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   327702篇
  免费   13559篇
  国内免费   1069篇
耳鼻咽喉   4394篇
儿科学   10794篇
妇产科学   8312篇
基础医学   42106篇
口腔科学   8637篇
临床医学   28256篇
内科学   62352篇
皮肤病学   6234篇
神经病学   23337篇
特种医学   15909篇
外国民族医学   97篇
外科学   50754篇
综合类   3031篇
现状与发展   1篇
一般理论   177篇
预防医学   28494篇
眼科学   7175篇
药学   22898篇
  4篇
中国医学   318篇
肿瘤学   19050篇
  2021年   2651篇
  2019年   2465篇
  2018年   6329篇
  2017年   5890篇
  2016年   5313篇
  2015年   7462篇
  2014年   8180篇
  2013年   9290篇
  2012年   18455篇
  2011年   13939篇
  2010年   7322篇
  2009年   8538篇
  2008年   10298篇
  2007年   11635篇
  2006年   11456篇
  2005年   19494篇
  2004年   20719篇
  2003年   15896篇
  2002年   11014篇
  2001年   5590篇
  2000年   2728篇
  1999年   7215篇
  1998年   2134篇
  1992年   7711篇
  1991年   7972篇
  1990年   8103篇
  1989年   7680篇
  1988年   7224篇
  1987年   6972篇
  1986年   6716篇
  1985年   6080篇
  1984年   4498篇
  1983年   3779篇
  1982年   2128篇
  1981年   1924篇
  1980年   1805篇
  1979年   4467篇
  1978年   3035篇
  1977年   2383篇
  1976年   2080篇
  1975年   2947篇
  1974年   3584篇
  1973年   3188篇
  1972年   3061篇
  1971年   3058篇
  1970年   2834篇
  1969年   2675篇
  1968年   2426篇
  1967年   2315篇
  1966年   2041篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
An important part of fundamental research in catalysis is based on theoretical and modeling foundations which are closely connected with studies of single-crystalline catalyst surfaces. These so-called model catalysts are often prepared in the form of epitaxial thin films, and characterized using advanced material characterization techniques. This concept provides the fundamental understanding and the knowledge base needed to tailor the design of new heterogeneous catalysts with improved catalytic properties. The present contribution is devoted to development of a model catalyst system of CeO2 (ceria) on the Cu(111) substrate. We propose ways to experimentally characterize and control important parameters of the model catalyst—the coverage of the ceria layer, the influence of the Cu substrate, and the density of surface defects on ceria, particularly the density of step edges and the density and the ordering of the oxygen vacancies. The large spectrum of controlled parameters makes ceria on Cu(111) an interesting alternative to a more common model system ceria on Ru(0001) that has served numerous catalysis studies, mainly as a support for metal clusters.  相似文献   
62.
The outbreaks of rabies in humans transmitted by Desmodus rotundus in 2004 and 2005, in the northeast of the Brazilian State of Para, eastern Amazon basin, made this a priority area for studies on this zoonosis. Given this, the present study provides data on this phenomenon in an urban context, in order to assess the possible circulation of the classic rabies virus (RABV) among bat species in Capanema, a town in the Amazon basin. Bats were collected, in 2011, with mist nets during the wet and dry seasons. Samples of brain tissue and blood were collected for virological and serological survey, respectively. None of the 153 brain tissue samples analyzed tested positive for RABV infection, but 50.34% (95% CI: 45.67-55.01%) of the serum samples analyzed were seropositive. Artibeus planirostris was the most common species, with a high percentage of seropositive individuals (52.46%, 95% CI: 52.31 52.60%). Statistically, equal proportions of seropositive results were obtained in the rainy and dry seasons (c2 = 0.057, d.f. = 1, p = 0.88). Significantly higher proportions of males (55.96%, 95% CI: 48.96-62.96%) and adults (52.37%, 95% CI: 47.35-57.39%) were seropositive. While none of the brain tissue samples tested positive for infection, the high proportion of seropositive specimens indicates that RABV may be widespread in this urban area.  相似文献   
63.
64.
65.
PurposePhysician burnout is reported in more than one out of every 2 practicing clinicians and is just as prevalent in training physicians. Burnout severity is also associated with increasing levels of financial debt. Medical professionals are notable for their high and increasing levels of debt; despite this, financial literacy is poor among physicians, and financial education is largely absent from medical education. Radiation oncologists (ROs) are no different in this regard, with 33% of residents reporting high levels of burnout symptoms, 33% carrying >$200,000 of educational debt, and 75% reporting being unprepared to handle future financial decisions. To fill this gap, we reviewed the basic tenets of personal financial health for the early career RO.Methods and materialsThe core concept of financial independence (FI) is introduced, and we review 4 basic tenets of personal financial health for the young medical professional: debt, behavior, investment, and asset protection strategies.ResultsFI is achieved by saving until the desired quality of life can be maintained, independent of employment income. Debt strategy involves minimizing debt accrual, understanding student loans, and having a debt management plan. Behavioral strategy involves setting financial goals, calculating worth and a savings rate, budgeting, and frugal living. The basics of investing include asset allocation, diversification, rebalancing, and minimizing expenses. Finally, asset protection includes insuring against catastrophic events with disability, life, health, liability, and property insurance.ConclusionsHealthy financial practices can lead to FI and may facilitate professional and personal freedoms with the goal of mitigating burnout-associated stressors. The tenets of strong financial health for ROs in the early stages of their career include sound debt, behavioral, investment, and asset protection strategies. Furthermore, initial and continuing financial education is an overlooked but important curriculum component. ROs with their financial houses in order can devote more resources to learning and practicing good medicine while living healthy, rewarding lives.  相似文献   
66.
67.
ABSTRACT

Forensic DNA analysis is dependent on comparing the known and the unknown. Expand the number of known profiles, and the likelihood of a successful match increases. Forensic use of DNA is moving towards comparing samples of unknown origin with publicly available genetic data, such as the records held by genetic genealogy providers. Use of forensic genetic genealogy has yielded a number of recent high-profile successes but has raised ethical and privacy concerns. Navigating family trees is complex, even more so when combined with a comparison of genetic relationships. This intelligence-gathering process has led to occasional false leads, and its use also risks a public backlash, similar to concerns over Cambridge Analytica. A cautious approach to use of this technique is therefore warranted.  相似文献   
68.
OBJECTIVE: To investigate whether cardiovascular mortality related to obesity could be modified by physical activity. DESIGN: Mortality follow-up. SETTING: Population study. PARTICIPANTS: Participants in a health survey: 34 868 women and 32 872 men free from known cardiovascular disease or diabetes at baseline. MAIN OUTCOME MEASURES: Total cardiovascular mortality. MAIN RESULTS: During 16 years of follow-up, 3026 women and 3526 men had died from cardiovascular causes. In middle age, obesity [body mass index (BMI) of 30 or higher] was associated with increased risk of cardiovascular death, but the association weakened with age. After 70, there was no association between BMI and cardiovascular death. At all ages, a lower level of physical activity was associated with a higher cardiovascular mortality. In women with high physical activity, indicated by at least 30 min of moderate to vigorous activity more than once a week, cardiovascular mortality was only slightly higher in the obese compared to lean women (adjusted relative risk, 1.27; 95% confidence interval, 0.80-2.00). In men with high physical activity, cardiovascular mortality was, however, significantly higher among the obese (relative risk, 1.62; 95% confidence interval, 1.09-2.40). In both genders cardiovascular mortality was substantially higher in obese people who reported no regular physical activity compared to obese people with a high level of physical activity. CONCLUSION: In obese women, being highly active may, to a large extent, compensate for the risk-increasing effect of being obese, whereas in obese men who engage in a high level of physical activity, the risk of cardiovascular death may be higher than in lean and equally active men.  相似文献   
69.
BACKGROUND: Presently, complementary and alternative medicine, including both therapies and herbal/oral supplements, is used globally. Few studies have examined the use of specific therapies, separate from herbal/oral supplements, in cardiac rehabilitation. This paper presents a systematic evaluation of current research evidence related to use of specific complementary and alternative medicine therapies in secondary prevention of cardiovascular disease, with a view to making recommendations for cardiac rehabilitation. DESIGN AND METHODS: A literature search was conducted using complementary and alternative medicine websites, Medline, Allied and Complementary Medicine, CINAHL, Cochrane databases, EMBASE, SportDiscus, Clinical Evidence, and Evidence-Based Practice to locate research-based scientific evidence related to the use of complementary and alternative medicine in cardiac rehabilitation. Search keywords included heart, cardiac, cardiovascular, coronary, myocardial and rehabilitation, combined with particular therapies. Herbal/oral supplements were not included in this evaluation. RESULTS: Some complementary and alternative medicine therapies may be useful to patients by themselves or coupled with traditional cardiac rehabilitation. Tai chi, as a complement to existing exercise interventions, can be utilized for low and intermediate risk patients. transcendental meditation may be used as a stress reduction technique. There was insufficient evidence found for the use of acupuncture or chelation therapy in cardiac rehabilitation or secondary prevention. CONCLUSIONS: Some complementary and alternative medicine therapies hold promise for patients in cardiac rehabilitation. Further research is essential, however, in all areas of complementary and alternative medicine to confirm its usefulness as an adjunct to cardiac rehabilitation.  相似文献   
70.
Nine wrists in eight patients were treated surgically between 1988 and 2003 for symptomatic Madelung's deformity. The pain of involved wrist followed by forearm deformation fulfilled criteria for surgery. Closing wedge osteotomy of the distal radius were carried out eight times accompanied by shortening of the ulna (four patients), excision of the distal ulna (one patient), and no ulnar surgery (three patients). Pain relieved after surgery. The follow up period ranged from 1 to 9.5 years. No pour results were stated in subjective patient's estimation during final check up. Wrist appearance were stated to be satisfactory. Limitation of the range of motion concerning supination and pronation of the forearm were stated invariably. X-ray retrospective assessment of the inclination angle, lunate coverage and presence of arthritic changes were conducted. Time and method of surgical treatment for Madelung's deformity should be considered individually.  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