全文获取类型
收费全文 | 201938篇 |
免费 | 2563篇 |
国内免费 | 262篇 |
专业分类
耳鼻咽喉 | 1362篇 |
儿科学 | 7133篇 |
妇产科学 | 3579篇 |
基础医学 | 19190篇 |
口腔科学 | 2185篇 |
临床医学 | 14195篇 |
内科学 | 38594篇 |
皮肤病学 | 1077篇 |
神经病学 | 18729篇 |
特种医学 | 9817篇 |
外科学 | 33676篇 |
综合类 | 2359篇 |
一般理论 | 5篇 |
预防医学 | 19070篇 |
眼科学 | 3233篇 |
药学 | 11029篇 |
中国医学 | 681篇 |
肿瘤学 | 18849篇 |
出版年
2023年 | 273篇 |
2022年 | 510篇 |
2021年 | 1045篇 |
2020年 | 598篇 |
2019年 | 872篇 |
2018年 | 22752篇 |
2017年 | 17944篇 |
2016年 | 20201篇 |
2015年 | 1785篇 |
2014年 | 1998篇 |
2013年 | 2241篇 |
2012年 | 9167篇 |
2011年 | 23007篇 |
2010年 | 19956篇 |
2009年 | 12624篇 |
2008年 | 21209篇 |
2007年 | 23351篇 |
2006年 | 2202篇 |
2005年 | 3814篇 |
2004年 | 4929篇 |
2003年 | 5657篇 |
2002年 | 3670篇 |
2001年 | 420篇 |
2000年 | 564篇 |
1999年 | 361篇 |
1998年 | 408篇 |
1997年 | 368篇 |
1996年 | 249篇 |
1995年 | 251篇 |
1994年 | 222篇 |
1993年 | 177篇 |
1992年 | 147篇 |
1991年 | 164篇 |
1990年 | 204篇 |
1989年 | 139篇 |
1988年 | 102篇 |
1987年 | 84篇 |
1986年 | 67篇 |
1985年 | 78篇 |
1984年 | 57篇 |
1983年 | 56篇 |
1982年 | 75篇 |
1981年 | 31篇 |
1980年 | 71篇 |
1974年 | 43篇 |
1938年 | 62篇 |
1937年 | 26篇 |
1934年 | 32篇 |
1932年 | 59篇 |
1930年 | 47篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
22.
23.
F. Murina R. Felice S. Di Francesco L. Nelvastellio I. Cetin 《Gynecological endocrinology》2020,36(5):431-435
AbstractThis study is a single-center, retrospective analysis of postmenopausal women presenting with dyspareunia and vulvar pain, aiming to evaluate relative effectiveness of vestibular CO2 laser therapy as a treatment. Three monthly sessions of laser were performed to each patient and thereafter a three-months follow-up was stablished. A total number of 72 patients undergoing vestibular laser treatment were recruited from patient files in the period between 2016 and 2018. Among these, 39 women also received a concomitant treatment with ospemifene (60?mg/day) during the study period. There was a statistically significant reduction of all the symptoms in both groups up to the three month follow-up. Regarding dryness and dyspareunia, the relief tent to be more prominent in the ospemifene?+?laser group at all follow-ups and remained statistically significant at three-month follow-up. Specifically, vestibular dryness was significantly lower in the ospemifene?+?laser group compared with the laser treatment group (?87% vs???34%, respectively), and the vestibular health score started declining faster in the ospemifene?+?laser group. Although, additional research is needed to understand the mechanism of action, our data shows that a combination regimen of laser and ospemifene may improve clinical effectiveness for long-term treatment of symptoms associated with the under-recognized genitourinary syndrome of menopause. 相似文献
24.
Viviana Maestrini Lucia I. Birtolo Sara Cimino Paolo Severino Massimo Mancone Marco Francone Sanjay M. Banypersad Flavia Ventriglia Luigi Tritapepe Fabio Miraldi Francesco Fedele 《Echocardiography (Mount Kisco, N.Y.)》2019,36(5):992-995
A 20‐year‐old Congolese woman presented with presyncope, dyspnea, and anasarca. Past medical history was unremarkable. Echocardiography revealed a rare combination of giant right atrium (RA), a dilated and hypertrophied right ventricle, subvalvular pulmonary stenosis (subPS), severe tricuspid regurgitation (TR), pericardial effusion and what appeared to be a spontaneously closed ventricular septal defect (VSD). Cardiac Magnetic Resonance and Cardiac Computed Tomography confirmed the findings excluding the presence of intra‐cardiac and extra‐cardiac shunt and other associated congenital anomalies. The patient underwent subPS resection, right atrioplasty, and tricuspid annuloplasty. Multimodality approach facilitated the detection of the abnormalities and provided clarity when determining the optimal surgical strategy. 相似文献
25.
Konrad Matyja Anna Małachowska-Jutsz Anna K. Mazur Kazimierz Grabas 《Ecotoxicology (London, England)》2016,25(5):924-939
Dehydrogenase activity is frequently used to assess the general condition of microorganisms in soil and activated sludge. Many studies have investigated the inhibition of dehydrogenase activity by various compounds, including heavy metal ions. However, the time after which the measurements are carried out is often chosen arbitrarily. Thus, it can be difficult to estimate how the toxic effects of compounds vary during the reaction and when the maximum of the effect would be reached. Hence, the aim of this study was to create simple and useful mathematical model describing changes in dehydrogenase activity during exposure to substances that inactivate enzymes. Our model is based on the Lagergrens pseudo-first-order equation, the rate of chemical reactions, enzyme activity, and inactivation and was created to describe short-term changes in dehydrogenase activity. The main assumption of our model is that toxic substances cause irreversible inactivation of enzyme units. The model is able to predict the maximum direct toxic effect (MDTE) and the time to reach this maximum (TMDTE). In order to validate our model, we present two examples: inactivation of dehydrogenase in microorganisms in soil and activated sludge. The model was applied successfully for cadmium and copper ions. Our results indicate that the predicted MDTE and TMDTE are more appropriate than EC50 and IC50 for toxicity assessments, except for long exposure times. 相似文献
26.
27.
Contraceptive use is an important strategy for the prevention of unwanted pregnancy and avoidance of induced abortion. Of all the contraception methods, emergency contraceptive (EC) offers the last chance to achieve this. However, few studies have documented the use of EC among young people in Ghana. This study explored knowledge and usage of EC as well as the factors associated with it among University of Cape Coast students. Data were obtained on the knowledge and usage of ECs among University of Cape Coast students in 2013. Logistic regression analysis was used to investigate the association between students’ socio-demographic characteristics and EC knowledge and use. More male students (72 %) than females (59 %) were sexually active. Fifty-seven percent of the respondents had ever heard of EC and 36 % had ever used EC. Although males were more likely to be sexually active, females were more likely to have knowledge of EC use compared to males. The study underscores the need to increase awareness regarding EC among University students in order to offer them the opportunity that EC provides if other forms of contraceptives are missed. 相似文献
28.
29.
Miguel A. Sanz Pau Montesinos Haesook T. Kim Guillermo J. Ruiz-Argüelles María S. Undurraga María R. Uriarte Lem Martínez Rafael H. Jacomo Homero Gutiérrez-Aguirre Raul A. M. Melo Rosane Bittencourt Ricardo Pasquini Katia Pagnano Evandro M. Fagundes Edo Vellenga Alexandra Holowiecka Ana J. González-Huerta Pascual Fernández Javier De la Serna Salut Brunet Elena De Lisa José González-Campos José M. Ribera Isabel Krsnik Arnold Ganser Nancy Berliner Raul C. Ribeiro Francesco Lo-Coco Bob L?wenberg Eduardo M. Rego 《Annals of hematology》2015,94(8):1347-1356
30.
Gastroesophageal reflux is the most common benign disorder of the esophagus and laparoscopic Nissen fundoplication has become the standard surgical treatment for its treatment. In our area, where the use of bougie calibration is debatable, postoperative dysphagia is encountered often after this surgery although it is usually not permanent. The aim of this study was to investigate the effect of using a soft silicone tube 39 F in diameter for esophageal calibration during laparoscopic Nissen fundoplication on the incidence of postoperative dysphagia. We divided cases scheduled to undergo laparoscopic Nissen fundoplication between January 2009 and November 2010 into two groups, each consisting 25 patients. Esophageal calibration with a 39 F silicone orogastric tube was used for the first group while there was no operative calibration in the second group. The surgical duration was recorded; the presence and severity of the postoperative dysphagia was calculated by using a dysphagia severity scoring system during the 1-year postoperative follow-up. The dysphagia severity scores were significantly lower in group 1 than group 2 on the postoperative second day and at the end of the first week and first month. We did not find a significant difference at the end of the 6-month and first year. There was also no significant difference regarding surgery duration. The use of a soft orogastric tube 39 F in diameter for esophagus calibration during laparoscopic Nissen fundoplication has significantly decreased the incidence of postoperative transient dysphagia without affecting the duration of surgery. Although dysphagia gradually resolves in the majority of patients, a safe and easy calibration method for its prevention is worth developing, and we believe that the use of our method in larger series could be beneficial. 相似文献