全文获取类型
收费全文 | 48862篇 |
免费 | 3787篇 |
国内免费 | 117篇 |
专业分类
耳鼻咽喉 | 388篇 |
儿科学 | 2084篇 |
妇产科学 | 1463篇 |
基础医学 | 6446篇 |
口腔科学 | 488篇 |
临床医学 | 6642篇 |
内科学 | 9161篇 |
皮肤病学 | 763篇 |
神经病学 | 4834篇 |
特种医学 | 1027篇 |
外国民族医学 | 38篇 |
外科学 | 4675篇 |
综合类 | 510篇 |
一般理论 | 99篇 |
预防医学 | 7112篇 |
眼科学 | 668篇 |
药学 | 2610篇 |
中国医学 | 85篇 |
肿瘤学 | 3673篇 |
出版年
2024年 | 53篇 |
2023年 | 455篇 |
2022年 | 619篇 |
2021年 | 1531篇 |
2020年 | 921篇 |
2019年 | 1447篇 |
2018年 | 1686篇 |
2017年 | 1227篇 |
2016年 | 1298篇 |
2015年 | 1372篇 |
2014年 | 1915篇 |
2013年 | 2794篇 |
2012年 | 3961篇 |
2011年 | 4063篇 |
2010年 | 2158篇 |
2009年 | 1880篇 |
2008年 | 3398篇 |
2007年 | 3359篇 |
2006年 | 3089篇 |
2005年 | 3027篇 |
2004年 | 2731篇 |
2003年 | 2439篇 |
2002年 | 2288篇 |
2001年 | 303篇 |
2000年 | 193篇 |
1999年 | 307篇 |
1998年 | 456篇 |
1997年 | 342篇 |
1996年 | 292篇 |
1995年 | 301篇 |
1994年 | 256篇 |
1993年 | 225篇 |
1992年 | 132篇 |
1991年 | 136篇 |
1990年 | 119篇 |
1989年 | 101篇 |
1988年 | 108篇 |
1987年 | 76篇 |
1986年 | 97篇 |
1985年 | 104篇 |
1984年 | 117篇 |
1983年 | 102篇 |
1982年 | 121篇 |
1981年 | 158篇 |
1980年 | 105篇 |
1979年 | 64篇 |
1978年 | 57篇 |
1977年 | 60篇 |
1976年 | 58篇 |
1974年 | 55篇 |
排序方式: 共有10000条查询结果,搜索用时 406 毫秒
51.
52.
Janet M Powell Sonya L Griffith Elizabeth M Kanny 《The American journal of occupational therapy》2005,59(4):467-474
PURPOSE: To provide a model for assessing occupational therapy workforce needs by using a demand-based approach to determine current workforce status in the Northwest region. Regional information may have implications for addressing national occupational therapy service needs. METHOD: A questionnaire was sent to a proportional random sample of 234 facilities that hire occupational therapy practitioners. Data were collected in July-August 2003 using structured mailing and follow-up procedures. RESULTS: Response rate was 79%. Twenty-four percent reported occupational therapy vacancies and 11% occupational therapy assistant vacancies; 48% predicted an increase in occupational therapy positions in the next 2 years and 41% an increase in occupational therapy assistant positions. Sixty-three percent of respondents reported difficulty in hiring. DISCUSSION: This study identifies an occupational therapy workforce shortage in the Northwest. Management of a shortage is critical, for even short-term adjustments could lead to permanent changes in service provision. This study demonstrates the importance of current information on the status of the national workforce and serves as a model for future studies. 相似文献
53.
54.
Emmanuel J Favaloro Roslyn Bonar Elizabeth Duncan Susan Rodgers Katherine Marsden 《Blood coagulation & fibrinolysis》2007,18(5):441-448
The PFA-100 is a relatively new laboratory instrument, first described in 1995. There have since been numerous studies assessing its utility as a screening tool for platelet dysfunction and/or von Willebrand's disease (VWD). The PFA-100 displays variable sensitivity to different types of platelet disorders, as well as to antiplatelet medication (e.g. aspirin), with similar caveats for monitoring of primary haemostasis-promoting therapies in platelet dysfunction. There is therefore considerable uncertainty regarding its utility within this context, and we have accordingly performed an audit of usage among participants of the Royal College of Pathologists of Australasia Quality Assurance Program. Of 105 laboratories surveyed, 40 responded that they performed platelet function testing, with 26 (65%) further indicating they utilized the PFA-100. We report a wide variety of laboratory usage among these users, including numbers of tests performed [annual median (range) = 270 (15-6000)], sources of requests (clinical sources and localities), testing criteria and follow-up action. Most tests were completed within 4 h of collection, as recommended by the manufacturer, and most tests were performed as a replacement, or as a preliminary screen of platelet function (i.e. classical aggregation). Most abnormal findings, however, were attributed to antiplatelet medication such as aspirin. 相似文献
55.
Chemoprevention refers to suppression or reversal of the carcinogenic process using pharmacologic or nutritional agents. Colorectal
carcinogenesis is a protracted, multistep process that offers opportunities for prevention. Aspirin and selective cyclooxygenase-2
inhibitors (coxibs) have been evaluated for the prevention of sporadic adenoma recurrence. Aspirin was shown to reduce adenoma
recurrence rates in patients with prior colorectal neoplasms; however, the optimal dosage remains unclear. Recent studies
of coxibs indicate that these agents are effective in reducing sporadic adenoma recurrence, but chronic use can result in
serious cardiovascular toxicity. These data underscore the need for chemopreventive agents with acceptable risk-to-benefit
ratios. In this regard, nitric-oxide-releasing aspirin shows chemopreventive efficacy in preclinical models and holds promise
for reduced toxicity in humans. Furthermore, ongoing chemoprevention trials are evaluating nutritional supplements, such as
folic acid and selenium, and results are eagerly awaited. 相似文献
56.
57.
58.
59.
60.
Tolerance of ocular iontophoresis in healthy volunteers. 总被引:4,自引:0,他引:4
Thomas M Parkinson Elizabeth Ferguson Salvatore Febbraro Arash Bakhtyari Martin King Mohan Mundasad 《Journal of ocular pharmacology and therapeutics》2003,19(2):145-151
To evaluate ocular tolerance, healthy volunteers were iontophoresed transclerally using novel OcuPhor trade mark hydrogel drug delivery applicators filled with balanced salt solution. In this three-period crossover study in 24 male and female subjects, 16 subjects received 0 mA and two of the following DC currents: 0.1, 0.5., 1.0, 2.0, 3.0, or 4.0 mA for 20 min; 6 subjects received 3 mA for 20 min and 1.5 mA for 40 min (both equivalent to 60 mAmin total charge). Safety and tolerance were determined by subjective VAS and objective ophthalmic assessments. Subjects were evaluated before and up to 22 hr after dosing. The applicators were well-tolerated and no clinically significant changes in symptomology or in ophthalmic assessments were seen following exposure to 0-3.0 mA for 20 min or 1.5 mA for 40 min. At 4.0 mA 2 of 4 subjects reported a burning sensation under the applicator during dosing which resolved by 22 hr post-dose; superficial changes in fluorescein staining were observed at 1 hr, but not at 22 hr. The OcuPhor trade mark system has promise for noninvasive drug delivery to the eye. 相似文献