全文获取类型
收费全文 | 2476篇 |
免费 | 146篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 17篇 |
儿科学 | 52篇 |
妇产科学 | 54篇 |
基础医学 | 361篇 |
口腔科学 | 21篇 |
临床医学 | 217篇 |
内科学 | 439篇 |
皮肤病学 | 93篇 |
神经病学 | 148篇 |
特种医学 | 195篇 |
外科学 | 390篇 |
综合类 | 30篇 |
预防医学 | 172篇 |
眼科学 | 29篇 |
药学 | 202篇 |
中国医学 | 1篇 |
肿瘤学 | 215篇 |
出版年
2022年 | 27篇 |
2021年 | 48篇 |
2020年 | 24篇 |
2019年 | 43篇 |
2018年 | 35篇 |
2017年 | 46篇 |
2016年 | 47篇 |
2015年 | 49篇 |
2014年 | 57篇 |
2013年 | 96篇 |
2012年 | 139篇 |
2011年 | 131篇 |
2010年 | 89篇 |
2009年 | 86篇 |
2008年 | 109篇 |
2007年 | 129篇 |
2006年 | 110篇 |
2005年 | 117篇 |
2004年 | 95篇 |
2003年 | 88篇 |
2002年 | 79篇 |
2001年 | 69篇 |
2000年 | 59篇 |
1999年 | 47篇 |
1998年 | 31篇 |
1997年 | 21篇 |
1996年 | 29篇 |
1995年 | 24篇 |
1994年 | 19篇 |
1993年 | 30篇 |
1992年 | 47篇 |
1991年 | 39篇 |
1990年 | 34篇 |
1989年 | 35篇 |
1988年 | 32篇 |
1987年 | 25篇 |
1986年 | 33篇 |
1985年 | 33篇 |
1984年 | 22篇 |
1983年 | 28篇 |
1982年 | 21篇 |
1981年 | 16篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1977年 | 18篇 |
1976年 | 17篇 |
1975年 | 20篇 |
1973年 | 12篇 |
1970年 | 12篇 |
1968年 | 16篇 |
排序方式: 共有2636条查询结果,搜索用时 0 毫秒
31.
32.
We report a case of central European tick-borne encephalitis with cervical myelitis presenting clinically as a lower motor
neuron syndrome of the upper limbs with proximal asymmetrical pareses and atrophies. There were no sensory deficits nor signs
of lesions of the spinal pathways or signs of encephalitis or meningitis. The affected motor fibers of the upper limbs were
electrically inexcitable, but sensory findings were normal. Electromyography of the paralyzed muscles revealed pathological
denervation activity without voluntary activation. The initial magnetic resonance imaging (MRI) showed a large hyperdense
lesion in the anterior part of the cervical cord from C3 to T1. Despite the fact that MRI changes disappeared completely within
6 weeks the patient showed only little improvement in the paralyzed muscles after 6 months. To our knowledge, these MRI changes
in patients with tick-borne encephalitis, consistent with an isolated anterior horn lesion, have never been reported previously.
The course may have been aggravated by an initial antibiotic treatment with cephalosporins.
Received: 4 May 1999 Received in revised form: 22 July 1999 Accepted: 26 July 1999 相似文献
33.
B Beer C A Klepner A S Lippa R F Squires 《Pharmacology, biochemistry, and behavior》1978,9(6):849-851
SQ 65,396, a clinically active anti-anxiety agent, enhanced the binding of 3H-diazepam at 1.5 nM. This effect was due to an increase in the affinity for the ligand, without a change in the number of 3H-diazepam binding sites. This action of SQ 65,396 may mediate its anti-anxiety effects by affecting the action of an endogenous modulator of the "benzodiazepine receptor." Several other substances and treatments increase the affinity of 3H-diazepam for its receptors by mechanisms which may be related to the effect produced by SQ 65,396. 相似文献
34.
35.
M. D'Incalci P. Farina C. Sessa C. Mangioni V. Conter G. Masera M. Rocchetti M. Brambilla Pisoni E. Piazza M. Beer F. Cavalli 《Cancer chemotherapy and pharmacology》1982,7(2-3):141-145
Summary Plasma pharmacokinetics of VP16-213 were investigated after a 30–60 min infusion in 14 adult patients and six children. In adults the elimination half-life (T1/2 ), plasma clearance (Clp) and volume of distribution (Vd) were respectively 7.05±0.67 h, 26.8±2.4 ml/min/m2, and 15.7±1.8 l/m2; in children 3.37±0.5 h, 39.34±6.6 ml/min/m2, and 9.97±3.7 l/m2. After repeated daily doses no accumulation of VP16-213 was found in plasma. The unchanged drug found in the 24 h urine after administration amounted to 20–30% of the dose.In eight choriocarcinoma patients plasma levels of VP16-213 were measured after oral capsules and drinkable ampoules. The bioavailability compared to the i.v. route was variable, mean values being 57% for capsules and 91% for ampoules. In one further patient, with abnormal d-Xylose absorption results, VP16-213 was not detectable in plasma after the oral ampoule dose.Steady state levels investigated in three patients after 72 h continuous VP16-213 infusion (100 mg/m2/24 h) were around 2–5 g/ml. Levels of VP16-213 were undetectable in CSF after i.v. or oral administration. 相似文献
36.
Time course of tumor metabolic activity during chemoradiotherapy of esophageal squamous cell carcinoma and response to treatment. 总被引:20,自引:0,他引:20
Hinrich A Wieder Bj?rn L D M Brücher Frank Zimmermann Karen Becker Florian Lordick Ambros Beer Markus Schwaiger Ulrich Fink J?rg Rüdiger Siewert Hubert J Stein Wolfgang A Weber 《Journal of clinical oncology》2004,22(5):900-908
PURPOSE: To evaluate the time course of therapy-induced changes in tumor glucose use during chemoradiotherapy of esophageal squamous cell carcinoma (ESCC) and to correlate the reduction of metabolic activity with histopathologic tumor response and patient survival. PATIENTS AND METHODS: Thirty-eight patients with histologically proven intrathoracic ESCC (cT3, cN0/+, cM0) scheduled to undergo a 4-week course of preoperative simultaneous chemoradiotherapy followed by esophagectomy were included. Patients underwent positron emission tomography with the glucose analog fluorodeoxyglucose (FDG-PET) before therapy (n = 38), after 2 weeks of initiation of therapy (n = 27), and preoperatively (3 to 4 weeks after chemoradiotherapy; n = 38). Tumor metabolic activity was quantitatively assessed by standardized uptake values (SUVs). Results Mean tumor FDG uptake before therapy was 9.3 +/- 2.8 SUV and decreased to 5.7 +/- 1.9 SUV 14 days after initiation of chemoradiotherapy (-38% +/- 18%; P <.0001). The preoperative scan showed an additional decrease of metabolic activity to 3.3 +/- 1.1 SUV (P <.0001). In histopathologic responders (< 10% viable cells in the resected specimen), the decrease in SUV from baseline to day 14 was 44% +/- 15%, whereas it was only 21% +/- 14% in nonresponders (P =.0055). Metabolic changes at this time point were also correlated with patient survival (P =.011). In the preoperative scan, tumor metabolic activity had decreased by 70% +/- 11% in histopathologic responders and 51% +/- 21% in histopathologic nonresponders. CONCLUSION: Changes in tumor metabolic activity after 14 days of preoperative chemoradiotherapy are significantly correlated with tumor response and patient survival. This suggests that FDG-PET might be used to identify nonresponders early during neoadjuvant chemoradiotherapy, allowing for early modifications of the treatment protocol. 相似文献
37.
Gene amplification in esophageal adenocarcinomas and Barrett's with high-grade dysplasia. 总被引:6,自引:0,他引:6
Charles T Miller Justin R Moy Lin Lin Matthew Schipper Daniel Normolle Dean E Brenner Mark D Iannettoni Mark B Orringer David G Beer 《Clinical cancer research》2003,9(13):4819-4825
PURPOSE: The purpose of this study was to determine the frequency and overall contribution of specific gene amplification events in the formation of Barrett's adenocarcinomas. The relationship of gene amplification to clinical-pathological variables and its potential usefulness as a marker for early cancer detection were also examined. EXPERIMENTAL DESIGN: We used quantitative PCR and Southern blot analysis to screen 87 cases of Barrett's adenocarcinoma for the presence or absence of 13 distinct gene amplification events. Gene amplification was then examined for correlation with other amplification events and clinical variables (survival, stage, nodal involvement, tumor invasion, smoking history, and gender). Additionally, 22 specimens of Barrett's with high-grade dysplasia (HGD) were examined for the presence of gene amplification. RESULTS: One or more amplification events were present in 50 of 87 (57%) adenocarcinomas. The ERBB2 gene was amplified in 19 of 87 (21.8%), CCNE1 in 11 of 87 (12.6%), GATA4 in 9 of 87 (10.3%), KRAS in 9 of 87 (10.3%), EGFR in 7 of 87 (8.0%), CCND1 in 6 of 87 (6.8%), HNF3alpha in 5 of 87 (5.7%), PIK3CA in 5 of 87 (5.7%), C-MYC in 4 of 87 (4.6%), DYRK2 in 2 of 87 (2.3%), and AIB1, AKT1, and IGF1R were amplified in 0 of 87 (0%) of the tumors. CCND1 amplification was found to correlate negatively with survival (P < 0.05). In addition, the ERBB2 amplicon positively correlated (P < 0.05) with GATA4 amplification. Increased copy number of the ERBB2 (1 of 22), GATA4 (1 of 22), KRAS (2 of 22), C-MYC (1 of 22), CCNE1 (2 of 22), and CCND1 (2 of 22) genes was also observed in one or more Barrett's adenocarcinomas with HGD. CONCLUSIONS: The high frequency of gene amplification in esophageal adenocarcinomas and HGD indicates the important role of these events in esophageal adenocarcinoma development. Additionally, these results underscore the possible usefulness of early detection approaches and chemotherapeutic strategies (ErbB2 and cyclin D1) targeted against amplified gene products. 相似文献
38.
Shebani KO Stucchi AF McClung JP Beer ER LaMorte WW Becker JM 《The Journal of surgical research》2000,90(1):67-75
BACKGROUND: Although ileal pouch-anal anastomosis has become the operation of choice for patients with chronic ulcerative colitis and familial adenomatous polyposis coli, ileal pouch inflammation or pouchitis remains a significant postoperative complication. Numerous factors such as fecal stasis have been implicated in the etiology of pouchitis; however, pouchitis remains poorly understood due to the lack of a small animal model. One of the primary goals of this study was to surgically create a reservoir or U-pouch in the ileum of a rat in which stasis would occur in a manner that was unimpeded by other complicating factors such as a colectomy. This model would allow investigation of the hypothesis that intestinal stasis leads to biochemical changes that predispose the ileal pouch to inflammation and oxidative stress. MATERIALS AND METHODS: A U-pouch was surgically created in the terminal ileum of Lewis rats just proximal to the ileocecal valve without a colectomy. Stasis was assessed by serial barium radiographs over 48 h. Thirty days after surgery, mucosa was obtained from the ileal U-pouches and nonoperated ileum to assess inflammation and neutrophil infiltration histologically and by measuring myeloperoxidase activity. Oxidative stress was assessed by measuring 8-isoprostane levels in urine. Once the model was validated and it was established that stasis and inflammation occurred in the pouch, either vitamin E or allopurinol was administered for 30 days after which myeloperoxidase and 8-isoprostane levels were again measured. RESULTS: In our experimental model, ileal stasis resulted in increases in both mucosal myeloperoxidase activity and urinary 8-isoprostane levels, suggesting that oxidative stress was associated with stasis. Thirty-day treatment with vitamin E or allopurinol reduced ileal myeloperoxidase activity and urinary 8-isoprostane levels. CONCLUSION: These studies demonstrated that stasis in the ileum occurred and was associated with neutrophil infiltration and oxidative stress. Antioxidant treatment reduced the inflammatory response suggesting a role for antioxidant therapy in the treatment of pouchitis. 相似文献
39.
This paper describes 130 patients with enteroceles and their treatment. It includes analysis of all cases with enterocele over a 17-month period in a pelvic floor dysfunction database. Procedures performed included the Moschcowitz procedure with suspension of the vaginal vault to the sacrum in 13 patients (10%), colposacrosuspension (CSS) (mesh from the upper posterior half of the vagina to the sacrum with mobilisation and fixation of the rectum to the mesh) in 39 patients (30%), perineocolposacrosuspension (PCSS) (similar to CSS, but the mesh is inserted further down to the perineum) in 48 patients (37%) and perineopubo-colposacrosuspension (PPCSS) (as PCSS, but with a second mesh between the bladder and vagina extending to the sacrum) in 30 patients (23%). An additional modified Burch colposuspension was performed in 87 patients (67%). A failure was defined as a recurrent vaginal prolapse of Grade II or more, or urinary incontinence requiring surgical correction. The patients' mean age was 60.5 years, their mean parity 3.3 and 92.3% were white. Preoperatively, 33.8% of the patients complained of constipation, 33.1% of difficulty in defaecation and 77% had bladder symptoms, suggesting urinary stress incontinence or detrusor instability. In 74.6% of the patients part of the vagina protruded through the vaginal introitus. The mean period of follow-up was 7.4 months (range 1-26) with only 13 patients (10%) not followed. Only two patients (1.5%) developed Grade II vaginal prolapse (both cystoceles and both from the PCSS group). Urinary stress incontinence in need of further treatment developed in 13 patients (10%). The failure rate, therefore, was 11.5%. In six patients (4.6%) the mesh had to be removed due to mesh reaction. In all cases the mesh was unabsorbable. Vaginal suspension procedures with mobilisation of the rectum provided satisfactory results for severe enterocele over the short term. 相似文献
40.