全文获取类型
收费全文 | 97938篇 |
免费 | 6492篇 |
国内免费 | 1168篇 |
专业分类
耳鼻咽喉 | 869篇 |
儿科学 | 3016篇 |
妇产科学 | 2535篇 |
基础医学 | 12919篇 |
口腔科学 | 1573篇 |
临床医学 | 8997篇 |
内科学 | 22466篇 |
皮肤病学 | 1823篇 |
神经病学 | 9859篇 |
特种医学 | 2781篇 |
外国民族医学 | 2篇 |
外科学 | 10450篇 |
综合类 | 2377篇 |
现状与发展 | 2篇 |
一般理论 | 44篇 |
预防医学 | 7337篇 |
眼科学 | 1438篇 |
药学 | 7879篇 |
8篇 | |
中国医学 | 1091篇 |
肿瘤学 | 8132篇 |
出版年
2024年 | 168篇 |
2023年 | 1062篇 |
2022年 | 2447篇 |
2021年 | 3967篇 |
2020年 | 2389篇 |
2019年 | 2844篇 |
2018年 | 3145篇 |
2017年 | 2558篇 |
2016年 | 2761篇 |
2015年 | 3205篇 |
2014年 | 4167篇 |
2013年 | 5201篇 |
2012年 | 7239篇 |
2011年 | 7294篇 |
2010年 | 4078篇 |
2009年 | 3593篇 |
2008年 | 5764篇 |
2007年 | 5818篇 |
2006年 | 5282篇 |
2005年 | 4897篇 |
2004年 | 4491篇 |
2003年 | 3958篇 |
2002年 | 3584篇 |
2001年 | 1663篇 |
2000年 | 1549篇 |
1999年 | 1501篇 |
1998年 | 784篇 |
1997年 | 625篇 |
1996年 | 548篇 |
1995年 | 451篇 |
1994年 | 439篇 |
1993年 | 349篇 |
1992年 | 769篇 |
1991年 | 661篇 |
1990年 | 619篇 |
1989年 | 626篇 |
1988年 | 532篇 |
1987年 | 491篇 |
1986年 | 465篇 |
1985年 | 384篇 |
1984年 | 351篇 |
1983年 | 279篇 |
1982年 | 195篇 |
1981年 | 163篇 |
1980年 | 151篇 |
1979年 | 239篇 |
1978年 | 163篇 |
1977年 | 146篇 |
1974年 | 142篇 |
1973年 | 145篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Advance provision of emergency contraception for pregnancy prevention: a meta-analysis 总被引:2,自引:0,他引:2
Polis CB Schaffer K Blanchard K Glasier A Harper CC Grimes DA 《Obstetrics and gynecology》2007,110(6):1379-1388
OBJECTIVE: Advance provision of emergency contraception can circumvent some obstacles to timely use. We performed a meta-analysis to summarize randomized controlled trials evaluating advance provision of emergency contraception to explore effects on pregnancy rates, sexually transmitted infections, and sexual and contraceptive behaviors. DATA SOURCES: In August 2006, we searched CENTRAL, EMBASE, POPLINE, MEDLINE, a specialized emergency contraception article database, and contacted experts to identify published or unpublished trials. METHODS OF STUDY SELECTION: We included randomized controlled trials comparing advance provision to standard access, defined as any of the following: counseling (with or without information about emergency contraception) or provision of emergency contraception on request at a clinic or pharmacy. TABULATION, INTEGRATION AND RESULTS: Two reviewers independently assessed study quality. We performed a meta-analysis using Review Manager software. Eight randomized controlled trials met inclusion criteria, representing 6,389 patients in the United States, China, and India. Advance provision did not decrease pregnancy rates, despite increased use (single use, odds ratio [OR] 2.52, 95% confidence interval [CI] 1.72-3.70; multiple use: OR 4.13, 95% CI 1.77-9.63) and faster use (weighted mean difference -14.6 hours, 95% CI -16.77 to -12.4 hours). Advance provision did not increase rates of sexually transmitted infections (OR 0.99, 95% CI 0.73-1.34), unprotected intercourse, or changes in contraceptive methods. Women who received emergency contraception in advance were as likely to use condoms as other women. CONCLUSION: Advance provision of emergency contraception did not reduce pregnancy rates and did not negatively affect sexual and reproductive health behaviors and outcomes compared with conventional provision. LEVEL OF EVIDENCE: III. 相似文献
992.
Borgfeldt C Iosif C Måsbäck A 《European journal of obstetrics, gynecology, and reproductive biology》2007,134(1):110-114
OBJECTIVE: The aim was to evaluate the outcome of fertility-sparing treatment in ovarian borderline tumors and early invasive ovarian cancer. MATERIALS AND METHODS: All women diagnosed with an ovarian borderline tumor or early invasive ovarian cancer who were treated with fertility-sparing surgery at the University Hospital in Lund between 1988 and 2002 were identified and included in the study (n=23). RESULTS: During the follow-up period of a median 92 months, range 11-185 months, no relapse was found in the patients with Stage 1a tumors, including both borderline tumors (n=12) and invasive well-differentiated (n=9) and moderately differentiated (n=1) ovarian cancers. One patient with poorly differentiated ovarian cancer Stage 1c was 13 weeks' pregnant at the time of the primary operation. Although, unilateral oophorectomy was performed she insisted on continuing the pregnancy. At 37 weeks she had a cesarean section and the ovarian cancer was disseminated. Chemotherapy was given but she died less than a year later. None of the other patients received chemotherapy. In total, 30 children were born to 15 patients. Prophylactic removal of the remaining ovary+/-hysterectomy was accepted in only in six of the women after fulfilling their desire to have more children. CONCLUSIONS: Young women with Stage 1a epithelial ovarian cancer and borderline tumors do not have to give up their fertility in order to receive successful and safe treatment of their disease. However, several of these patients do not accept the recommendation of prophylactic oophorectomy of the contralateral ovary and hysterectomy after completion of childbearing. 相似文献
993.
994.
Treatment of uterine fibromyoma with bilateral uterine artery embolization: state of the art 总被引:1,自引:0,他引:1
Lupattelli T Clerissi J Basile A Minnella DP Donati Sarti R Gerli S Di Renzo G 《Minerva ginecologica》2007,59(4):427-439
Uterine fibroids are common tumors of the female pelvis. Uterine artery embolization (UAE) is a minimally invasive alternative procedure in appropriate candidates to conventional myomectomy and hysterectomy for symptomatic uterine leiomyoma, reducing or eliminating leiomyoma-related symptoms of bleeding, bulk, and/or pain. In order to completely block the arterial blood supply to the fibroid, UAE is typically performed in both uterine arteries. At 1 year follow-up, the uterus may shrink by up to 55%, however, a re-growth of the fibroid may occur. The rate of major complications and amenorrhea following this procedure is low, ranging in most series from 1% to 3.5% and 1% to 7%, respectively. Nevertheless, the rate of amenorrhea in women over 45 seems to be higher. Women who wish to become pregnant should be cautioned about potential complications during pregnancy. Despite the lack of controlled studies that compared UAE with conventional surgery, and despite limited extended outcome data, UAE has gained rapid acceptance, primarily because this procedure preserves the uterus, is less invasive, and has less short-term morbidity than most surgical options. This review focuses on recent publications evaluating UAE and concludes that it is a safe treatment option, providing substantial improvement in both health-related quality of life and symptom control for most patients, with a very low rate of major complications. Any centre that offers UAE should adhere to published clinical guidelines, maintain ongoing assessment of quality improvement measures, and observe strict criteria to obtain procedural privileges. The gynecologist is likely to be the primary initial consultant to patients who present with myomas symptoms. Therefore, they must be familiar with the indications, exclusions, outcome expectations, and complications of UAE. When hysterectomy is the only option, UAE should be seriously taken into consideration. At this particular moment in time, data are needed from randomized controlled trials comparing UAE with surgical procedures. Current efforts to provide prospective objective assessment of treatment outcomes and complications after UAE will help to optimize women options and clinical guidelines. 相似文献
995.
The aim of this article is to illustrate the history of fetal auscultation from the 19(th) century, when the fetus was considered as an object and the obstetrician as a 'mechanic of the birth', to the present age, when the fetus is a subject and the obstetricians have at their disposal all the means they need to confirm his well-being and to early diagnose his pathologies, even using prenatal telemedicine. 相似文献
996.
Surgical treatment of stress urinary incontinence using the tension-free vaginal tape-obturator system (TVT-O) technique 总被引:1,自引:0,他引:1
Jakimiuk AJ Maciejewski T Fritz A Borucki W Namirski M Szafranko K 《European journal of obstetrics, gynecology, and reproductive biology》2007,135(1):127-131
OBJECTIVE: The purpose of the research was to provide a review of the efficacy of the TVT-O technique for the surgical treatment of stress urinary incontinence (SUI) and to assess surgical and postsurgical complications related to this technique. STUDY DESIGN: An initial assessment was carried out on 44 women who underwent TVT-O surgery between 16 September 2004 and 1 February 2005. The follow-ups after 3 and 12 months were attended by 37 and 35 patients, respectively. All 44 patients were included for the statistical estimation of intra- and postoperative complications, whereas improvement in the quality of life was assessed only in those patients who came for a follow-up visit. To assess the efficacy of the treatment, the participants were surveyed using the King questionnaire on the day preceding surgery and during a follow-up visit 3 and 12 months after surgery. The participants whose scores from the two questionnaires changed > or =90% were deemed to be cured. A considerable improvement in quality of life was recorded when the score was 89-75%. With scores of 74-50%, there was a reduction in SI symptoms. However, when the score was 50-0%, no improvement in quality of life was reported, and in participants with scores <0% the quality of life deteriorated. Statistical analysis was carried out using the Statistical Package for Social Sciences (SPSS) V. 10.0, with the Spearman correlation and Chi-squared tests. The results were considered statistically significant when P<0.05. RESULTS: After 12 months, total cure was achieved in 15 participants (42.8%), significant improvement was noted in 6 (17.1%), SUI symptoms abated in 4 (11.4%), no improvement was noted in 7 (20%), and quality of life deteriorated in 3 (8.7%). CONCLUSION: TVT-O surgery is an efficient and reasonably safe method of SUI treatment in women. The ease of use, short duration of surgery and hospitalisation, minor postsurgical discomfort and a small proportion of complications make this method acceptable to patients. With regard to the results of treatment, additional patients should be analysed for a longer period of time. 相似文献
997.
998.
999.
Mascaretti G Di Berardino C Mastrocola N Patacchiola F 《Clinical and experimental obstetrics & gynecology》2007,34(2):123-125
Endometriosis is a disease in continuous evolution due to its various aspects and atypical localizations. Every year many women all over the world are affected by it. In typical localizations the diagnosis is simple; the symptoms include pelvic pain and in most of cases sterility. In rare localizations the symptoms are non-specific and the diagnosis is difficult. In particular an intestinal isolated localization is often asymptomatic or can cause non-specific pelvic pain, irregular intestinal activity and in such case, a subocclusive condition often with a diagnosis of inflammatory bowel disease. Two cases of rare localizations of endometriosis are described in the intestinal wall and a cesarean section scar. An analysis of the etiopathogenesis and diagnostic approach in these rare localizations is presented. 相似文献
1000.
Hypoxic-ischemic encephalopathy (HIE) is a common cause of neonatal encephalopathy and is one of the most important causes of neonatal death and disabilities, especially those infants with moderate to severe encephalopathy. However, the pathogenesis of HIE still remains unclear. The purpose of this study was to explore the dynamic changes in plasma neuropeptide Y (NPY) and neurotensin (NT) as well as their role in regulating cerebral hemodynamics in HIE patients. The plasma levels of NPY and NT in the umbilical artery and peripheral blood on the first, third, and seventh days after birth in 40 term infants with HIE and 40 healthy controls were measured using radioimmunoassay. On the first day of life, the blood samples were collected immediately when ultrasound examinations were finished. The ultrasound transducer was placed on the temporal fontanelle to detect the hemodynamic parameters of the middle cerebral artery, including peak systolic flow velocity, end-diastolic flow velocity, time-average mean velocity, pulsatility index, and resistance index (RI) in both groups were measured by pulse Doppler ultrasound in the first day after birth. The relationship between RI and NPY or NT was analyzed by linear regression analysis. NPY levels in umbilical blood ([mean +/- standard deviation] 615.5 +/- 130.7 ng/L) and first-day peripheral blood (355.9 +/- 57.4 ng/L) in neonates with HIE were significantly higher than those in normal newborns' blood (199.1 +/- 63.2 and 214.4 +/- 58.0 ng/L, respectively; P < 0.01). NPY levels in HIE neonates then declined to control levels on the third day after birth ( P > 0.05). However, the levels of plasma NT in umbilical blood and peripheral blood were much higher in the HIE group than those in normal newborns during the first week ( P < 0.01). The results of Doppler ultrasound examinations showed that cerebral blood flow velocity significantly decreased, whereas RI increased markedly in HIE patients compared with healthy controls ( P < 0.01). Linear regression analysis revealed that the RI was positively correlated with NPY levels ( R = 0.614; P < 0.01) and negatively correlated with NT levels ( R = -0.579; P < 0.01). The results of this study showed that there was a significant increase in plasma NPY and NT levels in HIE patients and this was strongly related to the severity of HIE, and the hemodynamic parameter RI was significantly correlated with NPY and NT. Therefore, we believe that the dynamic changes in plasma NPY or NT levels participate in the mechanisms of HIE by regulating cerebral hemodynamic changes after neonatal asphyxia occurs. 相似文献