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   108219篇
  免费   7030篇
  国内免费   467篇
耳鼻咽喉   1181篇
儿科学   2752篇
妇产科学   1925篇
基础医学   13549篇
口腔科学   1966篇
临床医学   11619篇
内科学   21605篇
皮肤病学   1848篇
神经病学   10512篇
特种医学   4539篇
外国民族医学   3篇
外科学   17186篇
综合类   1216篇
一般理论   131篇
预防医学   9096篇
眼科学   2174篇
药学   7037篇
中国医学   109篇
肿瘤学   7268篇
  2023年   624篇
  2022年   983篇
  2021年   2175篇
  2020年   1427篇
  2019年   2209篇
  2018年   2703篇
  2017年   1951篇
  2016年   2113篇
  2015年   2431篇
  2014年   3663篇
  2013年   5013篇
  2012年   7831篇
  2011年   8272篇
  2010年   4783篇
  2009年   4373篇
  2008年   7422篇
  2007年   7789篇
  2006年   7496篇
  2005年   7221篇
  2004年   6994篇
  2003年   6304篇
  2002年   5945篇
  2001年   1084篇
  2000年   810篇
  1999年   1117篇
  1998年   1391篇
  1997年   1106篇
  1996年   905篇
  1995年   824篇
  1994年   706篇
  1993年   686篇
  1992年   610篇
  1991年   555篇
  1990年   490篇
  1989年   469篇
  1988年   429篇
  1987年   435篇
  1986年   373篇
  1985年   412篇
  1984年   405篇
  1983年   333篇
  1982年   415篇
  1981年   359篇
  1980年   276篇
  1979年   168篇
  1978年   180篇
  1977年   172篇
  1976年   139篇
  1975年   127篇
  1973年   128篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
The behavioral effects of the antidepressants nomifensine, diclofensine, bupropion, and imipramine were examined using a cocaine substitution drug self-administration procedure in baboons and a cocaine drug discrimination procedure in rats. Intravenous self-administration of the antidepressants was examined in baboons under conditions in which baseline responding was maintained by intravenous injections of cocaine HCl (0.32 mg/kg/injection). Drug was available under a fixed-ratio 80-response or 160-response schedule of intravenous injection. Each drug injection was followed by a 3-h time-out allowing a maximum of eight injections per day. The antidepressants or their vehicles were substituted for cocaine for a period of 15 days, followed by a return to the cocaine baseline. Nomifensine, diclofensine, and bupropion all maintained self-administration behavior at levels above those maintained by their respective vehicles. Some doses of nomifensine, diclofensine, and bupropion maintained levels of behavior similar to those maintained under baseline cocaine conditions. High doses of imipramine maintained levels of behavior above those maintained by its vehicle, but the amount of behavior maintained under these conditions was extremely small. In a second experiment rats were trained to discriminate 32 µmol/kg cocaine (IP 10 min presession) from no drug in a two-lever food reinforced drug discrimination procedure in which responding on one lever was reinforced following ten consecutive responses when the session was preceded by cocaine administration, while responding on the other lever was similarly reinforced in the absence of cocaine pretreatment. Cocaine, nomifensine, diclofensine, and bupropion all dose-dependently occasioned cocaine-appropriate responding. Imipramine did not occasion cocaine-appropriate responding over a range of behaviorally active doses.  相似文献   
73.
A patient with an unusual granulomatous response to infection with Pneumocystis carinii is described. The diagnosis was made by open lung biopsy after two negative bronchoalveolar lavages.  相似文献   
74.
1. The effect of inflammation induced by lipopolysaccharide (LPS) injection on plasma follistatin (FS) concentrations was investigated. 2. Plasma FS and tumour necrosis factor-α concentrations increase following LPS administration in ewes. 3. The rise in FS is similar, but more sustained, to that previously observed after surgery. 4. These results indicate a possible functional link between FS, inflammation and the acute-phase response.  相似文献   
75.
Platelet-derived growth factor (PDGF) and insulin-like growth factor I (IGF-I) in combination have previously been shown to enhance periodontal regeneration. The objective of this study was to further characterize the biological effects of this combination of growth factors in non-human primates and compare the effects to those of each growth factor individually. Ligature-induced periodontitis was initiated in 10 cynomolgus monkeys. After periodontal lesions were established, surgery was performed, and either a methylcellulose gel vehicle or vehicle containing 10 μg each of either PDGF-BB, IGF-I or both PDGF-BB and IGF-I was applied to exposed root surfaces. Biopsies were taken 4 and 12 wk after treatment and the extent of periodontal regeneration was assessed by histomorphometry. At both 4 and 12 wk vehicle-treated lesions generally revealed minimal osseous defect fill (ODF) (8.5±2.1% and 14.5±5.7%, respectively) and new attachment (NA) (34.1±5.2% and 26.6±10.5%, respectively). IGF-I treatment did not significantly alter healing compared to vehicle in any parameter at both 4 and 12 wk. PDGFBB-treated sites exhibited significant (p<0.05) regeneration of NA (69.6±12.0%) at 12 wk; trends for PDGF-BB treatment effect were also observed in other parameters at 4 and 12 wk. although these increases were not statistically significant. Treatment with PDGF-BB/IGF-I resulted in 21.6±5.1 % and 42.5±8.3% ODF at 4 and 12 wk, respectively, and 64.1±7.7% and 74.6±7.4% NA at 4 and 12 wk, respectively (all significantly greater than vehicle, p<0.05). The results from this study demonstrated that: 1) IGF-1 alone at the dose tested did not significantly alter periodontal wound healing; 2) PDGF-BB alone significantly stimulated NA, with trends of effect on other parameters; and 3) the PDGF-BB/IGF-I combination resulted in significant increases in NA and ODF above vehicle at both 4 and 12 wk.  相似文献   
76.
Stenting of the carotid artery is usually performed either to prevent an acute neurologic event or to treat episodes of recurrent transient ischemic attacks. Occasionally, it may be performed for other indications. We describe the case of a patient with prior coronary artery bypass grafting using a left internal mammary arterial graft, in addition to left carotid artery to left subclavian artery bypass for symptomatic left subclavian stenosis, who subsequently underwent left common carotid artery stenting to relieve anginal symptoms.  相似文献   
77.
Body pain and treatment response in late-life depression.   总被引:2,自引:0,他引:2  
OBJECTIVE: The authors investigated the influence of body pain on 1) time to treatment response and 2) suicidal ideation, in late-life depression. They hypothesized that higher levels of body pain would predict a longer time to and lower likelihood of response, and increased levels of suicidal ideation. METHODS: Subjects (N=187) were older adult outpatients (age > or =69 years), with current episodes of major depression, who were openly treated with paroxetine up to 40 mg daily and weekly interpersonal psychotherapy. Response was defined as 3 consecutive weeks of Hamilton Rating Scale for Depression at < or =10. Body pain was measured with the Bodily Pain Index of the SF-36 quality-of-life assessment. Authors used survival-analysis models on the responder sample to test the effect of body pain on response, after controlling for severity of depression. RESULTS: Overall response rate was 75.4%. Nonresponders reported more severe pain at baseline. After covarying for severity of baseline depression, no effect was found for physical pain on time-to-response or degree of suicidality. Bodily pain remained stable during acute treatment for responders, independent of depression response to combination psychotherapy and antidepressant treatment. CONCLUSIONS: Older adult patients with higher levels of physical pain can still respond to antidepressant treatment; however, reported bodily pain may be associated with a more difficult-to-treat depression.  相似文献   
78.
79.
80.
Despite recent advances in understanding the immunopathogenesis of oral lichen planus (LP), the initial triggers of lesion formation and the essential pathogenic pathways are unknown. It is therefore not surprising that the clinical management of oral LP poses considerable difficulties to the dermatologist and the oral physician. A consensus meeting was held in France in March 2003 to discuss the most controversial aspects of oral LP. Part 1 of the meeting report focuses on (1) the relationship between oral LP and viral infection with special emphasis on hepatitis C virus (HCV), and (2) oral LP pathogenesis, in particular the immune mechanisms resulting in lymphocyte infiltration and keratinocyte apoptosis. Part 2 focuses on patient management and therapeutic approaches and includes discussion on malignant transformation of oral LP.  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