全文获取类型
收费全文 | 10265篇 |
免费 | 367篇 |
国内免费 | 79篇 |
专业分类
耳鼻咽喉 | 322篇 |
儿科学 | 424篇 |
妇产科学 | 613篇 |
基础医学 | 652篇 |
口腔科学 | 362篇 |
临床医学 | 830篇 |
内科学 | 2482篇 |
皮肤病学 | 137篇 |
神经病学 | 527篇 |
特种医学 | 417篇 |
外科学 | 2527篇 |
综合类 | 146篇 |
一般理论 | 1篇 |
预防医学 | 211篇 |
眼科学 | 347篇 |
药学 | 348篇 |
中国医学 | 23篇 |
肿瘤学 | 342篇 |
出版年
2024年 | 2篇 |
2023年 | 87篇 |
2022年 | 121篇 |
2021年 | 268篇 |
2020年 | 150篇 |
2019年 | 193篇 |
2018年 | 248篇 |
2017年 | 197篇 |
2016年 | 316篇 |
2015年 | 393篇 |
2014年 | 517篇 |
2013年 | 627篇 |
2012年 | 791篇 |
2011年 | 732篇 |
2010年 | 498篇 |
2009年 | 510篇 |
2008年 | 822篇 |
2007年 | 865篇 |
2006年 | 765篇 |
2005年 | 758篇 |
2004年 | 617篇 |
2003年 | 509篇 |
2002年 | 406篇 |
2001年 | 57篇 |
2000年 | 27篇 |
1999年 | 26篇 |
1998年 | 42篇 |
1997年 | 29篇 |
1996年 | 33篇 |
1995年 | 23篇 |
1994年 | 13篇 |
1993年 | 10篇 |
1992年 | 14篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1974年 | 1篇 |
1970年 | 2篇 |
1968年 | 2篇 |
1966年 | 2篇 |
1964年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Apoptosis and proliferation in human undescended testes 总被引:2,自引:0,他引:2
OBJECTIVE: To study apoptosis and proliferation in the testes of children with undescended testes; the degree to which undescended testes contributes to a patient's ultimate fertility is debatable, but undescended testes have fewer germ cells, and some have proposed that apoptosis is an important cause. PATIENTS AND METHODS: Testis biopsies were taken at the time of orchidopexy in a consecutive series of children undergoing surgical repair for undescended testes. Immunohistological techniques were used to detect apoptosis and proliferation, and the numbers of cells undergoing apoptosis or proliferation per 50 seminiferous tubules were recorded. RESULTS: Inguinal testes had less apoptosis than abdominal testes, with a mean (sd) of 0.71 (1.31) vs 1.63 (1.95) apoptotic cells per 50 seminiferous tubules (P < 0.02). Similarly, there was less apoptosis in children aged > 1 years than in children aged < 1 years (0.68 (1.40) vs 1.35 (1.56); P < 0.03). Proliferation was very limited in all cryptorchid testes. In contrast to cryptorchid testes, five autopsy controls had many more apoptotic cells, (10.60 (1.34) per 50 seminiferous tubules), and many more proliferating cells, (8.40 (6.43) per 50 seminiferous tubules). CONCLUSION: In contrast to animal studies, neither apoptosis nor proliferation was common in undescended testes from 6 months of age onward. However, apoptosis was more common in abdominal testes and in children aged < 1 year. It is likely that, if substantial apoptosis occurs in human undescended testes, it occurs before 6 months of age. 相似文献
82.
Karademir K Baykal K Sen B Senkul T Iseri C Erden D 《Scandinavian journal of urology and nephrology》2005,39(3):230-233
OBJECTIVE: To perform Stoller afferent neurostimulation (SANS) with and without a low-dose anticholinergic (oxybutynin hydrochloride) in patients with detrusor overactivity and compare the results obtained with the two therapeutic approaches. MATERIAL AND METHODS: A total of 43 patients with symptoms of detrusor overactivity (frequency, urgency, urge incontinence) underwent urodynamic studies (UDS). Those in whom UDS revealed phasic detrusor overactivity were evaluated using a quality of life questionnaire and voiding diaries. Patients were randomized into two groups: Group 1 received SANS alone; Group 2 received SANS combined with a low-dose anticholinergic (5 mg of oral oxybutynin hydrochloride). Both groups were re-evaluated following 8 weeks of therapy. RESULTS: There were 21 patients in Group 1 and 22 in Group 2. The treatment response rate was 61.6% and 83.2% in Groups 1 and 2, respectively. In both groups, the best symptomatic improvements were obtained in patients with urge incontinence. The percentage decreases in the mean number of symptoms of frequency and urgency were 36.7% and 46.1%, respectively in Group 1 and 44.2% and 61.1%, respectively in Group 2. However, there were no statistically significant differences in the effects on frequency and urgency between the two groups. The anticholinergic drug was well tolerated by all patients in Group 2. One patient reported local tenderness, and a small hematoma developed in another following SANS therapy. CONCLUSION: SANS is an easy and inexpensive therapeutic method with low morbidity in patients with an overactive bladder. Combination with a low-dose anticholinergic increases the success rate without causing any significant side-effects. 相似文献
83.
Ozok U Eroglu M Imamoglu A Bakirtaş H Güvence N Kiper A 《Journal of endourology / Endourological Society》2005,19(10):1185-1187
BACKGROUND AND PURPOSE: Endoscopic subureteral injection of tissue-augmenting substances has become an alternative to antibiotic prophylaxis and open surgery for the management of vesicoureteral reflux (VUR). Several injectable materials have been tried for this purpose. In this study, we tried to determine the efficacy of dextranomer/hyaluronic acid copolymer (Dx/HA) injection for the treatment of VUR in renal-transplant candidates. PATIENTS AND METHODS: A total of 21 transplant candidates (29 ureteral units; 13 females, 8 males) with a mean age of 20.2 years (range 14-26 years) underwent endoscopic correction of VUR with Dx/HA. Diagnosis of VUR was made by voiding cystourethrography. The efficacy of the treatment was assessed with voiding cystourethrography at 3 months and 1 year postoperatively. Renal transplantation with living related donor organs was performed in 11 of the 21 patients. RESULTS: Endoscopic treatment was performed without complication in all cases. Higher success rates were obtained in patients with low-grade reflux, the overall success rate in the series being 82.7%. The mean follow- up after renal transplantation was 21.8 months (range 5-45 months). In one patient, reflux recurred after renal transplantation and was treated successfully by a repeat Dx/HA injection. The urine cultures of all patients remained sterile. CONCLUSION: Transplant candidates with VUR can be treated with Dx/HA, which cured the majority of our patients after one or two treatments with few low side effects. Endoscopic subureteral injection of Dx/HA has become an alternative treatment for VUR in transplant candidates. Long-term results are needed before making a final statement about its value. 相似文献
84.
Ayav A Bresler L Brunaud L Boissel P 《Journal of laparoendoscopic & advanced surgical techniques. Part A》2005,15(6):620-623
We report a novel technique for resection of symptomatic Zenker's diverticulum. Two consecutive patients underwent a transcervical video-assisted dissection and resection of Zenker's diverticular pouch. Both patients exhibited good anatomical and functional results at 10 months follow-up. 相似文献
85.
Ahmet Ozgur Yildirim Vuslat Sema Unal Ozdamar Fuad Oken Murat Gulcek Metin Ozsular Ahmet Ucaner 《Journal of children's orthopaedics》2009,3(4):265-269
Background Type III supracondylar humeral fracture is a common cause of emergency hospitalization among children requiring surgical treatment.
The configuration of the internal fixation material, surgical technique, and optimal timing of surgery (TS) have always been
popular topics of debate. The TS in uncomplicated cases is usually determined by surgeons.
Methods In this study, we prospectively followed children with type III supracondylar fractures. We aimed to clarify the effects of
injury side, gender, and post-injury delay on switching to open surgery and the ease of the reduction.
Results Based on our results, the probability of switching to open surgery increased by a factor of 4 every 5 h beginning 15 h after
injury. Open surgery was necessary after 32 h.
Conclusion Reduction became technically more difficult as TS increased. 相似文献
86.
The aim of this study was to compare ambulatory blood pressure monitoring (ABPM) parameters in offspring with at least one
hypertensive parent (HP) to offspring with normotensive parents (NP) and to determine whether gender of parent or child might
influence the association between parental hypertension and blood pressure (BP). Eighty-nine healthy children (mean age 11.1 ± 3.9 years)
with HP and 90 controls (mean age 10.5 ± 3.1 years) with NP were recruited. Age, gender, and height did not differ between
the two groups, whereas children of HP had higher weight, body mass index (BMI), and waist circumference compared with healthy
controls. No difference was found in casual BP between the two groups. In contrast, during ABPM daytime and nighttime mean
systolic and diastolic BP and mean arterial pressure (MAP) standard deviation scores (SDS) were significantly elevated in
children with HP. The mean percentage of nocturnal BP decline (dipping) was not significantly different between the two groups.
Children with hypertensive mothers had higher daytime systolic and MAP SDS than controls; no such difference was detected
for children with hypertensive fathers. Daytime systolic and MAP SDS were significantly elevated in boys with HP compared
with boys with NP but failed to be significant in girls. Multiple linear regression analysis showed that parental history
of hypertension (B = 0.29) and BMI (B = 0.03) were independently correlated with increase of daytime MAP SDS. Early changes
in ambulatory BP parameters were present in healthy children of HP. BP in HP offspring was influenced by the gender of the
affected parent and the offspring. 相似文献
87.
We evaluated the multidetector computed tomography (MDCT) findings of the sternoclavicular joint in patients with rheumatoid arthritis (RA) and compare them with general population. Chest MDCT scans of RA patients were reviewed. The control group was formed from age and sex-matched individuals. The most common CT findings were cortical irregularity, joint space narrowing, and osteophytes in study group. There were no statistically significant differences in the MDCT findings between the two groups except that osteophytes were observed more often in the control group. It is difficult to distinguish between the involvement of RA and age-related degenerative changes at the sternoclavicular joint. 相似文献
88.
Mecit Kantarcı Berhan Pirimoglu Nevzat Karabulut Ummugulsum Bayraktutan Hayri Ogul Gurkan Ozturk Bulent Aydinli Yesim Kizrak Suat Eren Sinan Yilmaz 《European radiology》2013,23(10):2713-2722
Objective
To evaluate the added role of T1-weighted (T1w) gadolinium ethoxybenzyl diethylenetriamine penta-acetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance cholangiography (MRC) compared with T2-weighted MRC (T2w-MRC) in the detection of biliary leaks.Methods
Ninety-nine patients with suspected biliary complications underwent routine T2w-MRC and T1w contrast-enhanced (CE) MRC using Gd-EOB-DTPA to identify biliary leaks. Two observers reviewed the image sets separately and together. MRC findings were compared with those of surgery and percutaneous transhepatic cholangiopancreatography. The sensitivity, specificity and accuracy of the techniques in identifying biliary leaks were calculated.Results
Accuracy of locating biliary leaks was superior with the combination of Gd-EOB-DTPA-enhanced MRC and T2w-MRC (P?<?0.05).The mean sensitivities were 79 % vs 59 %, and the mean accuracy rates were 84 % vs 58 % for combined CE-MRC and T2w-MRC vs sole T2w-MRC. Nineteen out of 21 patients with biliary-cyst communication, 90.4 %, and 12/15 patients with post-traumatic biliary extravasations, 80 %, were detected by the combination of Gd-EOB-DTPA-enhanced MRC and T2w-MRC images, P?<?0.05.Conclusions
Gd-EOB-DTPA-enhanced MRC yields information that complements T2w-MRC findings and improves the identification and localisation of the bile extravasations (84 % accuracy, 100 % specificity, P?<?0.05). We recommend Gd-EOB-DTPA-enhanced MRC in addition to T2w-MRC to increase the preoperative accuracy of identifying and locating extravasations of bile.Key Points
? Magnetic resonance cholangiography (MRC) does not always detect bile leakage and cysto-biliary communications. ? Gd-EOB-DTPA-enhanced MRC helps by demonstrating extravasation of contrast material into fluid collections. ? Gd-EOB-DTPA-enhanced MRC also demonstrates the leakage site and bile duct injury type. ? Combined Gd-EOB-DTPA-enhanced and T2w-MRC can provide comprehensive information about biliary system. ? Gd-EOB-DTPA-enhanced MRC is non-invasive and does not use ionising radiation. 相似文献89.
The purpose of this study was to evaluate the feasibility of using an open-configuration magnetic resonance (MR) imaging system with MR fluoroscopic guidance to perform percutaneous transthoracic fine-needle aspiration biopsy in patients with lung masses. Percutaneous transthoracic aspiration biopsies were performed with MR fluoroscopic guidance in 14 patients. The masses were 2-7 cm in diameter (mean, 4.1 cm). The needle was positioned by using a free-hand technique with MR fluoroscopic guidance. The needle tip reached the target lesion, and biopsy was performed. Analysis of the biopsy specimens facilitated a specific diagnosis in all patients. Pneumothorax was noted in two patients (14%) with chronic obstructive pulmonary disease. Study results showed that the described MR fluoroscopy-guided transthoracic biopsy technique can be used safely and successfully for lung masses. MR fluoroscopy can be used to reach the target lesion easily and accurately. 相似文献
90.
Omer Cakir Ahmet Oruc Sevval Eren Huseyin Buyukbayram Levent Erdinc Nesimi Eren 《European journal of cardio-thoracic surgery》2003,23(6):1040-1045
Objective: We hypothesized that direct pulmonary arterial infusion of sodium nitroprusside (SNP) would ameliorate lung injury under cardiopulmonary bypass. Methods: Experiments were performed on 12 adult mongrel dogs of both sexes weighing 20–28 kg. The animals were randomly divided into two groups of six animals each. All animals were subjected to total cardiopulmonary bypass (CPB) and moderate hypothermia (28°C core temperature). During total CPB, the aorta was clamped together with the pulmonary artery to prevent any antegrade flow to the lungs. After cardioplegic arrest for 120 min, the animals were rewarmed, weaned from CPB, and their condition stabilized for another 90 min. After the release of the aortic cross-clamp, the dogs received either a 5% glucose solution as a placebo (group I) or SNP (0.5 μg/kg per min) (group II), both infused into the pulmonary arterial line. The infusion was stopped after 60 min. To measure lung tissue malondialdehyde (MDA), water content and polymorphonuclear leukocytes count, lung tissue samples were taken before CPB and after weaning from CPB. In addition, alveolar-arterial oxygen difference (AaDO2) for tissue oxygenation was calculated by obtaining arterial blood gas samples. Results: Values of MDA before CPB of 42.0±5.3 nmol/g of tissue rose to 67.6±5.7 nmol/g of tissue after weaning from CPB in group I (P=0.028). In group II MDA values also increased from 43.1±4.3 to 52.4±5.7 nmol MDA/g of tissue after weaning from CPB (P=0.046). The MDA increase in group II after CPB was found to be significantly lower than that for group I (P=0.004). The wet-to-dry lung weight ratio in the sodium nitroprusside group was 5.1±0.2, significantly lower than in the control group (6.8±0.4), (P=0.01). AaDO2 increased significantly in group I (P=0.028). There was no statistically significant difference (P=0.065) between groups I and II. During histopathological examination it was observed that neutrophil counts in the lung parenchyma rose significantly after CPB in both groups. The increase in group I was significantly larger than that in group II (P<0.001). Conclusions: The results represented in our study indicate that pulmonary arterial infusion of sodium nitroprusside during reperfusion can reduce lung injury under cardiopulmonary bypass. 相似文献