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   834篇
  免费   64篇
  国内免费   60篇
耳鼻咽喉   2篇
儿科学   44篇
妇产科学   7篇
基础医学   109篇
口腔科学   18篇
临床医学   133篇
内科学   189篇
皮肤病学   22篇
神经病学   47篇
特种医学   104篇
外科学   92篇
综合类   25篇
一般理论   2篇
预防医学   58篇
眼科学   10篇
药学   55篇
中国医学   2篇
肿瘤学   39篇
  2019年   11篇
  2018年   20篇
  2017年   5篇
  2016年   13篇
  2015年   16篇
  2014年   31篇
  2013年   35篇
  2012年   17篇
  2011年   28篇
  2010年   35篇
  2009年   32篇
  2008年   37篇
  2007年   67篇
  2006年   24篇
  2005年   27篇
  2004年   20篇
  2003年   8篇
  2002年   18篇
  2001年   19篇
  2000年   15篇
  1999年   21篇
  1998年   36篇
  1997年   39篇
  1996年   24篇
  1995年   22篇
  1994年   31篇
  1993年   20篇
  1992年   10篇
  1991年   17篇
  1990年   7篇
  1989年   24篇
  1988年   22篇
  1987年   13篇
  1986年   8篇
  1985年   14篇
  1984年   10篇
  1983年   6篇
  1982年   11篇
  1981年   12篇
  1980年   12篇
  1979年   8篇
  1978年   7篇
  1977年   12篇
  1976年   12篇
  1975年   6篇
  1974年   7篇
  1970年   6篇
  1968年   6篇
  1966年   10篇
  1939年   5篇
排序方式: 共有958条查询结果,搜索用时 15 毫秒
1.
Balloon dacryocystoplasty: indications and contraindications   总被引:3,自引:0,他引:3  
  相似文献   
2.
OBJECTIVE: The purpose of this study was to determine the efficacy and safety of a targeted narrow band UVB/UVA1 therapy for the treatment of striae alba. METHODS: Fourteen individuals with skin types II-VI were enrolled in this 22-week trial that consisted of up to 10 treatments with a combination of UVB/UVA1 (MultiClear, Curelight Ltd, Israel). Participants were treated with a maximum of 10 treatments unless 100% repigmentation of stretch was achieved prior to the tenth treatment. Biopsies were taken from willing participants at baseline, immediately after the final treatment and 12 weeks after the last treatment. RESULTS: Nine participants completed all treatment visits. After the final treatment, all the participants had >51% repigmentation of the treated striae. At the 4-week follow-up visit, 67% of participants had greater than 51% improvement, and 56% had greater than 51% improvement at the 8-week and 12-week follow-ups. Hyperpigmentation of striae was seen in >50% of the participants treated. The pretreatment biopsies were confirmatory of striae. There were no diagnostic light microscopic differences in the 4-week post-treatment biopsy set available in one patient. CONCLUSION: This high intensity UVB\UVA1 device is an effective and safe modality for the short-term repigmentation of hypopigmented stretch marks. Additional morphologic studies over time are needed to confirm these clinical findings.  相似文献   
3.
Laparoscopic nephron-sparing surgery for the small exophytic renal mass.   总被引:1,自引:0,他引:1  
OBJECTIVES: Nephron-sparing surgery has emerged as the treatment of choice for the incidentally detected small renal mass, especially those less than 4 cm in size. We describe our technique and experience with the laparoscopic excision of these lesions. METHODS: Between June 2001 and October 2003, 20 patients underwent nephron-sparing surgery at our institution. Twenty-one laparoscopic partial nephrectomy procedures were performed. All tumors were detected incidentally by cross-sectional imaging. All patients had a solid renal mass or a complex cystic renal mass of Bosniak category III or greater. All solid tumors were exophytic and less than 4cm in diameter. Both transperitoneal and retroperitoneal approaches were used. Hemostasis was achieved without hilar control in 20 of the 21 cases. RESULTS: Twenty renal units were approached transperitoneally, and 1 retroperitoneally. Mean tumor size was 2.6 cm (range, 1.2 to 4). Mean estimated blood loss was 211 mL (range, 50 to 500), and mean operative time was 165 minutes. Pathology revealed renal cell carcinoma in 14 (70%). No intraoperative complications occurred. Two patients required blood transfusions postoperatively. CONCLUSION: Carefully selected patients with small, exophytic renal masses can safely undergo laparoscopic excision. When achievable, this procedure can be a more logical alternative to ablative techniques for the minimally invasive management of such lesions.  相似文献   
4.
This study recognizes recent advances in the understanding of the anatomy and physiology of peripheral nerves at the cellular level. It has reproduced study conditions originally advocated by de Medinaceli and coworkers, with modifications. Eighty-four rats were divided into three groups. Group A underwent sciatic nerve transection and standard perineurial repair. Group B nerves were frozen, severed with a vibrating blade, and reconnected by tubulization with a rubber cuff while bathed in solutions designed to inhibit Ca++-calmodulin activation, maintain colloid osmotic pressure, and mimic ambient electrolytic conditions. Group C underwent a similar procedure as group B, with the rubber cuff replaced by a polyglycolic acid mesh. All animals were randomized and evaluated functionally in terms of a sciatic index. By post-operative day 225, animals of group A recovered 37% of function, group B recovered 74%, and group C recovered 67%. Compound action potential recordings revealed a velocity recovery of 41% in group A, 70% in group B, and 81% in group C. Microscopic evaluation provided evidence for corresponding structural improvement. This new method of nerve repair is uncomplicated, relatively inexpensive, and easily adaptable to other animal models.  相似文献   
5.
The molecular mechanisms involved in luteolysis are still unclear in the primate. This study aimed to investigate the effect of induced luteolysis on the ovarian luteinizing hormone (LH) receptor and the steroidogenic enzyme, 3beta-hydroxysteroid dehydrogenase (3beta-HSD) in the marmoset monkey. Luteolysis was induced in the mid-luteal phase either directly by systemic prostaglandin F2alpha (PGF2alpha), or indirectly by LH withdrawal using systemic gonadotrophin releasing hormone antagonist (GnRHant) treatment. The LH receptor was studied by isotopic mRNA in-situ hybridization and in-situ ligand binding and 3beta-HSD expression was studied using isotopic mRNA in-situ hybridization and immunohistochemistry. Induced luteolysis was associated with a reduction in the expression of LH receptor (P < 0.0001) and 3beta-HSD mRNA, closely followed by a reduction in the LH receptor (P < 0.05) and 3beta-HSD protein concentrations within 24 h. There were no differences in the findings whether luteolysis was induced with PGF2alpha or GnRHant. This study shows that disparate mechanisms to induce luteolysis in the primate result in an identical rapid loss of the LH receptor and 3beta-HSD. In conclusion, induced luteolysis leads to rapid loss of the steroidogenic pathway in luteal cells.   相似文献   
6.
7.
Periodontitis, a disease responsible for tooth loss worldwide, is characterized by chronic inflammation of the periodontium, eventually leading to destruction of periodontal ligaments and supporting alveolar bone. Spirochetes, identified by dark-field microscopy as being the most predominant bacteria in advanced lesions, are thought to play a causative role. Various spirochetal morphotypes were observed, but most of these morphotypes are as yet uncultivable. To assess the role of these organisms we designed oligonucleotide probes for the identification of both cultivable and so far uncultivable spirochetes in periodontitis patients. Subgingival plaque specimens taken from diseased sites (n = 200) and healthy control sites (n = 44) from 53 patients with rapidly progressive periodontitis (RPP) were submitted to direct in situ hybridization or dot blot hybridization after prior amplification with eubacterial primers. Spirochetes were found in all patients, but their distributions varied considerably. Parallel use of oligonucleotide probes specific for cultivable or so far uncultivable treponemes suggested the presence of novel yet unknown organisms at a high frequency. These uncultivable treponemes were visualized by fluorescence in situ hybridization, and their morphologies, sizes, and numbers could be estimated. All RPP patients included in this study harbored oral treponemes that represent either novel species, e.g., Treponema maltophilum, or uncultivable phylotypes. Therefore, it is necessary to include these organisms in etiologic considerations and to strengthen efforts to cultivate these as yet uncultivable treponemes.  相似文献   
8.
9.
A strain of mouse adenovirus, found to have a striking tropism for the weanling mouse adrenal gland, enabled electron microscopic examination of adrenals in various stages of infection. Nucleolar hypertrophy and the successive formation of three types of inclusion bodies in association with nucleoli preceded virion production. Angular crystals of virions formed in the affected nuclei. Virus was released by lysis of nuclear membranes; rapid degeneration of cytoplasmic organelles followed. Rupture of external cell membranes released virus into the extracellular spaces where virions crossed vascular basement membranes to enter endothelial cells. Virions were also phagocytized by inflammatory cells which reentered vascular sinusoids, and by adrenal parenchymal cells. Disruption of virus-laden phagocytic vacuoles in parenchymal cells released virions into the cytoplasm. Typical viral inclusion bodies also formed in vascular endothelial cells and in inflammatory cells, but virion replication was not detected. The possibility that virus directly entered parenchymal cells through the external cell membrane without phagocytosis is discussed.  相似文献   
10.
We evaluated 14 patients with bilateral testicular tumour, one-sided tumour and contralateral carcinoma in situ (CIS) of the testis or testis tumour in single testis with respect to their fertility. We analysed semen parameters, serum hormones [follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone], testicular sonography, testicular volumes and testicular histology prior to further anti-cancer treatment. Ten out of 14 patients showed normal or reduced sperm concentrations, while 4/14 patients were azoospermic. Serum FSH levels showed a significant negative correlation with sperm concentrations in patients with testicular malignancies (r = -0.64, P = 0.025). Testicular volumes revealed a significant positive correlation with semen parameters in patients with testes that were affected by CIS (r = 0.733, P = 0.038). We conclude that even bilateral testicular cancer and/or CIS do not preclude fertility and, therefore, patients should be offered andrological investigation and therapy, including possibly surveillance strategy or the chance for cryopreservation of the semen prior to further treatment in order to preserve their chances for paternity.   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