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   736825篇
  免费   57574篇
  国内免费   4622篇
耳鼻咽喉   10680篇
儿科学   20178篇
妇产科学   20456篇
基础医学   103850篇
口腔科学   21178篇
临床医学   65478篇
内科学   137372篇
皮肤病学   14040篇
神经病学   58203篇
特种医学   29701篇
外国民族医学   155篇
外科学   113034篇
综合类   28847篇
现状与发展   8篇
一般理论   211篇
预防医学   57233篇
眼科学   17398篇
药学   56406篇
  53篇
中国医学   4699篇
肿瘤学   39841篇
  2021年   6180篇
  2018年   7333篇
  2016年   6624篇
  2015年   8204篇
  2014年   11246篇
  2013年   15700篇
  2012年   20954篇
  2011年   22048篇
  2010年   13362篇
  2009年   12083篇
  2008年   19874篇
  2007年   21905篇
  2006年   21647篇
  2005年   21094篇
  2004年   20959篇
  2003年   20780篇
  2002年   19763篇
  2001年   30285篇
  2000年   30315篇
  1999年   25525篇
  1998年   7895篇
  1997年   7309篇
  1996年   7123篇
  1995年   6672篇
  1994年   6436篇
  1992年   21485篇
  1991年   21064篇
  1990年   20608篇
  1989年   19936篇
  1988年   18602篇
  1987年   18291篇
  1986年   17406篇
  1985年   16838篇
  1984年   13122篇
  1983年   11268篇
  1982年   7153篇
  1981年   6525篇
  1979年   13494篇
  1978年   9632篇
  1977年   8181篇
  1976年   7436篇
  1975年   8126篇
  1974年   10105篇
  1973年   9741篇
  1972年   9255篇
  1971年   8565篇
  1970年   8191篇
  1969年   7898篇
  1968年   7127篇
  1967年   6615篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
52.
Little is known about the combined associations of cardiorespiratory fitness (CRF) and hand grip strength (GS) with mortality in general adult populations. The purpose of this study was to compare the relative risk of mortality for CRF, GS, and their combination. In UK Biobank, a prospective cohort of >?0.5 million adults aged 40–69 years, CRF was measured through submaximal bike tests; GS was measured using a hand-dynamometer. This analysis is based on data from 70,913 men and women (832 all-cause, 177 cardiovascular and 503 cancer deaths over 5.7-year follow-up) who provided valid CRF and GS data, and with no history of heart attack/stroke/cancer at baseline. Compared with the lowest CRF category, the hazard ratio (HR) for all-cause mortality was 0.76 [95% confidence interval (CI) 0.64–0.89] and 0.65 (95% CI 0.55–0.78) for the middle and highest CRF categories, respectively, after adjustment for confounders and GS. The highest GS category had an HR of 0.79 (95% CI 0.66–0.95) for all-cause mortality compared with the lowest, after adjustment for confounders and CRF. Similar results were found for cardiovascular and cancer mortality. The HRs for the combination of highest CRF and GS were 0.53 (95% CI 0.39–0.72) for all-cause mortality and 0.31 (95% CI 0.14–0.67) for cardiovascular mortality, compared with the reference category of lowest CRF and GS: no significant association for cancer mortality (HR 0.70; 95% CI 0.48–1.02). CRF and GS are both independent predictors of mortality. Improving both CRF and muscle strength, as opposed to either of the two alone, may be the most effective behavioral strategy to reduce all-cause and cardiovascular mortality risk.  相似文献   
53.
54.

Objectives

The availability of suicide prevention training programs for pharmacists is unknown and may depend on state training requirements. This study’s objectives were to: 1) report state training requirements for pharmacist suicide education; and 2) describe educational resources that are available to prepare pharmacists for interactions with patients at risk of suicide.

Methods

Each state’s board of pharmacy was contacted from July to November 2017 to determine whether that state required pharmacists to complete suicide prevention training. A scoping literature review completed in August 2017 identified suicide prevention resources for pharmacy professionals. A systematic search of 5 databases and Google yielded publications and online resources that were screened for full review. Two coders reviewed articles and resources that met inclusion criteria and extracted data on program format and length, intended audience (i.e., students, practicing pharmacists), learning methods, topics covered, and outcomes assessed.

Results

Only Washington State requires pharmacists to obtain suicide prevention training. Sixteen suicide education programs and resources targeted pharmacists, including 8 in-person courses, 6 online courses, and 2 written resources. Five resources exclusively targeted pharmacists and 2 exclusively targeted student pharmacists. Most programs included information on suicide statistics, how to identify individuals at risk of suicide, how to communicate with someone who is suicidal, and how to refer patients to treatment resources. The long-term effectiveness of the programs at improving outcomes was not reported.

Conclusion

Although only 1 state requires pharmacists to obtain training on suicide prevention, there are several resources available to help prepare pharmacists to interact with individuals at risk of suicide.  相似文献   
55.
Modulation of reactive oxygen and nitrogen species in a tumor could be exploited for nanotherapeutic benefits. We investigate the antitumor effect in Walker-256 carcinosarcoma of magnetic nanodots composed of doxorubicin-loaded Fe3O4 nanoparticles combined with electromagnetic fields. Treatment using the magnetic nanodot with the largest hysteresis loop area (3402 erg/g) had the greatest antitumor effect with the minimum growth factor 0.49 ± 0.02 day–1 (compared to 0.58 ± 0.02 day–1 for conventional doxorubicin). Electron spin resonance spectra of Walker-256 carcinosarcoma treated with the nanodots, indicate an increase of 2.7 times of free iron (that promotes the formation of highly reactive oxygen species), using the nanodot with the largest hysteresis loop area, compared to conventional doxorubicin treatment as well as increases in ubisemiquinone, lactoferrin, NO-FeS-proteins. Hence, we provide evidence that the designed magnetic nanodots can modulate the tumor redox state. We discuss the implications of these results for cancer nanotherapy.  相似文献   
56.
57.
58.
59.
60.
ObjectivesThe rise in carbapenem resistance among Gram-negative bacteria has renewed interest in colistin. Recently, the EUCAST-CLSI Polymyxin Breakpoints Working Group declared that broth microdilution (BMD) is the only valid method for colistin susceptibility testing. BMD is not easily incorporated into the routine work of clinical laboratories, and usually this test is incorporated serially, resulting in delayed susceptibility reporting. We tested a strategy of combining VITEK® 2 with a 2 μg/mL colistin agar dilution (VITEK® 2/AD) screening plate to improve performance and time to reporting of colistin susceptibility.MethodsColistin susceptibility for 364 clinical isolates was determined by VITEK® 2/AD and compared with the reference standard BMD according to the ISO 20776-1:2007 and CLSI guidelines. The EUCAST colistin susceptibility breakpoint of ≤2 μg/mL was used. Escherichia coli NCTC 13846 served as quality control strain. Agreement, very major error (VME) and major error rates were determined using ISO 20776-2:2007.ResultsThe VME rate for VITEK® 2 alone was 30.6% (15/49, 95% CI 18.3–45.4%), and was reduced to 10.2% (5/49, 95% CI 3.4–22.2%) using the VITEK® 2/AD combined testing. The combined testing had categorical agreement with BMD of 97% (354/364, 95% CI 95.0–98.7%), and a major error (ME) rate of 1.6% (5/315, 95% CI 0.5–3.7%). Using the combined testing, even against challenging strains, 349 (95.8%, 95% CI 93.3–97.7%) colistin susceptibility results could be reported, and only 15 isolates required further analysis by BMD.DiscussionOur method is simple to apply and allows rapid reporting of colistin susceptibility.  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