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   809篇
  免费   62篇
  国内免费   25篇
耳鼻咽喉   2篇
儿科学   19篇
妇产科学   15篇
基础医学   77篇
口腔科学   15篇
临床医学   129篇
内科学   168篇
皮肤病学   31篇
神经病学   47篇
特种医学   103篇
外科学   91篇
综合类   37篇
预防医学   63篇
眼科学   1篇
药学   73篇
肿瘤学   25篇
  2023年   3篇
  2021年   4篇
  2020年   8篇
  2019年   14篇
  2018年   13篇
  2017年   4篇
  2016年   6篇
  2015年   17篇
  2014年   17篇
  2013年   29篇
  2012年   61篇
  2011年   32篇
  2010年   26篇
  2009年   38篇
  2008年   35篇
  2007年   33篇
  2006年   30篇
  2005年   28篇
  2004年   24篇
  2003年   28篇
  2002年   25篇
  2001年   25篇
  2000年   21篇
  1999年   24篇
  1998年   28篇
  1997年   22篇
  1996年   33篇
  1995年   13篇
  1994年   24篇
  1993年   12篇
  1992年   12篇
  1991年   14篇
  1990年   17篇
  1989年   14篇
  1988年   29篇
  1987年   21篇
  1986年   19篇
  1985年   22篇
  1984年   11篇
  1983年   7篇
  1982年   7篇
  1981年   6篇
  1980年   6篇
  1979年   2篇
  1978年   7篇
  1977年   4篇
  1976年   8篇
  1975年   5篇
  1968年   3篇
  1965年   1篇
排序方式: 共有896条查询结果,搜索用时 31 毫秒
71.
The AIDS epidemic is increasing the demand on all levels of health care staff to provide care compassionately and safely to people with AIDS and HIV infection. Only appropriate, ongoing education of all health care workers will maintain an effective health care system as the number of cases rises. However, the fear engendered by the word AIDS can be a serious deterrent to effective care. Adult learning principles and fear reduction techniques provide the foundation for AIDS education. A train the trainer approach provides immediate AIDS expertise to health care providers within their institution or department. With adequate resources and training, health care professionals who are already in the workplace are in the best position to quell hysteria, educate health care workers about appropriate protective measures, and ensure that humane, compassionate care is provided to persons with AIDS and HIV infection.  相似文献   
72.
OBJECTIVE: To examine the impact of the Medicare inpatient rehabilitation facility (IRF) prospective payment system (PPS) on outcomes in a stroke rehabilitation program. DESIGN: An analysis was performed on a database including 945 stroke patients admitted to an inpatient stroke rehabilitation program 5 yrs before implementation of the IRF PPS and 3.5 yrs after implementation. Patients were classified with regard to stroke location (left vs. right), level of cognitive impairment, presence/absence of unilateral neglect, and level of depressive symptomatology. Functional status was evaluated at time of admission and discharge by functional independence measure (FIM). Other outcome measures included length of stay (LOS) and discharge destination. The impact of IRF PPS on LOS, progress in rehabilitation, and discharge destination was examined via univariate analyses of covariance and logistic regression. RESULTS: Patients admitted after implementation of the IRF PPS had shorter LOS but made less progress, had lower functional levels at discharge, and had higher rates of institutional discharge. CONCLUSIONS: Although associated with decreased LOS, implementation of the IRF PPS was associated with decreased functional gains, lower discharge FIM levels, and higher rates of institutional discharge. Cost savings associated with the PPS must be considered in light of these untoward outcomes.  相似文献   
73.
74.
There is abundant evidence of immune modulation induced by exposure to blood transfusions. Some studies have demonstrated a detrimental effect of transfusion on the recurrence of malignant disease and survival. We retrospectively studied the impact of blood transfusion exposure on 229 patients with breast cancer who were seen from July 1973 to September 1980, had at least 5 years' follow-up and had been randomized by therapy at the time of diagnosis. The patients were divided into four groups according to transfusion history: Group 1 (111 patients), no transfusion; Group 2 (34 patients), first transfusion after mastectomy; Group 3 (41 patients), first transfusion at mastectomy; and Group 4 (43 patients), first transfusion before mastectomy. All transfused patients received red cells or whole blood or both. At the time of analysis, 124 (54%) of the patients had died. Only Group 2 was statistically associated with decreased survival; recurrence of disease was 85 percent in this group, compared with 53 percent to 61 percent in the other three groups (p = 0.006, log-rank test). In general, Group 2 patients received transfusions because of recurrent disease. We conclude that transfusions before or at mastectomy are not associated with increased recurrence or reduced survival in patients with breast cancer.  相似文献   
75.
In most cases pancreatic cancer appears in a non-curatively resectable stage at time the diagnosis is made. Thus, palliative treatment concepts come to the fore in these patients. Patients without metastases, but presenting with marginally resectable or locally non-resectable tumours should not be treated in a palliative therapeutic scheme. These patients should be enrolled in neoadjuvant radiochemotherapy trials. After finishing treatment and restaging, a potentially curative resection can be achieved in approximately one-third of these patients. Within the scope of the best possible palliative care, excision of metastases together with resection of the primary cancer represents a therapeutic option to be contemplated in selected cases. For distinct locally unresectable or metastasised advanced pancreatic cancer, treatment of bile duct or duodenal obstruction is an essential part of the comprehensive palliative therapy. However, both endoscopic?/?percutaneous stenting procedures and surgical bypass makeshifts constitute safe and highly effective therapeutic alternatives in this context. In the case of operative drainage of the biliary tract the prophylactic creation of a gastro-intestinal bypass (double bypass) is recommended. The decision on a surgical versus an endoscopic procedure for palliation depends considerably on the tumour stage and the estimated prognosis and has to be determined interdisciplinary and individually in each case.  相似文献   
76.

Purpose

Design and evaluation of a novel laser-based method for micromoulding of microneedle arrays from polymeric materials under ambient conditions. The aim of this study was to optimise polymeric composition and assess the performance of microneedle devices that possess different geometries.

Methods

A range of microneedle geometries was engineered into silicone micromoulds, and their physicochemical features were subsequently characterised.

Results

Microneedles micromoulded from 20% w/w aqueous blends of the mucoadhesive copolymer Gantrez® AN-139 were surprisingly found to possess superior physical strength than those produced from commonly used pharma polymers. Gantrez® AN-139 microneedles, 600 ??m and 900 ??m in height, penetrated neonatal porcine skin with low application forces (>0.03 N per microneedle). When theophylline was loaded into 600 ??m microneedles, 83% of the incorporated drug was delivered across neonatal porcine skin over 24 h. Optical coherence tomography (OCT) showed that drug-free 600 ??m Gantrez® AN-139 microneedles punctured the stratum corneum barrier of human skin in vivo and extended approximately 460 µm into the skin. However, the entirety of the microneedle lengths was not inserted.

Conclusion

In this study, we have shown that a novel laser engineering method can be used in micromoulding of polymeric microneedle arrays. We are currently carrying out an extensive OCT-informed study investigating the influence of microneedle array geometry on skin penetration depth, with a view to enhanced transdermal drug delivery from optimised laser-engineered Gantrez® AN-139 microneedles.  相似文献   
77.

OBJECTIVE

To confirm that more than half of all idiopathic calcium oxalate (CaOx) stones grow on interstitial plaque, as CaOx stones can grow attached to interstitial apatite plaque but whether this is the usual mechanism of stone formation is uncertain.

PATIENTS AND METHODS

In nine idiopathic CaOx stone formers (ICSF) undergoing percutaneous nephrolithotomy or ureteroscopy all accessible renal papillae were endoscopically imaged using a digital endoscope. All stones were removed intact, and recorded by the operating surgeon as being attached or unattached; for all attached stones the surgeon determined if the site of attachment was to plaque. This determination was further verified by reviewing the intraoperative video record, and only instances where plaque was reliably seen on video were used for analysis. Surgical observations were further validated by a combination of microcomputed tomographic analysis and papillary biopsy. The results were analysed statistically using fixed‐sample testing and group sequential sampling.

RESULTS

The nine patients had a total of 115 stones, primarily CaOx; 90 stones were attached. Of these, 81 were attached to plaque; surgeons could not visualize the site of attachment with sufficient clarity to judge in the other nine cases. Based on these data, the final point estimate for the number of stones attached to plaque was 0.754 (95% confidence interval 0.575–0.933; P = 0.013).

CONCLUSIONS

In ICSF most stones grow attached to papillae, on plaque, so growth on plaque is the main mechanism for stone formation in this very common group of patients.  相似文献   
78.

Objective

High blood pressure is one of the most important risk factors, directly responsible for increasing the cardiovascular morbidity and mortality. The primary objective was to evaluate the efficacy of metoprolol XL/chlorthalidone against metoprolol XL/hydrochlorothiazide with respect to mean fall in systolic and diastolic blood pressure. The secondary objective was to compare the response rates and to evaluate the tolerability of study medications in patients with mild-tomoderate essential hypertension.

Methods

Total 130 eligible patients (65: metoprolol XL 25 mg/chlorthalidone 6.25 mg; 65: metoprolol XL 25 mg/HCTZ 12.5 mg) were enrolled in this randomized, comparative, multicentric, 12-weeks study. Sixty-two patients from each group completed the study. After 4-weeks of treatment, non-responders from chlorthalidone 6.25 mg combination group were shifted to metoprolol XL 50 mg/chlorthalidone 12.5 mg and non-responders from HCTZ 12.5 mg combination group were escalated to metoprolol XL 50 mg/HCTZ 12.5 mg.

Results

The study treatment groups were comparable with respect to demography and baseline disease characteristics. Both the starting therapies were comparable with respect to mean fall in SBP (p = 0.788) and DBP (p = 0.939), and response rates (p = 1.0) after 4-weeks of therapy. Also both the step-up therapies showed similar mean fall in SBP (p = 0.277) and DBP (p = 0.507) at the end of 12-weeks. However, significantly more number of patients from chlorthalidone 12.5 mg/metoprolol XL 50 mg group responded to therapy as compared to that from HCTZ 12.5 mg/metoprolol XL 50 mg group (p = 0.045). All the reported adverse events were of mild-to-moderate intensity. There were no clinically significant trends in electrolytes (Na+, K+, Cl-)and fasting blood sugar, evident across the treatment groups.

Conclusion

Chlorthalidone in combination with metoprolol XL is as effective and well tolerated as widely used combination of metoprolol XL/HCTZ, thus providing an alternative therapeutic option.  相似文献   
79.
80.
The molting cycle of the freshwater crayfish, Procambarus clarkii, has been used as a model to study the cellular physiology and molecular biology of Ca "supply" proteins that effect transcellular vectorial Ca(2+) movement to achieve organismal Ca homeostasis. Specifically, periods of net Ca(2+) influx (postmolt) have been compared with periods of net Ca(2+) balance (intermolt). The broader goal is to understand the paradox facing epithelial cells of maintaining low cytosolic Ca(2+)in the face of mass Ca(2+)transit across epithelial cells. This mini-review compares mRNA and protein expression profiles for a series of proteins that are of strategic importance in effecting transcellular Ca(2+) flux in a selected epithelium, the antennal gland (kidney analog) specifically during apical to basolateral Ca(2+) conveyance. Target proteins were selected as representative of key "stages" in the transcellular transfer of Ca(2+): import (epithelial Ca(2+) channel, ECaC); storage (sarco/endoplasmic reticulum Ca(2+) ATPase, SERCA); buffering (sarcoplasmic Ca(2+) binding protein, SCP); and export (plasma membrane Ca(2+) ATPase, PMCA and Na(+)/Ca(2+) exchanger, NCX). The purpose of this review is to assess coordination of expression of these target proteins at times of high Ca(2+) demand (premolt and postmolt) compared to low Ca demand (intermolt) as a function of cellular location (apical vs. basolateral; endomembranes vs. plasma membranes) and relative abundance within different regions of the antennal gland. Understanding the spatiotemporal regulation of Ca(2+) handling proteins involved in transcellular transport is fundamental to investigating their endocrine regulation.  相似文献   
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