全文获取类型
收费全文 | 261960篇 |
免费 | 47485篇 |
国内免费 | 501篇 |
专业分类
耳鼻咽喉 | 4030篇 |
儿科学 | 10164篇 |
妇产科学 | 5741篇 |
基础医学 | 40126篇 |
口腔科学 | 9579篇 |
临床医学 | 26398篇 |
内科学 | 63546篇 |
皮肤病学 | 12424篇 |
神经病学 | 28363篇 |
特种医学 | 6419篇 |
外国民族医学 | 31篇 |
外科学 | 36285篇 |
综合类 | 1143篇 |
一般理论 | 121篇 |
预防医学 | 24625篇 |
眼科学 | 4856篇 |
药学 | 18503篇 |
1篇 | |
中国医学 | 1525篇 |
肿瘤学 | 16066篇 |
出版年
2023年 | 1005篇 |
2022年 | 1682篇 |
2021年 | 5166篇 |
2020年 | 6926篇 |
2019年 | 14175篇 |
2018年 | 14703篇 |
2017年 | 14072篇 |
2016年 | 14759篇 |
2015年 | 15038篇 |
2014年 | 16245篇 |
2013年 | 19309篇 |
2012年 | 15497篇 |
2011年 | 15789篇 |
2010年 | 15060篇 |
2009年 | 10663篇 |
2008年 | 11931篇 |
2007年 | 11393篇 |
2006年 | 11212篇 |
2005年 | 11043篇 |
2004年 | 10400篇 |
2003年 | 9766篇 |
2002年 | 9419篇 |
2001年 | 6176篇 |
2000年 | 6214篇 |
1999年 | 5003篇 |
1998年 | 1604篇 |
1997年 | 1141篇 |
1996年 | 1096篇 |
1995年 | 953篇 |
1994年 | 810篇 |
1993年 | 738篇 |
1992年 | 2385篇 |
1991年 | 2262篇 |
1990年 | 2087篇 |
1989年 | 1869篇 |
1988年 | 1693篇 |
1987年 | 1652篇 |
1986年 | 1546篇 |
1985年 | 1493篇 |
1984年 | 1159篇 |
1983年 | 1010篇 |
1979年 | 1072篇 |
1978年 | 735篇 |
1975年 | 723篇 |
1974年 | 928篇 |
1973年 | 878篇 |
1972年 | 770篇 |
1971年 | 703篇 |
1970年 | 753篇 |
1969年 | 711篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Raúl González-García Francisco J Rodríguez-Campo Verónica Escorial-Hernández Mario F Mu?oz-Guerra Jesús Sastre-Pérez Luis Naval-Gías José L Gil-Díez Usandizaga 《Journal of oral and maxillofacial surgery》2006,64(11):1587-1591
PURPOSE: Temporomandibular joint (TMJ) arthroscopy has been considered a safe surgical procedure in the treatment of TMJ derangement. However, it is not exempt from complications. This study evaluates the complications of arthroscopy in patients with internal derangement of TMJ. PATIENTS AND METHODS: Five hundred consecutive patients (670 joints) with TMJ derangement who underwent arthroscopy between 1995 and 2004 were retrospectively analyzed. All the patients were classified as II to V in the Wilkes classification. Lysis and lavage, electrocautery of the posterior ligament, injection of corticoids, injection of ethanolamine, myotomy of lateral pterygoid muscle attachments, myotomy and electrocautery, motor debridement, injection of sodium hyaluronate, and meniscal suture were performed in different patients. RESULTS: Complications were recognized during or immediately after the surgery. They were observed in 5 of 341 (1.26%) arthroscopies of the right TMJ and 4 of 329 (1.21%) arthroscopies of the left TMJ. A 1.34% complication rate was found in the whole series. No blood clots within the external auditory canal were observed. Bleeding within the superior TMJ space was observed in 57 cases (8.5%), 36 of them in the right TMJ and 21 in the left TMJ, but they were not considered as true complications. Lacerations of the external auditory canal were found in 2 cases (0.3%), with no cases of perforation of the tympanic membrane. Lesion of the auriculotemporal nerve was observed in a case. Paresia of the facial nerve was found in 4 cases (0.6%). Alteration of visual accuracy of the ipsilateral eye was also observed in a patient immediately after the surgery. CONCLUSION: Special care must be taken to reduce complications within the upper joint space by means of an adequate instrumentation and by paying attention to essential points of the arthroscopic technique. 相似文献
102.
Henry Ho‐Lung Chan 《Clinical & experimental optometry》2005,88(6):410-414
The first‐order kernel analysis in multifocal electroretinogram (mfERG) using low contrast stimulation is suggested as a way to detect the inner retinal responses in animal studies. In this case report, this protocol is applied to human patients with glaucoma to demonstrate the possibility of using mfERG as a tool to detect glaucomatous damage. Two patients with glaucoma were recruited and had mfERG measurements with the 103‐scaled hexagonal stimulus pattern at low (50 per cent) contrast. Their responses were analysed and compared with those from normal subjects with the mfERG measured under the same condition. In the normal subjects, there were obvious oscillatory components on the ascending and descending limbs of the first‐order kernel response to 50 per cent contrast. In the glaucomatous patients, the oscillatory component on the descending limb was obviously diminished. In addition, this component was significantly diminished in the quadrant with a glaucomatous visual field defect. This suggests that the low‐contrast stimulation condition in mERG measurement may provide a good way to detect glaucomatous damage and this may help in clinical diagnosis of glaucoma. 相似文献
103.
Henyse G V Silva Rosangela P Tórtora Maria Lucia F Farias 《Gynecological endocrinology》2005,21(3):174-179
To evaluate the impact of pregnancy on bone, we studied bone turnover at the first (T1) and third (T3) trimester of gestation in 58 adolescents and 28 healthy adolescents who had never been pregnant. Total body (TB) and lumbar spine (LS) bone mineral density (BMD) and body composition were evaluated by dual-energy X-ray absorptiometry in all control patients (C) and after parturition in 28 pregnant patients (G). Paired and unpaired t tests, Mann-Whitney and Pearson correlation tests were used. Bone turnover markers were above the reference range for adult women in more than 80% of the adolescents, with no difference between C and G patients at T1. Increase in urinary N-telopeptide crosslinks of type I collagen and serum bone-specific alkaline phosphatase, markers of bone turnover, was seen during pregnancy ( p < 0.0001). Body composition did not differ between groups, but LS BMD, percentage of expected LS BMD, LS Z-score, percentage of expected TB BMD and TB Z-score were lower in G than C patients ( p < 0.05). TB BMD was positively correlated with LS BMD (r2 = 0.52). The inverse correlations between bone markers and LS BMD suggest that the increased bone turnover during pregnancy probably explains the low bone density after parturition. The impact on future peak bone mass must be studied. 相似文献
104.
A case of a pedunculated arachnoid cyst within the third ventricle is presented. The cyst was small so as not to appear as a significant expanding lesion on CT. The clinical history, however, suggested intermittent increase of the intracranial pressure. On CT there was some widening of the lateral and third ventricles, while the fourth ventricle had normal width. This finding in combination with the clinical history prompted further neuroradiologic examinations, including pneumoencephalography and ventriculography. The presence of a pedunculated mobile cystic lesion within the third ventricle was shown and its nature further elucidated by stereotactic puncture combined with contrast injection into the cyst. After emptying of the cyst, the patient has been free of symptoms during an observation time of 2 years. The diagnostic and differential diagnostic aspects are discussed and the value of traditional neuroradiologic methods emphasized. 相似文献
105.
106.
J Vargas-Barrón A Andrade-Freire J C Ramírez E Waisser J Martínez-Sánchez 《Archivos del Instituto de Cardiología de México》1989,59(2):121-124
The purpose of this study is to determine the importance of two-dimensional echocardiography performed soon after admission to the coronary care unit to provide useful information concerning wall-motion abnormalities, and to detect and characterize left ventricular thrombi. A major goal is to identify a subgroup of patients with acute myocardial infarction who are at risk for systemic embolization; in this subgroup the benefits of anticoagulation treatment would theoretically outweigh the associated risks. We studied 7 consecutive male patients, age range from 32 to 60 years, with acute myocardial infarction. Five patients had antero-septal infarction, 1 anterolateral and another had anterior wall infarction. We performed two-dimensional echocardiography within the first week after admission. All patients had severe apical-wall-motion abnormalities (akinesis or dyskinesis) and left ventricular thrombi. All patients received anticoagulation therapy. Two-dimensional echocardiography, performed one month after the first study, showed that the thrombi had decreased in size in 6 patients and could not be visualized in 1 patient. The noninvasive nature of echocardiography allows serial evaluations of patients with known left ventricular thrombi and permits assessment of the effect of therapy. 相似文献
107.
E. Wieczerzak E. Jankowska S. Rodziewicz‐Motowido A. Giedo J. giewka Z. Grzonka M. Abrahamson A. Grubb D. Brmme 《Chemical biology & drug design》2005,66(Z1):1-11
Abstract: We have designed and synthesized a new series of azapeptides which act as potential inhibitors of cathepsin B and/or cathepsin K. Their structures are based upon the inhibitory sites of natural cysteine protease inhibitors, cystatins. For the synthesized azapeptides, the equilibrium constants for dissociation of inhibitor–enzyme complex, Ki, were determined. Comparison of these values indicated that all of the azainhibitors act much stronger toward cathepsin B. Z‐Arg‐Leu‐His‐Agly‐Ile‐Val‐OMe ( 7 ) proved to be approximately 500 times more potent for cathepsin B than for cathepsin K. To be able to explain the obtained experimental values we used the molecular dynamics procedures to analyze the interactions between cathepsin B and compound 7 . We also determined the structure of the most potent and selective cathepsin B azainhibitor by means of NMR studies and theoretical calculations. In this report, we describe SAR studies of azapeptide inhibitors indicating the influence of the conformational flexibility of the examined compounds on inhibition of cathepsins B and K. 相似文献
108.
109.
Effect of impact exercise on bone mineral density in elderly women with low BMD: a population-based randomized controlled 30-month intervention 总被引:4,自引:3,他引:1
Raija Korpelainen Sirkka Keinänen-Kiukaanniemi Jorma Heikkinen Kalervo Väänänen Juha Korpelainen 《Osteoporosis international》2006,17(1):109-118
Evidence of the effect of exercise on bone loss comes mainly from studies in voluntary postmenopausal women, and no population-based, long-term interventions have been performed. The purpose of this population-based, randomized, controlled trial was to determine the effect of long-term impact exercise on bone mass at various skeletal sites in elderly women with low bone mineral density (BMD) at the radius and hip. Participants ( n =160) were randomly assigned to 30 months either of supervised and home-based impact exercise training or of no intervention. The primary outcome measures were femoral neck, trochanter and total hip BMD, and the secondary outcomes were bone density measures at the radius and calcaneum. Outcomes were assessed at baseline, 12 months and 30 months using blinded operators. The analyses were performed on an intention-to-treat analysis. Mean femoral neck and trochanter BMD decreased in the control group [–1.1%, 95% confidence interval (CI) –0.1% to –2.1% and –1.6%, 95% CI –0.4% to –2.7%], while no change occurred in the exercise group. Mean trochanter BMC decreased more in the control group (–7.7%, 95% CI –9.7% to –5.6% vs. –2.9%, 95% CI –5.3 to –0.9). There were six falls that resulted in fractures in the exercise group and 16 in the control group during the 30-month intervention ( P =0.019). A significant bone loss occurred in both groups at the radius and calcaneum. In multivariate analysis, weight gain was associated with increased BMD and BMC at all femur sites both in the exercise group and in the pooled groups. In conclusion, impact exercise had no effect on BMD, while there was a positive effect on BMC at the trochanter. Exercise may prevent fall-related fractures in elderly women with low bone mass.There was no conflict of interest. 相似文献
110.