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   218177篇
  免费   13878篇
  国内免费   1896篇
耳鼻咽喉   2837篇
儿科学   5493篇
妇产科学   6413篇
基础医学   30665篇
口腔科学   5667篇
临床医学   18964篇
内科学   43197篇
皮肤病学   3496篇
神经病学   16587篇
特种医学   7352篇
外国民族医学   6篇
外科学   33083篇
综合类   6613篇
现状与发展   1篇
一般理论   109篇
预防医学   16546篇
眼科学   5455篇
药学   16505篇
中国医学   960篇
肿瘤学   14002篇
  2021年   2603篇
  2020年   1450篇
  2019年   2616篇
  2018年   3506篇
  2017年   2556篇
  2016年   2753篇
  2015年   3263篇
  2014年   4593篇
  2013年   6737篇
  2012年   9677篇
  2011年   10195篇
  2010年   5892篇
  2009年   5385篇
  2008年   9471篇
  2007年   10402篇
  2006年   10095篇
  2005年   9796篇
  2004年   9452篇
  2003年   8843篇
  2002年   8714篇
  2001年   7524篇
  2000年   7468篇
  1999年   6462篇
  1998年   3102篇
  1997年   2511篇
  1996年   1900篇
  1995年   1827篇
  1994年   1636篇
  1993年   1522篇
  1992年   4292篇
  1991年   4320篇
  1990年   3993篇
  1989年   4010篇
  1988年   3862篇
  1987年   3720篇
  1986年   3533篇
  1985年   3459篇
  1984年   2754篇
  1983年   2543篇
  1982年   1958篇
  1981年   1737篇
  1980年   1638篇
  1979年   2353篇
  1978年   1712篇
  1977年   1566篇
  1975年   1618篇
  1974年   1696篇
  1973年   1744篇
  1972年   1604篇
  1971年   1416篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
This study represents the first of a two-stage project. The first phase of the study examined the funding sources for the 40 Community Services Boards in Virginia. Data provided from the Department of Mental Health and Mental Retardation in Virginia examined fee collections which are comprised of direct client, commercial insurance, Medicaid and Medicare. An analysis of quarterly reports from 1982 to 1984 revealed that Medicaid collections have decreased significantly, while commercial insurance reimbursements have increased significantly. These results, although limited to data from Virginia, point to the need to examine if these shifts are occurring nation-wide, and to determine if the shift toward commercial insurance is impacting upon the delivery of services in Community Mental Health Centers.  相似文献   
52.
53.
Abstract   We evaluated the associations between glycemic therapies and prevalence of diabetic peripheral neuropathy (DPN) at baseline among participants in the Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial on medical and revascularization therapies for coronary artery disease (CAD) and on insulin-sensitizing vs. insulin-providing treatments for diabetes. A total of 2,368 patients with type 2 diabetes and CAD was evaluated. DPN was defined as clinical examination score >2 using the Michigan Neuropathy Screening Instrument (MNSI). DPN odds ratios across different groups of glycemic therapy were evaluated by multiple logistic regression adjusted for multiple covariates including age, sex, hemoglobin A1c (HbA1c), and diabetes duration. Fifty-one percent of BARI 2D subjects with valid baseline characteristics and MNSI scores had DPN. After adjusting for all variables, use of insulin was significantly associated with DPN (OR = 1.57, 95% CI: 1.15–2.13). Patients on sulfonylurea (SU) or combination of SU/metformin (Met)/thiazolidinediones (TZD) had marginally higher rates of DPN than the Met/TZD group. This cross-sectional study in a cohort of patients with type 2 diabetes and CAD showed association of insulin use with higher DPN prevalence, independent of disease duration, glycemic control, and other characteristics. The causality between a glycemic control strategy and DPN cannot be evaluated in this cross-sectional study, but continued assessment of DPN and randomized therapies in BARI 2D trial may provide further explanations on the development of DPN.  相似文献   
54.
55.
ObjectiveTo assess for the presence of gastric dysmotility in familial and sporadic Parkinson disease (PD).Methods10 subjects with familial Parkinson disease (fPD), 35 subjects with sporadic Parkinson disease (sPD), and 15 controls, all from academic tertiary care movement disorders centers, were studied. fPD was defined as the presence of at least 2 affected individuals within 2–3 consecutive generations in a family. Molecular genetic analysis has not revealed, thus far, any known genomic abnormality in these families. Gastric emptying was assessed by dynamic abdominal scintigraphy over 92 min following ingestion of a solid meal containing 99mTc-labeled colloid of 40 MBq activity. The main outcome measures were gastric emptying half-time and radiotracer activity over the gastric area at 46 and at 92 min.ResultsGastric emptying time was delayed in 60% of subjects with PD. In comparison to mean t1/2 of 38 ± 7 min in controls, mean t1/2 was 58 ± 25 min in fPD (p = 0.02) and 46 ± 25 min in sPD (p = 0.10). Both fPD and sPD groups included subjects with delayed gastric emptying at an early stage of disease.ConclusionsPatients with fPD showed significantly delayed gastric emptying in comparison to normal age-matched individuals. Further studies of gastrointestinal dysfunction in PD, particularly fPD, are warranted.  相似文献   
56.
We report the case of a patient infected with human immunodeficiency virus who presented with fever and a disseminated papulous eruption, diagnosed as cutaneous miliary tuberculosis. The diagnosis was made by histological examination of a skin biopsy, which showed numerous acid‐fast bacilli. A culture grown from a skin biopsy isolated a resistant Mycobacterium tuberculosis strain. The papules disappeared within a few days after starting treatment with pyrazinamide, isoniazid and moxifloxacin.  相似文献   
57.
A mutant form of ammodytoxin A, a neurotoxic phospholipase A2 from the venom of the long nosed viper Vipera ammodytes ammodytes, was prepared by site-directed mutagenesis, conjugated to a nanogold particle and inoculated into the antero-lateral aspect of one hind limb of female mice. Eight hours later the mice were killed, the soleus muscles of both ipsi- and contra-lateral hind limbs were removed, exposed to a silver enhancing medium and then prepared for transmission electron microscopy. Silver-enhanced particles were subsequently found concentrated in the peri-synaptic area, particularly within the synaptic gutter and the deep synaptic folds, and in many cases had been taken up into the cytoplasm of the terminal boutons of the motor axon. The results suggest that the presynaptic neurotoxicity of snake venom phospholipases A2 involves several components of the neuromuscular apparatus, including intracellular organelles of the motor nerve terminal.  相似文献   
58.
59.
Usher syndrome: clinical findings and gene localization studies   总被引:3,自引:0,他引:3  
The issue of genetic heterogeneity is a critical problem in the localization of the gene(s) for Usher syndrome. Based on the data obtained on families studied to date, the differences between type I and type II Usher syndrome appear quite distinct with regard to auditory and vestibular function. Although the majority of families can be confidently diagnosed as typical type I or type II, clinical investigations revealed four families with findings that did not fit into either of the two more common subtypes. These findings emphasize the critical importance of an in-depth clinical analysis concomitant with the linkage investigation to assure accurate subtyping of Usher syndrome. Based on an analysis of only those families with definite type I or type II Usher syndrome, approximately 17% of the genome can be excluded as a potential site of the gene for type I, and 14% can be excluded as the site for the type II gene. This study will continue until the Usher gene(s) is successfully localized.  相似文献   
60.
Experience in the treatment of 30 cases with gas gangrene from war wounds   总被引:1,自引:0,他引:1  
Z Y Li  X L Wang  X S Wang 《中华外科杂志》1986,24(10):580-1, 637
  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