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   2192篇
  免费   112篇
  国内免费   21篇
耳鼻咽喉   38篇
儿科学   66篇
妇产科学   99篇
基础医学   210篇
口腔科学   35篇
临床医学   139篇
内科学   506篇
皮肤病学   22篇
神经病学   145篇
特种医学   132篇
外科学   538篇
综合类   31篇
一般理论   1篇
预防医学   94篇
眼科学   24篇
药学   105篇
中国医学   17篇
肿瘤学   123篇
  2023年   21篇
  2022年   35篇
  2021年   88篇
  2020年   50篇
  2019年   57篇
  2018年   72篇
  2017年   56篇
  2016年   64篇
  2015年   87篇
  2014年   118篇
  2013年   134篇
  2012年   161篇
  2011年   167篇
  2010年   112篇
  2009年   83篇
  2008年   125篇
  2007年   148篇
  2006年   156篇
  2005年   122篇
  2004年   100篇
  2003年   86篇
  2002年   84篇
  2001年   12篇
  2000年   12篇
  1999年   19篇
  1998年   18篇
  1997年   11篇
  1996年   7篇
  1995年   3篇
  1994年   2篇
  1993年   4篇
  1992年   3篇
  1991年   8篇
  1990年   9篇
  1989年   12篇
  1988年   5篇
  1987年   11篇
  1986年   7篇
  1985年   4篇
  1984年   6篇
  1983年   11篇
  1982年   8篇
  1981年   4篇
  1980年   4篇
  1979年   7篇
  1978年   5篇
  1977年   3篇
  1975年   1篇
  1970年   1篇
  1961年   1篇
排序方式: 共有2325条查询结果,搜索用时 15 毫秒
71.
BACKGROUND: Receptor-binding cancer antigen expressed on SiSo cells (RCAS1) is a novel tumour marker that has been described in various kinds of cancer. The majority of observations include immunohistochemical studies; however, there are not enough data about the utility of this antigen as a serum tumour marker and its tumour specificity. AIM: To measure the serum levels of RCAS1 in patients with gastrointestinal (GI) tract cancers and compare them with other GI tract tumour markers. PATIENTS AND METHODS: Sera collected from patients with GI cancers (14 esophagus, 32 gastric and 36 colon) and from healthy volunteers (30 individuals) were analyzed for RCAS1 and compared with carcinoembryonic antigen (CEA) and cancer antigen 19-9. The relationship between serum RCAS1, tumour stage and tumour grade was also evaluated. RESULTS: Mean serum RCAS1 level was higher in patients with GI tract cancers compared with the control group (P=0.001). Among GI tract cancers, RCAS1 had lowest and highest sensitivity for esophagus and colon cancer diagnosis, respectively. Serum RCAS1 had a higher sensitivity for malignancy, except in the colon, and lower specificity in all groups compared with CEA. In comparison with cancer antigen 19-9, serum RCAS1 was more sensitive but less specific for all GI cancer groups. Mean serum RCAS1 levels were not statistically significant among histopathological tumour types (P>0.05). Although serum RCAS1 levels were significantly higher in cases with lymph node involvement compared with lymph node-negative cases (P=0.009), there was no difference between cases with and without serosal involvement, vascular invasion and distant metastasis; no correlation was found between tumour size and RCAS1 levels. CONCLUSIONS: RCAS1 may be used and combined with CEA as a tumour marker in GI tract cancers.  相似文献   
72.

Background

This paper presents results from a public engagement effort in Nebraska, USA, which measured public opinions about governmental involvement in encouraging the use of electronic health records (EHRs).

Objective

We examine the role of trust in government in contributing to public support for government involvement in the development of EHR technologies. We hypothesize that trust in government will lead to support for federal and state governmental encouragement of the use of EHRs among doctors and insurance companies. Further, because individual experiences with health‐care professionals will reduce perceptions of risk, we expect that support for governmental involvement will be tempered by greater personal experience with the health‐care industry.

Design and Results

Examining a small survey of individuals on the issue, we find general support for both of our hypotheses. The findings suggest that trust in government does have a positive relationship with support for government involvement in the policy domain, but that the frequency of personal experiences with health‐care providers reduces the extent to which the public supports governmental involvement in the development of EHR technology.

Discussion and Conclusion

This inquiry contributes to our understanding of public attitudes towards government involvement in EHRs in the United States specifically and contributes to social science examining links between trust in government and support for governmental activity in the emerging policy domain regarding electronic health records systems.  相似文献   
73.

Background

Although ischemic stroke is a well-known complication of cardiovascular surgery it has not been extensively studied in patients undergoing noncardiac surgery. The aim of this study was to assess the predictors and outcomes of perioperative acute ischemic stroke (PAIS) in patients undergoing noncardiothoracic, nonvascular surgery (NCS).

Methods

We prospectively evaluated patients undergoing NCS and enrolled patients older than 18 years who underwent an elective, non-daytime, open surgical procedure. Electrocardiography and cardiac biomarkers were obtained 1 day before surgery, and on postoperative days 1, 3 and 7.

Results

Of the 1340 patients undergoing NCS, 31 (2.3%) experienced PAIS. Only age (odds ratio [OR] 2.5, 95% confidence interval [CI] 1.01–3.2, p < 0.001) and preoperative history of stroke (OR 3.6, 95% CI 1.2–4.8, p < 0.001) were independent predictors of PAIS according to multivariate analysis. Patients with PAIS had more cardiovascular (51.6% v. 10.6%, p < 0.001) and noncardiovascular complications (67.7% v. 28.3%, p < 0.001). In-hospital mortality was 19.3% for the PAIS group and 1% for those without PAIS (p < 0.001).

Conclusion

Age and preoperative history of stroke were strong risk factors for PAIS in patients undergoing NCS. Patients with PAIS carry an elevated risk of perioperative morbidity and mortality.  相似文献   
74.
75.
International Journal of Colorectal Disease - Post-operative pain following excisional haemorrhoidectomy poses a particular challenge for patient recovery, as well as a burden on hospital...  相似文献   
76.
Background: Most studies that have assessed impacts on mortality of future temperature increases have relied on a small number of simulations and have not addressed the variability and sources of uncertainty in their mortality projections.Objectives: We assessed the variability of temperature projections and dependent future mortality distributions, using a large panel of temperature simulations based on different climate models and emission scenarios.Methods: We used historical data from 1990 through 2007 for Montreal, Quebec, Canada, and Poisson regression models to estimate relative risks (RR) for daily nonaccidental mortality in association with three different daily temperature metrics (mean, minimum, and maximum temperature) during June through August. To estimate future numbers of deaths attributable to ambient temperatures and the uncertainty of the estimates, we used 32 different simulations of daily temperatures for June–August 2020–2037 derived from three global climate models (GCMs) and a Canadian regional climate model with three sets of RRs (one based on the observed historical data, and two on bootstrap samples that generated the 95% CI of the attributable number (AN) of deaths). We then used analysis of covariance to evaluate the influence of the simulation, the projected year, and the sets of RRs used to derive the attributable numbers of deaths.Results: We found that < 1% of the variability in the distributions of simulated temperature for June–August of 2020–2037 was explained by differences among the simulations. Estimated ANs for 2020–2037 ranged from 34 to 174 per summer (i.e., June–August). Most of the variability in mortality projections (38%) was related to the temperature–mortality RR used to estimate the ANs.Conclusions: The choice of the RR estimate for the association between temperature and mortality may be important to reduce uncertainty in mortality projections.Citation: Benmarhnia T, Sottile MF, Plante C, Brand A, Casati B, Fournier M, Smargiassi A. 2014. Variability in temperature-related mortality projections under climate change. Environ Health Perspect 122:1293–1298; http://dx.doi.org/10.1289/ehp.1306954  相似文献   
77.

Introduction and hypothesis

Little information is available on the effects of concomitant vaginal prolapse repair on the outcomes of the transobturator tape (TOT) procedure. The purpose of this study is to assess the results and complications of TOT when combined with vaginal prolapse repair with a long-term follow-up.

Methods

We conducted a retrospective cohort study of 232 female patients who underwent the TOT procedure at two institutions. There were two groups: group 1 consisted of patients who had undergone TOT alone and group 2 consisted of patients who had undergone concomitant vaginal prolapse repair. The outcomes were analyzed considering four postoperative parameters: objective cure, subjective cure, resolution of urgency urinary incontinence (UUI), and patient satisfaction. The mean follow-up was 66.3 months (range 60–85).

Results

A total of 117 patients in group 1 and 104 patients in group 2 were documented in this study. The subjective and objective cure rates were 87.17 %, 64.95 % in group 1 and 89.42 %, 68.26 % in group 2. Patient satisfaction rates (visual analog scale [VAS] score ≥80) were 71.79 and 83.65 % in groups 1 and 2 respectively (p?=?0.035). Complications were reported according to the Clavien–Dindo classification with grade I 7.7 %, grade II 69.2 %, grade IIIa 7.7 %, and grade IIIb 15.4 %, and grade I 9.5 %, grade II 47.6 %, grade IIIa 42.8 %, and grade IIIb 0 % in groups 1 and 2 respectively.

Conclusions

Concomitant vaginal prolapse repair with TOT does not have any negative effects on continence outcomes; on the contrary, it increases patient satisfaction.  相似文献   
78.
Desmoplastic small round cell tumors (DSRCTs) are highly aggressive sarcomas that most commonly occur intra‐abdominally, and are defined by EWSR1WT1 gene fusion. Intracranial DSRCTs are exceptionally rare with only seven previously reported fusion‐positive cases. Herein, we evaluate the clinical, morphologic, immunohistochemical and molecular features of five additional examples. All patients were male (age range 6–25 years; median 11 years), with four tumors located supratentorially and one within the posterior fossa. The histologic features were highly variable including small cell, embryonal, clear cell, rhabdoid, anaplastic and glioma‐like appearances. A prominent desmoplastic stroma was seen in only two cases. The mitotic index ranged from <1 to 12/10 HPF (median 5). While all tumors showed strong desmin positivity, epithelial markers such as EMA, CAM 5.2 and other keratins were strongly positive in only one, focally positive in two and negative in two cases. EWSR1WT1 gene fusion was present in all cases, with accompanying mutations in the TERT promoter or STAG2 gene in individual cases. Given the significant histologic diversity, in the absence of genetic evaluation these cases could easily be misinterpreted as other entities. Desmin immunostaining is a useful initial screening method for consideration of a DSRCT diagnosis, prompting confirmatory molecular testing. Demonstrating the presence of an EWSR1WT1 fusion provides a definitive diagnosis of DSRCT. Genome‐wide methylation profiles of intracranial DSRCTs matched those of extracranial DSRCTs. Thus, despite the occasionally unusual histologic features and immunoprofile, intracranial DSRCTs likely represent a similar, if not the same, entity as their soft tissue counterpart based on the shared fusion and methylation profiles.  相似文献   
79.
“Myxoid glioneuronal tumor, PDGFRA p.K385‐mutant” is a recently described tumor entity of the central nervous system with a predilection for origin in the septum pellucidum and a defining dinucleotide mutation at codon 385 of the PDGFRA oncogene replacing lysine with either leucine or isoleucine (p.K385L/I). Clinical outcomes and optimal treatment for this new tumor entity have yet to be defined. Here, we report a comprehensive clinical, radiologic, and histopathologic assessment of eight cases. In addition to its stereotypic location in the septum pellucidum, we identify that this tumor can also occur in the corpus callosum and periventricular white matter of the lateral ventricle. Tumors centered in the septum pellucidum uniformly were associated with obstructive hydrocephalus, whereas tumors centered in the corpus callosum and periventricular white matter did not demonstrate hydrocephalus. While multiple patients were found to have ventricular dissemination or local recurrence/progression, all patients in this series remain alive at last clinical follow‐up despite only biopsy or subtotal resection without adjuvant therapy in most cases. Our study further supports “myxoid glioneuronal tumor, PDGFRA p.K385‐mutant” as a distinct CNS tumor entity and expands the spectrum of clinicopathologic and radiologic features of this neoplasm.  相似文献   
80.
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