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   200485篇
  免费   1446篇
  国内免费   52篇
耳鼻咽喉   1884篇
儿科学   7173篇
妇产科学   5136篇
基础医学   19927篇
口腔科学   2514篇
临床医学   13248篇
内科学   35381篇
皮肤病学   1514篇
神经病学   18577篇
特种医学   9212篇
外科学   31393篇
综合类   2405篇
一般理论   1篇
预防医学   19772篇
眼科学   3818篇
药学   12375篇
中国医学   656篇
肿瘤学   16997篇
  2022年   352篇
  2021年   627篇
  2020年   182篇
  2019年   303篇
  2018年   22331篇
  2017年   17618篇
  2016年   19803篇
  2015年   1275篇
  2014年   1368篇
  2013年   1537篇
  2012年   7957篇
  2011年   22142篇
  2010年   19363篇
  2009年   11799篇
  2008年   20172篇
  2007年   22607篇
  2006年   1574篇
  2005年   3123篇
  2004年   4418篇
  2003年   5365篇
  2002年   3339篇
  2001年   955篇
  2000年   1074篇
  1999年   730篇
  1998年   375篇
  1997年   256篇
  1992年   412篇
  1991年   405篇
  1990年   482篇
  1989年   484篇
  1988年   519篇
  1987年   488篇
  1986年   482篇
  1985年   463篇
  1984年   371篇
  1983年   279篇
  1979年   531篇
  1978年   325篇
  1977年   260篇
  1976年   256篇
  1975年   346篇
  1974年   532篇
  1973年   516篇
  1972年   432篇
  1971年   409篇
  1970年   408篇
  1969年   429篇
  1968年   373篇
  1967年   274篇
  1966年   293篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
Haemangiomas are the most common tumours of infancy. They typically proliferate then involute with considerable variation as regards to their rates of proliferation and involution. Haemangioma of the nasal tip is a lesion of special characteristics. During proliferation, it expands, contracts and deviates the nasal cartilages. Particularly, it regresses slowly and frequently involutes incompletely. That is why excision of the lesion is frequently suggested. The present study was conducted to evaluate open rhinoplasty after initial non-excision treatment modalities namely, intra-lesional corticosteroid injections and laser treatment, as a protocol of treatment for nasal tip haemangiomas. Twelve patients with nasal tip haemangiomas were included in the present study. Patients of both sexes, of different ages, with deep and mixed haemangiomas were studied. Disfigurement was the constant presenting symptom. Initial non-excision treatment reported different responses as denoted by the regression of the lesions’ size. Haemangiomas constantly extended between the medial crura of the alar cartilages as noted by the constant widening of the columella pre-operatively and the obvious separation of the nasal cartilages intra-operatively. This separation was constantly found to require approximation by sutures. The results of the present study concluded that whenever an early presentation with nasal tip haemangioma could be established, initial non-excision treatment followed by open rhinoplasty could be a useful protocol of treatment. Within the limitations of the present study, this protocol could achieve an early, safe and effective treatment for nasal tip haemangiomas with provisionally acceptable cosmetic outcomes so far.  相似文献   
53.
This study investigates whether tissue recoil or patient intrinsic factors influence the final position of the nipple areola complex (NAC) after reduction mammoplasty. The age, pre-operative ptosis, BMI and weight of the tissue resected were recorded as patient intrinsic factors in 37 patients undergoing reduction mammoplasty. The “spring-back” value was defined as the distance from the sternal notch to a nipple landmark on the breast meridian with the patient sitting up, minus the same measurement repeated with the patient recumbent to eliminate the pull of gravity on the breast. Spring back was measured pre-operatively for the nipple and nipple mark then post-operative for the nipple. The difference in centimeters between the final post-operative distance from the sternal notch to the nipple and the level intended by the pre-operative nipple mark was termed the “judgment error.” The final position of the post-operative nipple and the judgment error was compared to the spring-back values and patient intrinsic factors. Pre-operative ptosis was statistically related to increasing patient BMI and mass of tissue resected per breast. Pre-operative spring-back values for the nipple increased with increasing ptosis, BMI and decreasing age. Spring-back values were greater in the lower pole of the breast than in the upper pole. The final position of the nipple was higher than the pre-operative mark in 65% of cases, lower in 8% and as marked in 27% of cases. The post-operative NAC was, on average, 0.6 cm higher than planned pre-operatively. The post-operative distance from the sternal notch to the nipple increased with increasing pre-operative ptosis, mass of breast tissue resected per breast and all three spring-back values. The difference between the level of the pre-operative mark and the final nipple position showed a weak correlation with post-operative spring-back values. The parameters of ptosis, BMI, weight of tissue resected per breast and pre-operative nipple spring back reflect body habitus and breast size. Spring-back values vary between the upper and lower pole of the breast. The final NAC position was higher than that intended at pre-operative marking in the majority of cases. The surgeon instinctively marks the nipple lower in patients with greater pre-operative ptosis and in whom a larger resection is anticipated. Judgment error did not relate to intrinsic factors nor to pre-operative spring-back values; hence, these parameters cannot be applied as predictive tools for more accurate pre-operative marking of the nipple position. This study suggests that the pre-operative nipple mark should be placed, with the patient sitting up, at least 23 cm from the sternal notch and 0.6 cm lower than the final position estimated using the inframammary crease as a landmark. An invited commentary on this paper is available at .  相似文献   
54.
55.
Conclusions  Noninvasive imaging of neurohumoral upregulation in remodeled myocardium suggests that an imaging strategy can be developed for predicting the rate of remodeling and likelihood of HF development. This should allow a more judicious use of neurohumoral antagonists especially in subjects who do not have manifest HF.74 In others specific targeted imaging may allow timely selection of individualized treatment strategies and ensure optimization of therapeutic intervention. Similar to ACE and AII receptors, multiple other targets in the hormonal cascades can identify the likelihood of adverse and favorable remodeling.74  相似文献   
56.
57.
alpha-Carboline substituted at C-6 with hydroxy-group is oxidized by human ceruloplasmin and fungal laccase into reactive intermediate which dimerizes, while 6-amino-alpha-carboline subjected to action of both enzymes yields the polymeric products. To prepare sufficient quantities of compounds needed for structure elucidation studies, laccase, immobilised in polyacrylamide gel was employed as a convenient reagent. The resulting products are suggested to be metabolities of 6-hydroxy- and 6-amino-alpha-carbolines formed in vivo.  相似文献   
58.
59.
The activity and principles of administration of Taurolin have been presented. That drug was used in 15 patients with chronic osteitis. Healing by first intention was obtained in 10 patients, necrosis of the skin occurred in 3 patients, recurrence of inflammation was found in one patient in whom accessory sequestroctomy was performed in the last case of osteitis and arteriosclerosis healing was obtained by second intention. The clinical observation of 15 patients has revealed: a) irritating influence of Taurolin on the soft tissue, b) increased phase of secretion of exudate since the 5 day after surgery, c) bactericidal influence of the drug. Sterilization of the focus occurred at 2 to 3 weeks after surgery. The use of Taurolin requires experience, complete abiding by the principles of use of this drug and equipment with a set of Charrier's drains. The authors are carrying on further observation of the use of Taurolin in the treatment of osteitis.  相似文献   
60.
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