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   10202篇
  免费   761篇
  国内免费   35篇
耳鼻咽喉   78篇
儿科学   298篇
妇产科学   296篇
基础医学   1379篇
口腔科学   232篇
临床医学   1270篇
内科学   2011篇
皮肤病学   260篇
神经病学   1071篇
特种医学   187篇
外科学   922篇
综合类   62篇
一般理论   16篇
预防医学   1272篇
眼科学   178篇
药学   700篇
中国医学   32篇
肿瘤学   734篇
  2023年   120篇
  2022年   107篇
  2021年   460篇
  2020年   264篇
  2019年   360篇
  2018年   376篇
  2017年   276篇
  2016年   317篇
  2015年   317篇
  2014年   398篇
  2013年   582篇
  2012年   836篇
  2011年   827篇
  2010年   480篇
  2009年   374篇
  2008年   639篇
  2007年   628篇
  2006年   578篇
  2005年   546篇
  2004年   463篇
  2003年   443篇
  2002年   396篇
  2001年   47篇
  2000年   36篇
  1999年   46篇
  1998年   70篇
  1997年   70篇
  1996年   60篇
  1995年   52篇
  1994年   40篇
  1993年   45篇
  1992年   37篇
  1991年   32篇
  1990年   26篇
  1989年   24篇
  1988年   28篇
  1987年   28篇
  1986年   26篇
  1985年   25篇
  1984年   33篇
  1983年   36篇
  1982年   35篇
  1981年   35篇
  1980年   41篇
  1979年   13篇
  1978年   17篇
  1977年   18篇
  1975年   14篇
  1973年   15篇
  1970年   12篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
62.
The isthmo-optic nuclei (ION) and ectopic neurons, which constitute the centrifugal visual system (CVS), are thought to be cholinoceptive and nitrergic. However, it is not clear which neurons express these markers, namely the ones that project to the retina rather than in neurons that only participate in a local circuit. Therefore, to characterize the neurochemical patterns of the centrifugal visual system in the post-hatched chick, retinopetal cells of the isthmo-optic nuclei and the ectopic region were identified via immunolabeling for cholera toxin, a neuronal tracer, which has been injected in the ocular globe. Then, double labeled with acetylcholinesterase histochemistry to reveal cholinergic synapses, or NADPH-diaphorase histochemistry as a nitrergic marker. Briefly, acetylcholinesterase activity was present mainly in cholera toxin labeled cell bodies of the isthmo-optic nucleus and the ectopic region indicating that retinal projecting neurons of centrifugal visual system comprise a cholinoceptive pathway. On the other hand, NADPH-diaphorase histochemistry was present in the neuropile and sparse cell bodies inside of the isthmo-optic nucleus and in ectopic neurons which were not cholera toxin positive suggesting their role in an intrinsic circuit of the centrifugal visual system. These data support the idea that these two neurochemical systems are present in distinct neuronal populations in the centrifugal visual system.  相似文献   
63.
dl-Ethylketazocine (EKC, 0.01 mg/kg) and saline were established as discriminative stimuli for food-maintained responding in macaque monkeys. Thirty consecutive presses on a right or left lever were reinforced with food, contingent on whether EKC or saline were administered before the session. For tests of antagonism, naltrexone, or UM 979 [(l)-5,9-alpha-dimethyl-2-(3-furylmethyl)-2-hydroxy-6,7-benzomorphan] was administered concomitantly with EKC,dl-cyclazocine, or nalorphine. Both antagonists blocked completely the EKC discriminative stimulus. The antagonism of the stimulus and rate-altering effects of EKC was surmountable, with considerable intersubject variability in the magnitude of the EKC dose increase required to overcome the blockade. Cyclazocine and nalophine, mixed agonist-antagonist opioids that share stimulus properties with EKC, were also susceptible to antagonism. Naltrexone antagonized completely the EKC stimulus effects of nalorphine; naltrexone and UM 979 antagonized completely the EKC stimulus effects of cyclazocine. Naltrexone antagonism of the cyclazocine stimulus was not surmountable, due to a lack of antagonism of the rate-decreasing effects of high cyclazocine doses.  相似文献   
64.
Maternal and Child Health Journal - The Maternal and Child Health (MCH) Pipeline Training Program, promotes development of a diverse health workforce by training undergraduate students from...  相似文献   
65.
Prevention Science - Screening is an essential prevention practice for a number of health conditions. However, screening coverage remains generally low. Studies that investigate determinants of...  相似文献   
66.
Maternal and Child Health Journal - Low birthweight (LBW) is a significant public health problem in sub-Saharan Africa and LBW in rural Zambia is high. Our study explored the prevalence of LBW for...  相似文献   
67.
Prevention Science - The NAMWEZA intervention was implemented, using a ten-session group format, to build skills targeting psychosocial vulnerabilities and enhancing HIV prevention among people...  相似文献   
68.
Fluorescence-advanced videodermatoscopy is not a widespread diagnostic technique. Its application in dermatology can facilitate the diagnosis of diseases such as cutaneous larva migrans by enabling us to recognize the precise position of larva in vivo on the skin. Using this noninvasive technique, we detected a case of cutaneous larva migrans in a patient.  相似文献   
69.
Campylobacteriosis is a disease of worldwide importance, but aspects of its transmission dynamics, particularly risk factors, are still poorly understood. We used data from a matched case-control study of 4,269 men who have sex with men (MSM) and 26,215 controls, combined with national surveillance data on Campylobacter spp., Salmonella spp., and Shigella spp., to calculate matched odds ratios (mORs) for infection among MSM and controls. MSM had higher odds of Campylobacter (mOR 14, 95% CI 10–21) and Shigella (mOR 74, 95% CI 27–203) infections, but not Salmonella (mOR 0.2, 95% CI 0–13), and were less likely than controls to have acquired Campylobacter infection abroad (χ2 = 21; p<0.001). Our results confirm that sexual contact is a risk factor for campylobacteriosis and also suggest explanations for unique features of Campylobacter epidemiology. These findings provide a baseline for updating infection risk guidelines to the general population.  相似文献   
70.
BackgroundFamily history of prostate cancer (PCa) is a well-known risk factor, and both common and rare genetic variants are associated with the disease.ObjectiveTo detect new genetic variants associated with PCa, capitalizing on the role of family history and more aggressive PCa.Design, setting, and participantsA two-stage design was used. In stage one, whole-exome sequencing was used to identify potential risk alleles among affected men with a strong family history of disease or with more aggressive disease (491 cases and 429 controls). Aggressive disease was based on a sum of scores for Gleason score, node status, metastasis, tumor stage, prostate-specific antigen at diagnosis, systemic recurrence, and time to PCa death. Genes identified in stage one were screened in stage two using a custom-capture design in an independent set of 2917 cases and 1899 controls.Outcome measurements and statistical analysisFrequencies of genetic variants (singly or jointly in a gene) were compared between cases and controls.Results and limitationsEleven genes previously reported to be associated with PCa were detected (ATM, BRCA2, HOXB13, FAM111A, EMSY, HNF1B, KLK3, MSMB, PCAT1, PRSS3, and TERT), as well as an additional 10 novel genes (PABPC1, QK1, FAM114A1, MUC6, MYCBP2, RAPGEF4, RNASEH2B, ULK4, XPO7, and THAP3). Of these 10 novel genes, all but PABPC1 and ULK4 were primarily associated with the risk of aggressive PCa.ConclusionsOur approach demonstrates the advantage of gene sequencing in the search for genetic variants associated with PCa and the benefits of sampling patients with a strong family history of disease or an aggressive form of disease.Patient summaryMultiple genes are associated with prostate cancer (PCa) among men with a strong family history of this disease or among men with an aggressive form of PCa.  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