全文获取类型
收费全文 | 23841篇 |
免费 | 2095篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 155篇 |
儿科学 | 692篇 |
妇产科学 | 590篇 |
基础医学 | 3440篇 |
口腔科学 | 338篇 |
临床医学 | 3126篇 |
内科学 | 4578篇 |
皮肤病学 | 472篇 |
神经病学 | 2358篇 |
特种医学 | 833篇 |
外科学 | 2836篇 |
综合类 | 654篇 |
一般理论 | 15篇 |
预防医学 | 2267篇 |
眼科学 | 341篇 |
药学 | 1621篇 |
中国医学 | 37篇 |
肿瘤学 | 1610篇 |
出版年
2022年 | 148篇 |
2021年 | 410篇 |
2020年 | 293篇 |
2019年 | 408篇 |
2018年 | 489篇 |
2017年 | 389篇 |
2016年 | 382篇 |
2015年 | 406篇 |
2014年 | 589篇 |
2013年 | 889篇 |
2012年 | 1303篇 |
2011年 | 1241篇 |
2010年 | 681篇 |
2009年 | 640篇 |
2008年 | 1133篇 |
2007年 | 1200篇 |
2006年 | 1143篇 |
2005年 | 1088篇 |
2004年 | 1107篇 |
2003年 | 1001篇 |
2002年 | 894篇 |
2001年 | 716篇 |
2000年 | 745篇 |
1999年 | 654篇 |
1998年 | 266篇 |
1997年 | 217篇 |
1996年 | 218篇 |
1995年 | 204篇 |
1994年 | 205篇 |
1993年 | 190篇 |
1992年 | 473篇 |
1991年 | 462篇 |
1990年 | 428篇 |
1989年 | 384篇 |
1988年 | 365篇 |
1987年 | 405篇 |
1986年 | 371篇 |
1985年 | 374篇 |
1984年 | 309篇 |
1983年 | 263篇 |
1982年 | 171篇 |
1981年 | 168篇 |
1980年 | 141篇 |
1979年 | 243篇 |
1978年 | 201篇 |
1977年 | 142篇 |
1974年 | 171篇 |
1973年 | 166篇 |
1972年 | 158篇 |
1971年 | 139篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
Dilatation and curettage (D+C) is the most common operation performed in Britain. The liberal use of D+C has been criticised.
The objective of this study was to evaluate the use of outpatient endometrial pipelle biopsy and determine its safety in terms
of detecting abnormalities. Complications and financial costs were also evaluated. Data were reviewed from an active gynaecological
unit from February 1993 to January 1995. A total of 303 D+Cs and 104 endometrial pipelle biopsies were performed in this period.
Nine malignancies were detected by D+C and 1 by pipelle biopsy. A total of 24 and 3 benign abnormalities were detected by
each method respectively. There was a higher complication rate in the D+C group but the failure rate was higher in the endometrial
pipelle biopsy group. The monetary savings over this period is estimated at £20,307. There were no missed malignancies to
our knowledge over the 8 yr period since endometrial pipelle biopsy was introduced to the hospital. 相似文献
32.
Dr. Caroline S. Zeind Pharm.D. Dr. Kerry O. Cleveland M.D. Dr. Madhavi Menon M.D. Dr. James R. Brown Pharm.D. Dr. David K. Solomon Pharm.D. 《Pharmacotherapy》1996,16(4):547-561
The optimum therapy for cryptococcal meningitis in patients with the acquired immunodeficiency syndrome (AIDS) remains unresolved. Traditional therapy consists of amphotericin B with or without flucytosine. Obstacles exist in administering these agents to patients with AIDS. Mortality rates during initial therapy are relatively high. Given the lack of proved benefit, we do not recommend adding flucytosine to amphotericin B routinely. The search for more efficacious and less toxic agents continues. The oral triazoles, especially fluconazole, have increased the options for treatment of this disease. New strategies and novel approaches in managing cryptococcal meningitis in patients with AIDS continue to be developed. 相似文献
33.
34.
35.
E Y S?zmen Z Kerry F Uysal G Yetik M Yasa L Ustünes T Onat 《Clinical chemistry and laboratory medicine》2000,38(1):21-25
There is a large body of literature describing the causative role of oxidative stress mediated by increased levels of reactive oxygen species in the pathogenesis of cardiovascular disease such as atherosclerosis, hypertension, and restenosis after angioplasty. The positioning of a soft silicone collar around the rabbit carotid artery elicits intimal thickening. The findings from recent studies demonstrated that both intimal thickening and atherosclerosis lead to synthesis of inducible nitric oxide synthase, resulting in abundant amounts of nitric oxide. We investigated the effects of collaring and nicardipine treatment on the activities of antioxidant enzymes, superoxide dismutase and catalase, and total nitrite/nitrate levels, stable products of nitric oxide. Placing the collar increased the total nitrite/ nitrate levels and decreased superoxide dismutase activity in collared arteries. Treatment with nicardipine (20 mg/kg/day, s.c.) prevented enhanced nitric oxide degradation without affecting superoxide dismutase and catalase activities. Our results suggest that enhanced nitric oxide production and superoxide anion are generated in response to the collaring, resulting in oxidative stress within the segment in this model. 相似文献
36.
Dennis J. Murphy 《Drug development research》1994,32(4):237-246
The known effects of drugs from a variety of pharmacologic/therapeutic classes on the respiratory system and worldwide regulatory requirements support the need for conducting respiratory evaluations in safety pharmacology. The objective of these studies is to evaluate the potential for drugs to cause secondary pharmacologic or toxicologic effects that influence respiratory function. Changes in respiratory function can result either from alterations in the pumping apparatus that controls the pattern of pulmonary ventilation or from changes in the mechanical properties of the lung that determine the transpulmonary pressures (work) required for lung inflation and deflation. Defects in the pumping apparatus are classified as hypo- or hyperventilation syndromes and are evaluated by examining ventilatory parameters in a conscious animal model. The ventilatory parameters include respiratory rate, tidal volume, minute volume, peak (or mean) inspiratory flow, peak (or mean) expiratory flow, and fractional inspiratory time. Defects in mechanical properties of the lung are classified as obstructive or restrictive disorders and can be evaluated in animal models by performing flow-volume and pressure-volume maneuvers, respectively. The parameters used to detect airway obstruction include peak expiratory flow, forced expiratory flow at 25 and 75% of forced vital capacity, and a timed forced expiratory volume, while the parameters used to detect lung restriction include total lung capacity, inspiratory capacity, functional residual capacity, and compliance. Measurement of dynamic lung resistance and compliance, obtained continuously during tidal breathing, is an alternative method for evaluating obstructive and restrictive disorders, respectively, and is used when the response to drug treatment is expected to be immediate (within minutes post-dose). The species used in the safety pharmacology studies conducted in our laboratory are the same as those used in toxicology studies since pharmacokinetic and toxicologic/pathologic data are available in these species. These data can be used to help select test measurement intervals and doses and to aid in the interpretation of functional change. The techniques and procedures for measuring respiratory function parameters are well established in guinea pigs, rats, and dogs. 相似文献
37.
J. O’Byrne S. Eustace M. M. Stephens M. N. M. R. Farahat G. Yanni R. Posten G. S. Panayi S. Sant R. Costello M. Barry J. Hassan C. Feighery B. Bresnihan A. Whelan F. Coakley A. M. de Paor R. B. Reilly E. B. Casey V. J. Tormey G. Kearns K. Gaffney P. J. Freyne M. Callaghan O. FitzGerald D. Veale E. O’Nuallain D. Reen D. Veale M. Farrell O. FitzGerald S. Rogers L. Barnes R. J. Coughlan C. McCarthy M. McDermott D. Hourihane C. O'Morain S. O'Reilly P. Hartley E. Casey L. Clancy F. Mulcahy N. Hall A. Murphy C. Breen D. Kelleher M. Abuzakouk C. O'Farrelly 《Irish journal of medical science》1992,161(6):438-442
38.
Patricia Aikins Murphy 《Journal of Midwifery & Women's Health》1993,38(6):324-335
Published reports of the effectiveness of preterm birth prevention programs have produced mixed results. Many larger observational studies suggest benefit. The randomized trials, however, suggest no effect on reducing rates of preterm birth in high-risk populations. This article reviews and critiques these reports and suggests areas for further research. 相似文献
39.
Effects of niacin (nicotinic acid or nicotinamide) supplementation of dairy cow diets on apparent total tract nutrient digestibility, milk yield and milk composition were determined using six mid-lactation Holstein cows in a replicated 3 x 3 Latin square design arranged to test for residual treatment effects. Treatments were control, 12 g/d of nicotinic acid or 12 g/d of nicotinamide. Periods were 14 d long; d 1 to 4 served as an adaptation period before treatment administration commenced (d 5 to 14). Effects of supplemental niacin on plasma nonesterified fatty acid (NEFA) concentrations and plasma glucose concentrations were tested following saline injection on d 10. Blood was then sampled for 5.5 h at 15-min intervals. On d 13, cows were treated similarly except that epinephrine replaced saline. The area below d-10 curves was subtracted from the area below d-13 curves to serve as an indicator of niacin's effect on plasma NEFA and glucose concentration responses to epinephrine injection. Niacin treatments did not change the area differences for plasma glucose compared to the control treatment; however, there was a trend for niacin to reduce the area difference compared to the control treatment for plasma NEFA. Niacin treatments did not alter dry matter intake, nutrient digestibility, milk yield or composition. Niacin supplementation increased the number of entodinia protozoa in rumen fluid. 相似文献
40.
Women's knowledge, practises, and intentions regarding correct pelvic floor exercises. 总被引:2,自引:0,他引:2
AIM: Although research has demonstrated the efficacy of pelvic floor exercises (PFXs) for the prevention and treatment of female urinary incontinence (FUI), adherence to PFX regimens is commonly poor. There is some evidence that this finding is in part due to a lack of knowledge about how to perform PFXs correctly and misconceptions about the required frequency and duration of PFX regimens. METHODS: By using a sample of 720 postpartum women, this study investigates women's PFX regimens both before and during pregnancy and postpartum. RESULTS: Findings demonstrated that most women were aware of the required frequency for PFXs (at least every second day): just over half had done them this often during pregnancy and 91% intended to do so postpartum. However, few had done them at this level before pregnancy and less than half knew that PFXs should be carried out indefinitely throughout the lifetime. Moreover, only two thirds were confident that they were doing PFXs correctly. CONCLUSION: The findings suggest that, despite good knowledge of the required frequency of PFXs, few women practise them regularly over their lifetime, many apparently perceiving PFXs as relevant only to the childbirth years. Implications for health professionals in addressing these gaps in women's knowledge and practises are discussed. 相似文献