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   197077篇
  免费   2179篇
  国内免费   257篇
耳鼻咽喉   1587篇
儿科学   6896篇
妇产科学   3249篇
基础医学   20568篇
口腔科学   2080篇
临床医学   14073篇
内科学   34862篇
皮肤病学   1535篇
神经病学   18082篇
特种医学   10123篇
外科学   31419篇
综合类   2434篇
现状与发展   1篇
一般理论   5篇
预防医学   19037篇
眼科学   3157篇
药学   11322篇
中国医学   907篇
肿瘤学   18176篇
  2023年   148篇
  2022年   510篇
  2021年   812篇
  2020年   404篇
  2019年   577篇
  2018年   22466篇
  2017年   17810篇
  2016年   20116篇
  2015年   1945篇
  2014年   2046篇
  2013年   2136篇
  2012年   8998篇
  2011年   22852篇
  2010年   19837篇
  2009年   12446篇
  2008年   20764篇
  2007年   22835篇
  2006年   1586篇
  2005年   3078篇
  2004年   4137篇
  2003年   5001篇
  2002年   3053篇
  2001年   819篇
  2000年   863篇
  1999年   540篇
  1998年   343篇
  1997年   308篇
  1996年   166篇
  1995年   188篇
  1994年   152篇
  1993年   100篇
  1992年   176篇
  1991年   229篇
  1990年   228篇
  1989年   194篇
  1988年   151篇
  1987年   145篇
  1986年   115篇
  1985年   114篇
  1984年   81篇
  1983年   78篇
  1982年   62篇
  1980年   69篇
  1979年   50篇
  1978年   57篇
  1977年   45篇
  1974年   49篇
  1938年   60篇
  1932年   56篇
  1930年   46篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
92.
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   
93.
Two successful cases of the surgical treatment for coronary artery aneurysm (non-Kawasaki disease) were reported. The first case had a saccular aneurysm on the left circumflex coronary artery (LCx) #14. Resection of the LCx aneurysm was performed subsequent to single vessel coronary artery bypass grafting (CABG) to the distal portion of LCx#14 under the cardioplegic cardiac arrest. The second case had aneurysms on both the left anterior descending artery (LAD) #7 (fusiform) and the LCx#11 (saccular). After double vessel CABG to LAD#7 and LCx#11, ligation or resection of two aneurysms was performed successfully. Postoperative courses have been uneventful with good angiographic results achieved. Since these surgical procedures demonstrated safety, the patients are expected to achieve a good long-term prognosis.  相似文献   
94.
Late-onset chylothorax occurred 49 days after right lower lobectomy for lung cancer in a 76-year-old man. Chylothorax was successfully managed by conservative treatment with chest tube drainage and an enteral low-fat diet. Chylothorax may occur in the late period after pulmonary resection and systematic mediastinal lymph node dissection for lung cancer, for which conservative management is the treatment of choice.  相似文献   
95.
Pituitary abscess is a rare and potentially lethal condition. Pituitary abscess in a pregnant woman has not been previously described. A 38-year-old pregnant woman (34 weeks gestation) with a pituitary mass complained of a progressive headache and sudden visual impairment. She was afebrile and had no inflammatory symptoms on admission. On MRI, the preoperative diagnosis was pituitary adenoma with sphenoid sinusitis. She underwent an uncomplicated transsphenoidal procedure for removal of the pituitary mass. The next day, labor commenced and a healthy preterm baby was delivered. Pathologic examination of the intrasellar mass showed polymorphonuclear cells, debris and no tumor cells. The sellar contents were cultured and Streptococcus viridans was grown. To our knowledge this is the first case of pituitary abscess reported during pregnancy. Although the patient was pregnant, the transsphenoidal approach was safe for the mother and the fetus. Surgical drainage and antibiotic therapy are required for the definitive treatment of this condition.  相似文献   
96.

Background  

Colorectal cancer, if detected early, has greater than 90% 5-year survival. However, survival has been shown to vary across racial/ethnic groups in the United States, despite the availability of early detection methods.  相似文献   
97.
Pituitary metastases of solid tumours are infrequent, specially as a first manifestation. When they happen, they are usually due to breast or lung cancer and are asymptomatic or produce diabetes insipidus. It is very strange that they produce hormonal deficiency. We present a case report of a bronchogenic adenocarcinoma in a 65-year-old man which began with panhypopituitarism, diabetes insipidus and visual alterations. Magnetic resonance imaging revealed a large sellar mass, with clivus infiltration and invading the right cavernous sinus. The biopsy result was adenocarcinoma metastases from lung cancer.  相似文献   
98.
Background. Accepted practices of informed consent often result in suboptimal patient understanding of research studies.Methods. This pilot study aimed to assess trial-specific tailored materials, compared to a widely used generic booklet about clinical trials, randomly assigned to 118 candidates for cancer clinical trials. Study outcomes were: satisfaction with decision-making; satisfaction with materials; and subjective understanding of the clinical trial.Results. There were no major differences between groups. Participants rated tailored materials higher as a useful reference.Conclusions. Trial-specific materials hold utility for reference during clinical trials. Studies of informed consent are feasible, although important factors limit research.  相似文献   
99.
The leaf essential oil of Eugenia zuchowskiae from Monteverde, Costa Rica, has been obtained by hydrodistillation and analyzed by GC–MS. The principal constituents of E. zuchowskiae leaf oil were α-pinene (28.3%), β-caryophyllene (13.2%), α-humulene (13.1%), and α-copaene (8.1%). The leaf essential oil of E. zuchowskiae showed pronounced in-vitro cytotoxic activity against MCF-7, MDA-MB-468, and UACC-257 human tumor cell lines. The major components showed cytotoxic activities comparable to doxorubicin (LC50 14–70 μg/ml).  相似文献   
100.
Transforming growth factor-β1 (TGF-β1) is known to be a potent growth inhibitor for many cell types, including most epithelial cells. In skin keratinocytes, TGF-β1 has been shown to inhibit growth and to rapidly reduce c-mycexpression. However, the molecular mechanism of TGF-β1 action on cell growth of cervical carcinoma has not yet been elucidated. We thus assessed the effect of TGF-β1 on the growth of cervical carcinoma cell lines. Two cervical squamous carcinoma cell lines, CUMC-3 and CUMC-6, were incubated with varying concentrations of TGF-β1, and growth inhibition was evaluated with tetrazolium-based colorimetric assay. After culture in TGF-β1 for 24 h, inhibition of growth was detected in a dose-dependent manner at concentrations of 0.1–10 ng/ml in both cell lines. This effect of TGF-β1 on cultured carcinoma cells was associated with apoptotic process including oligonucleosomal ladder DNA and apoptotic body formations. Northern blot analysis revealed c-mycmRNA expression was suppressed by 10 ng/ml of TGF-β1 following 3 h of treatment in both cell lines. Western blot analysis showed that the level of p27Kip1protein was increased after TGF-β1 treatment in both cell lines. These results suggest that the mechanisms by which TGF-β1 inhibits the growth of cervical carcinoma are complex and may include effects on down-regulation of c-mycgene, and overexpression of p27Kip1protein.  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