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   560篇
  免费   34篇
  国内免费   8篇
耳鼻咽喉   1篇
儿科学   34篇
妇产科学   70篇
基础医学   51篇
口腔科学   16篇
临床医学   45篇
内科学   89篇
皮肤病学   10篇
神经病学   29篇
特种医学   65篇
外科学   68篇
综合类   14篇
预防医学   18篇
眼科学   11篇
药学   41篇
肿瘤学   40篇
  2022年   4篇
  2021年   7篇
  2020年   4篇
  2019年   8篇
  2018年   11篇
  2017年   4篇
  2016年   4篇
  2015年   9篇
  2014年   10篇
  2013年   16篇
  2012年   16篇
  2011年   14篇
  2010年   23篇
  2009年   25篇
  2008年   22篇
  2007年   18篇
  2006年   15篇
  2005年   18篇
  2004年   14篇
  2003年   16篇
  2002年   10篇
  2001年   18篇
  2000年   15篇
  1999年   13篇
  1998年   39篇
  1997年   18篇
  1996年   23篇
  1995年   14篇
  1994年   9篇
  1993年   8篇
  1992年   4篇
  1991年   11篇
  1990年   7篇
  1989年   14篇
  1988年   17篇
  1987年   10篇
  1986年   10篇
  1985年   10篇
  1984年   6篇
  1982年   4篇
  1981年   5篇
  1980年   4篇
  1979年   12篇
  1977年   7篇
  1976年   6篇
  1970年   5篇
  1969年   4篇
  1968年   4篇
  1965年   5篇
  1948年   3篇
排序方式: 共有602条查询结果,搜索用时 0 毫秒
71.
72.
Structure-activity analyses of synthetic disorazole C(1) and eight of its analogs indicate that the presence of a vinyl oxirane moiety or a tetraene sequence is not necessary for potent cytotoxic and antimitotic properties. Using an automated multiparameter fluorescence-based cellular assay to simultaneously probe the effects of disorazole analogs on cellular microtubules, mitotic arrest, and cytotoxicity, we found that disorazole C(1) enhanced the mitotic index and chromatin condensation and arrested cells in the G2/M phase of the cell cycle. All structural analogs and synthesis precursors of disorazole C(1) were at least two orders of magnitude less potent than the parent compound, thus indicating that both the functional group array and the three-dimensional conformation of the parent compound are critical for interaction with the biological target. We conclude that disorazole C(1) is a potent inducer of mitotic arrest and hypothesize that this biological activity may be mediated by microtubule perturbation.  相似文献   
73.
74.
75.
76.
One-hundred-and-fourteen women of infertile marriages with negativepost-coital test (PCT) results were studied. The women weredivided into three grou those with anatomical anomalies of thecervix, abnormalities of the cervical mucus and a negative PCIand normal parameters in cervical mucus. Patients were treatedwith mestranol when the physicochemical characteristics of thecervical mucus were impaired. Those with antispermatozoal antibodiesfound by means of the Katsh test were treated with desensitizingtherapy, condoms and homologous artificial insemination (AIH).Among all the patients therapy resulted in 23 pregnancies. Afterapplying these treatments to women, 49 of them (43%) had positivePCT results.  相似文献   
77.

Objective

To evaluate the acaricidal activity of extracts of three essential oils of chamomile, marjoram and Eucalyptus against Tetranychus urticae (T. urticae) Koch.

Methods

Extracts of three essential oils of chamomile, marjoram and Eucalyptus with different concentrations (0.5%, 1.0%, 2.0%, 3.0% and 4.0%) were used to control T. urticae Koch.

Results

The results showed that chamomile (Chamomilla recutita) represented the most potent efficient acaricidal agent against Tetranychus followed by marjoram (Marjorana hortensis) and Eucalyptus. The LC50 values of chamomile, marjoram and Eucalyptus for adults were 0.65, 1.84 and 2.18, respectively and for eggs 1.17, 6.26 and 7.33, respectively. Activities of enzymes including glutathione-S-transferase, esterase (α-esterase and β-esterase) and alkaline phosphatase in susceptible mites were determined and activities of enzymes involved in the resistance of acaricides were proved. Protease enzyme was significantly decreased at LC50 of both chamomile and marjoram compared with positive control. Gas chromatography-mass spectrometer (GC-MS) proved that the major compositions of Chamomilla recutita are α-bisabolol oxide A (35.251%), and trans-β-farersene (7.758%), while the main components of Marjorana hortensis are terpinene-4-ol (23.860%), p-cymene (23.404%) and sabinene (10.904%).

Conclusions

It can be concluded that extracts of three essential oils of chamomile, marjoram and Eucalyptus possess acaricidal activity against T. urticae.  相似文献   
78.
Maio  M  Mackiewicz  A  Testori  A  曹琦 《中国处方药》2010,(4):53-53
胸腺肽α1(Tα1)为一种免疫调节多肽,可增强效应T细胞反应。此项大型随机试验主要评价了Tα1与达卡巴嗪(DTIC)和干扰素α(IFN—α)对于转移性黑色素瘤患者的疗效和安全性。  相似文献   
79.
The surfaces of high-density or ultra-high-molecular-weight polyethylenes were hydroxylated using a two-step process. The wetting and wear properties of the untreated (virgin) and surface hydroxylated polyethylenes were compared. The introduction of hydroxyl groups provided an increase in surface hydrophilicity resulting in reduced wear. Hydrophilicity was analyzed by optical analysis of water contact angle. Wear was determined by weight loss under conditions of a reciprocating pin-on-plate apparatus with the panels immersed in water or calf serum. These results suggest that hydroxylation of polyethylene friction-bearing orthopedic surfaces may lead to a longer joint life.  相似文献   
80.
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