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   3106篇
  免费   140篇
  国内免费   25篇
耳鼻咽喉   25篇
儿科学   151篇
妇产科学   94篇
基础医学   222篇
口腔科学   42篇
临床医学   355篇
内科学   687篇
皮肤病学   37篇
神经病学   124篇
特种医学   473篇
外科学   342篇
综合类   40篇
一般理论   2篇
预防医学   198篇
眼科学   35篇
药学   126篇
  1篇
中国医学   4篇
肿瘤学   313篇
  2022年   17篇
  2021年   30篇
  2020年   27篇
  2019年   27篇
  2018年   38篇
  2017年   29篇
  2016年   50篇
  2015年   61篇
  2014年   87篇
  2013年   92篇
  2012年   125篇
  2011年   129篇
  2010年   101篇
  2009年   96篇
  2008年   109篇
  2007年   102篇
  2006年   126篇
  2005年   136篇
  2004年   119篇
  2003年   104篇
  2002年   128篇
  2001年   113篇
  2000年   109篇
  1999年   98篇
  1998年   110篇
  1997年   113篇
  1996年   107篇
  1995年   77篇
  1994年   66篇
  1993年   60篇
  1992年   68篇
  1991年   60篇
  1990年   50篇
  1989年   59篇
  1988年   48篇
  1987年   56篇
  1986年   35篇
  1985年   48篇
  1984年   29篇
  1983年   27篇
  1982年   21篇
  1981年   21篇
  1980年   17篇
  1979年   17篇
  1977年   11篇
  1976年   14篇
  1975年   12篇
  1973年   13篇
  1971年   12篇
  1966年   10篇
排序方式: 共有3271条查询结果,搜索用时 15 毫秒
1.
2.
A rare case of basosquamous carcinoma of the orbit invading the maxillary sinus is presented. The authors discuss clinical and pathological findings. Techniques for removal and reconstructive plastic surgery are reported.  相似文献   
3.
Today, androgen deprivation therapy is a cornerstone of treatment for advanced prostate cancer, although it presents important complications such as osteoporosis. Neridronate, a relatively new bisphosphonate, is able to prevent bone loss in patients with prostate cancer during androgen ablation. INTRODUCTION: Androgen-deprivation therapy (ADT) is a cornerstone of treatment for advanced prostate cancer. This therapy has iatrogenic complications, such as osteoporosis. The aim of our study was to evaluate the efficacy of neridronate, a relatively new bisphosphonate, to prevent bone loss during androgen ablation. MATERIALS AND METHODS: Forty-eight osteoporotic patients with prostate cancer, treated with 3-month depot triptorelina, were enrolled and randomly assigned to two different treatment groups: group A (n = 24) was treated with a daily calcium and cholecalciferol supplement (500 mg of elemental calcium and 400 IU cholecalciferol), and group B (n = 24) received in addition to the same daily calcium and cholecalciferol supplement, 25 mg of neridronate given intramuscularly every month. All patients also received bicalutamide for 4 weeks. Lumbar and femoral BMD was evaluated by DXA at baseline and after 1 year of therapy; moreover, deoxypyridinoline (DPD) and bone alkaline phosphatase (BALP) were determined at the beginning, midway through, and at the end of the study. RESULTS: After 6 and 12 months, whereas patients treated only with calcium and cholecalciferol (group A) showed a marked bone loss, with increased levels of DPD and BALP compared with baseline values, patients treated also with neridronate (group B) had substantially unchanged levels of these markers. After 1 year of treatment, lumbar and total hip BMD decreased significantly in patients treated only with calcium and cholecalciferol (group A), whereas it did not change significantly at any skeletal site in patients treated also with neridronate (group B). No relevant side effects were recorded during our study. CONCLUSIONS: Neridronate is an effective treatment in preventing bone loss in the hip and lumbar spine in men receiving ADT for prostate cancer.  相似文献   
4.
Chronic low back pain: comparison of bone SPECT with radiography and CT   总被引:1,自引:0,他引:1  
Ryan  PJ; Evans  PA; Gibson  T; Fogelman  I 《Radiology》1992,182(3):849
  相似文献   
5.
The action of multiple liability genes is responsible for complex phenotypes at the same time, a single gene, could control several phenotypic features. This is the case of human period 3 gene (hper3), mainly involved in the setting of the biologic clock. Some variants of this gene, besides being associated with the Delayed Sleep Phase Syndrome, showed a key role in determining evening preference rather than morning one. According to this rationale, we hypothesized that this gene could influence circadian mood fluctuations, in mood disorders. Our study demonstrated that rare genetic variants of hper3 are significantly associated to a number of mood disorders features, such as age of onset, response to SSRIs treatment, circadian mood oscillations and characteristics of temperament. These preliminary results could shed further light on the involvement of circadian genes in various aspects of physiological and psychopathological mechanisms of the brain.  相似文献   
6.
Uroscopy in the 21st century: high-field NMR spectroscopy   总被引:1,自引:1,他引:0  
From the experiments described, it can be seen that there are different research approaches that can be taken and these are summarized in Table 1. Whereas much scientific research is principally hypothesis led, there remains, nevertheless, an important place for exploratory research. High resolution NMR can measure, directly and simultaneously, a wide range of endogenous metabolites in biological fluids and has the unique capability of providing structural information on the metabolites detected. It has proved to be a powerful research tool with which to study inherited metabolic diseases, renal disease, drug metabolism, and toxicity, and can be used to monitor the effects of drug therapy. For instance, by using a library of experimental toxins one can map the metabolic profile of site-specific nephron injury. With this approach in man one could eventually take an unknown disease such as Balkan nephropathy and predict the initial site of tubular injury, the mode of injury and therefore the kind of toxin capable of producing that injury. NMR spectroscopic techniques are still advancing rapidly, with ever increasing sensitivity and sophistication of NMR pulse sequences to enhance structural elucidation in complex mixtures. Given the advances in directly coupled HPLC-NMR and even HPLC-NMR-mass spectroscopy it is likely that these technologies in conjunction with pattern recognition will make major contribution to our understanding of renal processes and provide new diagnostic insights in the 21st century.   相似文献   
7.
Leukotriene B4 (LTB4) and the protein kinase C activator, 4-beta-phorbol dibutyrate (PDBu), both induced a pronounced and concentration-dependent stimulation of hydrogen peroxide (H2O2) generation by purified guinea pig peritoneal eosinophils in the concentration range 1 nM-1 microM. The LTB4 response was inhibited competitively by the specific LTB4 receptor antagonist, U-75302, with a KB of 25 nM, while the concentration-response curves for both stimuli were shifted rightwards (3.8-fold and 2.8-fold for LTB4 and PDBu, respectively) by the competitive protein kinase C inhibitor, 1-O-hexadecyl-2-O-methylglycerol at a concentration of 300 microM. LTB4 appears, therefore, to induce respiratory burst in eosinophils via a receptor-mediated mechanism involving protein kinase C.  相似文献   
8.
The use of different approaches to measurement in drug abuse treatment outcome studies has resulted in a lack of comparability across studies. This paper reviews different approaches to timing of baseline and follow-up periods and to dealing with time periods during which follow-up subjects are not "at risk" for drug use. Length and timing of baseline and follow-up periods are considered as well as periods of time within which specific drug use outcomes are measured. It is suggested that research focus on describing the natural course of drug use both prior to and following treatment, in order to determine the most appropriate length and timing of follow-up periods. It is recommended that investigators report drug use data from both "at risk" and "not at risk" periods, and that they choose methods of controlling for time "at risk" which do not eliminate important drug use data from analyses.  相似文献   
9.
After a 3-month, single-blind, run-in period, 151 patients with intermittent claudication were randomly allocated to receive the antiplatelet agent ticlopidine (250 mg twice per day) or an identical placebo. One hundred and twenty patients completed the double-blind phase of the trial, which lasted 21 months. The primary analysis was performed according to the "intention-to-treat principle" in all 151 enrolled patients. There was, continuing on from the third month after randomization, a progressive and sustained improvement of the pain-free and maximum walking distances in the two treatment groups that was significantly greater in the ticlopidine group. The ankle-arm systolic blood pressure ratio at rest and after exercise increased in a significant manner in the ticlopidine group only. In a secondary analysis, with exclusion of 25 patients because of protocol violations at selection, consistently significant differences in favor of the ticlopidine group were still observed for maximum walking distance and systolic ankle-arm blood pressure ratio, both at rest and after exercise. No major side effects were reported in the treated group. It is concluded that long-term treatment with ticlopidine improves walking ability and ankle systolic blood pressure in patients with claudication.  相似文献   
10.
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