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   1110篇
  免费   72篇
  国内免费   8篇
耳鼻咽喉   10篇
儿科学   67篇
妇产科学   10篇
基础医学   156篇
口腔科学   13篇
临床医学   111篇
内科学   215篇
皮肤病学   48篇
神经病学   84篇
特种医学   13篇
外科学   151篇
综合类   48篇
预防医学   59篇
眼科学   28篇
药学   102篇
中国医学   5篇
肿瘤学   70篇
  2023年   18篇
  2022年   22篇
  2021年   43篇
  2020年   20篇
  2019年   15篇
  2018年   39篇
  2017年   28篇
  2016年   34篇
  2015年   32篇
  2014年   44篇
  2013年   46篇
  2012年   76篇
  2011年   79篇
  2010年   48篇
  2009年   43篇
  2008年   40篇
  2007年   52篇
  2006年   55篇
  2005年   42篇
  2004年   36篇
  2003年   37篇
  2002年   46篇
  2001年   36篇
  2000年   31篇
  1999年   29篇
  1998年   16篇
  1997年   6篇
  1996年   5篇
  1995年   8篇
  1994年   9篇
  1993年   5篇
  1992年   15篇
  1991年   12篇
  1990年   10篇
  1989年   7篇
  1988年   13篇
  1987年   11篇
  1986年   9篇
  1985年   14篇
  1983年   5篇
  1981年   4篇
  1979年   5篇
  1977年   3篇
  1974年   3篇
  1973年   4篇
  1971年   3篇
  1970年   6篇
  1969年   4篇
  1968年   5篇
  1965年   4篇
排序方式: 共有1190条查询结果,搜索用时 15 毫秒
11.
In 1992 at Vivekanand Hospital in Latur, Maharashtra State, India, researchers randomly allocated 326 pregnant women, 15-45 years old, at full term, to either the modified squatting position group (study group) or the normal lithotomy delivery position group (control group) to determine whether the modified squatting position using a birth cushion has any advantages over the normal delivery position. The U-shaped cushion is inexpensive, constructed with coir and foam, and has a washable cover. Its two handles provide the woman support as she pushes and delivers the newborn. There were 145 women in the study group and 181 in the control group. Women in the squatting position did not receive any episiotomies. They spent less time pushing (i.e., in second stage of labor) than those in the control group (median, 21.2 vs. 39.32 min; p 0.01), especially among gravidae 2 and above. The time required to perform vaginal operative delivery was much shorter for the squatting position than for the normal delivery position (11.6 vs. 28.86 min; p 0.01). Fetal stress was more common among newborns delivered by the normal delivery position than among those delivered by the squatting position (7.73% vs. 3.44%; p 0.05). Women in the squatting group were more likely to have an intact perineum after delivery than those in the control group. None of the women in the control group had postpartum vulval edema, while five in the study group did. The edema was mild, however, and resolved itself within 24 hours of delivery. Most women in the squatting position group were satisfied with this position. These findings suggest that the squatting position using a birth cushion has more benefits than the normal delivery position. It allows better coordination and more effective pushing. Traditional birth attendants and female health workers at subcenter and primary health center levels can be trained to use the birth cushion during labor.  相似文献   
12.
Although abnormal collagen metabolism has been ascribed an important role in the high recurrence rates after surgical hernia repair, knowledge on tissue sampled in the region affected by inguinal hernias is poor. In the present study, we determined collagen type I and type III in the skin of adult patients with indirect and direct inguinal hernias by both immunohistochemistry and Western blot analysis. In addition, we quantified the immunohistochemical expression of fibronectin and matrix metalloproteinase (MMP)-1 and -13. The results indicated that the ratio of collagen type I/III was significantly decreased in the skin of patients with either indirect (n = 9) or direct hernia (n = 7), with a concomitant increase in collagen type III (p < 0.001 vs. controls, n = 7, without affection of the inguinal region). There was no significant difference between patients with indirect and direct hernia (p > 0.05). MMP-13 was not expressed in any of the skin samples investigated, whereas MMP-1 was found in the epidermis. Fibronectin was predominantly detected at the epidermal-dermal junction. MMP-1, MMP-13 and fibronectin levels were significantly different between patients and controls (p > 0. 05). We conclude that in contrast to the unchanged expression of fibronectin and MMP-1 and MMP-13, the decreased ratios of collagen tpye I/III with the basically increased amount of collagen type III could be of significant importance for the pathophysiology of hernias. The specific ratio collagen I/III probably reflects the altered structural integrity and mechanical stability of the connective tissue in both indirect and direct hernias. Moreover, our findings stress that hernias should be regarded as the manifestation of a systemic disease in the inguinal region with a genetic background, explaining the high recurrence rates after repeated suture repair, as well as the usefulness of surgical meshes in this clinical setting.  相似文献   
13.
14.
Polymers have been utilized to deliver the drug to targeted site in controlled manner, achieving the high-therapeutic efficacy. Polymeric drug conjugates having variable ligands as attachments have been proved to be biodegradable, stimuli sensitive and targeted systems. Numerous polymeric drug conjugates having linkers degraded by acidity or intracellular enzymes or sensitive to over expressed groups of diseased organ/tissue have been synthesized during last decade to develop targeted delivery systems. Most of these organs have number of receptors attached with different cells such as Kupffer cells of liver have mannose-binding receptors while hepatocytes have asialoglycoprotein receptors on their surface which mainly bind with the galactose derivatives. Such ligands can be used for achieving high targeting and intracellular delivery of the drug. This review presents detailed aspects of receptors found in different cells of specific organ and ligands with binding efficiency to these specific receptors. This review highlights the need of further studies on organ-specific polymer–drug conjugates by providing detailed account of polymeric conjugates synthesized till date having organ-specific targeting.  相似文献   
15.
Clinical manifestations of aortoarteritis (Takayasu's arteritis) are varied, depending on the involved segment of the aorta and its branches. A case of a young Indian woman with aortoarteritis presenting primarily with hypoparathyroidism is reported. Aortogram showed total occlusion of the arch arteries. To the best of our knowledge, the occurrence of hypoparathyroidism in aortoarteritis has not been reported. Possible mechanisms of such an involvement are discussed.  相似文献   
16.
Journal of Muscle Research and Cell Motility - Two single mutations, R694N and E45Q, were introduced in the beta isoform of human cardiac myosin to remove permanent salt bridges E45:R694 and...  相似文献   
17.
Inflammation Research - Isoproterenol (ISO) is widely used agent to study the effects of interventions which could prevent or attenuate the development of myocardial infarction. The sequence of...  相似文献   
18.

Background

Competitive sports training causes structural and conductive system changes manifesting by various electrocardiographic alterations. We undertook this study to assess the prevalence of abnormal ECG in trained Indian athletes and correlate it with the nature of sports training, that is endurance or strength training.

Methods

We evaluated a standard resting, lying 12 lead Electrocardiogram (ECG) in 66 actively training Indian athletes. Standard diagnostic criteria were used to define various morphological ECG abnormalities.

Results

33/66 (50%) of the athletes were undertaking endurance training while the other 33 (50%) were involved in a strength-training regimen. Overall 54/66 (81%) sportsmen had significant ECG changes. 68% of these changes were considered as normal training related features, while the remaining 32% were considered abnormal. There were seven common training related ECG changes–Sinus Bradycardia (21%), Sinus Arrhythmia (16%), 1st degree Atrioventricular Heart Block (6%), Type 1 2nd-degree Atrioventicular Heart Block (3%), Incomplete Right bundle branch block (RBBB) (24%), Early Repolarization (42%), Left Ventricular Hypertrophy (LVH) (14%); while three abnormal ECG changes--T-wave inversion (13%), RBBB(4%), Right ventricular hypertrophy (RVH) with strain (29%) were noted. Early repolarization (commonest change), sinus bradycardia, and incomplete RBBB were the commoner features noticed, with a significantly higher presence in the endurance trained athletes.

Conclusion

A high proportion of athletes undergoing competitive level sports training are likely to have abnormal ECG recordings. Majority of these are benign, and related to the physiological adaptation to the extreme levels of exertion. These changes are commoner during endurance training (running) than strength training (weightlifting).  相似文献   
19.
20.
OBJECTIVE. To quantify stromelysin and collagenase in synovial fluid (SF) from patients with rheumatoid arthritis (RA) or traumatic knee injury. METHODS. Stromelysin and collagenase were measured in the SF of 33 patients with RA or posttraumatic knee injury, using specific double-antibody sandwich enzyme-linked immunosorbent assays. Stromelysin was fractionated from representative SF, and the molecular form was identified by immunoblot analysis. RESULTS. The stromelysin concentration was approximately 20-fold higher than the collagenase concentration in the fluids from patients with RA and approximately 8-fold higher in the fluids from patients with traumatic injury. For both metalloproteinases, there was a higher enzyme concentration in RA SF than in the SF from patients with trauma (stromelysin 40.1 +/- 26 micrograms/ml [mean +/- SD] in RA SF, 8.5 +/- 15 micrograms/ml in trauma SF; collagenase 2.2 +/- 3.3 micrograms/ml in RA SF, 1.1 +/- 2.3 micrograms/ml in trauma SF). The majority of the stromelysin within the SF bound to reactive red-agarose and was identified as prostromelysin based on electrophoretic mobility and immunoblotting with monospecific antibodies. CONCLUSION. The finding of high levels of stromelysin in SF from patients with RA supports the proposal that this enzyme may play a role in the connective tissue degradation observed in this disease.  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