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   29489篇
  免费   2416篇
  国内免费   141篇
耳鼻咽喉   346篇
儿科学   1073篇
妇产科学   682篇
基础医学   3546篇
口腔科学   585篇
临床医学   3796篇
内科学   5523篇
皮肤病学   468篇
神经病学   2801篇
特种医学   1356篇
外国民族医学   1篇
外科学   3612篇
综合类   687篇
一般理论   46篇
预防医学   3208篇
眼科学   513篇
药学   2192篇
  2篇
中国医学   34篇
肿瘤学   1575篇
  2021年   401篇
  2020年   238篇
  2019年   354篇
  2018年   429篇
  2017年   297篇
  2016年   376篇
  2015年   422篇
  2014年   625篇
  2013年   955篇
  2012年   1176篇
  2011年   1344篇
  2010年   785篇
  2009年   590篇
  2008年   1174篇
  2007年   1334篇
  2006年   1291篇
  2005年   1235篇
  2004年   1191篇
  2003年   1035篇
  2002年   976篇
  2001年   974篇
  2000年   995篇
  1999年   789篇
  1998年   368篇
  1997年   357篇
  1996年   329篇
  1995年   294篇
  1994年   266篇
  1993年   254篇
  1992年   693篇
  1991年   730篇
  1990年   677篇
  1989年   646篇
  1988年   628篇
  1987年   594篇
  1986年   585篇
  1985年   580篇
  1984年   442篇
  1983年   431篇
  1982年   292篇
  1981年   269篇
  1980年   256篇
  1979年   431篇
  1978年   319篇
  1977年   281篇
  1976年   265篇
  1975年   244篇
  1974年   299篇
  1973年   261篇
  1972年   233篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
Separate experiments conducted in two different laboratories assessed the importance of the prepulse intensity in the ability of apomorphine to reduce prepulse inhibition of acoustic startle responses. Rats were presented with noise bursts alone or noise bursts 100 ms after presentation of prepulse stimuli ranging from 70 to 85 or 90 dB. Throughout testing, the background noise was maintained at 65 dB. In both laboratories, apomorphine markedly decreased the absolute magnitude of prepulse inhibition when the prepulse stimuli were no more than 10 dB above the background. With more intense prepulse stimuli, apomorphine had no significant effect on prepulse inhibition. Hence, apomorphine does not interfere with the inhibitory process which actually mediates prepulse inhibition, but appears to affect the detectability of the prepulse.  相似文献   
82.
The authors designed a three-phase prospective trial in which only those patients who developed an acute, neuroleptic-induced extrapyramidal side effect (EPSE) received benztropine (BZ) at 2 mg i.m. and then 1 mg p.o. b.i.d. for 2 days after their symptoms were rated for severity and type (Preparatory Phase 1). They were then randomly assigned under double-blind conditions to continue BZ or be switched to placebo for 8 days (Experimental Phase 2). Finally in Phase 3 (Followup), all patients continued on placebo in a single-blind design until Day 30. If the patient re-experienced an acute EPSE that was of sufficient severity to require immediate BZ administration, he or she was rated, treated, and then dropped from the study. EPSE scores and dropout rates did not differ in Phase 2 between the placebo- and BZ-treated groups. Implications for the continuation, cessation, or intermittent use of antiparkinsonian (AP) drugs are discussed.  相似文献   
83.
E Erturk  E Erturk  J Sheinfeld  R S Davis 《Urology》1988,32(2):165-167
It is well documented that under certain stimuli the bladder epithelium can undergo metaplasia. The origin of glandular epithelium, which may be found in the bladder, is somewhat controversial. Endoscopic and histopathologic features of an eighty-one-year-old white man with proliferative metaplastic cystitis are presented. This case demonstrates that glandular differentiation was due to progressive cystitis rather than congenital intestinal rest.  相似文献   
84.
85.
Treatment with the monoclonal antibody OKT3 specific for the CD3 complex associated with the T cell antigen receptor can reverse acute rejection of human renal allografts. However, efficacy of anti-CD3 antibodies for treatment of patients with acute graft-versus-host disease after marrow transplantation has not been established. The dose-limiting side effects resulting from T cell activation induced by some anti-CD3 antibodies in vivo have discouraged their use for this application. We now report a phase I-II study of GVHD treatment with the anti-CD3 antibody BC3, a monoclonal murine IgG2b that, unlike OKT3, does not activate T cells. Fourteen patients were treated with BC3 after progression of acute GVHD despite treatment with cyclosporine and corticosteroids, and three patients received BC3 as primary treatment for GVHD. BC3 was administered at a dose of 0.1 or 0.2 mg/kg/day for seven or eight days. Five patients achieved complete resolution of GVHD, eight patients had partial improvement, two patients had no change, and two patients had progression of GVHD on therapy. Responses were sustained in 8 of 13 patients. Mild chills, fever, hypertension, and chest discomfort occurred in various combinations following 6 of 17 (35%) initial infusions of BC3 and following 4 of 99 (4%) subsequent infusions. In each instance it was possible to continue BC3 therapy without adjusting the dose or treatment schedule. In each patient treated, the absolute count of peripheral blood lymphocytes decreased transiently but returned to baseline within 22 hr after the first infusion. Circulating T cells had surface CD3 molecules saturated by the infused antibody in all but one patient. Four patients survived longer than one year after treatment with antibody BC3, and 13 patients died of infection or organ failure. Administration of the nonmitogenic anti-CD3 antibody BC3 was associated with improvement in the clinical manifestations of GVHD with minimal acute toxicity. Efficacy of antibody treatment did not depend on depletion of circulating T cells. Therefore, antibody BC3 may be achieving therapeutic immunosuppression by modulating T cell function. Controlled studies in patients treated earlier in the course of GVHD should determine whether antibody BC3 can improve survival.  相似文献   
86.
87.
Why should depression screening be conducted in chronically ill populations? Depression is a disabling illness and is very common among patients who have chronic illnesses. Despite its high prevalence in this patient population, depression often goes unrecognized. Having a plan for a population-based screening program for depression can not only identify patients who are at risk of depression, but can also help to foster early treatment and enhanced care for these patients. This article provides an overview of commonly-used depression screening tools and presents an example of how this might be carried out in a healthcare organization.  相似文献   
88.
Lymphocytes in formalin-fixed skin biopsies from patients with cutaneous acute graft-versus-host disease (aGVHD) were studied with HECA-452 (an antibody recognizing lymphocytes with skin-homing properties) and a panel of antibodies recognizing pan-B (L26 [CD20]), pan-T (L60 [CD43] and A6 [CD45RA]), and T-helper subset (OPD4) antigens in paraffin sections. Biopsies from patients with erythema multiforme (EM) were similarly studied for comparison. In both conditions, T lymphocytes stained by OPD4 were predominantly confined to the dermis, whereas those stained by HECA-452 were concentrated in the epidermis; however, there was considerable variation between cases, and overlap between findings in the dermis and epidermis. Lymphocytes similarly studied in paraffin sections of liver, salivary gland, and gut affected by aGVHD were essentially unreactive with HECA-452, although they were largely stained by pan-T markers and showed some comparable reactivity with OPD4. The findings suggest that aGVHD of the skin is mediated by a different set of lymphocytes than in gut organs, and may have a similar immunologic mechanism to EM.  相似文献   
89.
Plasma growth hormone concentrations were measured at hourly intervals between 10 p.m. and 8 a.m. the next morning in 15 drug-free chronic schizophrenic male inpatients and 14 healthy males. Growth hormone secretion was significantly lower in the patients as compared with the controls. Growth hormone release peaked around 1 a.m. in the controls, but a growth hormone peak was absent in the patient group. Increased dopamine activity, increased serotonin activity, or both could explain the absence of a nocturnal growth hormone surge in the schizophrenic patients.  相似文献   
90.
There has been considerable progress in the treatment of chronic hepatitis C since the first report that interferon (IFN) monotherapy was effective in 1989. Early results were meager, with sustained loss of hepatitis C virus from blood in fewer than 10% of cases. The combination of IFN with the oral nucleoside analogue ribavirin was a major breakthrough in clinical hepatology; it led to dramatic increases in treatment responses, with 30% to 40% of patients clearing virus. Pegylated IFNs that have prolonged activity and can be dosed once a week have now replaced standard IFNs. The combination of pegylated IFN with ribavirin is the new standard of care; it causes sustained loss of virus in more than half of treated patients. Treatment responses continue to be highly dependent on viral genotype. Patients with genotype 1, the most common type in the United States, have a sustained clearance rate of 42% to 46%, whereas those with genotype 2 or 3 have a response rate approaching 80%.  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