 114篇 |
2016年 | 146篇 |
2015年 | 162篇 |
2014年 | 163篇 |
2013年 | 227篇 |
2012年 | 393篇 |
2011年 | 368篇 |
2010年 | 184篇 |
2009年 | 145篇 |
2008年 | 233篇 |
2007年 | 222篇 |
2006年 | 202篇 |
2005年 | 216篇 |
2004年 | 181篇 |
2003年 | 168篇 |
2002年 | 145篇 |
2001年 | 47篇 |
2000年 | 35篇 |
1999年 | 40篇 |
1998年 | 30篇 |
1997年 | 19篇 |
1996年 | 10篇 |
1995年 | 18篇 |
1994年 | 9篇 |
1993年 | 14篇 |
1992年 | 13篇 |
1991年 | 15篇 |
1990年 | 14篇 |
1989年 | 22篇 |
1988年 | 16篇 |
1987年 | 13篇 |
1986年 | 14篇 |
1985年 | 10篇 |
1984年 | 13篇 |
1983年 | 15篇 |
1982年 | 9篇 |
1981年 | 17篇 |
1980年 | 13篇 |
1979年 | 8篇 |
1977年 | 8篇 |
1976年 | 13篇 |
1972年 | 7篇 |
1971年 | 5篇 |
1969年 | 5篇 |
排序方式: 共有4565条查询结果,搜索用时 15 毫秒
21.
Eldeirawi K McConnell R Freels S Persky VW 《The Journal of allergy and clinical immunology》2005,116(1):42-48
BACKGROUND: There are wide global variations in the prevalence of asthma and wheezing. OBJECTIVES: We examined the associations of place of birth with doctor-diagnosed asthma, wheezing in the past 12 months, and other allergic conditions in Mexican American children. METHODS: The study used data on 4121 Mexican American children age 2 months to 16 years who participated in the Third National Health and Nutrition Examination Survey. RESULTS: The risk of asthma was associated with being born in the United States after adjusting for sex, age, history of ear infection, and having a regular place for health care (odds ratio, 2.19; 95% CI, 1.09-4.40). Among children with no previous history of ear infection, US-born children were more likely to report wheezing in the past 12 months than their peers born in Mexico after controlling for confounding variables (odds ratio, 2.05; 95% CI, 1.09-3.87). Mexican American children born in the United States were more likely to have positive skin reaction to cat, house mite, Alternaria alternata , peanut, Bermuda grass, and short ragweed but were less likely to have a positive skin test to German cockroaches after adjusting for sex, age, ear infection, having a regular place for health care, and area of residence. CONCLUSION: Our study indicated significant associations of place of birth with respiratory symptoms and allergic conditions in Mexican American children. These findings highlight the need for further studies to examine environmental factors that change by migration and explain the observed differential in the risk of asthma or wheezing. 相似文献
22.
In the United States, all newly developed drugs undergo a lengthy review process conducted by the US Food and Drug Administration (FDA). These regulatory delays have direct immediate costs for drug manufacturers and patients waiting for treatment. Under certain market conditions, regulatory delays may also affect future research and development (R&D) strategies of pharmaceutical companies. To estimate the magnitude of this effect, we match data on drugs in the development pipeline in 2006 to data that we collect on FDA review times for all drugs approved between 1999 and 2005. Employing a rich and novel set of controls that affect drug R&D decisions and, potentially, regulatory review lags, we find that on average, three additional months of delay result in one fewer drug in development in that drug category. Our results suggest that the length of the regulatory delay matters for pharmaceutical firms' R&D decisions and that the firms are likely unable to pass on these costs onto consumers. 相似文献
23.
Wen MC Wei CH Hu ZQ Srivastava K Ko J Xi ST Mu DZ Du JB Li GH Wallenstein S Sampson H Kattan M Li XM 《The Journal of allergy and clinical immunology》2005,116(3):517-524
BACKGROUND: Chinese herbal medicine has a long history of human use. A novel herbal formula, anti-asthma herbal medicine intervention (ASHMI), has been shown to be an effective therapy in a murine model of allergic asthma. OBJECTIVE: This study was undertaken to compare the efficacy, safety, and immunomodulatory effects of ASHMI treatment in patients with moderate-severe, persistent asthma with prednisone therapy. METHODS: In a double-blind trial, 91 subjects underwent randomization. Forty-five subjects received oral ASHMI capsules and prednisone placebo tablets (ASHMI group) and 46 subjects received oral prednisone tablets and ASHMI placebo capsules (prednisone group) for 4 weeks. Spirometry measurements; symptom scores; side effects; and serum cortisol, cytokine, and IgE levels were evaluated before and after treatment. RESULTS: Posttreatment lung function was significantly improved in both groups as shown by increased FEV(1) and peak expiratory flow findings (P<.001). The improvement was slightly but significantly greater in the prednisone group (P<.05). Clinical symptom scores, use of beta(2)-bronchodilators, and serum IgE levels were reduced significantly, and to a similar degree in both groups (P<.001). T(H)2 cytokine levels were significantly reduced in both treated groups (P<.001) and were lower in the prednisone-treated group (P<.05). Serum IFN-gamma and cortisol levels were significantly decreased in the prednisone group (P<.001) but significantly increased in the ASHMI group (P<.001). No severe side effects were observed in either group. CONCLUSION: Anti-asthma herbal medicine intervention appears to be a safe and effective alternative medicine for treating asthma. In contrast with prednisone, ASHMI had no adverse effect on adrenal function and had a beneficial effect on T(H)1 and T(H)2 balance. 相似文献
24.
Sangeeta Varty Dinesh Vaidya Kamal Parasram Divya Prabhat Sudhir Joshi 《Indian journal of otolaryngology and head and neck surgery》2000,52(2):143-146
Tuberculosis of the middle ear it a rare disease. Due to change in the typical clinical pattern and decrease in incidence,
there is a delayed or missed diagnosis and can lead to increased morbidity. We pretent 5 cases of Tuberculous Otitis Media
treated over a period of 2 years, highlighting the fact that it must be considered as a differential diagnosis of persistent
suppurative otitis media. 相似文献
25.
Summary RSV infection continues to be a major cause of morbidity and mortality throughout the world. Despite advances in the understanding
of its pathogenesis, limited progress has been made in prevention and treatment of RSV infection. Based on the experiences
thus far it seems that control of RSV infection will be a difficult and complex task. 相似文献
26.
Abdel Gawwad E Ahmed MH Kamal MM 《The Journal of the Egyptian Public Health Association》1999,74(1-2):139-173
The purpose of this study is to develop and test the reliability and validity of an Egyptian version of the Children's Health Locus of Control scale. A cross sectional study design was applied using a stratified random sample of 930 students from the final two grades of primary and all grades of the preparatory schools. A further convenience sample of 120 students was selected to examine test-retest reliability of the scale. A preliminary instrument was developed and consisted of 40 statements having one of two response forms; a Yes/No format and a 4-point Likert scale format From data analysis the later format showed higher validity and reliability than the former one. Construct validity of the scale is evidenced by the factor analysis which revealed five factors (Internal, Chance, Powerful Others, Fate and Self blame) consistent with the previous theoretical model of HLC. As indicated by eta coefficient the scale and the subscales showed strong discriminating power between subjects. The known group comparison indicated a good criterion validity of the scale and the subscales. The scale showed a considerable reliability as alpha coefficient was 0.73 with test-retest reliability of 0.65. Comparison of different groups of students indicated that the scale could be used with confidence for all age groups, though it was more reliable for the preparatory phase, for private and governmental schools for males and females and for different social strata. Further testing of the developed scale is indicated among Egyptian children in different cultures. 相似文献
27.
Peri-catheter calcification is an unusual and previously unreported complication of central venous (CV) catheterization in
infants. A 1.9 Fr Silastic CV catheter was placed in a term infant for administration of total parenteral nutrition and antibiotics
following intra-abdominal sepsis. The catheter was removed, without complication, at a later date after another septic episode.
Imaging studies performed in the investigation of a possible intra-abdominal abscess revealed a cylindrical density within
a clot in the inferior vena cava (IVC). The density was presumed to be a retained catheter fragment. Further investigation
indicated total occlusion of the IVC. Surgical exploration of the IVC revealed only a calcified thrombus. This case represents
a rare and previously unreported complication of CV catheterization in infants. Diagnosing this condition on radiographic
evidence alone can be difficult. It is hoped that awareness of the potential for this complication will avoid unnecessary
invasive procedures in the future. We also suggest a high level of clinical suspicion and routine Doppler ultrasound investigations
to detect IVC thrombosis when indwelling CV catheters are used in infants.
Accepted: 15 July 1997 相似文献
28.
29.
Kiramat Ali Shah Binbin Gao Robia Kamal Anam Razzaq Sun Qi Qiu-Ning Zhu Song Lina Linyu Huang Grainne Cremin Haroon Iqbal Farid Menaa Jing-Hao Cui 《Materials》2022,15(10)
Migraine is a neurological disorder characterized by severe headaches, visual aversions, auditory, and olfactory disorders, accompanied by nausea and vomiting. Zolmitriptan (ZMT®) is a potent 5HT1B/1D serotonin receptor agonist frequently used for the treatment of migraine. It has erratic absorption from the gastrointestinal tract (GIT), but its oral bioavailability is low (40–45%) due to the hepatic metabolism. This makes it an ideal candidate for oral fast dissolving formulations. Hence, the current study was undertaken to design and develop oral fast-dissolving films (OFDFs) containing ZMT for migraine treatment. The OFDFs were formulated by the solvent casting method (SCM) using Pullulan (PU) and maltodextrin (MDX) as film-forming agents and propylene glycol (PG) as a plasticizer. The strategy was designed using Box–Behnken experimental design considering the proportion of PU:MDX and percentage of PG as independent variables. The effectiveness of the OFDF’s was measured based on the following responses: drug release at five min, disintegration time (D-time), and tensile strength (TS). The influence of formulation factors, including percent elongation (%E), thickness, water content, moisture absorption, and folding endurance on ZMT-OFDFs, were also studied. The results showed a successful fabrication of stable ZMT-OFDFs, with surface uniformity and amorphous shape of ZMT in fabricated films. The optimized formulation showed a remarkable rapid dissolution, over 90% within the first 5 min, a fast D-time of 18 s, and excellent mechanical characteristics. Improved maximum plasma concentration (C max) and area under the curve (AUC 0–t) in animals (rats) treated with ZMT-OFDFs compared to those treated with an intra-gastric (i-g) suspension of ZMT were also observed. Copolymer OFDFs with ZMT is an exciting proposition with great potential for the treatment of migraine headache. This study offers a promising strategy for developing ZMT-OFDFs using SCM. ZMT-OFDFs showed remarkable rapid dissolution and fast D-time, which might endeavor ZMT-OFDFs as an auspicious alternative approach to improve patient compliance and shorten the onset time of ZMT in migraine treatment. 相似文献
30.
Y.T. Kamal Prawez Alam Saleh Ibrahim Alqasoumi Ahmed Ibrahim Foudah Mohammed Hamed Alqarni Hasan Soliman Yusufoglu 《Saudi Pharmaceutical Journal》2018,26(6):839-844
Pomegranate is a well known fruit for its unique flavor, taste and health benefits. The medicinal properties of this fruits directly associated with the phenolic content present, with great anti-oxidant potential. The research is intended to develop matrix solid phase dispersion method (MSPD) and HPLC quantification of four major anti-oxidant marker constituents (vitamin C, gallic acid, rutin & ellagic acid) in pomegranate molasses samples. The effects of several important experimental parameters like type of dispersant, sample-dispersant ratio, solvents and its volume, time of extraction were investigated. A C18 column with the specification (5?µm, 250?×?4.0?mm) was used for the separation. A gradient flow of mobile phase was selected after many trials containing 0.1%, v/v solution of orthophosphoric acid and acetonitrile. The flow rate was 1.0?mL/min; and the chromatograms were recorded at 254?nm. The validation parameters, like linearity (r2?=?0.9985, 0.9965, 0.9925 & 0.9986), accuracy (100.3, 99.5, 100.9 & 101.9%), intra-day precision (%RSD?=?1.09, 1.02, 1.26 & 0.97), inter-day precision (%RSD?=?1.32, 0.83, 1.07, & 1.15) LOD (0.07, 4.50, 0.45 & 0.40?µg/mL), LOQ (0.095, 9.50, 0.85 & 9.5?µg/mL) and robustness (% RSD?=?0.92, 0.76, 0.81 & 0.83) respectively for vitamin C, gallic acid, rutin & ellagic acid, were found satisfactory as per ICH guidelines. 相似文献