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   3814篇
  免费   275篇
  国内免费   16篇
耳鼻咽喉   75篇
儿科学   71篇
妇产科学   42篇
基础医学   443篇
口腔科学   74篇
临床医学   368篇
内科学   732篇
皮肤病学   55篇
神经病学   363篇
特种医学   268篇
外科学   667篇
综合类   26篇
一般理论   4篇
预防医学   283篇
眼科学   89篇
药学   220篇
中国医学   5篇
肿瘤学   320篇
  2023年   60篇
  2022年   105篇
  2021年   189篇
  2020年   120篇
  2019年   155篇
  2018年   163篇
  2017年   124篇
  2016年   124篇
  2015年   189篇
  2014年   178篇
  2013年   188篇
  2012年   292篇
  2011年   254篇
  2010年   148篇
  2009年   112篇
  2008年   189篇
  2007年   204篇
  2006年   151篇
  2005年   150篇
  2004年   146篇
  2003年   87篇
  2002年   101篇
  2001年   48篇
  2000年   53篇
  1999年   48篇
  1998年   19篇
  1997年   25篇
  1995年   12篇
  1994年   15篇
  1992年   29篇
  1991年   42篇
  1990年   33篇
  1989年   26篇
  1988年   24篇
  1987年   23篇
  1986年   23篇
  1985年   24篇
  1984年   15篇
  1983年   16篇
  1981年   9篇
  1979年   13篇
  1975年   8篇
  1973年   15篇
  1972年   11篇
  1971年   8篇
  1970年   8篇
  1969年   11篇
  1968年   9篇
  1967年   9篇
  1966年   9篇
排序方式: 共有4105条查询结果,搜索用时 281 毫秒
61.
62.
AIMS: To investigate the 'real world' effectiveness of robust statin therapy, focusing on the effect of dose and early treatment discontinuation on the risk of hospitalization for acute myocardial infarction (AMI). METHODS AND RESULTS: In the PHARMO database, including among others drug-dispensing and hospital discharge records for more than two million subjects in the Netherlands, 59,094 new users of statins in the period 1 January 1991 until 31 December 2004, >or=18 years of age were identified. In these patients, exposure to statins, both in terms of persistence and dose, was determined over the first two treatment years. To determine the risk for AMI, patients were followed from this 2-year time point until the first hospital admission for AMI, death, or end of the study period. A total of 31,557 patients (53%) discontinued statin use within 2 years; 20 883 patients (35%) were persistent users with an average equipotent dose>or=4. A 30% reduction in risk of hospitalization for AMI with persistent statin use was observed. The protective effect increased with a higher dose (20 and 40% risk reduction with an equipotent doseor=4, respectively). CONCLUSION: These results show that statins are suboptimally used in real life for having the maximum benefit in terms of preventing AMI.  相似文献   
63.
64.
This study examined the regulation of leptin production by dexamethasone and troglitazone. Subcutaneous and omental adipose tissue was obtained during bariatric surgical procedures (30 women and 16 men; body mass index, 52.5 +/- 1.7 kg/m2, age, 39 +/- 2 yr), and adipocytes were cultured in suspension. Subcutaneous adipocytes from females released significantly more leptin than did omental cells from the same subject (P < 0.05), but basal leptin release was not different in adipocytes from these depots in males. Dexamethasone (0.1 micromol/L) significantly increased leptin release within 24 h from sc (135 +/- 13% of control) and omental (227 +/- 53%) adipocytes of females, but not males. Dexamethasone-stimulated leptin production at 48 h was significantly greater in the omental adipocytes of females (398 +/- 64% of control) than in sc adipocytes of females (207 +/- 21%) or the omental (211 +/- 33%) and sc (180 +/- 23%) adipocytes of males. Troglitazone (10 micromol/L; 48 h) significantly inhibited dexamethasone-stimulated leptin release in sc (57 +/- 10.7% inhibition) and omental adipocytes (134 +/- 26% inhibition). There was no gender-related difference in the effect of troglitazone to inhibit dexamethasone-stimulated leptin release. Troglitazone significantly inhibited basal leptin production from omental adipocytes by 15.0 +/- 5.2%. The effect of dexamethasone and troglitazone to regulate leptin release was mediated through changes in ob gene expression, but did not involve changes in glucose uptake or metabolism to lactate. The data suggest that adipocytes from females are more responsive to the stimulatory effect of dexamethasone in vitro than are adipocytes from males. If adipocytes from females are more responsive to relevant in vivo stimuli for leptin secretion such as insulin or glucose, this could contribute to the gender difference in serum leptin. The data also suggest that leptin release from omental adipocytes may be more responsive to hormonal and nutrient regulation in vivo than are sc adipocytes.  相似文献   
65.

Background

During the post-partum period, most women wish to delay or prevent future pregnancies. Despite this, the unmet need for family planning up to a year after delivery is higher than at any other time. This study aims to assess fertility intention, contraceptive usage and unmet need for family planning amongst women who are six weeks postpartum, as well as to identify those at greatest risk of having an unmet need for family planning during this period.

Methods

Using the NICHD Global Network for Women’s and Children’s Health Research’s multi-site, prospective, ongoing, active surveillance system to track pregnancies and births in 100 rural geographic clusters in 5 countries (India, Pakistan, Zambia, Kenya and Guatemala), we assessed fertility intention and contraceptive usage at day 42 post-partum.

Results

We gathered data on 36,687 women in the post-partum period. Less than 5% of these women wished to have another pregnancy within the year. Despite this, rates of modern contraceptive usage varied widely and unmet need ranged from 25% to 96%. Even amongst users of modern contraceptives, the uptake of the most effective long-acting reversible contraceptives (intrauterine devices) was low. Women of age less than 20 years, parity of two or less, limited education and those who deliver at home were at highest risk for having unmet need.

Conclusions

Six weeks postpartum, almost all women wish to delay or prevent a future pregnancy. Even in sites where early contraceptive adoption is common, there is substantial unmet need for family planning. This is consistently highest amongst women below the age of 20 years. Interventions aimed at increasing the adoption of effective contraceptive methods are urgently needed in the majority of sites in order to reduce unmet need and to improve both maternal and infant outcomes, especially amongst young women.

Study registration

Clinicaltrials.gov (ID# NCT01073475)
  相似文献   
66.
67.
68.
69.
A specific subset of micro RNAs (miRs), including miR-133 and miR-206, is specifically expressed in muscle tissue, so that they are currently defined as muscular miRs (myomiRs). To further elucidate the role of myomiRs in muscle biology, we measured miR-133a and miR-206 in plasma of 28 middle-age recreational athletes. The study population consisted of 28 middle aged, recreation athletes (11 women and 17 men; mean age, 46?years) who completed a 21.1?km, half-marathon. The plasma concentration of miR-133a and miR-206, the serum concentration of creatine kinase (CK) and high-sensitivity (HS) cardiac troponin T (cTnT), as well as capillary lactate, were measured before and immediately after the run. The median serum concentration of total CK (257 versus 175?U/L; p?p??4; p??4; p?=?.001) were considerably increased immediately after the half-marathon run. In multivariate analysis only post-exercise capillary lactate was found to be independently associated with running time. A significant and independent correlation was observed between plasma variations of the two miRs, but not with other physiological or laboratory parameters. The results of this study suggest that the biological significance of miR-133a and 206 variation after middle-distance running parallels but not overlaps the release of biomarkers of nonspecific tissue damage. Enhanced plasma values of these myomiRs may hence reflect a physiological response to high-intensity and/or prolonged exercise rather than tissue injury.  相似文献   
70.
Münzkopfschmerz     

Background

Subcutaneous peripheral nerve field stimulation (sPNFS) is an established procedure for the treatment of chronic localized neuropathic pain of peripheral origin. The treatment of nummular headache primarily focuses on conservative methods with limited prospects of success. The role of sPNFS in the treatment of nummular headache has not been investigated as yet.

Question

Is the sPNFS an option in the management of nummular headache?

Materials and methods

In addition to a summary of established methods in the treatment of nummular headache, sPNFS as a possible form of therapy is discussed.

Results

A positive effect of sPNFS in terms of the treatment of nummular headache is shown.

Discussion

sPNFS stimulates free subcutaneous nerves and transmits a pleasant form of paraesthesia in the area of pain. If regular conservative therapy has already been exhausted, then sPNFS might be an effective new option in the treatment of nummular headache. sPNFS is a minimally invasive and low-risk procedure. However, the high treatment cost and restrictions regarding fitness to undergo MRI are points of criticism. Further studies are needed to define its potential and role in the treatment of nummular headache.
  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