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   13465篇
  免费   654篇
  国内免费   102篇
耳鼻咽喉   87篇
儿科学   313篇
妇产科学   287篇
基础医学   1589篇
口腔科学   187篇
临床医学   837篇
内科学   3823篇
皮肤病学   216篇
神经病学   850篇
特种医学   455篇
外科学   2491篇
综合类   46篇
预防医学   256篇
眼科学   84篇
药学   856篇
中国医学   38篇
肿瘤学   1806篇
  2023年   102篇
  2022年   205篇
  2021年   377篇
  2020年   220篇
  2019年   299篇
  2018年   339篇
  2017年   259篇
  2016年   316篇
  2015年   345篇
  2014年   442篇
  2013年   485篇
  2012年   921篇
  2011年   937篇
  2010年   541篇
  2009年   464篇
  2008年   819篇
  2007年   849篇
  2006年   875篇
  2005年   836篇
  2004年   864篇
  2003年   815篇
  2002年   844篇
  2001年   188篇
  2000年   131篇
  1999年   197篇
  1998年   197篇
  1997年   151篇
  1996年   138篇
  1995年   101篇
  1994年   105篇
  1993年   80篇
  1992年   105篇
  1991年   94篇
  1990年   64篇
  1989年   59篇
  1988年   47篇
  1987年   47篇
  1986年   35篇
  1985年   42篇
  1984年   44篇
  1983年   22篇
  1982年   28篇
  1981年   19篇
  1980年   25篇
  1979年   29篇
  1978年   13篇
  1977年   21篇
  1976年   10篇
  1974年   13篇
  1971年   9篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
An autopsy case of bronchiolo-alveolar adenocarcinoma in the lung is reported. The patient is a 70-year-old male who complained of severe cough with 500–600 ml watery sputum a day, loss of weight, and general fatigue. Autopsy revealed numerous whitish tumors in various sizes with multiple cysts in both lungs, with no metastasis being found in any other organs. Histological findings identified the tumor as a bronchiolo-alveolar adenocarcinoma originating from the lungs. Electron-microscopic findings showed that the tumor cells were covered by prominent microvilli, and contained abundant irregulary-shaped cytoplasmic vacuoles suggestive of mucin.  相似文献   
52.
53.
BACKGROUND: Either omega-5 gliadin or high molecular weight glutenin is known to be a major allergen in wheat-dependent exercise-induced anaphylaxis (WDEIA). It is generally considered that gluten specific IgE score is more reliable than that of wheat specific IgE score for the diagnosis of WDEIA. Our aim was to verify the significance of gluten specific IgE in the diagnosis of WDEIA. METHODS: We evaluated the result of gluten CAP-RAST score and omega-5 gliadin specific IgE score on four WDEIA patients who visited our hospital during the years 2004 and 2005, whose diagnosis were onfirmed by prick tests, immunoblot tests and provocation tests. RESULTS: Contrary to our expectations, all four patients showed negative gluten CAP-RAST scores, however all patient's omega-5 gliadin specific IgE scores were positive. CONCLUSION: Our results suggest that gluten specific CAP-RAST score is unreliable in the diagnosis of WDEIA. On the other hand omega-5 gliadin specific IgE score is possibly a better candidate as a diagnostic tool for WDEIA.  相似文献   
54.
The isomorphic response of Koebner can be observed not only in psoriasis, but also in other diseases, such as lichen planus and some systemic diseases including LE (lupus erythematosus) or sarcoidosis. Several clinical findings in LE skin were presented and discussed in this review. The mutually-interactive-, negative-, and internal-Koebner phenomena were introduced and discussed with some speculative views. Many forms of environmental stress on the skin were reported as provocating factors of the Koebner phenomenon, including trauma, scratching, UV-exposure, and various types of dermatitis. Clinical observations of the nature, localization, and movement of lesions should be carefully made. The pathophysiology of the Koebner phenomenon may be classified into two steps. A first non-specific inflammatory step and a second disease-specific step. The inflammatory products released from the first step would be targeted in the second step. In the first step, there could be many substances including cytokines, stress proteins, adhesion molecules, or autoantigens translocated from intra-cellular areas. In the second step after latent periods, there may be disease-specific reactions, including ones by T-cells, B-cells, autoantibodies, and immune deposits, under the restriction of genetic backgrounds. The Koebner phenomenon may prove useful in understanding the pathophysiology of diseases of unknown origin.  相似文献   
55.
In 2004, the Japanese Committee of Clinical Laboratory Standards (JCCLS) published a standard phlebotomy guideline, which not only ensures the safety of the patients and phlebotomists but is adopted to the healthcare setting in Japan. This phlebotomy standard is also essential for the standardization of clinical laboratory tests. This guideline was completed on the basis of current phlebotomy procedures widely in use in Japan using phlebotomy standards in the USA as references, while reconsidering their scientific reasoning as far as possible. At the same time, factors such as practicality and cost benefit were taken into account. The content of the guideline includes necessary facilities and equipment, a step by step safe but practical venipuncture procedure, an explanation of the individual steps, and other supplementary information such as alternative methods. The first edition, published as tentative guideline, is planned to be revised after a set period of time based on the comments and suggestions from a wide range of people concerned, so that it can be published as an approved guideline.  相似文献   
56.
Immediate hemolytic transfusion reactions (IHTR) occurred in the course of delayed hemolytic transfusion reactions (DHTR). An 84-year-old man had received a blood transfusion 20 years ago. Progressive anemia developed, because of continuous bleeding from a bladder tumor. He was transfused with concentrated red blood cells (CRC) which were Rh-E antigen negative, because he had anti-E antibodies (day 0). He received CRC on day 3, and underwent resection of bladder tumor on day 6. Although crossmatch-compatible CRCs were prepared for the operation, those were not required and were kept in a refrigerator in the ward. On day 9, when a CRC kept in the ward was transfused, he suddenly had a IHTR. In order to analyze a mechanism of IHTR, the anti-Jk(b) and anti-Di(b) antibodies, anti-HLA antibodies and the concentrations of inflammatory cytokines were measured in serum samples. The anti-Jk(b) and anti-Di(b) antibodies increased prior to IHTR experienced on day 9. The concentrations of IL-6 and IL-1beta increased from day 2, while the concentration of IL-8 increased from day 7. The anti-HLA class I antibody could be detected 2 days before IHTR. Thus, the anti-Jk(b) and anti-Di(b) antibodies induced the production of inflammatory cytokines and symptoms of DHTR and IHTR. The anti-HLA class I antibody could be produced in spite of using the filer for removing leukocytes, and may take part in the induction of IHTR. Further, blood products should be transfused soon after completing a crossmatch test in patients with anti-RBC alloantibodies.  相似文献   
57.
Molecular diagnosis makes a substantial contribution to precise diagnosis, subclassification, prognosis, and selection of therapy. Mutations in the PDS (SLC26A4) gene are known to be responsible for both Pendred syndrome and nonsyndromic hearing loss associated with enlarged vestibular aqueduct, and the molecular confirmation of the PDS gene has become important in the diagnosis of these conditions. In the present study, PDS mutation analysis confirmed that PDS mutations were present and significantly responsible in 90% of Pendred families, and in 78.1% of families with nonsyndromic hearing loss associated with enlarged vestibular aqueduct. Furthermore, variable phenotypic expression by the same combination of mutations indicated that these two conditions are part of a continuous category of disease. Interestingly, the PDS mutation spectrum in Japanese, including the seven novel mutations revealed by this study, is very different from that found in Caucasians. Of the novel mutations detected, 53% were the H723R mutation, suggesting a possible founder effect. Ethnic background is therefore presumably important and should be noted when genetic testing is being performed. The PDS gene mutation spectrum in Japanese may be representative of those in Eastern Asian populations and its elucidation is expected to facilitate the molecular diagnosis of a variety of diseases.  相似文献   
58.
Ohta H  Makita K  Komukai S  Nozawa S 《Maturitas》2002,43(1):27-33
OBJECTIVES: To investigate if menopause and oophorectomy may represent different risk factors for bone resorption/loss. METHODS: The urinary levels of pyridinoline (Pyr) and deoxypyridinoline (D-pyr), the serum levels of type I carboxy-terminal pyridinoline cross-linked telopeptide (ICTP), and lumbar bone mineral density (BMD), were compared in 80 Japanese women after menopause or oophorectomy. These women were divided into four groups of 20 women each as follows: early postmenopausal stage (early physiologic menopause < 3 years before study entry); late postmenopausal stage (physiologic menopause > or = 3 years before study entry); early postoophorectomy stage (oophorectomy < or = 03 years before study entry); or late oophorectomy stage (oophorectomy > 3 years before study entry). RESULTS: Lumbar BMD was significantly lower in the late groups compared to their respective early groups and was lowest in the late postoophorectomy group. The ratio of D-pyr/creatinine (Cr) was not significantly different among the four groups. The ratio of Pyr/Cr was significantly higher in the early postoophorectomy subjects compared with either late group. The serum level of ICTP was significantly higher in the early postoophorectomy group compared to all other groups. CONCLUSIONS: These findings suggest that serum ICTP may be useful in detecting changes in bone resorption after oophorectomy and that women are at greater risk for bone resorption after oophorectomy than after physiologic menopause, although this difference appears to diminish with time.  相似文献   
59.
Hantaan virus (HTN) and Seoul virus (SEO) are members of the genus Hantavirus in the family Bunyaviridae and are causative agents of hemorrhagic fever with renal syndrome. The complete and truncated nucleocapsid proteins (NP) of HTN and SEO were expressed by a recombinant baculovirus system. Antigenic characterization of the NP using monoclonal antibodies (MAbs) indicated that the binding sites for the serotype-specific MAbs were located between amino acids (aa) 155 and 429. A Western blot assay indicated that the serotype-specific epitopes were conformation dependent. An indirect immunofluorescence antibody (IFA) assay with the truncated NP (aa 155 to 429) was able to distinguish convalescent-phase sera from HTN and SEO patients. However, the antibody titers with the truncated NP were lower than those with the whole NP. The truncated NP of SEO (aa 155 to 429) could be used as an enzyme-linked immunosorbent assay (ELISA) antigen, but the truncated NP from HTN lost its reactivity when used for ELISA. The IFA assay using baculovirus-expressed truncated NP as an antigen is a rapid, simple, and safe test for distinguishing between HTN and SEO infections by serotype.  相似文献   
60.
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