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   37432篇
  免费   2143篇
  国内免费   205篇
耳鼻咽喉   432篇
儿科学   1170篇
妇产科学   1001篇
基础医学   3715篇
口腔科学   1219篇
临床医学   3293篇
内科学   8087篇
皮肤病学   671篇
神经病学   2237篇
特种医学   1318篇
外国民族医学   4篇
外科学   6847篇
综合类   867篇
现状与发展   3篇
一般理论   27篇
预防医学   2513篇
眼科学   1362篇
药学   2862篇
  1篇
中国医学   272篇
肿瘤学   1879篇
  2024年   45篇
  2023年   414篇
  2022年   1055篇
  2021年   1647篇
  2020年   1005篇
  2019年   1265篇
  2018年   1574篇
  2017年   1143篇
  2016年   1238篇
  2015年   1340篇
  2014年   1697篇
  2013年   2073篇
  2012年   3127篇
  2011年   3011篇
  2010年   1697篇
  2009年   1469篇
  2008年   2250篇
  2007年   2329篇
  2006年   2046篇
  2005年   1815篇
  2004年   1646篇
  2003年   1365篇
  2002年   1181篇
  2001年   367篇
  2000年   307篇
  1999年   283篇
  1998年   199篇
  1997年   132篇
  1996年   142篇
  1995年   107篇
  1994年   95篇
  1993年   78篇
  1992年   147篇
  1991年   160篇
  1990年   128篇
  1989年   123篇
  1988年   105篇
  1987年   97篇
  1986年   88篇
  1985年   116篇
  1984年   77篇
  1983年   52篇
  1982年   53篇
  1981年   55篇
  1980年   41篇
  1979年   50篇
  1978年   40篇
  1975年   35篇
  1974年   36篇
  1973年   35篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
42.
Ten patients with complex non-union of the tibia were treated by locked intramedullary nailing. These patients had scarred skin as a result of initial severe open fractures, multiple debridement or fasciotomies with external fixators and skin grafts applied. Seven of the patients also had previous osteomyelitis or pin track infections. Fully pain-free walking was achieved in all patients and radiological union in nine patients without the need for a bone graft. Four patients developed infection after nailing, of which three resolved with treatment.  相似文献   
43.
44.
INTRODUCTION: Reconstructive septorhinoplasty in complex nasal deformities often requires harvesting a large amount of tissue for grafting. Autogenous septal cartilage has generally been considered the gold standard grafting material. The aim of this paper was to report our experience with the use of costal cartilage grafts in cases with significant structural deformities and insufficient septal cartilage. DESIGN: Retrospective chart review. PATIENTS: Between 1998 and 2006, 37 patients underwent septorhinoplasty using costal cartilage as the primary source for grafting. Twenty-two men and 14 women with a median age of 42 were enrolled in the study. Patient demographics, indications for surgery, and immediate and late complications were reviewed. The follow-up range was 3 to 72 months. CONCLUSIONS: Autogenous costal cartilage graft is a viable option in reconstructive septorhinoplasty. We advocate the use of this graft in septorhinoplasty cases requiring a large volume of tissue and insufficient septal cartilage.  相似文献   
45.
Summary A recombinant vaccinia virus designated VgBt which expresses a truncated secreted herpes simplex virus gB (gBt) was constructed and compared to V11gB, a vaccinia recombinant previously studied which expresses gB exclusively on the surface of infected cells. Indirect immunofluorescence assay (IFA) revealed that gBt was strongly associated with the surface of infected cells despite being released slowly into the cell culture medium. Both gB and gBt existed as oligomers, and both membrane bound and secreted forms of gBt exhibited heparin-binding activity. In protection studies VgBt and V11gB conferred equivalent protection against both homologous (HSV-1) and heterologous (HSV-2) challenge with HSV.  相似文献   
46.
A new dimeric indoline alkaloid has been isolated from the leaves of PETCHIA CEYLANICA. Its structure has been assigned as 1 on the basis of spectral studies. Its stereochemistry has been established by NOE difference measurements.  相似文献   
47.
Chronic exposure to cannabis extract or delta-9-tetrahydrocannabinol (THC) has been reported to produce hippocampal neuropathology in rats, as well as classical "hippocampal" behavioral deficits. In an attempt to replicate and extend these findings, male rats were exposed to THC for 13 consecutive weeks, beginning in early adolescence. Drugs were administered five consecutive days a week (Monday through Friday). There were five dose levels: vehicle control, 5, 10, or 20 mg/kg, p.o., and 20 mg/kg THC four days a week (Monday-Thursday), followed by 60 mg/kg on Friday. Following THC exposure, all animals were withdrawn from drugs for seven weeks prior to behavioral testing. Three behavioral tasks previously shown to be sensitive to hippocampal damage were assessed. These were habituation of open-field activity, 24-hr passive avoidance response retention, and complex maze performance. A fourth task, emergence latency, was also included because it has been determined to be sensitive to "anxiety" levels. To facilitate interpretation of the complex maze data, two additional experiments are also reported. One experiment tested rats exposed to trimethyltin (TMT, a potent hippocampal neurotoxicant) on the complex maze. The second assessed the affects of chronic/acute benzodiazepine (BZ) exposure upon maze performance. Test results did not suggest that chronic THC exposure produced behavioral deficits resembling those seen following hippocampal damage. Habituation rates in an activity monitor were identical for all exposure groups, and there was no passive avoidance retention deficit. Further, while TMT caused pronounced abnormalities in the complex maze, chronic THC exposure at the two highest dose levels significantly improved maze performance, similar to BZ effects on this task. Chronic THC also appeared to reduce freezing on the emergence task, another anxiolytic-like effect. These results support other reports of persistent long-term behavioral effects of chronic THC exposure. However, they suggest that some behavioral effects may more closely resemble the effects of minor tranquilizers rather than hippocampal damage.  相似文献   
48.
Health and nutrition education involves not only conveying new information and concepts, but also persuading the target population to engage in innovative action and direct participation. This process can be thwarted if cultural factors are ignored, particularly in dealing with a tribal population. In a country like India, communication with tribals is influenced by ethnic and cultural diversities, different types of ecological settings, a low literacy level, geographic isolation, the lack of development infrastructure, language barriers, health taboos and problems, a lack of access to modern media forms, and food availability and use. Most suitable for working with tribal populations appear to be the media of the spoken work, song and drama, games, exhibitions at the weekly market and yearly festivals, and pictorial aids. Since communication is a 2-way process, there must be a shared frame of reference among scientists, communicators, and receivers. Moreover, even when health education messages are delivered through culture-specific entertainment programs, they must be part of a comprehensive health and development package in which extension workers are backed up by health professionals and integrated programs.  相似文献   
49.
The volume of the nuclei and nucleoli of certain hypothalamic centers (SON, PVN, SCN, AN, VMN) was determined in control rats and in rats after deafferentation of the mediobasal hypothalamus. Sex differences were found in the parvocellular formations of the control animals: The volumes of nuclei and nucleoli of neurons of AN and VMN, and also of the nucleolus of SCN neurons were larger in females than in males. After deafferentation of the mediobasal hypothalamus the volume of the cell nuclei was increased, especially in hypothalamic formations located outside the isolated zone. This increase was more clearly defined in rats constantly in a state of estrus after the operation. Statistically significant differences between volumes of both nuclei and nucleoli of the cells in subgroups of rats with permanent estrus and with permanent diestrus were found only in the case of SCN. No such differences were found for AN, despite the considerable difference in the constant of luteinizing hormone in the pituitary of the same rats. It is suggested that gonadotropin releasing factors are not produced by the cells of AN and that control over the succession of phases of the sex cycle may be exerted by SCN.Laboratory of Neuroendocrinology, I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR V. N. Chernigovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 89, No. 3, pp. 352–354, March, 1980.  相似文献   
50.
OBJECTIVE: The purpose of this study was to investigate the presence of emotional abuse and two psychosocial constructs (self-blame and self-silencing) in a sample of women diagnosed with irritable bowel syndrome (IBS) relative to a comparison sample of women diagnosed with inflammatory bowel disease (IBD). METHODS: Women diagnosed with IBS (N = 25) were compared with women diagnosed with IBD (N = 25) on measures of history of abuse, self-blame, and self-silencing. RESULTS: It was found that women in the IBS sample scored significantly higher on emotional abuse, self-blame, and self-silencing than did women in the IBD sample. These three variables were also found to be significantly intercorrelated in both the IBS and IBD samples. Finally, emotional abuse was significantly higher in IBS patients than in IBD patients beyond the differences accounted for by physical and/or sexual abuse history. CONCLUSIONS: These findings empirically demonstrate an association between IBS and emotional abuse, as well as a possible connection with psychosocial variables, that may mediate the connection between emotional abuse and functional bowel symptoms. We suggest that these variables be further evaluated in the context of clinically relevant research on IBS.  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