首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   977篇
  免费   35篇
  国内免费   2篇
耳鼻咽喉   42篇
儿科学   46篇
妇产科学   38篇
基础医学   51篇
口腔科学   34篇
临床医学   79篇
内科学   216篇
皮肤病学   11篇
神经病学   56篇
特种医学   35篇
外科学   283篇
综合类   18篇
预防医学   25篇
眼科学   29篇
药学   20篇
中国医学   1篇
肿瘤学   30篇
  2024年   1篇
  2023年   2篇
  2022年   13篇
  2021年   15篇
  2020年   15篇
  2019年   22篇
  2018年   30篇
  2017年   22篇
  2016年   30篇
  2015年   38篇
  2014年   58篇
  2013年   61篇
  2012年   85篇
  2011年   98篇
  2010年   37篇
  2009年   33篇
  2008年   81篇
  2007年   97篇
  2006年   81篇
  2005年   56篇
  2004年   49篇
  2003年   35篇
  2002年   25篇
  2001年   7篇
  2000年   3篇
  1999年   4篇
  1998年   2篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1993年   2篇
  1991年   2篇
  1990年   3篇
  1989年   1篇
  1983年   1篇
  1975年   1篇
排序方式: 共有1014条查询结果,搜索用时 15 毫秒
41.
42.
The aim of this study is to evaluate the impact of ovarian reserve and age of women on early morphokinetic parameters of embryos with a time-lapse monitoring system. In total, 197 infertile couples with poor ovarian reserve (Group 1, n?=?41), normal ovarian reserve (Group 2, n?=?59), or polycystic ovaries (Group 3, n?=?97) were included. The time from insemination to the following events were analyzed: pronuclear fading (Pnf) and cleavage to 2, 3, 4 and 5 cells. The optimal ranges for morphokinetic parameters of t5, s2 and cc2 in each group were also evaluated. In total, 1144 embryos were evaluated. Morphokinetic parameters did not differ statistically between the groups. Data were analyzed according to different age groups (20–30, 30–40,?>40). The morphokinetic parameters did not differ statistically in Group 1 and 3. In Group 2, the times from insemination to tPnf, t2, t3, t4 were significantly shorter in the younger age group than the older age group (p?相似文献   
43.
Purpose: Brucellosis is a worldwide zoonotic disease and still constitutes a major public health problem. In the study we claimed to identify Brucella species from clinical samples of patients with active brucellosis from Van region of Eastern Anatolia and to determine in vitro antimicrobial susceptibilities of these strains to commonly used anti-Brucella agents and a possible new alternative tigecycline.Materials and Methods: A total of 56 Brucella isolates were enrolled the study and the identification of the isolates were based on conventional methods. In vitro activities of antimicrobials were evaluated by the E test method.Results: All isolates were identified as B. melitensis. MIC90 values of doxycycline, streptomycin, rifampin, trimethoprim-sulfamethoxazole and tigecycline were 0.064 mg/L, 1 mg/L, 2 mg/L, 0.125 mg/L and 0.094 mg/L, respectively. Tigecycline had low MIC50 and MIC90 values against all B. melitensis strains; the highest MIC observed was 0.25 μg/mL.Conclusion: Our data suggest that tigecycline can be a therapeutic alternative option for the treatment of brucellosis.  相似文献   
44.
IntroductionStudies have shown that sarcopenia is associated with poor outcomes in patients with gastrointestinal cancer undergoing surgery. We aimed to investigate the relationship between postoperative complications of sarcopenic patients who had been operated on for colon cancer and the effects on short-term mortality.Material and methodsIn this study, patients who had undergone colon cancer surgery between January 2013 and December 2018 were collected retrospectively. Sarcopenia was diagnosed by the skeletal muscle index (SMI) derived from a preoperative computed tomography scan. Multiple logistic regression analysis was performed to determine whether sarcopenia is associated with postoperative major complications (POMC).ResultsThe study included 160 patients with a mean age of 62.4 ±12.6 years. Clavien-Dindo grade 1–2 (minor) complications were not significantly different between the groups (p = 0.896). However, grade ≥ 3 (major) complications were detected in 13 (17.8%) patients in the sarcopenic group (SG) and in 5 patients in the non-sarcopenic group (NSG) (5.7%) (p = 0.016). Length of intensive care unit (ICU) stay was longer in SG (p = 0.002) and there was no difference between 1-month and 6-month mortality rates (p = 0.273 and p = 0.402, respectively). According to univariate analyses, sarcopenia and age over 65 years were related to POMC. In multivariate analyses, sarcopenia (odds ratio = 3.039; 95% confidence interval 1.008–9.174; p = 0.048) and advanced age (odds ratio = 3.246; 95% confidence interval 1.078–9.803; p = 0.036) were found to be independent risk factors for POMC.ConclusionsThis study showed that while sarcopenia is a risk factor for POMC, sarcopenia also prolongs the duration of ICU stay. Also sarcopenia has no effect on short-term mortality.  相似文献   
45.
Herein we report the case of a patient with primary amenorrhea and cyclic menouria. The patient was a 20-year-old woman with primary amenorrhea and inability to achieve sexual intercourse. Clinical examination revealed normally developed labia majora and minora, clitoris, and external urethral orifice, but no vaginal opening. A mature female pubic hair pattern was present, and axillary hair development was normal. Breasts were normally developed. Abdominopelvic magnetic resonance imaging demonstrated a remnant upper vagina and unicornuate uterus filled with fluid, and left-sided renal agenesis. Intraoperatively, a congenital vesicouterine fistulous tract was observed. The fistulous tract was completely resected. Vaginal reconstruction using a sigmoid colon pedicled flap was performed. The proximal part of the neovagina was connected to the remnant cervix, and a Foley catheter was left in the uterine cavity for 7 days to prevent obstruction. The patient has been menstruating regularly since the operation. Menouria might be an early sign of congenital vesicouterine fistula. Resection of the fistulous tract with uterine preservation might be considered in patients with vaginal agenesis.  相似文献   
46.
Several deep‐learning models have been proposed to shorten MRI scan time. Prior deep‐learning models that utilize real‐valued kernels have limited capability to learn rich representations of complex MRI data. In this work, we utilize a complex‐valued convolutional network (?Net ) for fast reconstruction of highly under‐sampled MRI data and evaluate its ability to rapidly reconstruct 3D late gadolinium enhancement (LGE) data. ?Net preserves the complex nature and optimal combination of real and imaginary components of MRI data throughout the reconstruction process by utilizing complex‐valued convolution, novel radial batch normalization, and complex activation function layers in a U‐Net architecture. A prospectively under‐sampled 3D LGE cardiac MRI dataset of 219 patients (17 003 images) at acceleration rates R = 3 through R = 5 was used to evaluate ?Net . The dataset was further retrospectively under‐sampled to a maximum of R = 8 to simulate higher acceleration rates. We created three reconstructions of the 3D LGE dataset using (1) ?Net , (2) a compressed‐sensing‐based low‐dimensional‐structure self‐learning and thresholding algorithm (LOST), and (3) a real‐valued U‐Net (realNet) with the same number of parameters as ?Net . LOST‐reconstructed data were considered the reference for training and evaluation of all models. The reconstructed images were quantitatively evaluated using mean‐squared error (MSE) and the structural similarity index measure (SSIM), and subjectively evaluated by three independent readers. Quantitatively, ?Net ‐reconstructed images had significantly improved MSE and SSIM values compared with realNet (MSE, 0.077 versus 0.091; SSIM, 0.876 versus 0.733, respectively; p < 0.01). Subjective quality assessment showed that ?Net ‐reconstructed image quality was similar to that of compressed sensing and significantly better than that of realNet. ?Net reconstruction was also more than 300 times faster than compressed sensing. Retrospective under‐sampled images demonstrate the potential of ?Net at higher acceleration rates. ?Net enables fast reconstruction of highly accelerated 3D MRI with superior performance to real‐valued networks, and achieves faster reconstruction than compressed sensing.  相似文献   
47.
Morgagni hernia (MH) is a congenital herniation of the abdominal organs through the subcostosternal portion of the diaphragm. It is a rare type of diaphragmatic hernia that has been associated with other congenital anomalies. The purpose of this clinical review was to determine the incidence of associated anomalies in patients with MH at a major pediatric referral center. The medical records of all patients with the diagnosis of MH were reviewed retrospectively between 1983 and 2006. The age, sex, side of herniation, presenting symptoms and signs, associated anomalies, radiologic features, intraoperative findings, postoperative course, complications, and mortality were recorded. There were 11 males and 5 females. The average age of the patients was 34.5 months (range 2 months–14 years). Twelve patients (75%) had at least one associated congenital malformation and eight (66.6%) of them had multiple anomalies. Six (37.5%) patients had a chromosomal anomaly, Down’s syndrome in five and Turner syndrome in one. MH has a high incidence of associated congenital malformations.  相似文献   
48.
Recent studies show that melatonin reduces the blood pressure (BP) and ischemia/reperfusion (I/R)-induced damage. This study was designed to investigate the effects of melatonin on the renal I/R injury in rats given the nitric oxide synthase (NOS) inhibitor, N(omega)-nitro-L-arginine methyl ester (L-NAME). After right nephrectomy, I/R was induced by occlusion of the left renal vessels for 60 min, followed by 24h reperfusion. The administration of melatonin significantly attenuated BP in NOS-inhibited hypertensive rats. Malondialdehyde (MDA) levels, a stable metabolite of the free-radical-mediated lipid peroxidation cascade, were found to be significantly higher in the I/R group (3.48+/-0.2mg/l serum) than in the control group (2.69+/-0.2mg/l serum). L-NAME (40 mgkg(-1) for 15 days)+I/R significantly increased the MDA levels compared to I/R alone. Melatonin administration to L-NAME rats significantly reduced the MDA values resulting from I/R. We also demonstrated that I/R, and especially L-NAME+I/R, lead to structural changes in the kidney and that melatonin attenuates these changes. These results suggest that melatonin reduces BP and I/R injury in NOS inhibited rats by L-NAME.  相似文献   
49.

Objective

The purpose of our study was to evaluate the relationship between endometrial polyps and obesity, diabetes mellitus (DM) and hypertension (HT).

Materials and methods

202 patients who applied to our gynecology clinic with complaints of infertility, recurrent pregnancy loss and abnormal uterine bleeding, diagnosed to have endometrial polyps by hysteroscopy, were compared with 79 patients without polyps, retrospectively. The relationships between risk factors and presence of a polyp and polyp size were analyzed.

Results

The mean age of cases with endometrial polyps was significantly greater than the controls. The mean body mass index (BMI) of the cases with polyps was also significantly greater than the controls. There was no significant difference between groups with respect to prevalence of DM or HT.

Conclusion

This study suggests that obesity is an independent risk factor in the development of endometrial polyps. Clinicians should be aware in terms of endometrial polyps in the assessment of patients with BMI ≥30. There was no relationship between HT or DM with presence of polyps.  相似文献   
50.
The trigemino-cardiac reflex (TCR) is a well-known reflexive response in which bradycardia, hypotension, and gastric hypermotility are induced by stimulation of a peripheral or central portion of the trigeminal nerve. This reflex occurs during craniofacial surgery and other operations on or near the cerebellopontine angle, petrosal sinus, orbit and trigeminal ganglion. TCR is a well-known, although not well documented, phenomenon commonly observed during trans-sphenoidal surgery for resection of pituitary adenomas. We report a case in which asystole occurred during trans-sphenoidal surgery on a pituitary adenoma that was infiltrating the right cavernous sinus. When the anesthesiologist reported asystole, the team stopped manipulation and administered intravenous atropine. Intra-operative MRI showed a small tumour remnant in the right cavernous sinus. The operation was terminated but subsequent radiosurgery was planned for the residual tumor. Although TCR is rare and usually self-limiting, this case led us to change our treatment strategy. Surgeons who perform trans-sphenoidal surgery should be aware of this potential problem. Invasive pituitary adenomas should be removed gently and the risk of triggering TCR should be kept in mind.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号