全文获取类型
收费全文 | 1311278篇 |
免费 | 90040篇 |
国内免费 | 2635篇 |
专业分类
耳鼻咽喉 | 17921篇 |
儿科学 | 40109篇 |
妇产科学 | 33326篇 |
基础医学 | 186229篇 |
口腔科学 | 34917篇 |
临床医学 | 117538篇 |
内科学 | 252498篇 |
皮肤病学 | 28572篇 |
神经病学 | 103611篇 |
特种医学 | 51780篇 |
外国民族医学 | 214篇 |
外科学 | 199006篇 |
综合类 | 25072篇 |
现状与发展 | 4篇 |
一般理论 | 562篇 |
预防医学 | 94607篇 |
眼科学 | 29507篇 |
药学 | 103582篇 |
8篇 | |
中国医学 | 3720篇 |
肿瘤学 | 81170篇 |
出版年
2021年 | 12491篇 |
2019年 | 11940篇 |
2018年 | 16287篇 |
2017年 | 12843篇 |
2016年 | 14737篇 |
2015年 | 17265篇 |
2014年 | 23528篇 |
2013年 | 33470篇 |
2012年 | 47068篇 |
2011年 | 49575篇 |
2010年 | 28888篇 |
2009年 | 26626篇 |
2008年 | 45311篇 |
2007年 | 47884篇 |
2006年 | 47607篇 |
2005年 | 46206篇 |
2004年 | 44091篇 |
2003年 | 41798篇 |
2002年 | 40122篇 |
2001年 | 62369篇 |
2000年 | 63389篇 |
1999年 | 53269篇 |
1998年 | 15266篇 |
1997年 | 13448篇 |
1996年 | 13197篇 |
1995年 | 12239篇 |
1994年 | 11090篇 |
1993年 | 10474篇 |
1992年 | 39101篇 |
1991年 | 37508篇 |
1990年 | 36864篇 |
1989年 | 35322篇 |
1988年 | 31954篇 |
1987年 | 31086篇 |
1986年 | 29255篇 |
1985年 | 27598篇 |
1984年 | 20660篇 |
1983年 | 17541篇 |
1982年 | 10570篇 |
1981年 | 9260篇 |
1979年 | 17859篇 |
1978年 | 12365篇 |
1977年 | 11142篇 |
1976年 | 9677篇 |
1975年 | 10756篇 |
1974年 | 12339篇 |
1973年 | 11873篇 |
1972年 | 11193篇 |
1971年 | 10449篇 |
1970年 | 9599篇 |
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
991.
992.
K Thomsen B J Riis J S Johansen C Christiansen P R?dbro 《Gynecological endocrinology》1987,1(2):169-175
Bone turnover before and after withdrawal of estrogen/gestagen treatment was studied in a randomized trial with 110 healthy female volunteers, who had passed a natural menopause 6 months to 3 years before the start of the study. Urinary excretion of intravenously injected 99m-technetium diphosphonate was measured as an index of bone turnover; plasma bone Gla protein and serum alkaline phosphatase were measured as indices of bone formation; and fasting urinary excretion of hydroxyproline and calcium were measured as estimates of bone resorption. During 2 years of hormone treatment, all variables decreased highly significantly (p less than 0.001) to a constant low level. Three months after withdrawal all variables increased highly significantly (p less than 0.001) towards, but not above, pretreatment and placebo levels. We conclude that withdrawal of estrogen/gestagen replacement therapy in postmenopausal women increases bone turnover, but not in excess of pretreatment values. This indicates that bone loss (after withdrawal) is similar to that seen in the placebo group and that a rebound phenomenon is unlikely. 相似文献
993.
Paclitaxel with Cisplatin as Salvage Treatment for Patients with Previously Treated Advanced Transitional Cell Carcinoma of the Urothelial Tract
下载免费PDF全文
![点击此处可从《Neoplasia (New York, N.Y.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
994.
Addition of bevacizumab to bolus fluorouracil and leucovorin in first-line metastatic colorectal cancer: results of a randomized phase II trial. 总被引:11,自引:0,他引:11
Fairooz F Kabbinavar Joseph Schulz Michael McCleod Taral Patel John T Hamm J Randolph Hecht Robert Mass Brent Perrou Betty Nelson William F Novotny 《Journal of clinical oncology》2005,23(16):3697-3705
PURPOSE: Bevacizumab, a monoclonal antibody against vascular endothelial growth factor, increases survival when combined with irinotecan-based chemotherapy in first-line treatment of metastatic colorectal cancer (CRC). This randomized, phase II trial compared bevacizumab plus fluorouracil and leucovorin (FU/LV) versus placebo plus FU/LV as first-line therapy in patients considered nonoptimal candidates for first-line irinotecan. PATIENTS AND METHODS: Patients had metastatic CRC and one of the following characteristics: age > or = 65 years, Eastern Cooperative Oncology Group performance status 1 or 2, serum albumin < or = 3.5 g/dL, or prior abdominal/pelvic radiotherapy. Patients were randomly assigned to FU/LV/placebo (n = 105) or FU/LV/bevacizumab (n = 104). The primary end point was overall survival. Secondary end points were progression-free survival, response rate, response duration, and quality of life. Safety was also assessed. RESULTS: Median survival was 16.6 months for the FU/LV/bevacizumab group and 12.9 months for the FU/LV/placebo group (hazard ratio, 0.79; P = .16). Median progression-free survival was 9.2 months (FU/LV/bevacizumab) and 5.5 months (FU/LV/placebo); hazard ratio was 0.50; P = .0002. Response rates were 26.0% (FU/LV/bevacizumab) and 15.2% (FU/LV/placebo) (P = .055); duration of response was 9.2 months (FU/LV/bevacizumab) and 6.8 months (FU/LV/placebo); hazard ratio was 0.42; P = .088. Grade 3 hypertension was more common with bevacizumab treatment (16% v 3%) but was controlled with oral medication and did not cause study drug discontinuation. CONCLUSION: Addition of bevacizumab to FU/LV as first-line therapy in CRC patients who were not considered optimal candidates for first-line irinotecan treatment provided clinically significant patient benefit, including statistically significant improvement in progression-free survival. 相似文献
995.
Adjuvant radiotherapy in carcinomas of the uterine cervix: the prognostic value of hemoglobin levels
K. Münstedt P. Johnson M.K. Bohlmann M. Zygmunt R. von Georgi† & H. Vahrson 《International journal of gynecological cancer》2005,15(2):285-291
Anemia has been associated with a poorer treatment response and reduced survival in women undergoing primary radiotherapy (RT) or radiochemotherapy for advanced cervical carcinoma. This study aimed to determine the influence of anemia on outcome in patients with cervical carcinoma undergoing adjuvant RT. Medical records were reviewed for 183 cervical cancer patients who had received adjuvant RT because of risk factors after radical surgery (n= 109) or inadequate primary surgery (simple hysterectomy; n= 74). Kaplan-Meier and Cox regression analyses were used to study hemoglobin levels before and during adjuvant RT in relation to recurrence-free and overall survival. Hemoglobin values > or =11 g/dL were considered normal, while those <11 g/dL indicated anemia. Hemoglobin levels before RT influenced significantly overall survival and recurrence-free survival across the whole group (overall survival--log rank(all patients)= 7.5; df = 1; P= 0.006). However, subgroup analysis showed that the observed difference was mainly due to the group of women who had undergone inadequate primary surgery (overall survival--log rank(inadequate surgery)= 10.8; df = 1; P= 0.001). Multifactorial regression analyses comparing hemoglobin before RT with grading and tumor stage confirmed the prognostic value of hemoglobin values. Maintaining normal hemoglobin values before and during adjuvant RT seems to be important, especially in patients who have had inappropriate simple hysterectomy, which may resemble a therapeutic situation. 相似文献
996.
997.
Leslee J. Shaw Romalisa Miranda-Peats Piotr Slomka John Friedman Sean W. Hayes Daniel S. Berman Gary V. Heller Marcin Dada William E. Boden Paul Casperson Robert A. O’Rourke Ronald Schwartz William S. Weintraub David J. Maron Spencer King Koon Teo Pamela Hartigan 《Journal of nuclear cardiology》2006,13(5):685-698
Background Stress gated myocardial perfusion single photon emission computed tomography (gSPECT) is increasingly used before and after
intercurrent therapeutic intervention and is the basis for ongoing evaluation in the Department of Veterans Affairs clinical
outcomes utilizing revascularization and aggressive drug evaluation (COURAGE) trial.
Methods and Results The COURAGE trial is a North American multicenter randomized clinical trial that enrolled 2287 patients to aggressive medical
therapy vs percutaneous coronary intervention plus aggressive medical therapy. Three COURAGE nuclear substudies have been
designed. The goals of substudy 0 are to examine the diagnostic accuracy of the extent and severity of inducible ischemia
at baseline in COURAGE patients compared with patient symptoms and quantitative coronary angiography and to explore the relationship
between inducible ischemia and the benefit from revascularization when added to medical therapy. Substudy 1 will correlate
the extent and severity of provocative ischemia with the frequency, quality, and instability of recurrent symptoms in postcatheterization
patients. Substudy 2 (n _ 300) will examine the usefulness of sequential gSPECT monitoring 6 to 18 months after therapeutic
intervention. Together, these nuclear substudies will evaluate the role of gSPECT to determine the effectiveness of aggressive
risk-factor modifications, lifestyle interventions, and anti-ischemic medical therapies with or without revascularization
in reducing patients’ ischemic burdens.
Conclusions The unfolding of evidence on the application of gSPECT in trials such as COURAGE defines a new era for nuclear cardiology.
We hope the evidence that emerges from the COURAGE trial will further establish the role of nuclear imaging in the evidence-based
management of patients with stable coronary disease.
The COURAGE trial was supported by the Cooperative Studies Program of the Department of Veterans Affairs Office of Research
and Development in collaboration with the Canadian Institutes of Health Research. Unrestricted research grants were obtained
from Merck & Co; Pfizer Pharmaceuticals; Bristol-Myers Squibb Medical Imaging; Astellas Pharma; Kos Pharmaceuticals; Data
Scope; Astra Zeneca Pharmaceuticals; Astra-Zeneca-Canada; Schering-Plough Coorporation, Ltd; Sanofi-Aventis, Inc; First Horizon;
and GE Healthcare. All industrial funding for this trial was directed through the Department of Veterans Affairs. Additional
funding for this substudy was provided by grants to the Department of Veterans Affairs and Canadian Institutes of Health Research
from Astellas Pharma and Bristol-Myers-Squibb Medical Imaging. 相似文献
998.
I Kandarakis D Cavouras D Nikolopoulos A Episkopakis N Kalivas P Liaparinos I Valais G Kagadis K Kourkoutas I Sianoudis N Dimitropoulos C Nomicos G Panayiotakis 《Applied radiation and isotopes》2006,64(4):508-519
The aim of this study was to examine the angular distribution of the light emitted from radiation-excited scintillators in medical imaging detectors. This distribution diverges from Lambert's cosine law and affects the light emission efficiency of scintillators, hence it also affects the dose burden to the patient. In the present study, the angular distribution was theoretically modeled and was used to fit experimental data on various scintillator materials. Results of calculations revealed that the angular distribution is more directional than that predicted by Lambert's law. Divergence from this law is more pronounced for high values of light attenuation coefficient and thick scintillator layers (screens). This type of divergence reduces light emission efficiency and hence it increases the incident X-ray flux required for a given level of image brightness. 相似文献
999.
1000.