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   1570篇
  免费   89篇
  国内免费   3篇
耳鼻咽喉   22篇
儿科学   157篇
妇产科学   44篇
基础医学   238篇
口腔科学   50篇
临床医学   110篇
内科学   246篇
皮肤病学   29篇
神经病学   91篇
特种医学   24篇
外科学   179篇
综合类   54篇
一般理论   1篇
预防医学   112篇
眼科学   62篇
药学   169篇
中国医学   12篇
肿瘤学   62篇
  2023年   14篇
  2022年   38篇
  2021年   51篇
  2020年   41篇
  2019年   39篇
  2018年   53篇
  2017年   27篇
  2016年   38篇
  2015年   53篇
  2014年   55篇
  2013年   78篇
  2012年   70篇
  2011年   91篇
  2010年   63篇
  2009年   48篇
  2008年   70篇
  2007年   84篇
  2006年   91篇
  2005年   90篇
  2004年   67篇
  2003年   55篇
  2002年   47篇
  2001年   45篇
  2000年   47篇
  1999年   31篇
  1998年   15篇
  1997年   15篇
  1996年   13篇
  1995年   8篇
  1993年   3篇
  1992年   20篇
  1991年   15篇
  1990年   11篇
  1989年   19篇
  1988年   17篇
  1987年   14篇
  1986年   7篇
  1985年   12篇
  1984年   14篇
  1983年   8篇
  1981年   3篇
  1980年   7篇
  1979年   13篇
  1978年   6篇
  1976年   11篇
  1975年   5篇
  1974年   10篇
  1973年   3篇
  1972年   7篇
  1968年   5篇
排序方式: 共有1662条查询结果,搜索用时 0 毫秒
1.
A 50-yr-old man presented with synovitis of the metacarpophalangealjoints, Raynaud's phenomenon, recurrent pericarditis and a linearpalpable rash in both axillae.  相似文献   
2.
3.
Congenital thoracic ectopic kidney is a very rare developmental anomaly and the rarest form of all ectopic kidneys. It is usually asymptomatic and discovered incidentally on routine chest radiography. Herein we reported the first case of staghorn stone in a thoracic kidney managed successfully by percutaneous nephrolithotomy.  相似文献   
4.
Sturge-Weber syndrome is a rare neurocutaneous disorder characterized by a facial nevus flammeus and extensive angiomatous changes involving the leptomeninges, the dura, and vessels of the gray and white matter. Oculodermal melanocytosis is characterized by hyperpigmentation of the facial skin in the distribution of the ophthalmic, maxillary, and occasionally mandibular division of the trigeminal nerve.  相似文献   
5.
Due to deep seated location and presence of vital structures, the tumours of the parapharyngeal space poses difficulty in its early diagnosis, histological nature and surgical extirpation. Modes of radiological assessment in pre-computed tomography (GT) scan era were sialography of the parotid gland to see whether the tumour is of salivary origin and angiography to note the vascularity of the tumour. Post CT scan era has changed the assessment protocol. In this article, the authors have tried to make a comparative evalua?tion between non-contrast GT, GT with systemic contrast and GT sialogram in 14 cases of parapharyngeal tumours. Angiography was done only when the tumours showed marked enhancement with systemic contrast. Subsequently, 13 patients underwent surgery for removal of the mass. Application of high-resolution GT helped in not only to see the extent of the tumour but also to pinpoint the probable histologic nature.  相似文献   
6.
7.
We examined gliding motility and cell invasion by an early-branching apicomplexan, Cryptosporidium parvum, which causes diarrheal disease in humans and animals. Real-time video microscopy demonstrated that C. parvum sporozoites undergo circular and helical gliding, two of the three stereotypical movements exhibited by Toxoplasma gondii tachyzoites. C. parvum sporozoites moved more rapidly than T. gondii sporozoites, which showed the same rates of motility as tachyzoites. Motility by C. parvum sporozoites was prevented by latrunculin B and cytochalasin D, drugs that depolymerize the parasite actin cytoskeleton, and by the myosin inhibitor 2,3-butanedione monoxime. Imaging of the initial events in cell entry by Cryptosporidium revealed that invasion occurs rapidly; however, the parasite does not enter deep into the cytosol but rather remains at the cell surface in a membrane-bound compartment. Invasion did not stimulate rearrangement of the host cell cytoskeleton and was inhibited by cytochalasin D, even in host cells that were resistant to the drug. Our studies demonstrate that C. parvum relies on a conserved actin-myosin motor for motility and active penetration of its host cell, thus establishing that this is a widely conserved feature of the Apicomplexa.  相似文献   
8.
Infections by the protozoan parasite Toxoplasma gondii are widely prevalent worldwide in animals and humans. This paper reviews the life cycle; the structure of tachyzoites, bradyzoites, oocysts, sporocysts, sporozoites and enteroepithelial stages of T. gondii; and the mode of penetration of T. gondii. The review provides a detailed account of the biology of tissue cysts and bradyzoites including in vivo and in vitro development, methods of separation from host tissue, tissue cyst rupture, and relapse. The mechanism of in vivo and in vitro stage conversion from sporozoites to tachyzoites to bradyzoites and from bradyzoites to tachyzoites to bradyzoites is also discussed.  相似文献   
9.
Image registration is an important step in the radiotherapy treatment planning process. It provides a method of fusing different types of diagnostic imaging information. One such application is to combine magnetic resonance spectroscopic images (MRSI) of the prostate with anatomical MRI and/or computed tomography images that are routinely used in the radiation treatment planning of prostate cancer. MRSI provides in vivo information related to the underlying metabolic activity of tissues, and can be related to the presence of cancer. However, the inflated endorectal coil required during MRS imaging poses a potential problem by deforming the prostate when it is filled with approximately 100 cm3 of air during image acquisition. This pushes the prostate superiorly/anteriorly, deforming the prostate and consequently the spectroscopic imaging data in a nonlinear manner. In this application, the coil-deformed MRS images are warped back to a non-deformed state, using a single data set. A nonlinear warping algorithm is presented to achieve this. Results indicate that the algorithm attains an accuracy of 97% (4 cm3 difference) when reproducing the total prostate volume compared to a Radiation Oncologist defined prostate volume. This difference is slightly smaller than the measured intra-operator variance of +/-1.5 cm3 (deflated coil) and the measured algorithm variance of +/-1.0 cm3. Additionally, intraprostatic nodules were used to assess the accuracy of the warping algorithm in regions inside the prostate. While choosing anatomical tie points along the external prostate surface, analysis of the nodules revealed the algorithm accuracy reduced to 63-93%.  相似文献   
10.
The M2 receptor (M2-mAChR) is quantitatively the dominant muscarinic subtype in animal bladders. The alterations in its protein quantity and biosynthesis during diabetic cystopathy were investigated. Three-month-old male Wistar rats were divided into two groups: (1) 2-week-old diabetics; and (2) normoglycemic control rats. Diabetes was induced by single intravenous injection of 60 mg/kg streptozotocin. The amount of M2 receptor protein in the rat bladder body tissue was measured by Western immunoblotting using monoclonal antibodies. For determination of M2 muscarinic receptor mRNA in the bladder tissue, the method of Northern blotting was employed. The results of the Western immunoblotting showed that the amount of M2-mAChR protein in the diabetic bladder was significantly increased by 40.0 +/- 6.2% when compared with the control bladder (P < 0.05, n = 8). The Northern blotting demonstrated a 69.3 +/- 8.5% increase of the M2-mAChR mRNA in the diabetic bladder (P < 0.05, n = 8). The findings of the present study demonstrated an up-regulation of M2-mAChR biosynthesis in the diabetic urinary bladder. This phenomenon could lead to increased reactivity to acetylcholine and thus results in detrusor instability.  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