全文获取类型
收费全文 | 861505篇 |
免费 | 71532篇 |
国内免费 | 1838篇 |
专业分类
耳鼻咽喉 | 12808篇 |
儿科学 | 24632篇 |
妇产科学 | 25115篇 |
基础医学 | 124310篇 |
口腔科学 | 25487篇 |
临床医学 | 75353篇 |
内科学 | 164587篇 |
皮肤病学 | 16979篇 |
神经病学 | 70116篇 |
特种医学 | 35200篇 |
外国民族医学 | 171篇 |
外科学 | 136245篇 |
综合类 | 24611篇 |
现状与发展 | 2篇 |
一般理论 | 263篇 |
预防医学 | 66887篇 |
眼科学 | 20526篇 |
药学 | 64698篇 |
中国医学 | 1602篇 |
肿瘤学 | 45283篇 |
出版年
2018年 | 7342篇 |
2015年 | 7729篇 |
2014年 | 11123篇 |
2013年 | 16799篇 |
2012年 | 22736篇 |
2011年 | 23867篇 |
2010年 | 13880篇 |
2009年 | 13077篇 |
2008年 | 22583篇 |
2007年 | 24631篇 |
2006年 | 24512篇 |
2005年 | 24146篇 |
2004年 | 23706篇 |
2003年 | 22846篇 |
2002年 | 21943篇 |
2001年 | 35827篇 |
2000年 | 36470篇 |
1999年 | 30903篇 |
1998年 | 9224篇 |
1997年 | 8548篇 |
1996年 | 8476篇 |
1995年 | 8011篇 |
1994年 | 7723篇 |
1992年 | 26664篇 |
1991年 | 26104篇 |
1990年 | 25622篇 |
1989年 | 24684篇 |
1988年 | 23224篇 |
1987年 | 22889篇 |
1986年 | 21749篇 |
1985年 | 21101篇 |
1984年 | 16387篇 |
1983年 | 13998篇 |
1982年 | 8855篇 |
1981年 | 8203篇 |
1980年 | 7675篇 |
1979年 | 16745篇 |
1978年 | 12119篇 |
1977年 | 10181篇 |
1976年 | 9331篇 |
1975年 | 10148篇 |
1974年 | 12642篇 |
1973年 | 12138篇 |
1972年 | 11538篇 |
1971年 | 10686篇 |
1970年 | 10219篇 |
1969年 | 9912篇 |
1968年 | 8900篇 |
1967年 | 8230篇 |
1966年 | 7654篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
961.
962.
963.
Christopher D Gardner James L Zehnder Alison J Rigby Joel R Nicholus John W Farquhar 《Blood coagulation & fibrinolysis》2007,18(8):787-793
Several case reports have implicated Ginkgo biloba in clinically adverse bleeding disorders. Ginkgo biloba has been reported to increase pain-free walking distance among patients with peripheral artery disease (PAD). Standard PAD therapy includes 325 mg/day aspirin. The objective of this study was to examine potential adverse effects of concomitant aspirin and Ginkgo biloba on platelet function. Ginkgo biloba (EGb 761, 300 mg/day) was compared with placebo for effects on measures of platelet aggregation among adults consuming 325 mg/day aspirin in a randomized, double-blind, placebo-controlled, parallel design trial of 4-week duration. Participants were adults, age 69 +/- 10 years, with PAD or risk factors for cardiovascular disease. Outcome measures included platelet function analysis (PFA-100 analyzer) using ADP as an agonist (n = 26 placebo; n = 29 ginkgo), and platelet aggregation using ADP, epinephrine, collagen and ristocetin as agonists (n = 21 placebo; n = 23 ginkgo). Participants kept daily logs of bleeding or bruising episodes. There were no clinically or statistically significant differences between treatment groups for any agonists, for either PFA-100 analysis or platelet aggregation. Reports of bleeding or bruising were infrequent and similar for both study groups. In conclusion, in older adults with PAD or cardiovascular disease risk, a relatively high dose of Ginkgo biloba combined with 325 mg/day daily aspirin did not have a clinically or statistically detectable impact on indices of coagulation examined over 4 weeks, compared with the effect of aspirin alone. No adverse bleeding events were observed, although the trial was limited to a small sample size. 相似文献
964.
Marcelo W. Hinojosa Zuri A. Murrell Viken R. Konyalian Steven Mills Ninh T. Nguyen Michael J. Stamos 《Journal of gastrointestinal surgery》2007,11(11):1423-1430
Few studies have examined outcomes of laparoscopic and open sigmoid colectomy performed at US academic centers. Using ICD-9
diagnosis and procedural codes, data was obtained from the University HealthSystem Consortium (UHC) Clinical Database of 10,603
patients who underwent laparoscopic or open sigmoid colectomy for benign and malignant disease between 2003–2006. A total
of 1,092 patients (10.3%) underwent laparoscopic sigmoid colectomy. Laparoscopic sigmoid colectomy was associated with a significantly
shorter length of stay (5.4 vs 7.4 days), lower overall complication rate (19.7 vs 26.0%), lower 30-day readmission rate (3.4
vs 4.6), and a lower hospital cost ($13,814 vs $15,626). When a subset analysis of malignant and benign groups was performed,
a significantly shorter length of stay in both the malignant laparoscopic group (6.4 ± 6.4 vs 7.8 ± 6.6 days) and in the benign
laparoscopic groups (5.1 ± 3.5 vs 7.2 ± 7.6) exists. A lower wound complication rate (2.1 vs 5.5%, malignant and 4.0 vs 6.1,
benign) is also evident. Laparoscopic sigmoid colectomy was associated with a shorter length of stay, less complications,
and a lower 30-day readmission rate. The shorter length of stay and wound infection rate maintain significance when comparing
laparoscopic vs open sigmoid resections for malignant and benign disease.
Presented at the 48th annual meeting of the Society for Surgery of the Alimentary Tract at Digestive Disease Weak, Washington,
DC, May 21st 2007.
The information contained in this article was based on the Clinical Data Base provided by the University HealthSystem Consortium. 相似文献
965.
BACKGROUND: Studies have shown that alcoholics have smaller brain volumes than non-alcoholic cohorts, but an effect of family history (FH) of heavy drinking on brain volume has not been demonstrated. We examined the relationship between an FH of heavy drinking and both brain shrinkage as measured by the ratio of brain volumes to intracranial volume (ICV) as well as maximal brain growth as measured by ICV in early-onset and late-onset alcoholics. METHODS: With T1-weighted resonance imaging, we measured ICV, brain volume, and white and gray matter volume in adult treatment-seeking late-onset and early-onset alcoholics with either a positive or a negative FH of heavy alcohol use, and in healthy control subjects. We also calculated brain shrinkage using a ratio of soft tissue volumes to ICV. RESULTS: The FH positive alcoholic patients had significantly smaller ICVs than FH negative patients, suggesting smaller premorbid brain growth. Brain shrinkage did not correlate with FH. Late-onset alcoholics showed a greater difference in ICV between FH positive and FH negative patients than early-onset alcoholics. Late-onset FH positive patients also had significantly lower IQ scores than late-onset FH negative patients, and IQ scores were correlated with ICV. CONCLUSIONS: These data provide evidence that parental alcohol use might increase risk for alcoholism in offspring in part by a genetic and/or environmental effect that might be related to reduced brain growth. 相似文献
966.
Introduction Facial nerve paralysis can be a disabling condition functionally, psychologically and aesthetically. When there has been an acquired proximal injury to the facial nerve in the presence of previously functional facial musculature, such as in acoustic neuroma surgery, neurotisation of the distal facial nerve is an appropriate choice of management. The hypoglossal nerve is most commonly used. However this is not without its limitations, notably subsequent hemilingual atrophy and facial synkinesis. We present an alternative technique of facial reinnervation utilising a motor branch of the trigeminal nerve, the nerve to masseter. We believe this technique has the potential to overcome problems encountered with use of other extra‐facial nerves. Methods Three patients with acquired facial nerve palsy following tumour resection underwent transfer of the ipsilateral masseteric nerve to facial nerve. In two patients the nerve was directly coapted to the trunk of the facial nerve while the third patient had transfer to the buccal branch. Results By twelve months postoperatively all three patients demonstrated significant improvement in facial muscle tone and symmetry at rest. All patients were able to produce a symmetrical smile with minimal synkinesis. Two of the three patients also had evidence of occasional spontaneous movements. Conclusion Use of the ipsilateral motor nerve to masseter offers an alternative technique for neurotisation of the facial nerve. The advantages of this technique include ease of dissection, constant and reliable anatomy, powerful innervation of the facial muscles, minimal donor site morbidity and the potential for return of spontaneous facial movements. 相似文献
967.
Understanding the minimum clinically important difference: a review of concepts and methods. 总被引:2,自引:0,他引:2
Anne G Copay Brian R Subach Steven D Glassman David W Polly Thomas C Schuler 《The spine journal》2007,7(5):541-546
BACKGROUND CONTEXT: The effectiveness of spinal surgery as a treatment option is currently evaluated through the assessment of patient-reported outcomes (PROs). The minimum clinically important difference (MCID) represents the smallest improvement considered worthwhile by a patient. The concept of an MCID is offered as the new standard for determining effectiveness of a given treatment and describing patient satisfaction in reference to that treatment. PURPOSE: Our goal is to review the various definitions of MCID and the methods available to determine MCID. STUDY DESIGN: The primary means of determining the MCID for a specific treatment are divided into anchor-based and distribution-based methods. Each method is further subdivided and examined in detail. METHODS: The overall limitations of the MCID concept are first identified. The basic assumptions, statistical biases, and shortcomings of each method are examined in detail. RESULTS: Each method of determining the MCID has specific shortcomings. Three general limitations in the accurate determination of an MCID have been identified: the multiplicity of MCID determinations, the loss of the patient's perspective, and the relationship between pretreatment baseline and posttreatment change scores. CONCLUSIONS: An ideal means of determining the MCID for a given intervention is yet to be determined. It is possible to develop a useful method provided that the assumptions and methodology are initially declared. Our efforts toward the establishment of a MCID will rely on the establishment of specific external criteria based on the symptoms of the patient and treatment intervention being evaluated. 相似文献
968.
Fractures of the calcaneus generally occur in the event of high-energy trauma, resulting in complex, three-dimensionally oriented fracture patterns. Surgical management is generally indicated for displaced intra-articular fractures, which allows restoration of calcaneal height, width and overall morphology, in addition to the posterior facet articular surface where possible, and allows for a late in situ arthrodesis as a means of salvage in the event of posttraumatic arthritis. What follows is a brief discussion of our preferred methods in the diagnosis and management of calcaneal fractures. 相似文献
969.
J.D. Schold T.R. Srinivas G. Guerra A.I. Reed R.J. Johnson I.D. Weiner R. Oberbauer J.S. Harman A.W. Hemming H.U. Meier-Kriesche 《American journal of transplantation》2007,7(3):550-559
Research suggests that end-stage renal disease patients with elevated body mass index (BMI) have superior outcomes on dialysis. In contrast, low and high BMI patients represent the highest risk cohorts for kidney transplant recipients. The important question remains concerning how to manage transplant candidates given the potentially incommensurate impact of BMI by treatment modality. We conducted a retrospective analysis of waitlisted and transplanted patients in the United States from 1990 to 2003. We constructed Cox models to evaluate the effect of BMI on mortality of waitlisted candidates and identified risk factors for rapid weight change. We then assessed the impact of weight change during waitlisting on transplant outcomes. Decline in BMI on the waiting list was not protective for posttransplant mortality or graft loss across BMI strata. Substantial weight loss pretransplantation was associated with rapid gain posttransplantation. The highest risk for death was among listed patients with low BMI (13-20 kg/m(2), adjusted hazard ratio = 1.47, p < 0.01). Approximately one-third of candidates had a change in BMI category prior to transplantation. While observed declines in BMI may be volitional or markers of disease processes, there is no evidence that candidates have improved transplant outcomes attributable to weight loss. Prospective trials are needed to evaluate the efficacy of weight loss protocols for candidates of kidney transplantation. 相似文献
970.
G. Y. Meyer‐Rochow A. J. Gill L. W. Delbridge S. B. Sidhu M. S. Sywak 《ANZ journal of surgery》2007,77(Z1):A22-A22
Purpose Parathyroid carcinoma (PC) is rare and accounts for less than 1% of all cases of primary hyperparathyroidism (PHPT). The definitive histopathologic diagnosis of PC requires unequivocal invasion or metastasis which may be absent at first presentation. As a result, many cases of PC can only be diagnosed retrospectively. Parafibromin is the protein encoded by HRPT2 which is mutated and not expressed in many parathyroid carcinomas. Given that PCs generally weigh more than parathyroid adenomas (PA)s, we hypothesized that amongst large PAs there may be a high incidence of occult PC which could be identified by negative staining for parafibromin. Methodology 57 parathyroid glands weighing greater than 2 grams excised from 1998–2006 were identified from the University of Sydney Endocrine Surgical Database. Two specimens with a histopathologic diagnosis of PC were excluded. Immunohistochemical staining for parafibromin was performed on the remaining 55 PAs. Results Of the 55 specimens stained for parafibromin only one definite negative stain was detected. This case was originally classified as an “atypical adenoma” because it showed nuclear and architectural atypia without unequivocal evidence of invasive growth. In view of the negative staining for parafibromin it therefore probably represents occult carcinoma. There has been no evidence of recurrence or metastasis after 6.5 years. Conclusions Complete loss of staining for parafibromin is very rare in giant parathyroid adenomas suggesting that occult carcinoma is equally rare. As a result routine immunohistochemical staining for parafibromin does not appear to be an effective screening test for carcinoma in large PA without histopathologic features of PC. 相似文献