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   15535篇
  免费   1155篇
  国内免费   70篇
耳鼻咽喉   265篇
儿科学   601篇
妇产科学   450篇
基础医学   1899篇
口腔科学   240篇
临床医学   1597篇
内科学   3498篇
皮肤病学   483篇
神经病学   1282篇
特种医学   513篇
外科学   2524篇
综合类   184篇
一般理论   20篇
预防医学   983篇
眼科学   338篇
药学   956篇
中国医学   32篇
肿瘤学   895篇
  2023年   113篇
  2022年   180篇
  2021年   587篇
  2020年   343篇
  2019年   456篇
  2018年   522篇
  2017年   379篇
  2016年   424篇
  2015年   416篇
  2014年   553篇
  2013年   740篇
  2012年   1062篇
  2011年   1083篇
  2010年   585篇
  2009年   551篇
  2008年   836篇
  2007年   923篇
  2006年   836篇
  2005年   786篇
  2004年   737篇
  2003年   627篇
  2002年   546篇
  2001年   223篇
  2000年   202篇
  1999年   206篇
  1998年   136篇
  1997年   88篇
  1996年   78篇
  1995年   67篇
  1994年   71篇
  1993年   75篇
  1992年   120篇
  1991年   130篇
  1990年   111篇
  1989年   120篇
  1988年   106篇
  1987年   106篇
  1986年   116篇
  1985年   113篇
  1984年   102篇
  1983年   84篇
  1982年   83篇
  1981年   102篇
  1980年   70篇
  1979年   85篇
  1978年   74篇
  1977年   65篇
  1975年   45篇
  1974年   51篇
  1972年   45篇
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
71.
A case of hyperreactio luteinalis in an otherwise normal pregnancy is reported. Ascites was present, but no peritoneal implants or adenopathy were seen. Findings that would have suggested the correct diagnosis are the symmetrical and bilateral pattern of the mass, as well as the rather uniform size of the loculi, which were 1 to 3 cm in diameter.  相似文献   
72.
This article reviews the interrelationship between panic disorder and vestibular function. There is a possibility of both somatopsychic and psychosomatic interactions between panic and the vestibular system. Another possibility is that vestibular dysfunction could be associated with certain mental disorders, including panic disorder, as a nonspecific marker. Somatopsychic interactions are suggested by findings of high prevalence of vestibular dysfunction in selected patients with panic disorder, by the occurrence of "space and motion phobia" in patients with panic disorder, and by the report of anxiety and pseudoagoraphobia in some patients with a primary complaint of vertigo. Psychosomatic influences include symptoms of dizziness and increased sensitivity of the vestibular system due to anxiety or hyperventilation. Vestibular dysfunction as a nonspecific marker is discussed in the context of a review of studies of the vestibular system in schizophrenia. Before more definite conclusions can be drawn whether panic disorder is related to vestibular dysfunction in some cases, further research is needed to establish the specificity of vestibular dysfunction for panic disorder.  相似文献   
73.
Patients with diminutive polyps in the rectum or sigmoid colon were randomized to "hot biopsy" treatment for either 1) electrocautery for 2 s (fixed duration cautery) or 2) cautery until visible necrosis of the polyp base was evident (variable duration cautery). Sigmoidoscopy was performed 4 wk after treatment to determine the adequacy of polyp eradication. In the fixed duration cautery group, 11 of 21 polyps (52%) were eradicated, compared with 12 of 14 polyps (86%) in the variable duration cautery group (p = 0.04). When analyzed according to whether or not visible necrosis was achieved (some of the polyps in the fixed duration cautery group showed necrosis with 2 s cautery), 19 of 23 polyps (83%) were eradicated when necrosis was evident, compared to 5 of 12 (42%) without necrosis (p = 0.004). We conclude that hot biopsy treatment for diminutive polyps is significantly more effective when visible necrosis is achieved during cautery. Furthermore, even with visible necrosis, there is a 17% failure rate of polyp eradication.  相似文献   
74.
The method of the play interview offers the fearful child an opportunity to express himself by speaking for a series of dolls representing siblings, parents, teachers or himself. It is not the child who is aggressive, fearful, jealous or desires the parent's affection, but the doll. In this manner, the child learns to make connections between his fears and his unacceptable bad thoughts, feelings or wishes. Improvement occurs after several play interviews.This article is dedicated to Dr. Leo Kanner (1894–1981), former Director of the Children's Psychiatric Service of the Johns Hopkins HospitalLecture given to the Division of Child Psychiatry, Department of Psychiatry and Behavioral Sciences The Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, Md, 21205, on September 6, 1988.  相似文献   
75.
76.
Reactive arthritis (ReA) induced by infection with several gram-negative bacteria is strongly associated with expression of the major histocompatibility complex class I molecule HLA-B27. It is thought that due to the intracellular lifestyle of ReA-inducing bacteria, bacterial fragments can be presented by HLA-B27. Cytotoxic T cells recognizing such bacterial peptides or other induced host peptides could cross-react with self peptides presented in the joints, giving rise to disease. Studies to analyze the B27 peptide repertoire in relation to infection were severely hampered, as complex peptide profiles obtained from separate infected and noninfected cell preparations had to be compared. For this study, we applied a new approach to examine the effect of Salmonella enterica serovar Typhimurium infection on the B27 peptide repertoire presented by the HLA-B*2704 subtype associated with disease. Firstly, we showed that both host cell and S. enterica serovar Typhimurium proteins can be tagged metabolically with stable-isotope-labeled arginine. We then designed experiments so that either the tagged endogenous or tagged bacterial B*2704-presented peptide repertoires from infected cells could be analyzed by mass spectrometry from single peptide preparations that included uninfected controls. Using this new approach, we found no evidence for significant changes in endogenous B*2704 peptide presentation after infection or for any S. enterica serovar Typhimurium-derived B27-bound peptide. In conclusion, the hypothesis that S. enterica serovar Typhimurium induces changes in B27 peptide presentation could not be supported.  相似文献   
77.
DNA vaccination is an efficient way to induce CD8+ T cell memory, but it is still unclear to what extent such memory responses afford protection in vivo. To study this, we induced CD8+ memory responses directed towards defined viral epitopes, using DNA vaccines encoding immunodominant MHC class I-restricted epitopes of lymphocytic choriomeningitis virus covalently linked to beta2-microglobulin. This vaccine construct primed for a stronger recall response than did a more conventional minigene construct. Despite this, vaccinated mice were only protected against systemic infection whereas protection against the consequences of peripheral challenge was limited. Phenotypic analysis revealed that DNA vaccine-primed CD8+ T cells in uninfected mice differed from virus-primed CD8+ T cells particularly regarding expression of very-late antigen (VLA)-4, an adhesion molecule important for targeting T cells to inflammatory sites. Thus, our DNA vaccine induces a long-lived memory CD8+ T cell population that provides efficient protection against high-dose systemic infection. However, viral replication in solid non-lymphoid organs is not curtailed sufficiently fast to prevent significant virus-induced inflammation. Our results suggest that this is due to qualitative limitations of the primed CD8+ T cells.  相似文献   
78.
Dermal and pulmonary tuberculous lesions were produced in rabbits with BCG, biopsied, incubated in vitro with tritiated thymidine (3HT) under hyperbaric oxygen, quickly frozen, sectioned in a cryostat, stained for the lysosomal enzyme β-galactosidase, autoradiographed, stained for acid-fast bacilli and counterstained with hematoxylin. As macrophages developed into epithelioid cells, they could still divide—ie, incorporate 3HT. However, once they became fully mature epithelioid cells that were 4-plus in β-galactosidase, they could not do so. Tuberclebacilli did not stimulate macrophage division. On the contrary, macrophages containing bacilli did not divide, except when the lesions began. During the development of tuberculous lesions, macrophages (including those rich in enzymes and those containing bacilli) died, forming caseous centers. Therefore, local cell division did not seem to be the main mechanism by which macrophages reduced their bacillary load. Such division seemed mainly to occur in young macrophages that had recently immigrated into the lesions from the bloodstream and had not yet ingested bacilli.  相似文献   
79.
80.
Zusammenfassung Es wird über zwei beobachtete Fälle von akuter Myokarditis berichtet, welche im Verlaufe bzw. im Anschlusse an eine akute Infektionskrankheit auftraten, bei denen die elektrokardiographisch festgestellten Störungen des Rhythmus und des Erregungsablaufes für die Stellung der Diagnose von großem Werte waren. In beiden Fällen trat nach einer kurzen Krankheitsdauer völlige Erholung ein.  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