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   133416篇
  免费   6584篇
  国内免费   433篇
耳鼻咽喉   1754篇
儿科学   4219篇
妇产科学   3429篇
基础医学   17989篇
口腔科学   4580篇
临床医学   9555篇
内科学   31893篇
皮肤病学   4269篇
神经病学   10980篇
特种医学   3152篇
外国民族医学   30篇
外科学   17327篇
综合类   720篇
一般理论   39篇
预防医学   12603篇
眼科学   2276篇
药学   8801篇
中国医学   525篇
肿瘤学   6292篇
  2023年   812篇
  2022年   1616篇
  2021年   3468篇
  2020年   1840篇
  2019年   3220篇
  2018年   4082篇
  2017年   2636篇
  2016年   2690篇
  2015年   2944篇
  2014年   4173篇
  2013年   5680篇
  2012年   8591篇
  2011年   9051篇
  2010年   4885篇
  2009年   4403篇
  2008年   7293篇
  2007年   7559篇
  2006年   7231篇
  2005年   7245篇
  2004年   6563篇
  2003年   6163篇
  2002年   5869篇
  2001年   3662篇
  2000年   3833篇
  1999年   3194篇
  1998年   1068篇
  1997年   792篇
  1996年   697篇
  1995年   618篇
  1994年   490篇
  1993年   488篇
  1992年   1552篇
  1991年   1474篇
  1990年   1318篇
  1989年   1144篇
  1988年   1031篇
  1987年   994篇
  1986年   919篇
  1985年   864篇
  1984年   631篇
  1983年   563篇
  1979年   540篇
  1978年   377篇
  1975年   409篇
  1974年   461篇
  1973年   456篇
  1972年   403篇
  1971年   387篇
  1970年   389篇
  1969年   377篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
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   
82.

Background  

The justification for Nazi programs involving involuntary euthanasia, forced sterilisation, eugenics and human experimentation were strongly influenced by views about human dignity. The historical development of these views should be examined today because discussions of human worth and value are integral to medical ethics and bioethics. We should learn lessons from how human dignity came to be so distorted to avoid repetition of similar distortions.  相似文献   
83.
This case report demonstrates how extracting a maxillary deciduous canine affects the eruption path of a labially displaced ectopically erupting permanent canine. A long-term follow-up is presented, and the biologic mechanisms are discussed.  相似文献   
84.
85.
Zygophyllum fahago is a herbaceous plant found widely in the Mediterranean area. There are no previous reports of its allergenicity. An aerobiologic and clinical survey was conducted in Murcia, southern Spain, to determine the quantity of airborne pollen and establish the possible role of this pollen as a cause of allergic symptoms. With a Hirst volumetric trap, we determined the atmospheric concentrations of this pollen in 1993, 1994,1995, and 1996. Of 1180 patients tested, 181 (15,34%) had a positive skin test. To determine its allergenicity, we divided 47 patients into three groups: in group 1, all the patients had symptoms of rhinoconjunctivitis plus asthma; in groups 2 and 3, rhinoconjunctivitis. In group 1, we performed a bronchial provocation test (BPT): in groups 2 and 3, we performed nasal provocation (NPT) and conjunctival provocation (CPT) tests, respectively, SDS-PAGE was used to characterize the antigenic fractions and RAST inhibition to determine cross-reactivity with other pollens. The pollen dispersion period is from May to September (445 grains/m3), BPT was positive in 13 of 15 patients, NPT in 14 of 16 patients, and CPT in 13 of 16 patients. RAST inhibition revealed cross-reactivity with Mercurialis, Ricinus, Olea. and Betula. SDS-PAGE identified 25 IgE antibody-binding components, five of which (60, 65, 41, 38, and 15.5/14,7 kDa) were recognized by 40% of the sera. By SDS-PAGE immunoblotting with sunflower antiprofilin rabbit serum and affinity chromatography we established that the Z. fahago extract has profilin. This study shows that this pollen becomes airborne and elicits an IgE response which triggers respiratory symptoms in allergic subjects.  相似文献   
86.
Split-skin harvesting is a procedure which requires effective anaesthesia. The application of EMLA® cream to the skin effectively serves this purpose as was shown as early as 1985 [7]. This study with 146 patients indicated that dermal analgesia with EMLA cream is less risky for patients and also cheaper, although there were no data to support the latter. Accordingly, another 122 patients were selected retrospectively. They were from the same department and had undergone split-skin harvesting for the same indications and over a similar period but under general or regional block anaesthesia. In addition, these 122 patients received postanaesthesia care in a recovery ward. These 122 patients and the 146 patients from the previous study are compared in this analysis of economy and risk. The analysis indicated considerable cost savings and less risk for patients treated with EMLA.  相似文献   
87.
88.
89.
The present study demonstrates the effects of the antidepressant, amitriptyline, and the acetylcholine antagonist, atropine, on the stimulation-induced rise in cytosolic, free Ca2+ (Cai2+). The changes in Cai2+ of collagenase-isolated rat parotid acini were measured by means of the Ca2(+)-sensitive dye, fura-2. It was found that stimulation by carbachol resulted in a maximal increase of 582 +/- 34 nM (mean +/- S.E.) in Cai2+ with a ks of 5.8 +/- 1.3 microM. Adrenaline caused a rise of 380 +/- 22 nM in Cai2+ with a ks of 0.5 +/- 0.2 microM. Amitriptyline and atropine were found to inhibit the carbachol-induced rise in Cai2+ with dissociation constants (kI) of 105 and 1.25 nM, respectively, in the absence of agonist. The adrenergic-induced rise in Cai2+ was inhibited by amitriptyline with a kI of 45 nM. Amitriptyline was found to inhibit both receptor classes by a competitive or mixed type of inhibition. Similarly, atropine exerted the same type of inhibition on the acetylcholine receptor. Amitriptyline and atropine were found to be mutually exclusive for competing for substrate binding on the receptor. These findings are consistent with a common binding site for amitriptyline and atropine on the acetylcholine receptor, possibly in close proximity with, but different from the substrate binding site. The stimulation-induced cell shrinkage evoked by the loss of electrolytes and water from the acini was measured by a 90 degree light scattering signal. It was found that this method makes possible the detection of autonomic side-effects of antidepressants on acini suspended in protein-containing media.  相似文献   
90.
Test meals with 10.9 g dietary fibre from sugar beet and corresponding control meals were given to eight healthy subjects, aged 67 ± 9 years. The postprandial glucose, triglyceride, hormone and glycerol responses were monitored during 3 hours. After the beet fibre meal the insulin and C-peptide areas were reduced by 28 ( P < 0.01) and 22% ( P > 0.025), respectively, and the somatostatin levels increased by approximately 30% ( P > 0.05). Further, the maximum relative postprandial reduction of plasma glycerol levels was less evident after the fibre-rich meal than after the control meal (36 ± 4% v. 46 ± 4%, P < 0.05). There was no apparent difference in the overall glycaemic response between the meals. The triglyceride levels were similar after both test meals.
Suspension of beet fibre bread given to rats by oro-gastric intubation induced lower blood glucose response than a control bread at 15 and 30 min ( P < 0.001), respectively, but a similar insulin response.
The results suggest an effect of beet fibre on the rate of carbohydrate absorption, expressed as a lower insulin response in the healthy volunteers and a reduced glucose response in the rat.
The mechanism behind this effect in healthy subjects could possibly be mediated by an increased somatostatin response.  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