全文获取类型
收费全文 | 63363篇 |
免费 | 4605篇 |
国内免费 | 334篇 |
专业分类
耳鼻咽喉 | 635篇 |
儿科学 | 1603篇 |
妇产科学 | 1543篇 |
基础医学 | 7848篇 |
口腔科学 | 1537篇 |
临床医学 | 6360篇 |
内科学 | 14420篇 |
皮肤病学 | 809篇 |
神经病学 | 5000篇 |
特种医学 | 1916篇 |
外国民族医学 | 2篇 |
外科学 | 9748篇 |
综合类 | 1010篇 |
现状与发展 | 1篇 |
一般理论 | 103篇 |
预防医学 | 5255篇 |
眼科学 | 1864篇 |
药学 | 4428篇 |
中国医学 | 140篇 |
肿瘤学 | 4080篇 |
出版年
2023年 | 293篇 |
2022年 | 465篇 |
2021年 | 1157篇 |
2020年 | 728篇 |
2019年 | 1013篇 |
2018年 | 1246篇 |
2017年 | 848篇 |
2016年 | 969篇 |
2015年 | 1137篇 |
2014年 | 1774篇 |
2013年 | 2809篇 |
2012年 | 3775篇 |
2011年 | 4117篇 |
2010年 | 2348篇 |
2009年 | 2192篇 |
2008年 | 4010篇 |
2007年 | 4194篇 |
2006年 | 4020篇 |
2005年 | 4115篇 |
2004年 | 3843篇 |
2003年 | 3457篇 |
2002年 | 3415篇 |
2001年 | 736篇 |
2000年 | 626篇 |
1999年 | 727篇 |
1998年 | 742篇 |
1997年 | 609篇 |
1996年 | 492篇 |
1995年 | 491篇 |
1994年 | 469篇 |
1993年 | 441篇 |
1992年 | 533篇 |
1991年 | 509篇 |
1990年 | 417篇 |
1989年 | 438篇 |
1988年 | 396篇 |
1987年 | 373篇 |
1986年 | 355篇 |
1985年 | 419篇 |
1984年 | 432篇 |
1983年 | 394篇 |
1982年 | 528篇 |
1981年 | 443篇 |
1980年 | 485篇 |
1979年 | 301篇 |
1978年 | 321篇 |
1977年 | 321篇 |
1976年 | 261篇 |
1975年 | 287篇 |
1974年 | 246篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
George Triadafilopoulos M.D. F.A.C.G. Alex Asian M.D. 《The American journal of gastroenterology》1991,86(8):952-955
Performance of same-day upper and lower endoscopy has many potential advantages, as it may reduce costs, shorten hospital stay, and expedite patient care, but its feasibility, efficacy, and potential have not been carefully defined. We report here our experience with a group of 87 patients who underwent same-day upper and lower endoscopy (174 procedures) over a 2-yr period at a tertiary care VA Hospital, compared with an alternate-day upper and lower endoscopy group of 50 patients (100 procedures) over the same time period. Most patients were elderly males. Common indications for endoscopy were occult or overt gastrointestinal bleeding, previous or concomitant history of pertinent pathology (i.e., polyps, ulcers), abdominal pain, diarrhea, or other symptoms, abnormal radiological studies, and iron deficiency anemia. Both groups required similar amounts of intravenous sedation. There were no complications in either group. In both groups, common positive findings were inflammation (i.e., colitis, esophagitis), benign neoplasms, diverticulae, peptic ulcer, and cancer. In both groups, only 2-6% had negative upper and lower endoscopy, whereas either one procedure was negative in 25% and 18% of cases, respectively. We conclude that the practice of same-day inpatient upper and lower endoscopy is feasible, has excellent diagnostic yield, even in the elderly, and carries no increased risks. When indicated, the practice of same-day upper and lower endoscopy should be encouraged. 相似文献
82.
83.
Christopher A Pierce George Jewell Mark Mennemeier 《Journal of the International Neuropsychological Society》2003,9(1):72-78
Psychophysical functions are used to characterize both normal perception and altered perception among patients with neglect, yet the reliability of these functions is rarely examined. The present study examined two-week, test-retest reliability for power functions derived from line bisection data among 58 normal, young and old, male and female subjects. Power function exponents and constants were, at best, moderately reliable over time. The size of the exponent tended to decrease at retesting. Reliability coefficients varied by age and gender; they were highly significant for young men, marginally significant for older men, and non-significant for women. Race influenced reliability as coefficients were significant for Caucasian subjects but not for African American subjects. Age and gender effects in this study parallel those in the literature on pseudoneglect, and they may reflect hemispheric differences in visuo-spatial processing, magnitude estimation, or both. 相似文献
84.
The Arden Syntax for sharing medical knowledge bases is described. Its current focus is on knowledge that is represented as a set of independent modules that can provide therapeutic suggestions, alerts, diagnosis scores, etc. The syntax is based largely upon HELP and the Regenstrief Medical Record System. Each module, called a Medical Logic Module or MLM, is made of slots grouped into maintenance, library, and knowledge categories. The syntax has provisions for querying a clinical database and representing time. Several clinical information systems were analyzed and appear to be compatible with the syntax. The syntax has been tested for syntactic ambiguities using the tools lex and yacc. Seventeen institutions are currently in the process of adopting the Arden Syntax for their decision-support systems. A subcommittee of ASTM has been formed to develop standards for sharing medical knowledge bases. The Arden Syntax has been published by ASTM as a initial standard for sharing medical knowledge. 相似文献
85.
86.
Ana Ortega Ph.D. George Dranitsaris M.Sci.Phm. Jeremy Sturgeon M.D. Heather Sutherland M.Sci. Amit Oza M.D. 《Gynecologic oncology》1997,66(3):454-463
The standard treatment for patients with advanced ovarian cancer (AOC) has been cyclophosphamide and cisplatin (CP). Recently, the results of a large randomized comparative trial demonstrated that the combination of paclitaxel and cisplatin (TP) provided a progression-free survival benefit of 5 months. In this study, a cost–utility analysis was performed from a Canadian health care system perspective to estimate the incremental cost-effectiveness of the TP combination. Twelve AOC patients who received treatment with TP were matched for age and disease stage on a 1-to-2 basis with a CP control. Total hospital resource consumption was then collected for all patients. Treatment preferences were estimated from a cohort of 20 patients and 40 healthy female volunteers using the time trade-off technique. The outcomes were then generated through a decision-analytic model. First-line treatment costs with TP were approximately fourfold greater on a per-cycle basis than the CP alternative (Can$1911 vs Can$459). When progression-free survival benefit and patient treatment preferences were incorporated into the analysis, the results of the decision model revealed an incremental cost between Can$12,000 and Can$24,000 per quality-adjusted progression-free year with the TP protocol. Even though the TP combination has a considerably higher drug acquisition cost, the results of the current analysis suggest that this new chemotherapy regimen does provide patients with substantial quality-adjusted progression-free survival benefit at a reasonable cost to the Canadian health care system. 相似文献
87.
Helene Z. Hill Maimu Ohanian George J. Hill Richard Winne 《Journal of surgical oncology》1987,34(4):264-267
Intraoperative radiation therapy (IORT) research is limited by the lack of small-animal models. We have implanted B16 melanoma into mouse kidneys, which we subsequently operated upon and irradiated with beta rays from a 90Sr ophthalmic applicator. The IORT has effectively prolonged survival and produced some cures. The strategy should be applicable to other murine tumors and to other internal implantation sites. 相似文献
88.
A new look at grief 总被引:1,自引:0,他引:1
George T. Karl MDIV MA 《Journal of advanced nursing》1987,12(5):641-645
89.
Increased sensitization in urban vs. rural environment – Rural protection or an urban living effect?
Kostas N. Priftis Michael B. Anthracopoulos Alexandra Nikolaou-Papanagiotou Vasiliki Mantziou Athanasios G. Paliatsos George Tzavelas Polyxeni Nicolaidou Eva Mantzouranis 《Pediatric allergy and immunology》2007,18(3):209-216
In a population-based longitudinal cohort study, we tested the hypothesis that children growing up in a high-traffic polluted urban area (UA) in the Athens' basin have higher prevalence of allergies and sensitization when compared with those growing up in a Greek provincial rural area (RA). We recruited 478 and 342 children aged 8-10 living in the UA and the RA, respectively. Respiratory health was assessed by a parent-completed questionnaire in three phases: 1995-96 (phase 1), 1999-2000 (phase 2), 2003-04 (phase 3) and skin-prick testing to common indoor and outdoor aeroallergens was performed at phases 1 and 2. Reported asthma and eczema did not differ between the two areas, whereas reported hay fever was persistently more prevalent in the UA than in the RA (16.5%, 17.0%, 18.2% vs. 7.0%, 8.3%, 9.6%, respectively). Sensitization was more prevalent in the UA at both phases (19.0% vs. 12.1% in phase 1, 20.0% vs. 14.1% in phase 2). Residential area contributed independently to sensitization to >or=1 aeroallergens (OR: 0.29; 95% CI: 0.13-0.66; p = 0.003) and to polysensitization (OR: 0.28; 95% CI: 0.10-0.82; p = 0.020) in phase 1. These associations were independent of farming practices. No significant contributions were found in phase 2. Our results suggest that long-term exposure to urban environment is associated with a higher prevalence of hay fever but not of asthma or eczema. The negative association between rural living and the risk of atopy during childhood, which is independent of farming practices, implies that it is mainly driven by an urban living effect. 相似文献
90.
OBJECTIVE: This study proposes a method for self-report health questionnaires to adjust test-retest reliability for changes during the test-retest interval based on an external measure, and to distinguish such changes from random response errors. METHODS: In our application, eighty participants completed the Symptoms of Illness Checklist (SIC) on two occasions, two weeks apart, immediately before interviews given on each occasion by one of two physicians in a crossover design. The physician interview scores served as external measures, and structural equation modeling was used to estimate the parameters of a model that corrected for the occasion-specific effect of participants' responses using information from the interviews. RESULTS: Correcting for changes in symptoms during the test-retest interval increased SIC test-retest reliability from .744 to .804 and significantly improved model fit (chi2(diff)(1) = 30.78, p < .001). CONCLUSIONS: The results suggest methods that can improve the evaluation of self-report health questionnaire test-retest reliability by identifying changes using an external measure, and distinguishing these from random response errors; these increased the estimated SIC test-retest reliability and indicated that the SIC was indeed able to measure changes over the studied time interval. This method can be applied across a broad range of questionnaires. 相似文献