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   3288947篇
  免费   251038篇
  国内免费   5854篇
耳鼻咽喉   48127篇
儿科学   104066篇
妇产科学   91133篇
基础医学   467709篇
口腔科学   95225篇
临床医学   293674篇
内科学   640653篇
皮肤病学   68696篇
神经病学   270239篇
特种医学   129368篇
外国民族医学   1170篇
外科学   496934篇
综合类   74471篇
现状与发展   2篇
一般理论   1217篇
预防医学   262142篇
眼科学   77289篇
药学   247436篇
  5篇
中国医学   6228篇
肿瘤学   170055篇
  2018年   34451篇
  2017年   25994篇
  2016年   28624篇
  2015年   32584篇
  2014年   46058篇
  2013年   70346篇
  2012年   96108篇
  2011年   101700篇
  2010年   59566篇
  2009年   56327篇
  2008年   96100篇
  2007年   103036篇
  2006年   103891篇
  2005年   101453篇
  2004年   97596篇
  2003年   93854篇
  2002年   92814篇
  2001年   147017篇
  2000年   151955篇
  1999年   128707篇
  1998年   37575篇
  1997年   33795篇
  1996年   33703篇
  1995年   32424篇
  1994年   30480篇
  1993年   28355篇
  1992年   103921篇
  1991年   101126篇
  1990年   98416篇
  1989年   95090篇
  1988年   88338篇
  1987年   86903篇
  1986年   82621篇
  1985年   79098篇
  1984年   59807篇
  1983年   51221篇
  1982年   31046篇
  1981年   27629篇
  1979年   56524篇
  1978年   39918篇
  1977年   33806篇
  1976年   31978篇
  1975年   34194篇
  1974年   41652篇
  1973年   39694篇
  1972年   37495篇
  1971年   34720篇
  1970年   32658篇
  1969年   30645篇
  1968年   28355篇
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
941.
942.
943.
944.
945.
OBJECTIVE: To introduce 1,1,1,2 tetrafluoroethane (TFE), as a new material for cryosurgery of gingival melanin pigmentation (GMP). STUDY DESIGN: Twenty-one patients with GMP were treated using a TFE-cooled cotton swab. Standard digital images of pigmented areas were measured preoperatively and postoperatively with image-analyzing software. The Mann-Whitney U test was used for statistical analysis. RESULTS: Keratinization was completed 3 to 4 weeks after application, without any trace of pigmentation. Statistical analysis revealed a significant difference between preoperative and postoperative measurements of pigmented areas (P < .05). During the follow-up period, no side effects were observed and improved esthetics were maintained up to month 30. CONCLUSIONS: The clinical outcomes of cryosurgery with TFE for treatment of GMP are very satisfactory. The use of TFE for cryosurgical treatment of GMP is practical and inexpensive. Moreover, unlike other cryosurgery methods no special equipment is required, and it is safe to store in the dental clinic.  相似文献   
946.
947.
Surrounding bovine chromaffin cells by a semipermeable membrane may protect the transplanted cells from a host immune response and shield them from the inflammatory process resulting from the surgical trauma. Encapsulation of the chromaffin cells was achieved by inter-facial adsorption of a polycation on a polyanionic colloid matrix in which the chromaffin cells were entrapped. Basal and potassium-evoked release of catecholamines from encapsulated bovine chromaffin cells was analyzed over a 4-week period in vitro. Norepinephrine and dopamine release remained constant over time whereas epinephrine release significantly decreased. The chromaffin cells also retained the capacity for depolarization-elicited catecholamine release 4 weeks following the encapsulation procedure. Morphological analysis revealed the presence of intact chromaffin cells with well-preserved secretory granules. Striatial implantation of chromaffin cell-loaded capsules significantly reduced apomorphine-induced rotation compared to empty polymer capsules in animals lesioned with 6-hydroxydopamne frr at least 4 weeks. Intact chromaffin cells expressing tyrosine hydroxylase and dopamine-β-hydroxylase were observed in all capsules implanted in the striatum for 4 weeks. The assessment of the clinical potential of transplanting encapsulated adrenal chromaffin cells of either allo- or xenogeneic origin for Parkinson's disease will require long-term behavioral studies. The present study suggests, however, that the polymer encapsulation procedure may offer an alternative to adrenal autografts as a source of dopaminergic tissue.  相似文献   
948.
Most theories of grieving derive from Sigmund Freud and Erich Lindemann's understanding of mourning and include two assumptions: (a) Grieving is time limited; the process should be completed or resolved after a year or two; and (b) The main task of grieving is to achieve “decathexis.” One should detach oneself from emotional ties to the deceased so as to be able to form new relationships. This study presents evidence that these assumptions are flawed and that modern theories of grieving fall short of explaining the complicated reality of the mourning process. An alternative model is presented arguing that when a “high-grief” death occurs, a griever may be able to adapt and adjust to loss, but the grieving continues indefinitely. Implications of this model for older grievers are explored.  相似文献   
949.
950.
We conducted a double blind controlled trial in 28 Duchenne muscular dystrophy (DMD) patients with Deflazacort (DF), an oxazoline derivative of prednisolone which reduces its side-effects. Myometric muscle strength measurements, Scott Score and timed tests showed statistically significant improvement for the treated group (P less than 0.05). Side-effects after 9 months of treatment included mild cushingoid appearance in four patients (28%) and moderate in only one (7%), increased appetite in seven (50%), increased body hair in four (28%), irritability and hyperactivity in three (21%). Increased body weight was not prominent and was controlled with dietary measures. No patient had to be withdrawn from medication. More research and long-term follow-up are needed in order to establish the mechanism of improvement and the consequences of long-term steroid administration in DMD. In this regard DF appears as an alternative to prednisone preserving its benefits but with fewer side-effects.  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