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   4984篇
  免费   281篇
  国内免费   25篇
耳鼻咽喉   109篇
儿科学   123篇
妇产科学   103篇
基础医学   755篇
口腔科学   98篇
临床医学   376篇
内科学   1322篇
皮肤病学   231篇
神经病学   271篇
特种医学   86篇
外科学   697篇
综合类   11篇
一般理论   1篇
预防医学   192篇
眼科学   39篇
药学   333篇
中国医学   9篇
肿瘤学   534篇
  2023年   37篇
  2022年   48篇
  2021年   121篇
  2020年   75篇
  2019年   113篇
  2018年   95篇
  2017年   94篇
  2016年   110篇
  2015年   115篇
  2014年   130篇
  2013年   173篇
  2012年   346篇
  2011年   358篇
  2010年   211篇
  2009年   206篇
  2008年   310篇
  2007年   343篇
  2006年   342篇
  2005年   359篇
  2004年   362篇
  2003年   318篇
  2002年   347篇
  2001年   41篇
  2000年   32篇
  1999年   47篇
  1998年   51篇
  1997年   57篇
  1996年   70篇
  1995年   51篇
  1994年   47篇
  1993年   37篇
  1992年   21篇
  1991年   19篇
  1990年   20篇
  1989年   17篇
  1988年   18篇
  1987年   14篇
  1986年   17篇
  1985年   9篇
  1984年   9篇
  1983年   12篇
  1982年   13篇
  1981年   10篇
  1980年   8篇
  1978年   9篇
  1976年   7篇
  1974年   7篇
  1956年   7篇
  1955年   3篇
  1954年   3篇
排序方式: 共有5290条查询结果,搜索用时 6 毫秒
61.
The aim of this study was to reveal the clinical features of anterior urethral recurrence in patients with superficial bladder cancer, and to determine the appropriate treatment. Three hundred and three patients with superficial bladder cancer, who were newly diagnosed and initially treated conservatively in our hospital between 1965 and 1990, were followed for at least 5 years and their clinical outcomes were analyzed. Clinical factors, including anterior urethral recurrence, were evaluated statistically regarding tumor progression. Eight patients (2.6%) had anterior urethral recurrence following superficial bladder cancer. Twenty-four patients (7.9%) had tumor progression and 149 (49.2%) had tumor recurrence. In a multivariate analysis using a logistic model, anterior urethral recurrence was the most important factor, followed by histological grade. Four of 5 patients who were treated for anterior urethral recurrent tumors by transurethral resection showed progression and died of the cancer within one year. Two of the remaining three patients who underwent radical cysto-urethrectomy at the time of anterior urethral recurrence survived. Anterior urethral recurrence following superficial bladder cancer is a predictor for rapid subsequent malignant progression. Once there is anterior urethral recurrence, radical intensive therapy, including radical cysto-urethrectomy, should be carried out immediately.  相似文献   
62.
In the present study, we established transgenic mice overexpressing Del1, a ligand of integrins, to examine the effect of overexpression of Del1 on vascular morphogenesis. In the wild-type mouse, mesenteric vessels are shaped like rakes consisting of a long stalk and short branches at the periphery. In contrast, those in transgenic mice showed typical dendritic architecture consisting of a few large primary branches with smaller spreading branches. The phenotype of mice overexpressing Del1 suggests the existence of a tissue-specific mechanism for branching morphogenesis in the mesentery.  相似文献   
63.
64.
Our laboratory was capable of analyzing less than 20 drugs and toxic substances at the time of the establishment of the Center in 1994. Since the poisoning crimes in 1998, such as the curry poisoning with arsenic in Wakayama, the sodium azide poisoning in Niigata, and the potassium cyanide poisoning in Nagano, we have introduced methods for rapid qualitative analysis of arsenic compounds, cyanides and azides, and developed methods for qualitative analysis of three types of surfactants (cationic, anionic, and nonionic) on the basis of the statistics for intoxication patients transferred to the Center. In 1999, the Analysis Method Investigation Committee of the Japanese Society for Clinical Toxicology requested individual medical institutions to analyze 15 selected intoxicating substances, focusing on the following three aspects. 1. Intoxication with a high degree of fatality. 2. Intoxication where analysis plays an immediate role in treatment. 3. Intoxication with a high frequency of requests by clinical physicians for analysis. The selected substances included methanol, barbital drugs, benzodiazepines, tricyclic or tetracyclic antidepressants, methamphetamine, acetaminophen, salicylic acid, bromovalerylurea, organophosphorus pesticides, carbamate pesticides, paraquat, glufosinate, cyanides, arsenic, and theophylline. Responding to the Committee's request, out laboratory has been making efforts so that analysis of drugs and intoxicating substances can play an immediate role in emergency medical service, giving the highest priority to the aforementioned 15 substances. As a result, anyone of us can now rapidly analyze about 35 substances, including those listed by the Society, day and night.  相似文献   
65.
Systemic pathological alterations were studied in thirty-seven autopsied patients with Kawasaki disease. Systemic vasculitis was the most characteristic pathological finding and was present in all the patients. In addition to the vasculitis, there was a high incidence of inflammatory lesions in various organs and tissues: in the heart, endocarditis, myocarditis, and pericarditis; in the digestive system, stomatitis, sialoduct-adenitis, catarrhal enteritis, hepatitis, cholangitis, pancreatitis, and pancreas ductitis; in the respiratory system, bronchitis and segmental interstitial pneumonia; in the urinary system, focal interstitial nephritis, cystitis, and prostatitis; in the nervous system, aseptic leptomeningitis, choriomeningitis, ganglionitis, and neuritis; in the hematopoietic system, lymphadenitis, splenitis, and thymitis. Dermatitis, panniculitis or myositis were also observed in some patients. Therefore, Kawasaki disease is a systemic inflammatory disease which mainly affects the cardiovascular system. These systemic inflammatory lesions are considered to correspond to the variegated clinical manifestaitions. The relationship between Kawasaki disease and infantile polyarteritis nodosa (IPN) were discussed, based on the clinicopathological characteristics.  相似文献   
66.
67.
To isolate Babesia equi genes encoding immunodominant proteins, a cDNA expression library prepared from B. equi mRNA was immunoscreened with B. equi-infected horse serum. Eighteen positive cDNA clones were obtained, and the clone that showed the strongest immunoreactivity, designated Be82, was further characterized. The Be82 gene consisted of 1,953 bp and contained a partial open reading frame lacking the 5'-terminal sequence. As shown by Western blot analyses, immune sera from mice intraperitoneally injected with the Be82 gene product recognized the 82- and 52-kDa proteins of B. equi but not those of Babesia caballi. The glutathione S-transferase fusion protein expressed in Escherichia coli that was purified and used as the antigen in the enzyme-linked immunosorbent assay reacted specifically with B. equi-infected horse sera. These results suggest that the Be82 gene product is a potential diagnostic antigen candidate in the detection of B. equi infection in horses that will be useful both in the performance of epidemiological studies and in the granting of quarantine passes.  相似文献   
68.
The Raman spectra of solutions of poly(N-vinyl-2-pyrrolidone) (PVP; M?w = 1 000, 10 000, 40 000 and 360 000) in D2O and dimethyl sulfoxide (DMSO) were measured at various concentrations. PVP is hydrated by D2O in a manner different from N-ethyl-2-pyrrolidone (NEP) and N-methyl-2-pyrrolidone (NMP), monomer analogues of PVP. The self-association of DMSO molecules in the solution of PVP was found to be different from that in the solution of NMP by using difference spectroscopy. These phenomena were attributed to a net-like structure of concentrated solutions of PVP.  相似文献   
69.
Using Giemsa staining, C-banding and Ag-NOR staining techniques, we analyzed chromosomes in adult male and female Hynobius quelpaertensis and in embryos of this species in egg sacs collected from eight localities of Cheju Island, South Korea. Chromosome pair 21 was consistently homomorphic in male specimens, while it was heteromorphic in female specimens, suggesting the occurrence of ZZ/ZW sex chromosome constitution in this species. The W chromosome, being much larger than the Z chromosome, was of three morphologically distinct types: WA, WB and WC. Lampbrush chromosomes examined in the oocytes of one female specimen having the WA chromosome showed that the short arm of the WA chromosome and the long arm of the Z chromosome paired closely and hence are genetically homologous. We also tried to analyze the structural relationship among the three types of W chromosomes based on their C-banding and Ag-NOR patterns.  相似文献   
70.
We characterized the visual pathways involved in the stereoscopic recognition of the random dot stereogram based on the binocular disparity employing a functional magnetic resonance imaging (fMRI). The V2, V3, V4, V5, intraparietal sulcus (IPS) and the superior temporal sulcus (STS) were significantly activated during the binocular stereopsis, but the inferotemporal gyrus (ITG) was not activated. Thus a human M pathway may be part of a network involved in the stereoscopic processing based on the binocular disparity. It is intriguing that areas 44 (Broca's area) and 45 in the left hemisphere were also active during the binocular stereopsis. However, it was reported that these regions were inactive during the monocular stereopsis. To separate the specific responses directly caused by the stereoscopic recognition process from the nonspecific ones caused by the memory load or the intention, we designed a novel frequency labeled tasks (FLT) sequence. The functional MRI using the FLT indicated that the activation of areas 44 and 45 is correlated with the stereoscopic recognition based on the binocular disparity but not with the intention artifacts, suggesting that areas 44 and 45 play an essential role in the binocular disparity.  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