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   1741篇
  免费   92篇
  国内免费   4篇
耳鼻咽喉   11篇
儿科学   41篇
妇产科学   86篇
基础医学   223篇
口腔科学   83篇
临床医学   139篇
内科学   444篇
皮肤病学   17篇
神经病学   68篇
特种医学   39篇
外科学   282篇
综合类   23篇
预防医学   66篇
眼科学   29篇
药学   182篇
中国医学   6篇
肿瘤学   98篇
  2023年   39篇
  2022年   86篇
  2021年   107篇
  2020年   53篇
  2019年   69篇
  2018年   89篇
  2017年   64篇
  2016年   64篇
  2015年   42篇
  2014年   61篇
  2013年   72篇
  2012年   137篇
  2011年   139篇
  2010年   75篇
  2009年   65篇
  2008年   77篇
  2007年   80篇
  2006年   68篇
  2005年   89篇
  2004年   67篇
  2003年   45篇
  2002年   47篇
  2001年   12篇
  2000年   8篇
  1999年   17篇
  1998年   12篇
  1997年   10篇
  1996年   10篇
  1995年   2篇
  1994年   4篇
  1993年   3篇
  1992年   13篇
  1991年   10篇
  1990年   9篇
  1989年   9篇
  1988年   4篇
  1987年   11篇
  1986年   5篇
  1985年   13篇
  1984年   4篇
  1983年   7篇
  1982年   5篇
  1981年   4篇
  1980年   5篇
  1979年   5篇
  1978年   6篇
  1977年   4篇
  1976年   2篇
  1975年   2篇
  1965年   1篇
排序方式: 共有1837条查询结果,搜索用时 0 毫秒
1.
2.
A 24-year-old man presented with a 24-hour history of pain and numbness in his left arm. The patient's clinical presentation of peripheral embolism was corroborated by angiography. Echocardiographic study showed masses in both right and left atria. Pathologic specimen from the embolus confirmed the diagnosis of aspergillosis.  相似文献   
3.
Conference Reports: This section contains reports on topical conferences. Reports are usually written at the request of the editorial office, but unsolicited contributions are also welcome. Suggestions should be sent to the editorial office of the Macromolecular journals, preferably by E‐mail to macromol@wiley‐vch.de.  相似文献   
4.
Burns during pregnancy: a gloomy outcome   总被引:2,自引:0,他引:2  
The effect of burns on fetal and maternal survival is known to be detrimental. This prospective study describes the performance of pregnant burned patients who were managed and followed up for fetal and maternal outcomes at Ain Shams University's burn unit and Maternity Hospital during the period from October 1995 to September 1996. During the 12-month period, 27 pregnant burned patients were managed. Fetal and maternal mortality correlated with the total body surface area (TBSA) burned, the mortality rate being 63 per cent for both mothers and fetuses in the 25–50 per cent TBSA group. A fetal loss of 56 per cent with no maternal loss were recorded in the 15–25 per cent TBSA group. Experience in dealing with pregnant burned patients proves that early surgical excision and skin grafting, with timely termination of pregnancy are the best lines of treatment. Prevention or minimizing the effects of the burns may be achieved by proper education and guidance of the pregnant woman.  相似文献   
5.
1. In an attempt to explain the previous electrophysiological data on the ontogeny of beta-adrenergic and muscarinic cholinergic interactions on cardiac Ca2+ current, biochemical studies were performed on the ontogeny of beta-adrenoceptors, muscarinic cholinoceptors and Ca2+ channels in cardiac muscle of developing rats: 16-20 days old foetuses, 0-20 days old neonates, and 2-3 months old adults. 2. Developmental changes in cardiac beta-adrenoceptors, muscarinic cholinoceptors, and Ca2+ channels were determined with the use of specific radioligands, [3H]-dihydroalprenolol (DNA), [3H]-quinuclidinyl benzilate (QNB), and [3H]-nitrendipine (NTD), respectively. 3. The Bmax value (fmol mg-1 tissue) for [3H]-DNA binding started to increase on post-gestation day 20, reached almost its maximum level on neonatal day 6, kept almost the same level until neonatal day 20, and then decreased slightly to its adult level. 4. The Bmax value (fmol mg-1 tissue) for [3H]-QNB binding started to increase on post-gestation day 16, reached almost its maximum level on neonatal day 0, remained almost constant until neonatal day 15, and then decreased to its adult level. 5. The Bmax value (fmol mg-1 tissue) for [3H]-NTD binding increased with age between post-gestation day 18 and neonatal day 15, stayed almost constant until neonatal day 20, and then decreased to its adult level. 6. The Kd values for [3H]-DHA, [3H]-QNB, and [3H]-NTD bindings remained almost constant during the developmental period examined.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
6.
OBJECTIVE: In a prospective study, the effect of thymectomy on the pulmonary status of 50 consecutive patients with myasthenia gravis was evaluated over a time range of 4 years in the Chest and Chest surgery departments in the Cairo University Clinics and Thoracic Surgery Department of the Evangelisches Krankenhaus Duisburg-Nord. METHODS: The patients were divided into two groups: Group I included 26 patients who underwent thymectomy through median sternotomy. The mean age of the patients in this group was 24.8+/-10.5 (5-41) years. They were 19 females and seven males. Thirteen of the patients were in Myasthenia Gravis Foundation of America (MGFA) class IIa, and 12 were in class IIb, and one was in class IIIa. Group II included 24 patients who underwent thymectomy through manubriotomy. The mean age of the patients in this group was 25.2+/-9.2 (12-41) years. They were 13 females and 11 males. Eight of the patients were in MGFA class 2a, 14 were in class IIb, and two were in class IIIa. RESULTS: When compared to group I in which postoperative ventilation was required in 15.4% of patients, postoperative ventilation was not necessary in patients of group II with a statistically significant difference (P=0.04). The mean duration of stay in the intensive care unit was 111.4h in group II, and 169.7h in group I (P=0.03). The peak inspiratory flow rate and the forced vital capacity were also statistically significantly better in group II. There was no mortality in both groups, and the morbidity was higher in the median sternotomy group. CONCLUSION: Thymectomy through a manubriotomy, which allows extensive removal of ectopic thymic tissue in addition to the thymus through a less invasive approach than a full median sternotomy, is associated with a significantly smoother postoperative course and less pulmonary complications, when compared with thymectomy through a full median sternotomy.  相似文献   
7.
8.
ABSTRACT: Human leukocyte antigen (HLA) genes are candidates for susceptibility genes in insulin-dependent diabetes mellitus (IDDM). Recently, the association of DR and DQ with IDDM has been reported, but the role of HLA-DP genes remains uncertain. To address the question, we analyzed the DPB1 gene of 20 Japanese IDDM patients and 30 control subjects using a combination of polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis (PCR-RFLP method). DPB1*0501 was the most frequent allele both in Japanese patients and control subjects. There was no appreciable association between IDDM and the DPB1 allele in Japanese. The absence of association between IDDM and DP, in spite of the known association between this disease and both DR and DQ, suggests that the HLA locus (loci) telomeric to DP encodes susceptibility to IDDM.  相似文献   
9.
Deletions or translocations of chromosome band 13q14, the locus of the retinoblastoma gene (RB1), have been observed in a variety of hematological malignancies including myelodysplastic syndrome (MDS). We describe here a novel unbalanced translocation der(13)t(7;13)(p13;q14) involving 13q14 in a patient with MDS. A 66-year-old woman was diagnosed as having MDS, refractory anemia with excess of blasts (RAEB-1) because of 7.4% blasts and trilineage dysplasia in the bone marrow cells. G-banding and spectral karyotyping analyses showed complex karyotypes as follows: 46,XX,der(6)t(6;7)(q11;?),der(7)del(7)(?p13)t(6;7)(q?;q11)t(6;13)(q?;q?),der(13)t(7;13)(p13;q14). Fluorescence in situ hybridization (FISH) analyses demonstrated that one allele of the RB1 gene and the microsatellite locus D13S319, located at 13q14 and telomeric to the RB1 gene, was deleted. Considering other reported cases, our results indicate that submicroscopic deletions accompanying 13q14 translocations are recurrent cytogenetic aberrations in MDS. The RB1 gene or another tumor suppressor gene in the vicinity of D13S319, or both, may be involved in the pathogenesis of MDS with 13q14 translocations by monoallelic deletion.  相似文献   
10.
Oxidative stress induces the activation of multiple signaling pathways related to various cellular responses. In B cells, Syk has a crucial role in intracellular signal transduction induced by oxidative stress as well as antigen receptor engagement. Treatment of B cells with hydrogen peroxide (H(2)O(2)) induces enzymatic activation of Syk. Syk is essential for Ca(2+) release from intracellular pools through phospholipase C-gamma2 and the activation of c-Jun N-terminal kinase, p38 mitogen-activated protein kinase, and phosphatidylinositol 3-kinase-Akt survival pathway following H(2)O(2) stimulation. Oxidative stress-induced cellular responses in B cells follow different patterns, such as necrosis, apoptosis, and mitotic arrest, according to the intensity of H(2)O(2) stimulation. Syk is involved in the protection of cells from apoptosis and induction of G2/M arrest. Syk leads to the activation of the phosphatidylinositol 3-kinase-Akt survival pathway, thereby enhancing cellular resistance to oxidative stress-induced apoptosis. On the other hand, Syk-dependent phospholipase C-gamma2 activation is required for acceleration toward apoptosis following oxidative stress. These findings suggest that oxidative stress-induced Syk activation triggers the activation of several pathways, such as proapoptotic and survival pathways, and the balance among these various pathways is a key factor in determining the fate of a cell exposed to oxidative stress.  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