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   22091篇
  免费   1837篇
  国内免费   36篇
耳鼻咽喉   304篇
儿科学   577篇
妇产科学   686篇
基础医学   2772篇
口腔科学   351篇
临床医学   2543篇
内科学   4323篇
皮肤病学   271篇
神经病学   2269篇
特种医学   731篇
外科学   3150篇
综合类   463篇
一般理论   32篇
预防医学   2039篇
眼科学   316篇
药学   1839篇
中国医学   20篇
肿瘤学   1278篇
  2023年   146篇
  2022年   254篇
  2021年   598篇
  2020年   355篇
  2019年   580篇
  2018年   647篇
  2017年   487篇
  2016年   544篇
  2015年   518篇
  2014年   820篇
  2013年   980篇
  2012年   1466篇
  2011年   1577篇
  2010年   863篇
  2009年   721篇
  2008年   1255篇
  2007年   1250篇
  2006年   1152篇
  2005年   1146篇
  2004年   1083篇
  2003年   929篇
  2002年   895篇
  2001年   423篇
  2000年   433篇
  1999年   391篇
  1998年   201篇
  1997年   190篇
  1996年   152篇
  1995年   127篇
  1994年   135篇
  1993年   109篇
  1992年   225篇
  1991年   235篇
  1990年   276篇
  1989年   214篇
  1988年   189篇
  1987年   206篇
  1986年   181篇
  1985年   212篇
  1984年   164篇
  1983年   112篇
  1982年   83篇
  1980年   74篇
  1979年   115篇
  1978年   106篇
  1975年   76篇
  1974年   103篇
  1973年   90篇
  1972年   87篇
  1971年   72篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
61.
Background : A patient with a solitary pulmonary metastasis who had breast cancer in the past may benefit from pulmonary resection. Methods : Between 1984 and 1996, 17 patients underwent metastatectomy for metastatic breast cancer. There were 15 females and two males whose average age was 59 (range: 40–74 years). The median tumour-free interval after the primary breast-cancer operation was 5.1 years (range: 8 months-18.2 years). Sixteen patients had complete resections, which included six lobectomies and 10 lesser resections. Results : The postoperative mortality was nil and the morbidity rate was 6%. Follow-up was complete in all patients. Recurrent disease developed in four patients and two patients died of their disease. The 5-year survival was 62%. Conclusion : An aggressive surgical approach is warranted in patients with isolated resectable pulmonary metastases from breast cancer.  相似文献   
62.
During an exposure monitoring study, 78 saw maintenance tradesmen were randomly assigned to be interviewed about their exposures using one of two questionnaire formats: open-ended and partly prompted questions about five categories of materials; and detailed prompting about 75 agents. The more open-ended questionnaire elicited fewer exposure responses overall, but more responses about agents not included on the detailed questionnaire. Composite materials and trade name products were more frequently cited as exposures than individual metals or compounds. Validity of responses was ascertained using air measurements (individual metals) or observations of the employees (composite materials). Sums of sensitivities and specificities were very low (near 1.0) for most of the metals for both types of questionnaire. For composite materials, validity improved substantially. Sensitivities with the partly prompted format (0.44–0.85) were always lower than with detailed prompting (0.80–1.00). Specificities were usually, but not always, higher with partial prompting (0.66–0.92) than with detailed prompting (0.18–0.86). Selection of questionnaire format for an epidemiologic study would depend on the likely prevalence of exposure in controls and the effects of trade-offs in sensitivity and specificity.  相似文献   
63.
OBJECTIVES: To investigate the etiology of nasal polyps and its relationship to allergy. The prevalence of positive food and inhalant skin tests in patients with nasal polyps and nonatopic controls was compared. STUDY DESIGN AND SETTING: Prospective controlled study in tertiary referral rhinology clinic. RESULTS: Seventy percent (70%) of the patients with nasal polyps had positive skin tests to an average of four foodstuffs, compared to 34 percent of controls (P = 0.006). Only 35 percent of the nasal polyp patients also had positive inhalant skin tests. Overall, the prevalence of positive inhalant skin tests was similar in the nasal polyp patients and controls. CONCLUSIONS: These findings suggest that the positive skin tests to foods are not merely a reflection of the general atopic status of patients with nasal polyps. It may be that non-IgE-mediated hypersensitivities, such as to ingested foods, play a role on the basis of a significant number of patients with positive intradermal skin tests to foods. SIGNIFICANCE: Evaluation of the allergic status of patients with polyposis is important. Dietary manipulation may be indicated, though its role needs further investigation.  相似文献   
64.
Pharmacy and therapeutics committees commonly cite a lack of generalizability as a reason for not incorporating cost-effectiveness information into decision making. To address this concern, many committees undertake site-specific economic evaluations, which are often limited by small sample sizes and nonrandomized designs. We show how 2 complementary approaches were used to minimize these limitations in an economic evaluation of abciximab at 1 institution. Using a propensity score methodology, we selected patients who did not receive abciximab for the comparison cohort. Then, we adopted a Bayesian, hierarchical, random-effects model to integrate site-specific and clinical trial data. We applied the posterior distributions of effectiveness with local cost data in a traditional decision-analytic model. In 74% of the simulations, abciximab was cost-effective at 1 institution at the $50,000 per life year saved threshold, assuming a 50:50 split of patients undergoing coronary stenting and angioplasty. Among patients undergoing coronary stenting, the cost-effectiveness ratio of the addition of abciximab was at or below the $50,000 per life year saved threshold in 66.0% of the simulations.  相似文献   
65.
66.
Holter technology has endured for more than 40 years, and proven to be a valuable adjunctive noninvasive diagnostic technology to record the ambulatory or long‐term electrocardiogram in the study of living creatures. During this span of time, many scientists, physicians, and innovators contributed to the development and evolution of Holter technology. This essay seeks to document a view of the history and evolution of the technology during that time, and concomitantly give recognition to the scientists, physicians, and engineers who contributed so greatly.  相似文献   
67.
68.
69.
Plasma levels of cannabidiol (CBD) were ascertained weekly in 14 Huntington's disease patients undergoing a double-blind, placebo-controlled, crossover trial of oral CBD (10 mg/kg/day = about 700 mg/day) for 6 weeks. The assay procedure involved trimethylsilyl (TMS) derivatization of CBD and the internal standard delta-6-tetrahydrocannabinol (THC), capillary column gas chromatography, ion trap mass spectroscopy in positive ion chemical ionization mode using isobutane, and calculations of CBD levels based on peak ion intensity of the 387 M + H peak of delta-6-THC-TMS and the 459 M + H peak of CBD-2TMS. The sensitivity of the assay was about 500 pg/ml, and the precision was about 10-15%. Mean plasma levels of CBD ranged from 5.9-11.2 ng/ml over the 6 weeks of CBD administration. CBD levels averaged 1.5 ng/ml one week after CBD was discontinued, and were virtually undetectable thereafter. The elimination half-life of CBD was estimated to be about 2-5 days, and there were no differences between genders for half-life or CBD levels. Additionally, no plasma delta-1-THC, the major psychoactive cannabinoid of marijuana, was detected in any subject.  相似文献   
70.
T Khansur  A Kennedy 《Cancer》1991,67(8):2030-2032
Seven patients with advanced locoregional or metastatic squamous cell carcinoma of the skin were treated with cis-daimminedichloroplatin (cisplatin) and 5-fluorouracil (5-FU). Responses were seen in six of seven patients (three partial responses [PR] and three complete responses [CR]). One patient is alive and disease-free at 2 years. These results indicate that cisplatin and 5-FU is an effective combination regimen that should be used in future clinical trials in squamous cell carcinoma of the skin.  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