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   1879篇
  免费   99篇
  国内免费   9篇
耳鼻咽喉   24篇
儿科学   45篇
妇产科学   61篇
基础医学   263篇
口腔科学   85篇
临床医学   178篇
内科学   321篇
皮肤病学   28篇
神经病学   119篇
特种医学   42篇
外科学   163篇
综合类   33篇
预防医学   133篇
眼科学   132篇
药学   245篇
中国医学   16篇
肿瘤学   99篇
  2024年   5篇
  2023年   21篇
  2022年   82篇
  2021年   105篇
  2020年   66篇
  2019年   63篇
  2018年   80篇
  2017年   59篇
  2016年   80篇
  2015年   75篇
  2014年   102篇
  2013年   128篇
  2012年   173篇
  2011年   182篇
  2010年   96篇
  2009年   82篇
  2008年   104篇
  2007年   109篇
  2006年   69篇
  2005年   64篇
  2004年   50篇
  2003年   51篇
  2002年   39篇
  2001年   13篇
  2000年   9篇
  1999年   6篇
  1998年   7篇
  1997年   6篇
  1996年   6篇
  1995年   3篇
  1994年   5篇
  1993年   6篇
  1992年   6篇
  1990年   1篇
  1989年   3篇
  1986年   2篇
  1984年   1篇
  1983年   3篇
  1982年   2篇
  1981年   3篇
  1980年   2篇
  1978年   2篇
  1977年   1篇
  1976年   3篇
  1975年   2篇
  1974年   1篇
  1973年   6篇
  1971年   1篇
  1969年   1篇
  1968年   1篇
排序方式: 共有1987条查询结果,搜索用时 15 毫秒
81.
The fabricated NaY(WO4)2 was identified through diverse analysis methods. Therefore, to optimize NaY(WO4)2 morphology, saccharide carbohydrates were manipulated as a capping agent. In this study, glucose, fructose, lactose, cellulose, and starch were utilized as the capping agents. SEM images show that fructose was the optimal capping agent for achieving uniform and well-shaped nanoparticles. The photodegradation of organic dyes such as M.O and Rd.B by NaY(WO4)2 was evaluated under UV and Vis light. The bandgap energy of the as-prepared sample was measured by the Tauc plot, and was found to be nearly 3.85 eV. To study the photocatalytic characteristics, the influence of dye dosage and reusability on photodegradation behavior were investigated.

NaY(WO4)2 nanoparticles were fabricated via a simple hydrothermal method using saccharide carbohydrates as capping agents. The photocatalytic behavior of the as-prepared NaY(WO4)2 nanostructures was studied.  相似文献   
82.
83.
84.
85.
Whereas diffuse adenomyosis is a common finding in parous women, cystic adenomyosis causing severe dysmenorrhoea is very rarely reported and possibly under-diagnosed, particularly in adolescents. We report a case of juvenile cystic adenomyosis in a 19-year-old nulliparous patient presenting with secondary dysmenorrhoea and non-cyclical pain. A 20-mm adenomyotic cyst in the fundal myometrium was successfully excised laparoscopically by modified myomectomy. It is mandatory to take persistent primary and early secondary dysmenorrhoea seriously, especially after poor response to medical treatment and to have a low threshold for further investigations, because a diagnosis of cystic adenomyosis requires targeted therapeutic intervention.  相似文献   
86.
Aim: This study was conducted to investigate the effect of oral vitamin E on mucositis and neutropenia in patients with leukemia. Methods: This was a randomized double‐blind placebo controlled clinical trial of 60 patients with leukemia (acute lymphoblastic, acute myelogenous leukemia and chronic myelogenous leukemia) who were consecutive recipients of allogenic bone marrow transplantation (BMT), randomly assigned to receive 400 mg vitamin E twice daily (supplemented group) or placebo (control). The incidence and severity of mucositis and the mean duration of neutropenia were compared. Results: The mean duration of neutropenia and the incidence of the mucositis between the two groups was the same (P = 1.0). The difference between the placebo group and mucositis grade 1 (P = 0.31), grade 2 (P = 0.25), grade 3 (P = 0.93) and grade 4 (P = 0.32) was not statistically significant. Moreover the variables of age, sex, BMI and underlying disease had no effect. Conclusion: In this study supplementation with oral vitamin E had no effect on mucositis and neutropenia in patients with leukemia who were recipients of allogenic BMT. More interventional trials are warranted.  相似文献   
87.
88.
The present study investigated the effects of aerial parts of Phlomis anisodonta methanolic extract (PAE) on streptozotocin (STZ)-induced diabetic rats by measuring fasting blood glucose, serum insulin, change in body weight, ferric reducing antioxidant power (FRAP), lipid peroxidation (LPO), and liver antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Male Wistar rats were randomly divided into six groups of six animals. Treatment of diabetic rats with oral administration of PAE at doses of 100, 200 and 400 mg kg(-1) for 10 days resulted in a significant reduction in fasting blood glucose, and an increase in serum insulin levels in comparison with diabetic control group. PAE also protected rats from STZ-induced loss in body weight. Hepatic FRAP increased and LPO in diabetic rats decreased after treatment by PAE at doses of 200 and 400 mg kg(-1). PAE-treated diabetic rats at three doses indicated a significant increase in hepatic SOD, CAT, and GPx activities. These results suggest that PAE is beneficial in the control of diabetes by reduction of blood glucose and increasing insulin levels and combating oxidative stress by activation of hepatic antioxidant enzymes.  相似文献   
89.
This study evaluated airborne acrylamide exposures experienced by laboratory personnel using either crystalline or commercially available solutions of acrylamide to make polyacrylamide gels. Exposures were monitored for a short-term (15-min) sampling period, during the weighing of the crystalline acrylamide or the removal of the acrylamide solution from its original container, and a long-term period, during which a sample was collected for as long as the subject was potentially exposed to acrylamide. Mean air concentrations for the 15-min exposures were 7.20 +/- 5.64 micrograms/m3 and 5.81 +/- 4.53 micrograms/m3 for the users of crystalline and solution acrylamide, respectively, although this difference was not statistically significant (p > 0.05). Mean concentrations for the long-term exposures were 12.77 +/- 24.20 micrograms/m3 for workers employing crystalline acrylamide and 4.22 +/- 7.05 micrograms/m3 for personnel using acrylamide solutions. This difference was also not statistically significant. Although the results indicate that the research laboratory personnel were generally exposed to measurable concentrations of acrylamide, with several subjects exposed to elevated levels, the calculated 8-hour time-weighted average exposures were below current occupational exposure limits. However, because the neurotoxic effects of acrylamide are cumulative and it is a suspected carcinogen, all exposures should be kept as low as reasonably achievable.  相似文献   
90.
The role of ionotropic glutamate receptors and voltage-dependent calcium channels (VDCCs) in potentiation phenomenon and epileptic activity induced by a transient pentylenetetrazol (PTZ) application in the CA1 region of rat hippocampal slices was investigated. Also we examined whether adenosine as an inhibitory neuromodulator would interact with expression of the long-lasting effect of transient PTZ. Population spikes (PS) were recorded in the CA1 cell body layer of the hippocampal slices following stratum radiatum stimulation. Changes in the PS amplitude potentiation and number of extra PS, which induced by transient PTZ were used as indices to quantify the effects of drugs. PS input-output curve was significantly increased 10 min after PTZ application and persisted at least for 60 min after PTZ washout. Polyspikes also appeared, but did not persist. Both ketamine and APV reduced the extent of potentiation of PS amplitude but had no effect on number of extra PS. The selective non-NMDA receptor antagonist CNQX prevented the amplitude potentiation and the generation of extra PS. The blocker of VDCCs, verapamil, prevented the amplitude potentiation and inhibited polyspike activity. Co-application of adenosine and PTZ produced a rapid and reversible decrease in the PS amplitude, but PTZ-induced potentiation phenomenon was observed after washout. It is concluded that ionotropic glutamate receptors as well as VDCCs involve in the PTZ-induced LTP of PS amplitude. PTZ-induced LTP is also insensitive to adenosine. The epileptiform activity induced by a transient PTZ application could be attributed to VDCCs. The polyspikes mediated by VDCCs are dependent on prior activation of AMPA receptors.  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