全文获取类型
收费全文 | 933804篇 |
免费 | 65375篇 |
国内免费 | 4149篇 |
专业分类
耳鼻咽喉 | 13017篇 |
儿科学 | 29168篇 |
妇产科学 | 26933篇 |
基础医学 | 130559篇 |
口腔科学 | 25225篇 |
临床医学 | 78827篇 |
内科学 | 189021篇 |
皮肤病学 | 19748篇 |
神经病学 | 73250篇 |
特种医学 | 37607篇 |
外国民族医学 | 353篇 |
外科学 | 145499篇 |
综合类 | 23268篇 |
现状与发展 | 4篇 |
一般理论 | 253篇 |
预防医学 | 66820篇 |
眼科学 | 20857篇 |
药学 | 67336篇 |
23篇 | |
中国医学 | 3427篇 |
肿瘤学 | 52133篇 |
出版年
2019年 | 7523篇 |
2018年 | 10299篇 |
2017年 | 8219篇 |
2016年 | 8702篇 |
2015年 | 10243篇 |
2014年 | 14223篇 |
2013年 | 21059篇 |
2012年 | 28241篇 |
2011年 | 29992篇 |
2010年 | 18326篇 |
2009年 | 17082篇 |
2008年 | 27997篇 |
2007年 | 29505篇 |
2006年 | 29711篇 |
2005年 | 29192篇 |
2004年 | 27560篇 |
2003年 | 26681篇 |
2002年 | 26093篇 |
2001年 | 42127篇 |
2000年 | 43286篇 |
1999年 | 36941篇 |
1998年 | 10410篇 |
1997年 | 9552篇 |
1996年 | 9404篇 |
1995年 | 8745篇 |
1994年 | 8353篇 |
1993年 | 7774篇 |
1992年 | 28475篇 |
1991年 | 27232篇 |
1990年 | 26600篇 |
1989年 | 25494篇 |
1988年 | 23723篇 |
1987年 | 23309篇 |
1986年 | 22356篇 |
1985年 | 21252篇 |
1984年 | 15871篇 |
1983年 | 13515篇 |
1982年 | 8109篇 |
1979年 | 14618篇 |
1978年 | 10232篇 |
1977年 | 8642篇 |
1976年 | 8162篇 |
1975年 | 8976篇 |
1974年 | 10708篇 |
1973年 | 10204篇 |
1972年 | 9671篇 |
1971年 | 8923篇 |
1970年 | 8599篇 |
1969年 | 8033篇 |
1968年 | 7687篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
We report a case of intestinal obstruction in a 73-year-old woman caused by ileocolic intussusception. The underlying cause was a giant submucosal ulcerating lipoma (6?×?3.3?×?3.8 cm) extending from the superior mucosal lip of Bauhin’s valve. Abdominal ultrasonography showed a pathognomonic target-like mass appearing as multiple concentric rings. CT scan confirmed the diagnosis. Because of apparent obstruction, a laparotomy with right hemicolectomy and ileocolic anastomosis was performed. Lipomas most frequently occur in the cecum and ascending colon where they represent the most common submucosal mesenchymal tumor. They typically occur in elderly women with an incidence that varies from 0.15 to 0.56 %. Pain, rectal bleeding, and obstruction are typical symptoms. When faced with an intussusception in children, reduction with air per rectum can be performed. In adults, however, malignant cell spreading and seeding is of big concern. Since approximately 20–50 % of all underlying causes are malignant, explorative surgery is favored in adults. 相似文献
22.
23.
Toidi Adekambi Chris C. Ibegbu Stephanie Cagle Ameeta S. Kalokhe Yun F. Wang Yijuan Hu Cheryl L. Day Susan M. Ray Jyothi Rengarajan 《The Journal of clinical investigation》2015,125(5):1827-1838
BACKGROUND. The identification and treatment of individuals with tuberculosis (TB) is a global public health priority. Accurate diagnosis of pulmonary active TB (ATB) disease remains challenging and relies on extensive medical evaluation and detection of Mycobacterium tuberculosis (Mtb) in the patient’s sputum. Further, the response to treatment is monitored by sputum culture conversion, which takes several weeks for results. Here, we sought to identify blood-based host biomarkers associated with ATB and hypothesized that immune activation markers on Mtb-specific CD4+ T cells would be associated with Mtb load in vivo and could thus provide a gauge of Mtb infection.METHODS. Using polychromatic flow cytometry, we evaluated the expression of immune activation markers on Mtb-specific CD4+ T cells from individuals with asymptomatic latent Mtb infection (LTBI) and ATB as well as from ATB patients undergoing anti-TB treatment.RESULTS. Frequencies of Mtb-specific IFN-γ+CD4+ T cells that expressed immune activation markers CD38 and HLA-DR as well as intracellular proliferation marker Ki-67 were substantially higher in subjects with ATB compared with those with LTBI. These markers accurately classified ATB and LTBI status, with cutoff values of 18%, 60%, and 5% for CD38+IFN-γ+, HLA-DR+IFN-γ+, and Ki-67+IFN-γ+, respectively, with 100% specificity and greater than 96% sensitivity. These markers also distinguished individuals with untreated ATB from those who had successfully completed anti-TB treatment and correlated with decreasing mycobacterial loads during treatment.CONCLUSION. We have identified host blood-based biomarkers on Mtb-specific CD4+ T cells that discriminate between ATB and LTBI and provide a set of tools for monitoring treatment response and cure.TRIAL REGISTRATION. Registration is not required for observational studies.FUNDING. This study was funded by Emory University, the NIH, and the Yerkes National Primate Center. 相似文献
24.
Kui Li Jiawen Wang Shengxiong Liu Sen Su Chenjian Feng Xiaoxiang Fan Zhiyong Yin 《中华创伤杂志(英文版)》2015,18(2):65-73
Objective: To study the biomechanical mechanism of head injuries beaten with sticks, which is common in the battery or assaultive cases.
Methods: In this study, the Hybrid-III anthropomorphic test device and finite element model (FEM) of the total human model for safety (THUMS) head were used to determine the biomechanical response of head while being beaten with different sticks. Total eight Hybrid-III tests and four finite element simulations were conducted. The contact force, resultant acceleration of head center of gravity, intracranial pressure and von Mises stress were calculated to determine the different biomechanical behavior of head with beaten by different sticks.
Results: In Hybrid-III tests, the stick in each group demonstrated the similar kinematic behavior under the same loading condition. The peak values of the resultant acceleration for thick iron stick group, thin iron stick group, thick wooden stick group and thin wooden stick group were 203.4 g, 221.1 g, 170.5 g and 122.2 g respectively. In finite element simulations, positive intracranial pressure was initially observed in the frontal comparing with negative intracranial pressure in the contra-coup site. Subsequently the intracranial pressure in the coup site was decreasing toward negative value while the contra-coup intracranial pressure increasing toward positive values.
Conclusions: The results illustrated that the stiffer and larger the stick was, the higher the von Mises stress, contact force and intracranial pressure were. We believed that the results in the Hybrid-III tests and THUMS head simulations for brain injury beaten with sticks could be reliable and useful for better understanding the injury mechanism. 相似文献
25.
Nirmanmoh Bhatia Buddhadeb Dawn Tariq S. Siddiqui Marcus F. Stoddard 《Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital》2015,42(1):16-24
Determining aortic stenosis (AS) severity is clinically important. Calculating aortic valve (AV) area by means of the continuity equation assumes a circular left ventricular outflow tract (LVOT). The full impact of this assumption in calculating AV area is unknown. Predictors of noncircular LVOT shape in patients with AS are undefined.In 109 adult patients with AS who underwent multiplanar transesophageal echocardiography, we calculated AV area by means of the standard continuity method and by a modified method involving planimetric LVOT area.We found 54 circular, 37 horizontal-oval, 8 vertical-oval, and 10 irregular LVOTs. Area derived by direct planimetry correlated better with the modified than the standard continuity method (r=0.89 vs r=0.85; both P=0.0001). Valve areas of patients with mild, moderate, or severe AS by planimetry were more often mischaracterized with use of the standard than modified method (29 vs 18; P <0.0001). Horizontal-oval AV area derived by planimetry (1.28 ± 0.55 cm2) was underestimated by the standard method (1.05 ± 0.47 cm2; P=0.001), but not by the modified method. Congenital AV morphology and low cardiac index were the only multivariate predictors of horizontal-oval shape. Low cardiac index was the only predictor of noncircular shape.More than half our patients with AS had noncircular LVOTs. Using the modified method reduces mischaracterizations of AS severity. Congenital AV morphology and low cardiac index predict horizontal-oval or noncircular shape. These data suggest the value of direct LVOT measurement to calculate AS severity in patients who have congenital AV or a low cardiac index. 相似文献
26.
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
27.
28.
29.
30.
Bj?rn Stessel Audrey A. Fiddelers Elbert A. Joosten Daisy M.N. Hoofwijk Hans-Fritz Gramke Wolfgang F.F.A. Buhre 《Medicine》2015,94(39)
Traditionally, major complications and unanticipated admission/readmission rates were used to assess outcome after day surgery. However, in view of the relative absence of major complications the quality of recovery (QOR) should be considered one of the principal endpoints after day surgery. In our study, the level of QOR is defined by a combination of the Global Surgical Recovery (GSR) Index and the Quality of Life (QOL).The aim of this study was to analyze prevalence and predictors of QOR after day surgery on the fourth postoperative day.Elective patients scheduled for day surgery from November 2008 to April 2010 were enrolled in a prospective cohort study. Outcome parameters were measured by using questionnaire packages at 2 time points: 1 week preoperatively and 4 days postoperatively. Primary outcome parameter is the QOR and is defined as good if the GSR index >80% as well as the postoperative QOL is unchanged or improved as compared with baseline. QOR is defined as poor if both the GSR index ≤80% and if the postoperative QOL is decreased as compared with baseline. QOR is defined as intermediate in all other cases. Three logistic regression analyses were performed to determine predictors for poor QOR after day surgery.A total of 1118 patients were included. A good QOR was noted in 17.3% of patients, an intermediate QOR in 34.8%, and a poor QOR in 47.8% 4 days after day surgery. The best predictor for poor QOR after day surgery was type of surgery. Other predictors were younger age, work status, and longer duration of surgery. A history of previous surgery, expected pain (by the patient) and high long-term surgical fear were significant predictors of poor QOR in only 1 of 3 prediction models.The QOR at home 4 days after day surgery was poor in the majority of patients and showed a significant procedure-specific variation. Patients at risk for poor QOR can be identified during the preoperative period based on type of surgery, age, work status, and the duration of the surgery. 相似文献