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   5938篇
  免费   314篇
  国内免费   53篇
耳鼻咽喉   58篇
儿科学   82篇
妇产科学   57篇
基础医学   684篇
口腔科学   172篇
临床医学   334篇
内科学   1436篇
皮肤病学   202篇
神经病学   588篇
特种医学   217篇
外科学   995篇
综合类   20篇
一般理论   1篇
预防医学   125篇
眼科学   228篇
药学   314篇
中国医学   6篇
肿瘤学   786篇
  2023年   46篇
  2022年   83篇
  2021年   187篇
  2020年   100篇
  2019年   129篇
  2018年   166篇
  2017年   121篇
  2016年   163篇
  2015年   155篇
  2014年   198篇
  2013年   233篇
  2012年   431篇
  2011年   425篇
  2010年   273篇
  2009年   240篇
  2008年   383篇
  2007年   374篇
  2006年   362篇
  2005年   351篇
  2004年   365篇
  2003年   344篇
  2002年   297篇
  2001年   67篇
  2000年   57篇
  1999年   72篇
  1998年   68篇
  1997年   46篇
  1996年   50篇
  1995年   52篇
  1994年   38篇
  1993年   42篇
  1992年   45篇
  1991年   35篇
  1990年   35篇
  1989年   23篇
  1988年   25篇
  1987年   15篇
  1986年   24篇
  1985年   21篇
  1984年   19篇
  1983年   14篇
  1982年   11篇
  1980年   9篇
  1978年   13篇
  1977年   9篇
  1976年   10篇
  1975年   13篇
  1974年   10篇
  1972年   7篇
  1971年   7篇
排序方式: 共有6305条查询结果,搜索用时 15 毫秒
1.
Two cultivars of Japanese parsley were harvested in different seasons; their antioxidant capacities were evaluated by oxygen radical absorbance capacity (ORAC) methods, and the contents of hydrophilic and lipophilic antioxidants were compared. Japanese parsley possessed potent antioxidant capacities both in hydrophilic and lipophilic extracts when evaluated by ORAC methods. LC/MS/MS analyses revealed that chlorogenic acid and four kinds of quercetin glycosides were major antioxidants in the hydrophilic extract. Lutein was the main contributor to the antioxidant capacity of the lipophilic extract. Antioxidant capacities of the hydrophilic extracts of both cultivars tended to be higher in winter because of the increase in the contents of chlorogenic acid and quercetin glycosides. An obvious trend in the lipophilic antioxidant capacities or lutein contents was not observed irrespective of the cultivar.  相似文献   
2.
3.
1. The relationship between work-rate and the antihypertensive effect of exercise in hypertensives, and the mechanism of that effect, were investigated by a crossover clinical trial. 2. Ten mild hypertensives were randomly divided into two groups. One group performed low work-rate exercise (LWE) on a cycle ergometer for 10 weeks (blood lactate threshold; ~50% of maximum oxygen consumption [V?O2max]). After a 10 week interval without exercise training, these subjects were then switched to a high work-rate exercise (HWE) regimen (4 mmol/ L of blood lactate; ~75% of V?O2max) for another 10 weeks. In the other group, the order of exercise training was reversed. Since two patients withdrew from the protocol during HWE periods, statistical analysis was performed on the data from the remaining eight patients. There were no order effects observed in any of the data from the two groups. 3. During both LWE and HWE, resting blood pressure (BP) fell significantly after the initiation of exercise therapy (P<0.05). Furthermore, the overall effects of 10 weeks of LWE and HWE on BP were not significantly different. 4. The work-rate at the lactate threshold, which reflects physical fitness, had increased significantly by 16 W (P<0.01) after the LWE period and by 11 W (P<0.01) after the HWE. 5. During the LWE period, changes in haemodynamic and humoral variables were not significant, except for a reduction in plasma norepinephrine at week 10 (P<0.05). In the HWE period, changes in haemodynamic and humoral variables were not significant. 6. Based on these findings, LWE is recommended for mild hypertensives because of its safety.  相似文献   
4.
5.
6.
The purpose of our study is to evaluate whether the hamstring tendons can regrow after harvesting for anterior cruciate ligament (ACL) reconstruction and whether the regenerate tissue can be histologically characterized as tendinous. Eleven of the patients (eight female and three male; mean age, 23 years; range 17–37 years) consented to participate in this study. One year after the ACL reconstruction, surgical biopsy was done. Regeneration of the tendon was detected macroscopically in 9 of the 11 patients. Histologically and immunohistochemically, the regenerated tendons closely resembled normal ones. The results of this study show the hamstring tendons can regenerate after harvesting for the ACL reconstruction.  相似文献   
7.
In patients with either bilateral renal malignancies or with carcinoma occurring in a solitary kidney, the principle of en bloc removal of the tumor-bearing kidney cannot be applied. Recently we have performed surgical enucleation in two cases of asynchronous bilateral renal cell carcinoma. Case 1. A 60-year-old woman was hospitalized with diagnosis of left renal tumor 10 years tumor 10 years after right nephrectomy for renal cell carcinoma. The tumor was enucleated while occluding the renal vessels. Pathological examination revealed that the tumor (a nodule of 35 g) was renal cell carcinoma of grade I and perfectly covered by pseudocapsule. Hemodialysis was not required. The patient has been well for more than 11 months postoperatively and Ccr is 65 ml/min. Case 2. A 62-year-old man with slight elevation of serum GOT and GPT level was examined by CT, which revealed a space occupying lesion in the left kidney. He had undergone nephrectomy for renal cell carcinoma of right kidney 11 years ago. Three nodules of 56 g, 6 g and 3 g were removed by in situ enucleation. They were renal cell carcinoma of grade II and there was no malignant penetration of the pseudocapsule pathologically. After surgery hemodialysis was required 10 times for 21 days. Renal function has been refined gradually and the patient is well with 47.3 ml/min of Ccr at 4 months postoperatively. Before this report of 2 cases there were 22 cases of asynchronous bilateral renal cell carcinoma in Japanese literature.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
8.
Background: Although isoflurane, a volatile anesthetic, can block the motor response to noxious stimulation (immobility and analgesia) and suppress autonomic responsiveness, how it exerts these effects at the neuronal level in the spinal cord is not fully understood.

Methods: The effects of a clinically relevant concentration (1 rat minimum alveolar concentration [MAC]) of isoflurane on electrically evoked and spontaneous excitatory/inhibitory transmission and on the response to exogenous administration of the [gamma]-aminobutyric acid type A receptor agonist muscimol were examined in lamina II neurons of adult rat spinal cord slices using the whole cell patch clamp technique. The effect of isoflurane on the action potential-generating membrane property was also examined.

Results: Bath-applied isoflurane (1.5%, 1 rat MAC) diminished dorsal root-evoked polysynaptic but not monosynaptic excitatory postsynaptic currents. Glutamatergic miniature excitatory postsynaptic currents were also unaffected by isoflurane. In contrast, isoflurane prolonged the decay phase of evoked and miniature [gamma]-aminobutyric acid type A receptor-mediated inhibitory postsynaptic currents and increased the amplitude of the muscimol-induced current. Isoflurane had little effect on action potential discharge activity.  相似文献   

9.
10.
A patient is presented with paroxysmal choreoathetosis precipitated by movement, sound and photic stimulation associated with an arterio-venous malformation (AVM) who responded to carbamazepine treatment. Hemodynamic circulatory disorder of the sensory-motor cortices having AVM may alter striatal function and produce paroxysmal choreoathetosis. This finding supports the concept that paroxysmal choreoathetosis results from an abnormality at the connections between basal ganglia and cerebral cortices.  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