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   805篇
  免费   38篇
  国内免费   12篇
耳鼻咽喉   39篇
儿科学   41篇
妇产科学   2篇
基础医学   91篇
口腔科学   19篇
临床医学   66篇
内科学   115篇
皮肤病学   5篇
神经病学   50篇
特种医学   47篇
外科学   177篇
综合类   13篇
一般理论   1篇
预防医学   61篇
眼科学   17篇
药学   75篇
中国医学   3篇
肿瘤学   33篇
  2023年   5篇
  2022年   14篇
  2021年   24篇
  2020年   14篇
  2019年   28篇
  2018年   21篇
  2017年   11篇
  2016年   22篇
  2015年   18篇
  2014年   22篇
  2013年   34篇
  2012年   66篇
  2011年   62篇
  2010年   36篇
  2009年   22篇
  2008年   43篇
  2007年   54篇
  2006年   61篇
  2005年   47篇
  2004年   41篇
  2003年   42篇
  2002年   31篇
  2001年   13篇
  2000年   11篇
  1999年   5篇
  1998年   4篇
  1997年   3篇
  1996年   5篇
  1995年   7篇
  1994年   4篇
  1993年   2篇
  1991年   4篇
  1989年   3篇
  1987年   4篇
  1986年   5篇
  1985年   7篇
  1984年   4篇
  1983年   3篇
  1982年   3篇
  1981年   8篇
  1980年   5篇
  1979年   5篇
  1978年   2篇
  1977年   3篇
  1976年   4篇
  1974年   2篇
  1973年   6篇
  1969年   2篇
  1935年   1篇
  1923年   1篇
排序方式: 共有855条查询结果,搜索用时 15 毫秒
61.
A cross sectional study was conducted on 1000 school children between the ages of 8–16 years, to find out the normal testicular volume. At 8 years the testicular volume averaged 1.4 ml. This increased at the rate of 0.5 ml per year, till it reached 2.9 ml at the age of 11 years. A spurt in testicular growth (increment of 1.6 ml) was recorded between 11 and 12 years. This accelerated growth continued at a rate of about 2.5 ml to 4.0 ml/year, so as to attain a mean testicular volume of 15.6 ml by 16 years of age. It is suggested that a testicular size upto 2.0 ml may be considered infantile as this size correlated with prepubertal stages G1 and PH1 and an increase in the size beyond this may be regarded as the earliest evidence of puberty.  相似文献   
62.
63.
64.
Interleukin (IL)-10 deficiency results in highly elevated levels of interferon (IFN)-γ, as well as the IFN-γ-inducible chemokines CXCL9 and CXCL10 within murine cytomegalovirus (MCMV)-infected brains. To test the hypothesis that these elevated chemokine levels would result in enhanced brain infiltration, we compared immune cell infiltration in response to MCMV brain infection between wild-type and IL-10 knockout (KO) mice. Longitudinal analysis following adoptive transfer of cells from β-actin-luciferase transgenic wild-type mice showed maximal brain infiltration by peripheral immune cells occurred at 5 days post infection. Although the overall percentage of CD45(hi) cells infiltrating the brain was not altered by IL-10 deficiency, paradoxically, despite elevated chemokine levels, reduced T lymphocyte (CD8+) and natural killer (NK) (CD49b+) cell infiltration into the brain was observed in IL-10-deficient animals. This decreased lymphocyte infiltration was associated with elevated levels of the lymph node homing receptor L-selectin/CD62L on CD8+ T cells. Lymph node cells obtained from MCMV-infected mice deficient in IL-10 also displayed reduced migration towards CXCL10 when compared to wild-type animals. Taken together, these data show that despite elevated chemokine levels, absence of IL-10 results in reduced lymphocyte infiltration into MCMV-infected brains.  相似文献   
65.
Fifty patients with major fractures of the pelvis (Trunkey's classification types I and II) treated in an urban Level I Trauma Center were analysed to assess the role of peritoneal lavage and urological studies in the initial evaluation. The mechanisms of injury were automobile v. pedestrian (44 per cent), falls from heights (44 per cent), and motor vehicular accidents (12 per cent). Important hypotension was present in 46 per cent of patients on arrival. Peritoneal tap or lavage was selectively used in 11 patients (22 per cent). Four patients in refractory hypotension despite vigorous resuscitation had positive results. There were no false-positive results or missed intra-abdominal injuries in any of the 50 patients. Laparotomy was carried out in 10 of 50 patients. IVP or cystography was performed in 25 of 50 patients. However, injuries of the urinary tract requiring operative correction (eight injuries in six patients) were all associated with gross haematuria. Urological studies were negative in patients with 1 to 3+ microscopic haematuria. Peritoneal lavage is recommended on a selective basis in patients with pelvic fractures. Microscopic haematuria does not warrant contrast studies of the urinary tract.  相似文献   
66.
67.
Background  Sporotrichosis is commonly encountered due to traumatic implantation of thorns or decayed vegetation with the dimorphic fungi, Sporothrix schenckii . Zoonotic spread of Sporotrichosis is rare and we describe here the first case of feline transmission of lymphocutaneous sporotrichiosis encountered in India.
Methods  An excision biopsy of nodulo-ulcerative lesion from the patients right elbow and forearm were collected for histopathology and portion of the specimen processed for mycological work up. Animal pathogenicity test performed in Swiss albino mice with intraperitoneal & foot pad inoculation. In addition an investigation of the ulcerative skin lesion from the domesticated cat was carried out.
Results  Histopathology examination of tissue sample from the patient and feline lesion revealed granulomatous reaction and a few slender elongated yeast cells consistent with Sporotrichosis. The diagnosis was confirmed by culturing Sporothrix schenkii and demonstration of thermal dimorphism. Pathogenicity testing in mice lead to orchitis in 12–15 days and the organism was re-isolated in pure culture. The patient was treated with oral saturated potassium iodide solution with complete resolution of the lesions.
Conclusion  Close contact with infected domesticated feline can be a potential source of transmission for Sporotrichosis as evidenced in this report.  相似文献   
68.
OBJECTIVE: Utilizing a rabbit anterior cruciate ligament model of ligamentous subfailure injury, biomechanical properties of injured ligament treated with radiofrequency energy were evaluated. It was hypothesized that an injured ligament treated with radiofrequency probe would demonstrate restoration of biomechanical properties lost through injury. BACKGROUND: Radiofrequency probe, thermal treatment has been utilized in the clinical setting to address joint instability caused by ligamentous laxity from injury or repetitive microtrauma. The biomechanical effects of radiofrequency probe thermal treatment on injured ligamentous tissues have not been studied in the laboratory. DESIGN: Three groups of specimens: Control, Sham, and Treatment, 10 each, were tested under identical conditions. METHODS: Viscoelastic behavior was analyzed using a relaxation test (6% strain, up to 180 s) performed before injury, after injury, and after injury plus sham or injury plus radiofrequency probe treatment. RESULTS: After injury the normalized forces in the relaxation test decreased by approximately 50%. The post-treatment relaxation test revealed significant ( P < 0.01 ) restoration of the average relaxation force in the Treatment group to that of the Control group (0.79, SD 0.11 vs. 0.80, SD 0.10). Both of these groups were significantly different from the Sham group (0.44, SD 0.11). Additionally, stretch-to-failure test showed partial restoration of the toe region of the load-deformation curve by the radiofrequency treatment. CONCLUSIONS: The radiofrequency probe treatment is shown to be an effective mechanism for restoring initial ligament tensile stiffness and viscoelastic characteristics lost by the subfailure injury in vitro.  相似文献   
69.
OBJECTIVE: To evaluate the radiofrequency treatment applied to an intact anterior cruciate ligament, and to quantify the mechanical effects of controlled cyclic loading (simulating activities of daily living) post-treatment. DESIGN: An in vitro radiofrequency energy application to the rabbit anterior cruciate ligament and cyclic loading of the treated ligament. BACKGROUND: Effect of cyclic loading on the radiofrequency treated ligament in a controlled environment is not known. METHODS: In the treatment group radiofrequency treatment was applied to an intact ligament and then the ligament was cyclically loaded for 3000 cycles, and stretched-to-failure. Control group was similar to treatment, except that the radiofrequency treatment was not applied. The cyclic loading (approximately 6% tensile strain) was kept below the injury threshold of the rabbit anterior cruciate ligament and was designed to simulate loading post-treatment. A relaxation test (5% constant strain for 180 s) was used to compare the results at different steps in the experiment; within each group and between the two groups. RESULTS: Relaxation force increased in the treatment group (average 108% of intact, P<0.05), but decreased after the cyclic loading (average 71% of intact, P<0.05). There were significant differences in the force-deformation-failure curves between the treatment and control groups: average treated ligament failed at 59% and 57% of the control values respectively for the deformation and force (P<0.05). CONCLUSIONS: Using radiofrequency treatment makes rabbit anterior cruciate ligament weaker following cyclic loading. RELEVANCE: The radiofrequency treatment weakens the anterior cruciate ligament, and therefore, it perhaps should be protected until healing and adaptation restore its full strength.  相似文献   
70.
Alzheimer's disease (AD) is the most common cause of dementia among the elderly, affecting 5% of Americans over age 65, and 20% over age 80. An excess of senile plaques (beta-amyloid protein) and neurofibrillary tangles (tau protein), ventricular enlargement, and cortical atrophy characterizes it. Unfortunately, targeted drug delivery to the central nervous system (CNS), for the therapeutic advancement of neurodegenerative disorders such as Alzheimer's, is complicated by restrictive mechanisms imposed at the blood-brain barrier (BBB). Opsonization by plasma proteins in the systemic circulation is an additional impediment to cerebral drug delivery. This review gives an account of the BBB and discusses the literature on biodegradable polymeric nanoparticles (NPs) with appropriate surface modifications that can deliver drugs of interest beyond the BBB for diagnostic and therapeutic applications in neurological disorders, such as AD. The physicochemical properties of the NPs at different surfactant concentrations, stabilizers, and amyloid-affinity agents could influence the transport mechanism.  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