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   312篇
  免费   14篇
儿科学   34篇
妇产科学   5篇
基础医学   38篇
口腔科学   5篇
临床医学   22篇
内科学   58篇
皮肤病学   14篇
神经病学   25篇
特种医学   2篇
外科学   54篇
综合类   5篇
一般理论   1篇
预防医学   13篇
眼科学   4篇
药学   10篇
中国医学   2篇
肿瘤学   34篇
  2017年   2篇
  2016年   3篇
  2015年   5篇
  2014年   8篇
  2013年   4篇
  2012年   6篇
  2010年   9篇
  2009年   7篇
  2008年   7篇
  2007年   5篇
  2006年   14篇
  2005年   2篇
  2004年   3篇
  2002年   2篇
  2001年   2篇
  2000年   2篇
  1999年   2篇
  1998年   9篇
  1997年   16篇
  1996年   18篇
  1995年   11篇
  1994年   15篇
  1993年   13篇
  1992年   10篇
  1991年   5篇
  1990年   5篇
  1989年   2篇
  1988年   4篇
  1987年   8篇
  1986年   9篇
  1985年   2篇
  1984年   4篇
  1983年   2篇
  1982年   4篇
  1981年   2篇
  1980年   5篇
  1978年   4篇
  1970年   1篇
  1968年   1篇
  1967年   2篇
  1961年   1篇
  1959年   6篇
  1958年   9篇
  1957年   20篇
  1956年   23篇
  1955年   8篇
  1954年   12篇
  1952年   1篇
  1949年   2篇
  1948年   2篇
排序方式: 共有326条查询结果,搜索用时 203 毫秒
1.
ABSTRACT: The culture supernatant of the TTK-1 cell line, established from human decidual tissue, was found to contain a factor that strongly suppressed the mixed lymphocyte reaction (MLR). The mechanism of the MLR-suppressive activity as well as the biochemical characterization of this factor was analyzed. The TTK-1 supernatant suppressed the MLR much more strongly than the culture supernatants of the three other malignant cell lines examined. The molecular weight of this factor was estimated to be between 43 kilodaltons (kd) and 67 kd by gel filtration chromatography. The TTK-1 supernatant also suppressed the proliferation of the interleukin 2 (IL-2)-dependent T cell lines, but did not suppress that of the IL-2-independent T cell lines, suggesting that the TTK-1 supernatant inhibited the action of IL-2 and subsequently suppressed the MLR. The fact that the TTK-1 cell line originated from human decidual tissue might imply the important role of this factor in immunological fetomaternal balance.  相似文献   
2.
Recent studies have shown that proto–oncogene c–fos mRNA is induced in the central nervous system by a variety of stimuli including generalised convulsions. In this study, the expression of c–fos protein (c–Fos) following lignocaine–induced convulsions was examined and compared with that following convulsions induced by non–anesthetic convulsants, such as pentylenetetrazol, kainic acid and electroconvulsive shocks, in rat brain.
Administration of 120 mg kg-1 lignocaine by the intraperitoneal route induced generalised convulsions in all rats examined within 10 min. C–Fos was markedly induced in the piriform cortex and amygdala, and slightly induced in the neocortex and thalamus, while no c–Fos expression was observed in the hippocampus. In contrast, c–Fos expression following generalised convulsions induced by non–anaesthetic convulsants was very marked in the hippocampal region, piriform cortex and amygdala, and extended to the thalamus and neocortex.
These results contradict those of previously reported local cerebral metabolic studies using 2–deoxyglucose as a metabolic marker, and suggest that lignocaine–induced convulsions, unlike those induced by non–anaesthetic convulsants, may not cause severe sequelae (plastic changes) in the hippocampus.  相似文献   
3.
Background: The direct effect of halothane on vascular smooth muscle is mediated in part via its effects on the sarcoplasmic reticulum (SR). Little information is available concerning the effects of other volatile anesthetics including isoflurane and sevoflurane, whose vascular effects differ from those of halothane. The aim of the present study was to compare the effects of halothane, isoflurane and sevoflurane on the SR by testing the contraction induced by caffeine in vascular smooth muscle. Methods: Rings without endothelium from isolated canine mesenteric artery were mounted in physiological saline solution (PSS) for isometric tension recording. After complete depletion of Ca2+ from the SR by adding 35 mM caffeine, the rings were exposed to normal Ca2+ containing PSS (Ca2+ loading), to Ca2+-free PSS for 10 min, and then to 15 mM caffeine to induce contraction. Anesthetics were administered during Ca2+ loading, the Ca2+-free phase and simultaneously with caffeine administration. Results: Halothane (0.5-2%) attenuated the caffeine-induced contraction of canine mesenteric artery when administered during Ca2+ loading in the SR (P<0.001), whereas isoflurane and sevoflurane (1–4%) failed to affect the contraction. When given simultaneously with caffeine, halothane (1–2%) potentiated the caffeine-induced contraction (P<0.05), but isoflurane and sevoflurane had no effect. When given before caffeine administration, halothane (0.5-2%), isoflurane (24%) and sevoflurane (4%) all potentiated the caffeine-induced contraction (P<0.05). Conclusion: It has been shown that halothane not only potentiates caffeine- induced Ca2+ release from the SR, but also induces contraction by releasing Ca2+ from the SR. We conclude that halothane decreases Ca2+ accumulation in the SR while exerting facilitative and additive effects on caffeine-induced Ca2+ release from the SR when applied before caffeine administration and simultaneously with caffeine, respectively, whereas isoflurane and sevoflurane lack both the ability to decrease Ca2+ accumulation and an additive effect on caffeine-induced Ca2+ release from the SR, but are able to facilitate Ca2+ release by caffeine.  相似文献   
4.
We have measured the direct effects of propofol 10–7-10–4mol litre–1 on isolated canine cerebral, coronary, mesenteric,femoral and renal arteries. In arterial strips precontractedsubmaximally with potassium chloride or prostaglandin F2  相似文献   
5.
6.
ABSTRACT: Changes in lymphocyte subsets in whole blood of normal pregnant and postpartum women were examined by flow cytometry with an automated leukocyte differential system. From the first trimester and throughout pregnancy, the absolute counts of T(CD3) and B(CD20) and T-cell subsets (CD4, CD8) decreased with a decrease in the absolute lymphocyte count, although the proportions of these cells remained unchanged except for a decrease in the percentage of T helper-inducer (CD4) cells in the first trimester. On the contrary, the percentage of NK/K (Leu 7) cells, but not of NK/K (CD16) cells, increased in the first trimester and then both gradually decreased in the second and third trimesters. In the postpartum period, the percentages and absolute counts of T(CD3) and NK/K (Leu 7) cells, but not of other cells, increased transiently. These changes of lymphocyte subsets may indicate suppression of immunological activity during pregnancy and its “increase” in the postpartum period.  相似文献   
7.
We analysed the clinical significance of ANCA in patients with ulcerative colitis. On either an indirect immunofluorescence assay or an ELISA with fixed neutrophils, 71% (25/35) of the patients were positive for ANCA. However, only half of them reacted with either cathepsin G or lactoferrin. Western blot assays revealed positive bands in 40% (10/25) of the antibody-positive patients. The sizes of the bands detected were ≈58, 47, 44, 40, and 28 kD. No significant correlation was found between the ANCA positivity and various variables, i.e. disease activity, extent of lesion, or treatment of the disease. The anti-cathepsin G and 28-kD positivity, however, significantly correlated with a refractory type of ulcerative colitis.  相似文献   
8.
One of the merits of recently introduced exoscopes, including ORBEYE, is that they are superior to a conventional microscope in terms of ergonomic features. Taking advantage of it, the retrosigmoid approach can be performed in the supine position using ORBEYE. We report a consecutive series of 14 operations through the retrosigmoid approach in the supine position using ORBEYE. Fourteen consecutive patients who underwent surgery through the retrosigmoid approach for cerebellopontine (CP) angle lesions in the supine position using ORBEYE were targeted, and surgical outcomes and complications were examined. We evaluated the posture of the operator and the surgical field during this approach compared with those using a conventional microscope. In all 14 cases, all operative procedures were accomplished only using the ORBEYE. There were no operative complications due to this approach. Using ORBEYE, even when the angle of the operative visual axis was horizontal, the operators could manipulate in a comfortable posture. They were not forced to be in an uncomfortable posture that extended their arms, as is often the case with a conventional microscope. Therefore, they could use shorter surgical instruments. As the cerebellum shifted downward with gravity even using slight retraction during this approach, the working space of the surgical field was easily secured. Through this approach, the operators can perform stable microsurgery of CP angle lesions in a comfortable posture. This approach can reduce the burden on the operator and the patient, leading to a refined surgical procedure.  相似文献   
9.
Marked advances have been made in the past decade in the management of adults with systemic lupus erythematosus (SLE). Therefore, a nationwide retrospective survey was conducted between 1980 and 1994 to investigate the clinical manifestations of SLE in Japanese children and adolescents. Questionnaires were sent to 340 hospitals. Of 405 patients reported by 176 hospitals, 373 patients, diagnosed by the criteria established by the Pediatric Study Group of the Japanese Ministry of Health and Welfare in 1985, were enrolled in the study. Forty-nine of the 354 patients (13.8%) had relatives with a connective tissue disease within the third degree of consanguinity. The frequent manifestations in 373 patients were the presence of antinuclear antibody (98.9%), immunologic disorders (93.0%), hypocomplementemia (87.1%), malar rash (79.6%) and fever (74.0%). Lupus nephritis was present in 148 of the 309 patients (47.9%) at their first visit to a clinic, and 261 of the 373 patients (70.0%) developed renal involvement during the observation period. Of 370 patients, 92 patients (24.9%) exhibited central nervous system lupus. Of 368 patients, 192 patients (52.2%) were treated by methylprednisolone pulse therapy and 148 patients (40.2%) received immunosuppressants in combination with steroid therapy at some stage during the observation period. Survival rate at 5 years from onset was 95.9%. Management of infection, coagulopathies, and central nervous system involvement is essential to improve the prognosis of SLE in Japanese children and adolescents.  相似文献   
10.
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