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   160840篇
  免费   10718篇
  国内免费   1252篇
耳鼻咽喉   2251篇
儿科学   3030篇
妇产科学   3742篇
基础医学   24005篇
口腔科学   3346篇
临床医学   15226篇
内科学   30714篇
皮肤病学   4335篇
神经病学   12016篇
特种医学   8132篇
外科学   21869篇
综合类   2172篇
现状与发展   5篇
一般理论   81篇
预防医学   9687篇
眼科学   4302篇
药学   13642篇
中国医学   1598篇
肿瘤学   12657篇
  2023年   756篇
  2022年   2664篇
  2021年   4822篇
  2020年   2466篇
  2019年   3584篇
  2018年   4401篇
  2017年   3235篇
  2016年   4187篇
  2015年   5642篇
  2014年   6909篇
  2013年   8376篇
  2012年   12646篇
  2011年   12277篇
  2010年   7255篇
  2009年   6074篇
  2008年   9256篇
  2007年   9145篇
  2006年   8383篇
  2005年   7988篇
  2004年   7119篇
  2003年   6185篇
  2002年   5374篇
  2001年   4378篇
  2000年   4029篇
  1999年   3267篇
  1998年   1322篇
  1997年   1016篇
  1996年   969篇
  1995年   869篇
  1994年   759篇
  1993年   649篇
  1992年   1573篇
  1991年   1571篇
  1990年   1353篇
  1989年   1244篇
  1988年   1160篇
  1987年   1036篇
  1986年   1016篇
  1985年   885篇
  1984年   649篇
  1983年   566篇
  1982年   403篇
  1981年   384篇
  1980年   343篇
  1979年   520篇
  1978年   406篇
  1977年   389篇
  1976年   349篇
  1974年   358篇
  1973年   327篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Yarrowia lipolytica is a weakly pathogenic yeast that is rarely isolated from the blood. We observed transient recurrent catheter-related fungemia attributable to this organism in a leukemic patient. The fungemia and accompanying fever subsided spontaneously. The data suggest that it might be possible to withhold specific treatment for Y. lipolytica fungemia even in an immunocompromised patient.  相似文献   
992.
The purpose of this study was to determine whether 20 patients who received an early postmastectomy rehabilitation treatment program showed more improvement in range of shoulder motion and functional activities than 13 patients who received instruction for exercise only. Data were obtained at preoperatively, three days after operation, at discharge and at postdischarge one month for each patient on parameters such as range of motion of the ipsilateral shoulder joint, upper extremity circumferential measurements, as well as 10 elements of shoulder function. Postoperatively, both groups showed an increased range of motion of the shoulder joint and improved functional activities, but the group that received postoperative rehabilitation management had a better range of shoulder motion and less difficulty in five items for functional assessment. This study also showed that an early rehabilitation program did not increase postoperative complications. We concluded that an early rehabilitation program or intensive instruction program only by a well-trained physical therapist or physiatrist was beneficial to postmastectomy patients in regaining the function and range of shoulder motion, and significantly better in a rehabilitation group.  相似文献   
993.
994.
Young  P.  McDonnell  P.  Dunnington  D.  Hand  A.  Laydon  J.  Lee  J. 《Inflammation research》1993,39(1):C67-C69

The mechanism by which SK&F 86002 and other pyridinyl imidazoles inhibit the production of IL-1 and TNF from LPS-stimulated human monocytes was examined. Inhibition of IL-1 and TNF production was found to depend on the time of addition of SK&F 86002, with diminishing effect when added more than 2 h after LPS stimulation. Analysis of Western blots confirmed that both intracellular IL-1β and extracellular TNF were significantly reduced in response to SK&F 86002, but these reductions were not paralleled by changes in IL-1 and TNF mRNA.35S methionine pulse and pulse-chase studies on IL-1 biosynthesis suggest that significant inhibition by SK&F 86002 and related compounds occurs at the translational level.

  相似文献   
995.
We employ diffuse optical tomography (DOT) to track treatment progress in a female subject presenting with locally advanced invasive carcinoma of the breast during neoadjuvant chemotherapy. Three-dimensional images of total hemoglobin concentration and scattering identified the tumor. Our measurements reveal tumor shrinkage during the course of chemotherapy, in reasonable agreement with magnetic resonance images of the same subject. A decrease in total hemoglobin concentration contrast between tumor and normal tissue was also observed over time. The results demonstrate the potential of DOT for measuring physiological parameters of breast lesions during chemotherapy.  相似文献   
996.
To verify the changes of mesopic and photopic contrast sensitivity function of sound eye whose visual acuity was kept the same after occlusion therapy in the amblyopic children. Fourteen sound eyes of amblyopic children (mean; 7.67 years; S.D., 1.50 years) who kept their visual acuity the same after the occlusion therapy were tested. The children had 6 hours of part-time patch therapy for 3 months prior to this examination. Among 14 amblyopic children, 8 were anisometric and 6 were strabismic amblyopes. Using the visual capacity analyzer which measures the minimal contrast level at from low to high spatial frequencies, the contrast sensitivity of sound eye was measured, under both photopic and mesopic condition, before and after 3 months of occlusion therapy. Comparing the contrast sensitivity of sound eye after the occlusion therapy to that before the occlusion, there was no statistical difference in photopic condition. When it comes to mesopic condition, the contrast sensitivity decreased at the intermediate spatial frequency level (3-13 c.p.d, p=0.028) after the occlusion therapy. The occlusion caused statistically significant decrease in mesopic contrast sensitivity, when the visual acuity was not changed after the occlusion therapy. It may indicate that mesopic contrast sensitivity can be considered as a useful tool for early detection of hidden occlusion amblyopia.  相似文献   
997.
998.
Biphenotypic acute leukemias account for 4% to 8% of all acute leukemias. Most of these leukemias are of myeloid-B-cell or myeloid-T-cell lineage. Acute myeloid-natural killer cell leukemia has been recognized recently. We report the first case, to our knowledge, of CD56(+) acute leukemia showing unequivocal myeloid and B-cell differentiation in a 20-year-old woman, whose blast cells were positive for myeloperoxidase, CD13, CD33, CD117, terminal deoxynucleotidyl transferase, CD19, CD20, CD22, CD34, HLA-DR, and CD56 but negative for CD3, CD5, CD7, and CD10. Rare Auer rods were identified in the blast cells. Polymerase chain reaction assays showed rearrangement of immunoglobulin heavy-chain gene and absence of Epstein-Barr virus DNA. We propose that this novel form of multilineage leukemia may represent the neoplastic counterpart of a progenitor that can give rise to myeloid, B, and natural killer cells.  相似文献   
999.
BACKGROUND: To assess the nature and prevalence of skin disorders among psychiatric patients on chronic lithium therapy and to compare them with patients on other psychotropic medications. METHOD: 51 patients on lithium and 57 patients on other psychotropics were recruited. Dermatological assessment included a semi-structured questionnaire and clinical examination of the subjects by two dermatologists who were blind to the psychiatric diagnosis and treatment. Secondary cutaneous reaction was defined as skin eruption that developed or deteriorated after commencement of psychiatric medication. RESULTS: Lithium treated patients developed significantly more secondary cutaneous reactions than the control group. This applied particularly to acne and psoriasis. Male patients on lithium were more likely to be affected than female patients. CONCLUSION: Lithium aggravates or triggers cutaneous conditions that are characterized by the pathological findings of neutrophilic infiltration. Since these cutaneous problem can be distressing to patients and may affect medication compliance, there should be heightened attention to skin problems in patients receiving lithium treatment.  相似文献   
1000.
The discovery of nucleated erythrocytes in maternal circulationprovides a potential source for non-invasive prenatal diagnosis.We have evaluated the use of a three-stage procedure to determinethe number of cells that are of fetal rather than maternal origin.First, monoclonal antibodies specific for CD45 and CD14 wereused in conjunction with a magnetic (MACS) column to depleteunwanted leukocytes from maternal blood. This was followed bya positive MACS enrichment for nucleated erythrocytes, usingan anti-CD71 (transferrin receptor) monoclonal antibody. Todiscriminate between fetal nucleated erythrocytes and thoseof maternal origin, enriched fractions were simultaneously stainedwith an anti-fetal haemoglobin (HbF) antibody and hybridizedwith probes specific for X and Y chromosomes. Samples were thensubjected to blind analysis along with negative control samplesfrom non-pregnant volunteers. Using this dual analysis, we wereable to determine that less than one nucleated erythrocyte perml of maternal blood was of fetal origin. Small numbers of thesefetal cells were found in 87.5% of pregnancies, ranging from6 to 35 weeks gestational age. Comparison of HbF and X/Y probedata also suggests that the fetal cells are less suitable forfluorescence in-situ hybridization (FISH) analysis than similarpreparations from other sources. cell separation methods/fluorescence in-situ hybridization/hereditary diseases/polymerase chain reaction/pregnancy  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