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   775篇
  免费   37篇
  国内免费   6篇
儿科学   19篇
妇产科学   4篇
基础医学   159篇
口腔科学   59篇
临床医学   34篇
内科学   157篇
皮肤病学   10篇
神经病学   31篇
特种医学   23篇
外科学   115篇
综合类   6篇
预防医学   49篇
眼科学   26篇
药学   62篇
中国医学   2篇
肿瘤学   62篇
  2022年   7篇
  2021年   8篇
  2020年   7篇
  2019年   6篇
  2018年   11篇
  2017年   5篇
  2016年   7篇
  2014年   6篇
  2013年   14篇
  2012年   26篇
  2011年   29篇
  2010年   20篇
  2009年   16篇
  2008年   29篇
  2007年   28篇
  2006年   32篇
  2005年   29篇
  2004年   23篇
  2003年   30篇
  2002年   31篇
  2001年   25篇
  2000年   36篇
  1999年   29篇
  1998年   13篇
  1997年   7篇
  1996年   7篇
  1995年   6篇
  1993年   5篇
  1992年   22篇
  1991年   16篇
  1990年   17篇
  1989年   23篇
  1988年   27篇
  1987年   26篇
  1986年   20篇
  1985年   18篇
  1984年   13篇
  1983年   9篇
  1982年   6篇
  1981年   6篇
  1980年   7篇
  1979年   16篇
  1978年   14篇
  1977年   10篇
  1976年   5篇
  1975年   11篇
  1974年   8篇
  1973年   7篇
  1972年   8篇
  1971年   5篇
排序方式: 共有818条查询结果,搜索用时 15 毫秒
61.
The effectiveness of LAK cells (lymphokine-activated killer cells) on malignant tumors in vivo and in vitro was discussed. LAK cells induced from lymphocytes by interleukin-2 (IL-2) were able to kill target malignant cells in a nonspecific manner. Combination of IL-2 enhanced LAK activity. Adoptive immunotherapy with LAK cells and IL-2 carried out in the USA has produced effective results in several cases; complete regression of skin metastases of malignant melanoma and partial regression of other malignancies. However, high doses of IL-2 mediated a toxic side effect, capillary permeability leak syndrome. Our studies have revealed that LAK cells after one to two weeks incubation do not require such a high concentration of IL-2, and that adoptive immunotherapy using such, LAK cells and IL-2 can be carried out safely.  相似文献   
62.
Three cases of cancer treated with SSM (Special Substance, Maruyama: a polysaccharide extract from Mycobacterium tuberculosis ) for a long period were studied pathologically following biopsies and autopsies. The most significant antitumor activity resulting from SSM treatment was found to be collagenation from stromal cells and the cancer cells themselves. Another significant finding was that collagenation was promoted by macrophages which had been stimulated non-specifically. However, it was apparent that SSM-A or B had to be used efficiently and quickly in order to prevent invasion or metastasis of cancer. Collagenation due to SSM treatment was more marked in metastatic cancer lesions in the liver than those in the lung. In a case of breast cancer reported in a previous investigation of SSM treatment, remarkable calcification was found in a metastatic cancer lesion which had become confined through collagenation, thus preventing cancer cell metastasis.
The collagenation of cancerous lesions through SSM treatment resembled the healing of caseous tuberculosis lesions through a similar mechanism.  相似文献   
63.
Effects of bunazosin on the norepinephrine-induced electrical and mechanical activities of smooth muscles of the rabbit proximal urethra were investigated using microelectrode and tension recording methods. Responses to norepinephrine were mediated by activation of both alpha-1 and beta adrenoceptors. In the presence of propranolol, the norepinephrine-induced contraction increased and, with yohimbine, the phasic but not tonic contraction was only inhibited slightly. Contributions of the alpha-2 adrenoceptor to the norepinephrine-induced contraction were negligible. Bunazosin inhibited in a concentration-dependent manner both the phasic and tonic responses of the norepinephrine-induced contraction, and the concentration-response relationship for norepinephrine shifted to the right. The Schild plot obtained from measurements of tonic responses in this antagonism yielded a straight line with a slope of 0.96. The pA2 value for bunazosin was 8.39 and the KB value was 4.1 nM. Prazosin had similar effects (the corresponding values being 0.96, 8.21 and 6.2 nM, respectively). The mechanical response evoked by field stimulation was composed of cholinergic, noradrenergic alpha-1 and noncholinergic-nonadrenergic contractions and of a subsequent nonadrenergic-noncholinergic relaxation. Bunazosin inhibited the twitch contraction evoked by field stimulation more than did prazosin, albeit not completely. These results indicate that although the smooth muscle tone in the urethra is regulated by multiple neural factors, the elevation of the tone is regulated predominantly by activation of the alpha-1 adrenoceptors. Bunazosin has an antagonistic action on this receptor. The actions of bunazosin are discussed in relation to the clinical application in cases of inadequate micturition.  相似文献   
64.
Mycobacterium abscessus accounts for 80% of rapidly growing mycobacterial pulmonary infections and can be lethal. Treatment is difficult because of the paucity of effective drugs. We describe a patient with pulmonary M. abscessus infection who was treated with a regimen that included faropenem, a novel oral penem, and clarithromycin. He showed favorable responses to the treatment for more than 12 months. In vitro, faropenem had considerable inhibitory activities against 56 strains of rapidly growing mycobacteria, including M. peregrinum, M. chelonae, M. fortuitum, and M. abscessus (stated in order of increasing minimal inhibitory concentrations). Thus, faropenem has the potential to be used as an adjunctive drug with clarithromycin for the treatment of infection with rapidly growing mycobacteria, including M. abscessus. Received: December 10, 2001 / Accepted: March 18, 2002  相似文献   
65.
Long-term-cultured poly(Tyr, Glu)-poly-D,L,-Ala-poly-Lys [(T,G)-A--L]- reactive T cells and clones derived from (high responder x low responder)F1 [(C57BL/6 x A/J)F1] mice were shown to recognize (T,G)-A-- L presented by cells from low responder strain A/J mice. The antigen- presenting determinant(s) that allowed recognition of (T,G)-A--L by such T cell clones was controlled by the I-A subregion of the major histocompatibility complex. These results suggest that there is no functional defect in the ability of low responder Ir gene products (I-A antigens) to associate with (T,G)-A--L for effective recognition by T cells. Although these results might tentatively be interpreted to suggest that Ir gene-controlled low responsiveness is due to the inability of the T cell to recognize the association between (T,G)-A--L and low responder I-A gene products, it is similarly possible that there might be a defect in the functional capabilities of low responder antigen-presenting cells to effectively process (T,G)-A--L into immunodominant epitopes.  相似文献   
66.
67.
Recent studies indicate that the Pig-a assay is a promising tool for evaluating in vivo mutagenicity. We have developed novel rat Pig-a assays that facilitate measuring mutant frequencies in two early arising populations of blood cells, bone marrow erythroids (BMEs) and peripheral blood (PB) reticulocytes (RETs). In these assays, bone marrow cells of erythroid origin and PB red blood cells (RBCs) were identified using an antibody against rat erythroid-specific marker HIS49. In addition, RETs were selectivity enriched from PB using magnetic separation of cells positive for CD71, a transferrin receptor expressed on the surface of BMEs and RETs, but not on the surface of mature RBCs. With magnetic enrichment, more than 1 x 10(6) CD71-positive RETs could be evaluated by flow cytometry for Pig-a mutant frequency within 5 to 8 min. CD59-deficient RET and BME frequencies of more than 100 x 10(-6) and 80 x 10(-6) were detected 1 week after treating rats with 40 mg/kg N-ethyl-N-nitrosourea; by comparison, the frequency of CD59-deficient total RBCs in these rats was 13.2 x 10(-6). The frequency of spontaneous Pig-a mutant RETs and BMEs was less than 5 x 10(-6) and 15 x 10(-6), respectively. Since approximately 98% of nucleated cells in the BME fraction were erythroblasts, it should be possible to use BMEs to determine the spectrum of CD59-deficient Pig-a mutations in cells of erythroid lineage. Conducting concurrent Pig-a assays on RETs and BMEs may be useful for evaluating the in vivo mutagenicity of chemicals, especially when prolonged mutant manifestation is not feasible or when the confirmation of mutation induction is necessary.  相似文献   
68.
Background. MZB is a purine analog, and is used as a disease modifying anti-rheumatic drug (DMARD). We conducted an open label uncontrolled clinical trial to evaluate the efficacy and safety of combination therapy with methotrexate (MTX) and mizoribine (MZB). Methods. Thirty one RA patients (9 males, 22 females, 68±12 year-old) who fulfilled ACR criteria of RA and did not show sufficient clinical response to MTX were included. MZB (150 mg/day, once a day) were added to MTX. DAS28-CRP was measured at day 0 and 1, 3, 6, and 12 months after the treatment. Adverse events were recorded. Results. Overall DAS28-CRP was significantly decreased from 4.4±1.0 to 3.1±1.3 at 3 months (p<0.01), 2.7±0.68 at 6 months (p<0.01), 2.4±1.4 at 12 months (p<0.01). Seventeen patients (55%) achieved significant improvement of DAS28-CRP. Number of swollen joints of responders before the treatment was significantly fewer than that of non-responders. Improvement of DAS28-CRP was significantly different between the responders (0.91±0.74) and non-responders (0.18±0.66) at 1 month (p<0.01). Nine patients (29%) could achieve remission Four patients experienced adverse events. Conclusions. MTX and MZB combination therapy was effective and relatively safety.  相似文献   
69.
The mechanism by which nonsteroidal anti-inflammatory drugs (NSAIDs) suppress gastric mucosal blood flow is not fully understood, although the depletion of mucosal prostaglandin E2 has been proposed as one possible explanation. We investigated the role of gastric acid on gastric mucosal blood flow in NSAID-treated rats. A rat stomach was mounted in an ex vivo chamber, and gastric mucosal blood flow was measured sequentially in a 5-mm2 area of the gastric corpus using a scanning laser Doppler perfusion image system. Results showed that diclofenac (5 mg/kg s.c.) and indomethacin (10 mg/kg s.c.) did not affect gastric mucosal blood flow, although both strongly decreased mucosal prostaglandin E2 when saline was instilled into the gastric chamber. On replacement of the saline in the chamber with 100 mM hydrochloric acid, these drugs caused a decrease in gastric mucosal blood flow levels within 30 min. The specific cyclooxygenase (COX)-2 inhibitors celecoxib (50 mg/kg s.c.) and rofecoxib (25 mg/kg s.c.) did not affect mucosal prostaglandin E2 level, nor did they decrease gastric mucosal blood flow, even when hydrochloric acid was added to the chamber. Furthermore, measurement of vasoconstrictive factors present in the mucosa showed that endothelin-1 levels increased after administration of diclofenac s.c. in the presence of intragastric hydrochloric acid. This indicates that the presence of mucosal hydrochloric acid plays an important role in the NSAID-induced decrease in gastric mucosal blood flow, while the COX-1-derived basal prostaglandin E2, which is unlikely to control gastric mucosal blood flow itself, protects microcirculatory systems from mucosal hydrochloric acid.  相似文献   
70.
Pigmented cosmetic dermatitis‐like (Riehl's melanosis‐like) pigmentation was reported in three of 27 patients with primary Sjögren's syndrome. But case reports of such eruptions are rare. We describe three cases of such eruptions associated with primary Sjögren's syndrome or anti‐SSA antibody and possible associations with specific types of human leukocyte antigen (HLA) and infiltrating lymphocytes. These middle‐aged Japanese women had reticular facial pigmentation and histopathological examination revealed interface dermatitis, melanophages, and dense lymphocytic infiltration around hair follicles and sweat ducts. HLA typing revealed common antigenic equivalents or genetic typing of HLA‐A2, DR52, DPA1(02:02) and DPB1(05:01). Immunohistochemical staining revealed major subsets of T cells to be CD8 and CD45RO. Some Foxp3‐ and few IL17‐positive cells were found in strong contrast to the major CD4 subset of infiltrated T cells in annular erythema associated with Sjögren's syndrome. Apparently, our patients' pigmentation represented a specific etiology associated with primary Sjögren's syndrome or anti‐SSA antibody.  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