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:      
  示例: 沙坡头地区,人工植被区,变化  检索词用空格隔开表示必须包含全部检索词,用“,”隔开表示只需满足任一检索词即可!
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   25497篇
  免费   787篇
  国内免费   155篇
耳鼻咽喉   240篇
儿科学   527篇
妇产科学   468篇
基础医学   3676篇
口腔科学   263篇
临床医学   2365篇
内科学   6191篇
皮肤病学   365篇
神经病学   2155篇
特种医学   1072篇
外国民族医学   8篇
外科学   4228篇
综合类   69篇
一般理论   4篇
预防医学   1346篇
眼科学   221篇
药学   1358篇
  1篇
中国医学   41篇
肿瘤学   1841篇
  2024年   105篇
  2023年   145篇
  2022年   226篇
  2021年   623篇
  2020年   387篇
  2019年   603篇
  2018年   694篇
  2017年   464篇
  2016年   567篇
  2015年   718篇
  2014年   938篇
  2013年   1207篇
  2012年   1913篇
  2011年   1889篇
  2010年   1098篇
  2009年   1103篇
  2008年   1683篇
  2007年   1700篇
  2006年   1661篇
  2005年   1705篇
  2004年   1573篇
  2003年   1482篇
  2002年   1392篇
  2001年   203篇
  2000年   147篇
  1999年   218篇
  1998年   264篇
  1997年   231篇
  1996年   192篇
  1995年   159篇
  1994年   116篇
  1993年   144篇
  1992年   105篇
  1991年   81篇
  1990年   78篇
  1989年   52篇
  1988年   57篇
  1987年   40篇
  1986年   50篇
  1985年   44篇
  1984年   38篇
  1983年   49篇
  1982年   41篇
  1981年   48篇
  1980年   37篇
  1979年   21篇
  1978年   16篇
  1977年   15篇
  1976年   14篇
  1975年   18篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Waardenburg syndrome type 4 (WS4) is a rare neural crest disorder defined by the combination of Waardenburg syndrome (sensorineural hearing loss and pigmentation defects) and Hirschsprung disease (intestinal aganglionosis). Three genes are known to be involved in this syndrome, that is, EDN3 (endothelin-3), EDNRB (endothelin receptor type B), and SOX10. However, 15-35% of WS4 remains unexplained at the molecular level, suggesting that other genes could be involved and/or that mutations within known genes may have escaped previous screenings. Here, we searched for deletions within recently identified SOX10 regulatory sequences and describe the first characterization of a WS4 patient presenting with a large deletion encompassing three of these enhancers. Analysis of the breakpoint region suggests a complex rearrangement involving three Alu sequences that could be mediated by a FosTes/MMBIR replication mechanism. Taken together with recent reports, our results demonstrate that the disruption of highly conserved non-coding elements located within or at a long distance from the coding sequences of key genes can result in several neurocristopathies. This opens up new routes to the molecular dissection of neural crest disorders.  相似文献   
992.
993.
Recent editorials in this journal have defended the right of eminent biologist James Watson to raise the unpopular hypothesis that people of sub-Saharan African descent score lower, on average, than people of European or East Asian descent on tests of general intelligence. As those editorials imply, the scientific evidence is substantial in showing a genetic contribution to these differences. The unjustified ill treatment meted out to Watson therefore requires setting the record straight about the current state of the evidence on intelligence, race, and genetics. In this paper, we summarize our own previous reviews based on 10 categories of evidence: The worldwide distribution of test scores; the g factor of mental ability; heritability differences; brain size differences; trans-racial adoption studies; racial admixture studies; regression-to-the-mean effects; related life-history traits; human origins research; and the poverty of predictions from culture-only explanations. The preponderance of evidence demonstrates that in intelligence, brain size, and other life-history variables, East Asians average a higher IQ and larger brain than Europeans who average a higher IQ and larger brain than Africans. Further, these group differences are 50-80% heritable. These are facts, not opinions and science must be governed by data. There is no place for the "moralistic fallacy" that reality must conform to our social, political, or ethical desires.  相似文献   
994.
Allergen-specific immunotherapy represents a curative treatment of type I allergies. Subcutaneous immunotherapy is conducted with allergens adsorbed on aluminum hydroxide or calcium phosphate particles, whereas sublingual immunotherapy relies on high doses of soluble allergen without any immunopotentiator. There is a potential benefit of adjuvants enhancing regulatory and Th1 CD4+T cell responses during specific immunotherapy. Molecules affecting dendritic cells favor the induction of T regulatory cell and Th1 responses and represent valid candidate adjuvants for allergy vaccines. Furthermore, the interest in viruslike particles and mucoadhesive particulate vector systems, which may better address the allergen(s) to tolerogenic antigen-presenting cells, is documented.  相似文献   
995.
996.
997.
Contaminated mud and soil may play roles as reservoirs and sources of transmission for avian influenza A virus. However, the persistence of highly pathogenic avian influenza (HPAI) H5N1 virus in soil or mud has not been well documented, and specific methods of H5N1 virus detection in mud and soil specimens have not been described. The aim of this work was to evaluate the capacities of five different commercial kits and one elution-concentration technique to extract nucleic acids from H5N1 virus and to detect infectious viral particles in experimentally infected mud specimens. The viral RNA detection thresholds for the QIAamp kit, Trizol LS and the MagNA Pure LC kit were 5 × 10(2)RNA copies per gram of mud. Trizol reagent and the RNA PowerSoil? kit were unsuccessful in recovering any viral RNA from mud. When the elution-concentration technique was performed prior to nucleic acid extraction, the performance of the MagNA Pure kit increased to a level that allowed the detection of H5N1 nucleic acids in naturally contaminated environmental samples that had previously tested negative after direct extraction using commercial kits. The levels of detection of infectious virus after inoculation into embryonated eggs were higher in concentrates than in eluates.  相似文献   
998.
999.
The inflammation which occurs around the silicone prosthesis is a complex process that can provoke the failure of the device and compromise the health of the implanted patient. Toll-like receptors (TLRs), which are transmembrane proteins, are now known to act in the innate immune response and in endogenous inflammation. The aim of our study was to assess the role of TLR4 in the foreign body reaction to a silicone shell prosthesis. Disks of shell silicone prosthesis were implanted in the subcutaneous tissue of C57BL6-TLR4-/- and C57BL6-WT mice. At day 14, inflammatory cell infiltrate and vessel sections around the prosthesis were less numerous in TLR4-/- than in WT mice. A histomorphometric analysis showed that the capsule around the implant was 1.96-fold less thick in depleted TLR4 than in wild-type mice. In addition, vascular endothelial growth factor and transforming growth factor 1 were underexpressed in the surrounding tissue of the prosthesis in TLR4-/- mice. Our study suggests, from this foreign body response model against silicone in mice, that TLR4 plays a key role in the reaction process around silicone implants.  相似文献   
1000.

Objective

To evaluate the feasibility of laparoscopic supracervical hysterectomy (LSH) by single port access (SPA) with transcervical morcellation.

Study design

Observational study conducted between September 2010 and March 2012 in two departments of Gynaecology. Forty women who required hysterectomy underwent LSH by SPA with transcervical morcellation.

Results

LSH by SPA with transcervical morcellation was completed successfully in 37/40 (93.5 %) patients. Mean operating time was 128 (±55) min and mean hospital stay was 3.5 (±1) days. The mean of uterus weight was 310 (±214) g. The mean estimated blood loss was 250 (±110) ml. Four women (10 %) required a second surgical intervention including two cases of endocervical bleeding.

Conclusion

LSH by SPA with transcervical morcellation is a feasible procedure.  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