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   4901篇
  免费   540篇
  国内免费   252篇
耳鼻咽喉   24篇
儿科学   362篇
妇产科学   115篇
基础医学   710篇
口腔科学   67篇
临床医学   566篇
内科学   852篇
皮肤病学   64篇
神经病学   464篇
特种医学   158篇
外科学   1072篇
综合类   105篇
预防医学   458篇
眼科学   51篇
药学   321篇
中国医学   3篇
肿瘤学   301篇
  2022年   29篇
  2021年   70篇
  2019年   67篇
  2018年   93篇
  2017年   54篇
  2016年   68篇
  2015年   70篇
  2014年   85篇
  2013年   144篇
  2012年   201篇
  2011年   234篇
  2010年   104篇
  2009年   126篇
  2008年   252篇
  2007年   260篇
  2006年   283篇
  2005年   255篇
  2004年   253篇
  2003年   210篇
  2002年   223篇
  2001年   218篇
  2000年   202篇
  1999年   152篇
  1998年   92篇
  1997年   73篇
  1996年   80篇
  1995年   72篇
  1994年   47篇
  1993年   50篇
  1992年   128篇
  1991年   115篇
  1990年   102篇
  1989年   107篇
  1988年   98篇
  1987年   93篇
  1986年   69篇
  1985年   62篇
  1984年   66篇
  1983年   51篇
  1982年   37篇
  1981年   31篇
  1979年   55篇
  1978年   45篇
  1977年   45篇
  1976年   33篇
  1973年   37篇
  1972年   31篇
  1971年   39篇
  1967年   30篇
  1966年   32篇
排序方式: 共有5693条查询结果,搜索用时 468 毫秒
991.
992.
993.
This study evaluated the effects of the cationic manganese(III) tetrakis(N,N'-diethylimidazolium-2-yl)porphyrin catalytic antioxidant Mn(III)TDE-2-ImP5+ (AEOL 10150) on outcome from spinal cord compression (SCC) in the mouse. C57BL/6J mice were subjected to 60 min thoracic SCC after discontinuation of halothane anesthesia. In Experiment 1, mice were given intravenous Mn(III)TDE-2-ImP5+ (0.5 mg/kg bolus followed by 1 mg kg(-1) h(-1) for 24 h), methylprednisolone (30 mg/kg bolus followed by 5.4 mg kg(-1) h(-1) for 24 h), or vehicle (n = 25 per group). In Experiment 2, mice were given intrathecal Mn(III)TDE-2-ImP5+ (2.5 or 5.0 microg/kg) or vehicle (n = 18 per group). In both experiments, treatment began 5 min post-SCC onset. Rotarod performance was measured on post-SCC days 3, 7, 14, and 21. On post-SCC day 21, the spinal cord was histologically examined and a total damage score was calculated. Neither intravenous Mn(III)TDE-2-ImP5+ nor methylprednisolone altered rotarod performance (accelerated rate P = 0.11, fixed rate P = 0.11) or mean +/- S.D. total damage score (Mn(III)TDE-2-ImP5+ = 21 +/- 9, methylprednisolone = 24 +/- 8, vehicle = 22 +/- 10; P = 0.47; shams = 0). Intrathecal Mn(III)TDE-2-ImP5+ (both 2.5 and 5.0 microg) given at SCC-onset improved rotarod performance (P = 0.05) and total damage score (2.5 microg = 19 +/- 10, P = 0.04; 5.0 microg =19 +/- 8, P = 0.03) versus vehicle (26 +/- 10). These studies demonstrate sustained benefit from manganese(III) porphyrin catalytic antioxidant therapy after SCC. However, efficacy was dependent upon route of administration suggesting that bioavailability is critical in defining efficacy.  相似文献   
994.
Spleen cells, thoracic duct lymphocytes and adherent peritoneal exudate cells from mice immunized to syngeneic plasma cell tumors were capable of transferring specific protective immunity to these tumors. Pre-treatment of these cells with anti-Θ serum or anti-lymphocyte serum, but not with anti-ΘK serum, effectively abolished the ability of lymphoid cells to transfer this immune response. These studies demonstrate that T cells are essential in the adoptive transfer of immunity. Furthermore, immunization of athymic (nude) mice to plasma cell tumors was not achieved. Attempts to activate normal macrophages in vitro with sensitized lymphoid cells were unsuccessful. Admixture of immune lymphoid cells and target tumor cells to unrelated tumor cells did not inhibit the growth of the unrelated tumor cells. It is proposed that the immune response to syngeneic tumor associated antigens of plasma cell tumors not only involves essential sensitization of T lymphocytes, but that activated cytotoxic T lymphocytes are directly responsible for inhibiting target tumor growth.  相似文献   
995.
A factor analysis of the Wechsler Memory Scale (WMS) with 30-minute delayed recall scores (percent retained) for the Logical Memory, Visual Reproduction, and Associate Learning subtests indicated that this variant of the WMS taps different types of learning and memory for new material. With regard to the verbal learning/recall subtests, Logical Memory appears to be related to attention/ concentration ability, while Associate Learning is relatively independent. The results also showed that both the easy and hard items from Associate Learning tap the same ability, providing evidence that this subtest is a measure of rote verbal learning. These results support the clinical utility of the WMS with delayed recalls in neuropsychiatric populations.  相似文献   
996.
BACKGROUND: A unique way of determining patterns of parent-offspring transmission of risk to affective disorders is to focus on aggregation within sibling pairs. We attempt to extend our previous finding that sibling aggregation is notable for anxiety disorders in a 10-year follow-up of siblings at high and low risk for depression, by virtue of parental diagnosis. METHODS: The sample, which included 173 unique sibling pairs in the high risk cohort, and 83 pairs in the low risk cohort, had been assessed using semi-structured clinical interviews three times over a 10-year period, spanning from childhood to adulthood. Sibling aggregation was quantified using pairwise odds ratios. RESULTS: Sibling aggregation in the high risk cohort was greater than aggregation in the low risk cohort for anxiety disorders, especially those that emerged in childhood, and later co-morbid disorders, especially major depressive disorder and suicide attempts. CONCLUSIONS: Familial liability to affective disorders may be reflected most strongly by a developmental sequence of anxiety disorders in childhood followed by later depressive and suicidal in adolescence and adulthood.  相似文献   
997.
The effects of H-2 type and gender on the lifespan of A and C57BL/6 mice and their F1, F2, and backcross offspring were studied. The proportion of mice remaining alive, percent survivors, was calculated at monthly intervals for each mating group. Statistical analyses of these survival data showed that, in agreement with studies from other laboratories, C57BL/6 (H-2b) mice lived significantly longer than A (H-2a) mice. When the survival curves for A and C57BL/6 backcross and F2 offspring were analyzed to test for the presence of an H-2 effect on mouse lifespan, no statistically significant association was detected, although a trend toward increased 10th decile survivorship among female H-2a mice was noted. The mice used in this study were also evaluated for the presence of an effect of gender on lifespan. Female mice of the A strain, and F1, F2, and backcross groups, but not the C57BL/6 mice, exhibited significantly longer lifespans when compared with their male counterparts. Thus these data show a significant gender effect, but only a trend towards an H-2 effect, on the lifespan of A and C57BL/6 mice and their F1, F2, and backcross offspring.  相似文献   
998.
999.
Two separate primary carcinomas occurring simultaneously in the esophagus and stomach are uncommon. The authors report three cases of this entity, squamous cell carcinoma of the osophagus and adenocarcinoma of the stomach, one of which is classified as a collision carcinoma of the stomach. Because of the rarity of collision tumors of this histologic variety, the world literature was reviewed. Diagnostic features and the relative prognosis of dual primary carcinomas are discussed.  相似文献   
1000.

Purpose

Rural and highly religious Intermountain West states demonstrate low levels of HPV vaccination uptake. The Intermountain West HPV Vaccination Coalition (IWHVC) was formed to improve HPV vaccination by enhancing collaborations between cancer centers, health departments, health clinics, religious groups, and community organizations. Coalition members’ perceptions and experiences are described within.

Methods

A cross-sectional online survey was distributed to the IWHVC. N?=?86 responded to the online survey. Six subsequent focus groups were conducted (N?=?36). Participant demographics, barriers, and facilitators of HPV vaccination were summarized. The first three focus groups were coded in an iterative manner based on a coding scheme. The final three focus groups were selectively coded for content related to five themes: barriers and facilitators to HPV vaccination, how the coalition has been useful, future directions of the coalition, and how to engage religious communities.

Results

Participants suggested that HPV vaccination should occur in a doctor’s office (70.9%), public health clinic (64.0%), or at a community health fair (58.1%). Perceived barriers included a lack of education/low knowledge about the HPV vaccine (55.8%), concerns about sexuality/promiscuity (44.2%), and not knowing the vaccine is recommended for boys (38.4%). Participants stressed the importance of gaining buy-in from religious leaders, and felt the coalition helped them advocate for HPV vaccination through networking, idea and information sharing, and voicing their community’s needs. Future goals emphasized targeted outreach, sustainable funding, expanded environmental scans, gaining religious support, and policy reforms.

Conclusions

Targeted coalition work builds community capacity and coordinates HPV vaccination efforts. A community driven coalition approach could help improve HPV vaccination in other rural and highly religious regions.
  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