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   20535篇
  免费   1230篇
  国内免费   61篇
耳鼻咽喉   331篇
儿科学   1105篇
妇产科学   497篇
基础医学   1779篇
口腔科学   359篇
临床医学   1607篇
内科学   4905篇
皮肤病学   328篇
神经病学   1034篇
特种医学   728篇
外科学   3719篇
综合类   465篇
一般理论   3篇
预防医学   1090篇
眼科学   906篇
药学   1548篇
  1篇
中国医学   71篇
肿瘤学   1350篇
  2023年   164篇
  2022年   344篇
  2021年   758篇
  2020年   405篇
  2019年   607篇
  2018年   703篇
  2017年   489篇
  2016年   498篇
  2015年   506篇
  2014年   785篇
  2013年   992篇
  2012年   1488篇
  2011年   1348篇
  2010年   851篇
  2009年   668篇
  2008年   1001篇
  2007年   1018篇
  2006年   959篇
  2005年   880篇
  2004年   791篇
  2003年   676篇
  2002年   601篇
  2001年   479篇
  2000年   510篇
  1999年   406篇
  1998年   162篇
  1997年   141篇
  1996年   119篇
  1995年   119篇
  1994年   108篇
  1993年   84篇
  1992年   279篇
  1991年   251篇
  1990年   219篇
  1989年   212篇
  1988年   175篇
  1987年   176篇
  1986年   156篇
  1985年   170篇
  1984年   148篇
  1983年   141篇
  1982年   65篇
  1981年   76篇
  1979年   116篇
  1978年   86篇
  1977年   63篇
  1974年   75篇
  1973年   110篇
  1972年   100篇
  1971年   68篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
This report documents the outcome of 25 pregnancies with elevated serum alpha-fetoprotein levels on two separate samplings despite normal anatomic appearance of the fetus on a detailed "consultative" sonographic examination. Six of these also had elevated amniotic fluid alpha-fetoprotein. All fetuses in this series were anatomically normal at time of delivery; one aborted fetus was triploid. Of the 25 pregnancies, 16 had sonographically demonstrable placental hemorrhage, eight retroplacental and eight subchorionic. One had hydropic changes in the placenta associated with triploidy. Of the subgroup of six pregnancies in which both serum and amniotic fluid values were elevated, one had a retroplacental hemorrhage, one had a subchorionic hemorrhage, and one had diffuse hydropic changes in the placenta. A control group of 112 patients with normal alpha-fetoprotein levels yielded four with small (less than 2 cm3) subchorionic hemorrhage. The occurrence rate of placental hemorrhage in women with elevated alpha-fetoprotein and normal fetus was 64%, whereas the control group of patients with normal alpha-fetoprotein had a 3.6% occurrence rate of placental hemorrhage. Sonographically detectable placental abnormalities may be associated with elevated alpha-fetoprotein in serum and/or amniotic fluid samples. Such abnormalities may occur because of fetomaternal admixture associated with placental hemorrhage and/or intraamniotic bleeding resulting from subchorionic hemorrhage.  相似文献   
92.
In an unusual nosocomial outbreak, 13 staff and 11 patients in an acute and chronic health care facility were infected with the zoophilic dermatophyte, Microsporum canis. The dermatophyte was apparently introduced into the facility by a single infected patient. Likely modes of subsequent disease transmission include person-to-person contact, handling of contaminated laundry, and use of a shared razor. Infection control measures for managing such outbreaks are discussed.  相似文献   
93.

29. Tagung der ?sterreichischen Gesellschaft für Chirurgie und Ihrer Assoziierten Fachgesellschaften Innsbruck, 2. bis 4. Juni 1988 Herausgeber: E. Bodner und G. Szinicz Abstracts

Der chirurgische Part im Rahmen multimodaler Therapiekonzepte in der Onkologie-Schilddrüse  相似文献   
94.
A tissue culture procedure has been developed for the rapid multiplication of VALERIANA WALLICHII D C. through shoot tip and axillary bud explants. MS medium containing Kn or BAP (5.0 mg/l (-1)) in combination with IAA (1.0 mg/l (-1)) induced an optimal growth of shoots within 6-8 days from both apical and axillary bud explants. The roots developed on the same medium within 2-3 weeks. Hardening of IN VITRO grown plantlets in pots under glass-house conditions was dependent upon the temperature and humidity. A cold-temperate climate favoured early establishment. Following the given procedure, a large number of plants have been established under field conditions at two locations. The method has implications in the early introduction of an elite population as well as its improvement.  相似文献   
95.
96.
It has been speculated that exposure to the chronic stress of racism contributes to the high rates of hypertension among African Americans. Social support may buffer the effects of stress on cardiovascular (CV) health by attenuating stress-induced CV responses that have been linked to hypertension. In this study we investigated the effects of racism and social support on CV reactivity in African American women. Participants showed greater increases in CV and emotional responses while responding and listening to racist provocation. Augmented blood pressure (BP) persisted through recovery following racial stress. Participants receiving no support showed the greatest increases in anger during racist provocation. No significant effects were seen for support on CV reactivity. These results provide some of the first evidence that interactive confrontation with racism elicits significant increases in CV reactivity and emotional distress. Furthermore, individuals receiving less support may be at greater risk for the potentially health-damaging effects of racial stress. These findings may have significant implications for the health of African Americans.  相似文献   
97.
To address knowledge gaps about Turner syndrome (TS) associated disease mechanisms, the Turner Syndrome Society of the United States created the Turner Syndrome Research Registry (TSRR), a patient‐powered registry for girls and women with TS. More than 600 participants, parents or guardians completed a 33‐item foundational survey that included questions about demographics, medical conditions, psychological conditions, sexuality, hormonal therapy, patient and provider knowledge about TS, and patient satisfaction. The TSRR platform is engineered to allow individuals living with rare conditions and investigators to work side‐by‐side. The purpose of this article is to introduce the concept, architecture, and currently available content of the TSRR, in anticipation of inviting proposals to utilize registry resources.  相似文献   
98.
An open comparative trial was conducted in 58 adult obese patients (Body Mass Index > or = 25 kg/square metre). Group I (n = 27), non-drug, was advised diet (1200-1600 cals) and a brisk walk for 30 minutes. Group II, in addition, received Guggulu (Medohar) 1.5-3 gms/day for 30 days. Mean difference in weight loss between Guggulu and non-drug group was 0.32 kg (ns) on day 15 and 0.58 kg on day 30 (ns). The mean weight reduction in patients (> 90 kgs) was 1.92 kg (ns) and 2.25 kg (ns) higher in Guggulu group. All patients weighing > 90 kg lost weight in Guggulu group whilst 3 in non-drug group did not lose weight. Guggulu was tolerated well. The data from this pilot study suggest a synergistic diet-Guggulu interaction over 30 days in patients weighing > 90 kgs which needs to be confirmed in a large placebo controlled study.  相似文献   
99.
BACKGROUND: Evidence for the effectiveness of topical treatments, in providing symptomatic relief from ocular allergy, remains uncertain. AIMS: To assess the effectiveness and relative efficacy of topical treatments for the management of seasonal allergic conjunctivitis. DESIGN OF STUDY: A systematic review and meta-analysis. SETTING: A literature search of the Cochrane Library, Medline, and EMBASE bibliographic databases. METHOD: Double-masked randomised controlled trials were identified, that compared the use of topical mast cell stabilisers (sodium cromoglycate, nedocromil, lodoxamide) with placebo, topical antihistamines with placebo, and topical mast cell stabilisers with topical antihistamines. RESULTS: A meta-analysis of six trials showed that patients using sodium cromoglycate were 17 times (95% confidence interval [CI] = 4 to 78) more likely to perceive benefit compared with those using a placebo, although this estimate may be partially influenced by publication bias. Five trials indicated that those patients using nedocromil were 1.8 times (95% CI = 1.3 to 2.6) more likely to perceive their allergy to be moderately or totally controlled than those using a placebo. Four trials showed that those using antihistamines were 1.3 times (95% CI = 0.8 to 2.2) more likely to perceive a 'good' treatment effect than those using mast cell stabilisers, although this beneficial effect was not statistically significant. Limited evidence suggests that antihistamines might have a faster therapeutic effect compared to mast cell stabilisers. CONCLUSION: Overall, these findings confirm the benefit of topical mast cell stabilisers and antihistamines over placebo for the treatment of allergic conjunctivitis. There is, however, insufficient evidence to recommend the use of one type of medication over another. Treatment preferences should therefore be based on convenience of use (with reduced frequency of instillation for some preparations), patient preference, and costs, especially as important side effects were not reported with any medication.  相似文献   
100.
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